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gerrit-public.fairphone.software / kernel / msm / 848bb4c8e7f29977ea303dbff7ffb7ac5c6ecdf1 / . / drivers / tty / n_smux.c
blob: 14b8ca2f79c85b048c74664fd79a3c0885a4ef30 [file] [log] [blame]
/* drivers/tty/n_smux.c
*
* Copyright (c) 2012, Code Aurora Forum. All rights reserved.
*
* This software is licensed under the terms of the GNU General Public
* License version 2, as published by the Free Software Foundation, and
* may be copied, distributed, and modified under those terms.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
*/
#include <linux/module.h>
#include <linux/types.h>
#include <linux/errno.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>
#include <linux/tty_driver.h>
#include <linux/smux.h>
#include <linux/list.h>
#include <linux/kfifo.h>
#include <linux/slab.h>
#include <linux/types.h>
#include <linux/platform_device.h>
#include <linux/delay.h>
#include <mach/subsystem_notif.h>
#include <mach/subsystem_restart.h>
#include <mach/msm_serial_hs.h>
#include <mach/msm_ipc_logging.h>
#include "smux_private.h"
#include "smux_loopback.h"
#define SMUX_NOTIFY_FIFO_SIZE 128
#define SMUX_TX_QUEUE_SIZE 256
#define SMUX_PKT_LOG_SIZE 128
/* Maximum size we can accept in a single RX buffer */
#define TTY_RECEIVE_ROOM 65536
#define TTY_BUFFER_FULL_WAIT_MS 50
/* maximum sleep time between wakeup attempts */
#define SMUX_WAKEUP_DELAY_MAX (1 << 20)
/* minimum delay for scheduling delayed work */
#define SMUX_WAKEUP_DELAY_MIN (1 << 15)
/* inactivity timeout for no rx/tx activity */
#define SMUX_INACTIVITY_TIMEOUT_MS 1000000
/* RX get_rx_buffer retry timeout values */
#define SMUX_RX_RETRY_MIN_MS (1 << 0) /* 1 ms */
#define SMUX_RX_RETRY_MAX_MS (1 << 10) /* 1024 ms */
enum {
MSM_SMUX_DEBUG = 1U << 0,
MSM_SMUX_INFO = 1U << 1,
MSM_SMUX_POWER_INFO = 1U << 2,
MSM_SMUX_PKT = 1U << 3,
};
static int smux_debug_mask = MSM_SMUX_DEBUG | MSM_SMUX_POWER_INFO;
module_param_named(debug_mask, smux_debug_mask,
int, S_IRUGO | S_IWUSR | S_IWGRP);
static int disable_ipc_logging;
/* Simulated wakeup used for testing */
int smux_byte_loopback;
module_param_named(byte_loopback, smux_byte_loopback,
int, S_IRUGO | S_IWUSR | S_IWGRP);
int smux_simulate_wakeup_delay = 1;
module_param_named(simulate_wakeup_delay, smux_simulate_wakeup_delay,
int, S_IRUGO | S_IWUSR | S_IWGRP);
#define IPC_LOG_STR(x...) do { \
if (!disable_ipc_logging && log_ctx) \
ipc_log_string(log_ctx, x); \
} while (0)
#define SMUX_DBG(x...) do { \
if (smux_debug_mask & MSM_SMUX_DEBUG) \
IPC_LOG_STR(x); \
} while (0)
#define SMUX_ERR(x...) do { \
pr_err(x); \
IPC_LOG_STR(x); \
} while (0)
#define SMUX_PWR(x...) do { \
if (smux_debug_mask & MSM_SMUX_POWER_INFO) \
IPC_LOG_STR(x); \
} while (0)
#define SMUX_PWR_PKT_RX(pkt) do { \
if (smux_debug_mask & MSM_SMUX_POWER_INFO) \
smux_log_pkt(pkt, 1); \
} while (0)
#define SMUX_PWR_PKT_TX(pkt) do { \
if (smux_debug_mask & MSM_SMUX_POWER_INFO) { \
if (pkt->hdr.cmd == SMUX_CMD_BYTE && \
pkt->hdr.flags == SMUX_WAKEUP_ACK) \
IPC_LOG_STR("smux: TX Wakeup ACK\n"); \
else if (pkt->hdr.cmd == SMUX_CMD_BYTE && \
pkt->hdr.flags == SMUX_WAKEUP_REQ) \
IPC_LOG_STR("smux: TX Wakeup REQ\n"); \
else \
smux_log_pkt(pkt, 0); \
} \
} while (0)
#define SMUX_PWR_BYTE_TX(pkt) do { \
if (smux_debug_mask & MSM_SMUX_POWER_INFO) { \
smux_log_pkt(pkt, 0); \
} \
} while (0)
#define SMUX_LOG_PKT_RX(pkt) do { \
if (smux_debug_mask & MSM_SMUX_PKT) \
smux_log_pkt(pkt, 1); \
} while (0)
#define SMUX_LOG_PKT_TX(pkt) do { \
if (smux_debug_mask & MSM_SMUX_PKT) \
smux_log_pkt(pkt, 0); \
} while (0)
/**
* Return true if channel is fully opened (both
* local and remote sides are in the OPENED state).
*/
#define IS_FULLY_OPENED(ch) \
(ch && (ch)->local_state == SMUX_LCH_LOCAL_OPENED \
&& (ch)->remote_state == SMUX_LCH_REMOTE_OPENED)
static struct platform_device smux_devs[] = {
{.name = "SMUX_CTL", .id = -1},
{.name = "SMUX_RMNET", .id = -1},
{.name = "SMUX_DUN_DATA_HSUART", .id = 0},
{.name = "SMUX_RMNET_DATA_HSUART", .id = 1},
{.name = "SMUX_RMNET_CTL_HSUART", .id = 0},
{.name = "SMUX_DIAG", .id = -1},
};
enum {
SMUX_CMD_STATUS_RTC = 1 << 0,
SMUX_CMD_STATUS_RTR = 1 << 1,
SMUX_CMD_STATUS_RI = 1 << 2,
SMUX_CMD_STATUS_DCD = 1 << 3,
SMUX_CMD_STATUS_FLOW_CNTL = 1 << 4,
};
/* Channel mode */
enum {
SMUX_LCH_MODE_NORMAL,
SMUX_LCH_MODE_LOCAL_LOOPBACK,
SMUX_LCH_MODE_REMOTE_LOOPBACK,
};
enum {
SMUX_RX_IDLE,
SMUX_RX_MAGIC,
SMUX_RX_HDR,
SMUX_RX_PAYLOAD,
SMUX_RX_FAILURE,
};
/**
* Power states.
*
* The _FLUSH states are internal transitional states and are not part of the
* official state machine.
*/
enum {
SMUX_PWR_OFF,
SMUX_PWR_TURNING_ON,
SMUX_PWR_ON,
SMUX_PWR_TURNING_OFF_FLUSH, /* power-off req/ack in TX queue */
SMUX_PWR_TURNING_OFF,
SMUX_PWR_OFF_FLUSH,
};
union notifier_metadata {
struct smux_meta_disconnected disconnected;
struct smux_meta_read read;
struct smux_meta_write write;
struct smux_meta_tiocm tiocm;
};
struct smux_notify_handle {
void (*notify)(void *priv, int event_type, const void *metadata);
void *priv;
int event_type;
union notifier_metadata *metadata;
};
/**
* Get RX Buffer Retry structure.
*
* This is used for clients that are unable to provide an RX buffer
* immediately. This temporary structure will be used to temporarily hold the
* data and perform a retry.
*/
struct smux_rx_pkt_retry {
struct smux_pkt_t *pkt;
struct list_head rx_retry_list;
unsigned timeout_in_ms;
};
/**
* Receive worker data structure.
*
* One instance is created for every call to smux_rx_state_machine.
*/
struct smux_rx_worker_data {
const unsigned char *data;
int len;
int flag;
struct work_struct work;
struct completion work_complete;
};
/**
* Line discipline and module structure.
*
* Only one instance since multiple instances of line discipline are not
* allowed.
*/
struct smux_ldisc_t {
struct mutex mutex_lha0;
int is_initialized;
int platform_devs_registered;
int in_reset;
int remote_is_alive;
int ld_open_count;
struct tty_struct *tty;
/* RX State Machine (singled-threaded access by smux_rx_wq) */
unsigned char recv_buf[SMUX_MAX_PKT_SIZE];
unsigned int recv_len;
unsigned int pkt_remain;
unsigned rx_state;
/* RX Activity - accessed by multiple threads */
spinlock_t rx_lock_lha1;
unsigned rx_activity_flag;
/* TX / Power */
spinlock_t tx_lock_lha2;
struct list_head lch_tx_ready_list;
unsigned power_state;
unsigned pwr_wakeup_delay_us;
unsigned tx_activity_flag;
unsigned powerdown_enabled;
unsigned power_ctl_remote_req_received;
struct list_head power_queue;
};
/* data structures */
struct smux_lch_t smux_lch[SMUX_NUM_LOGICAL_CHANNELS];
static struct smux_ldisc_t smux;
static const char *tty_error_type[] = {
[TTY_NORMAL] = "normal",
[TTY_OVERRUN] = "overrun",
[TTY_BREAK] = "break",
[TTY_PARITY] = "parity",
[TTY_FRAME] = "framing",
};
static const char * const smux_cmds[] = {
[SMUX_CMD_DATA] = "DATA",
[SMUX_CMD_OPEN_LCH] = "OPEN",
[SMUX_CMD_CLOSE_LCH] = "CLOSE",
[SMUX_CMD_STATUS] = "STATUS",
[SMUX_CMD_PWR_CTL] = "PWR",
[SMUX_CMD_BYTE] = "Raw Byte",
};
static const char * const smux_events[] = {
[SMUX_CONNECTED] = "CONNECTED" ,
[SMUX_DISCONNECTED] = "DISCONNECTED",
[SMUX_READ_DONE] = "READ_DONE",
[SMUX_READ_FAIL] = "READ_FAIL",
[SMUX_WRITE_DONE] = "WRITE_DONE",
[SMUX_WRITE_FAIL] = "WRITE_FAIL",
[SMUX_TIOCM_UPDATE] = "TIOCM_UPDATE",
[SMUX_LOW_WM_HIT] = "LOW_WM_HIT",
[SMUX_HIGH_WM_HIT] = "HIGH_WM_HIT",
[SMUX_RX_RETRY_HIGH_WM_HIT] = "RX_RETRY_HIGH_WM_HIT",
[SMUX_RX_RETRY_LOW_WM_HIT] = "RX_RETRY_LOW_WM_HIT",
};
static const char * const smux_local_state[] = {
[SMUX_LCH_LOCAL_CLOSED] = "CLOSED",
[SMUX_LCH_LOCAL_OPENING] = "OPENING",
[SMUX_LCH_LOCAL_OPENED] = "OPENED",
[SMUX_LCH_LOCAL_CLOSING] = "CLOSING",
};
static const char * const smux_remote_state[] = {
[SMUX_LCH_REMOTE_CLOSED] = "CLOSED",
[SMUX_LCH_REMOTE_OPENED] = "OPENED",
};
static const char * const smux_mode[] = {
[SMUX_LCH_MODE_NORMAL] = "N",
[SMUX_LCH_MODE_LOCAL_LOOPBACK] = "L",
[SMUX_LCH_MODE_REMOTE_LOOPBACK] = "R",
};
static const char * const smux_undef[] = {
[SMUX_UNDEF_LONG] = "UNDEF",
[SMUX_UNDEF_SHORT] = "U",
};
static void *log_ctx;
static void smux_notify_local_fn(struct work_struct *work);
static DECLARE_WORK(smux_notify_local, smux_notify_local_fn);
static struct workqueue_struct *smux_notify_wq;
static size_t handle_size;
static struct kfifo smux_notify_fifo;
static int queued_fifo_notifications;
static DEFINE_SPINLOCK(notify_lock_lhc1);
static struct workqueue_struct *smux_tx_wq;
static struct workqueue_struct *smux_rx_wq;
static void smux_tx_worker(struct work_struct *work);
static DECLARE_WORK(smux_tx_work, smux_tx_worker);
static void smux_wakeup_worker(struct work_struct *work);
static void smux_rx_retry_worker(struct work_struct *work);
static void smux_rx_worker(struct work_struct *work);
static DECLARE_WORK(smux_wakeup_work, smux_wakeup_worker);
static DECLARE_DELAYED_WORK(smux_wakeup_delayed_work, smux_wakeup_worker);
static void smux_inactivity_worker(struct work_struct *work);
static DECLARE_WORK(smux_inactivity_work, smux_inactivity_worker);
static DECLARE_DELAYED_WORK(smux_delayed_inactivity_work,
smux_inactivity_worker);
static void list_channel(struct smux_lch_t *ch);
static int smux_send_status_cmd(struct smux_lch_t *ch);
static int smux_dispatch_rx_pkt(struct smux_pkt_t *pkt);
static void smux_flush_tty(void);
static void smux_purge_ch_tx_queue(struct smux_lch_t *ch, int is_ssr);
static int schedule_notify(uint8_t lcid, int event,
const union notifier_metadata *metadata);
static int ssr_notifier_cb(struct notifier_block *this,
unsigned long code,
void *data);
static void smux_uart_power_on_atomic(void);
static int smux_rx_flow_control_updated(struct smux_lch_t *ch);
static void smux_flush_workqueues(void);
static void smux_pdev_release(struct device *dev);
/**
* local_lch_state() - Return human readable form of local logical state.
* @state: Local logical channel state enum.
*
*/
const char *local_lch_state(unsigned state)
{
if (state < ARRAY_SIZE(smux_local_state))
return smux_local_state[state];
else
return smux_undef[SMUX_UNDEF_LONG];
}
/**
* remote_lch_state() - Return human readable for of remote logical state.
* @state: Remote logical channel state enum.
*
*/
const char *remote_lch_state(unsigned state)
{
if (state < ARRAY_SIZE(smux_remote_state))
return smux_remote_state[state];
else
return smux_undef[SMUX_UNDEF_LONG];
}
/**
* lch_mode() - Return human readable form of mode.
* @mode: Mode of the logical channel.
*
*/
const char *lch_mode(unsigned mode)
{
if (mode < ARRAY_SIZE(smux_mode))
return smux_mode[mode];
else
return smux_undef[SMUX_UNDEF_SHORT];
}
/**
* Convert TTY Error Flags to string for logging purposes.
*
* @flag TTY_* flag
* @returns String description or NULL if unknown
*/
static const char *tty_flag_to_str(unsigned flag)
{
if (flag < ARRAY_SIZE(tty_error_type))
return tty_error_type[flag];
return NULL;
}
/**
* Convert SMUX Command to string for logging purposes.
*
* @cmd SMUX command
* @returns String description or NULL if unknown
*/
static const char *cmd_to_str(unsigned cmd)
{
if (cmd < ARRAY_SIZE(smux_cmds))
return smux_cmds[cmd];
return NULL;
}
/**
* Convert SMUX event to string for logging purposes.
*
* @event SMUX event
* @returns String description or NULL if unknown
*/
static const char *event_to_str(unsigned cmd)
{
if (cmd < ARRAY_SIZE(smux_events))
return smux_events[cmd];
return NULL;
}
/**
* Set the reset state due to an unrecoverable failure.
*/
static void smux_enter_reset(void)
{
SMUX_ERR("%s: unrecoverable failure, waiting for ssr\n", __func__);
smux.in_reset = 1;
smux.remote_is_alive = 0;
}
/**
* Initialize the lch_structs.
*/
static int lch_init(void)
{
unsigned int id;
struct smux_lch_t *ch;
int i = 0;
handle_size = sizeof(struct smux_notify_handle *);
smux_notify_wq = create_singlethread_workqueue("smux_notify_wq");
smux_tx_wq = create_singlethread_workqueue("smux_tx_wq");
smux_rx_wq = create_singlethread_workqueue("smux_rx_wq");
if (IS_ERR(smux_notify_wq) || IS_ERR(smux_tx_wq)) {
SMUX_DBG("smux: %s: create_singlethread_workqueue ENOMEM\n",
__func__);
return -ENOMEM;
}
i |= kfifo_alloc(&smux_notify_fifo,
SMUX_NOTIFY_FIFO_SIZE * handle_size,
GFP_KERNEL);
i |= smux_loopback_init();
if (i) {
SMUX_ERR("%s: out of memory error\n", __func__);
return -ENOMEM;
}
for (id = 0 ; id < SMUX_NUM_LOGICAL_CHANNELS; id++) {
ch = &smux_lch[id];
spin_lock_init(&ch->state_lock_lhb1);
ch->lcid = id;
ch->local_state = SMUX_LCH_LOCAL_CLOSED;
ch->local_mode = SMUX_LCH_MODE_NORMAL;
ch->local_tiocm = 0x0;
ch->options = SMUX_CH_OPTION_AUTO_REMOTE_TX_STOP;
ch->remote_state = SMUX_LCH_REMOTE_CLOSED;
ch->remote_mode = SMUX_LCH_MODE_NORMAL;
ch->remote_tiocm = 0x0;
ch->tx_flow_control = 0;
ch->rx_flow_control_auto = 0;
ch->rx_flow_control_client = 0;
ch->priv = 0;
ch->notify = 0;
ch->get_rx_buffer = 0;
INIT_LIST_HEAD(&ch->rx_retry_queue);
ch->rx_retry_queue_cnt = 0;
INIT_DELAYED_WORK(&ch->rx_retry_work, smux_rx_retry_worker);
spin_lock_init(&ch->tx_lock_lhb2);
INIT_LIST_HEAD(&ch->tx_queue);
INIT_LIST_HEAD(&ch->tx_ready_list);
ch->tx_pending_data_cnt = 0;
ch->notify_lwm = 0;
}
return 0;
}
/**
* Empty and cleanup all SMUX logical channels for subsystem restart or line
* discipline disconnect.
*/
static void smux_lch_purge(void)
{
struct smux_lch_t *ch;
unsigned long flags;
int i;
/* Empty TX ready list */
spin_lock_irqsave(&smux.tx_lock_lha2, flags);
while (!list_empty(&smux.lch_tx_ready_list)) {
SMUX_DBG("smux: %s: emptying ready list %p\n",
__func__, smux.lch_tx_ready_list.next);
ch = list_first_entry(&smux.lch_tx_ready_list,
struct smux_lch_t,
tx_ready_list);
list_del(&ch->tx_ready_list);
INIT_LIST_HEAD(&ch->tx_ready_list);
}
/* Purge Power Queue */
while (!list_empty(&smux.power_queue)) {
struct smux_pkt_t *pkt;
pkt = list_first_entry(&smux.power_queue,
struct smux_pkt_t,
list);
list_del(&pkt->list);
SMUX_DBG("smux: %s: emptying power queue pkt=%p\n",
__func__, pkt);
smux_free_pkt(pkt);
}
spin_unlock_irqrestore(&smux.tx_lock_lha2, flags);
/* Close all ports */
for (i = 0 ; i < SMUX_NUM_LOGICAL_CHANNELS; i++) {
ch = &smux_lch[i];
SMUX_DBG("smux: %s: cleaning up lcid %d\n", __func__, i);
spin_lock_irqsave(&ch->state_lock_lhb1, flags);
/* Purge TX queue */
spin_lock(&ch->tx_lock_lhb2);
smux_purge_ch_tx_queue(ch, 1);
spin_unlock(&ch->tx_lock_lhb2);
/* Notify user of disconnect and reset channel state */
if (ch->local_state == SMUX_LCH_LOCAL_OPENED ||
ch->local_state == SMUX_LCH_LOCAL_CLOSING) {
union notifier_metadata meta;
meta.disconnected.is_ssr = smux.in_reset;
schedule_notify(ch->lcid, SMUX_DISCONNECTED, &meta);
}
ch->local_state = SMUX_LCH_LOCAL_CLOSED;
ch->remote_state = SMUX_LCH_REMOTE_CLOSED;
ch->remote_mode = SMUX_LCH_MODE_NORMAL;
ch->tx_flow_control = 0;
ch->rx_flow_control_auto = 0;
ch->rx_flow_control_client = 0;
/* Purge RX retry queue */
if (ch->rx_retry_queue_cnt)
queue_delayed_work(smux_rx_wq, &ch->rx_retry_work, 0);
spin_unlock_irqrestore(&ch->state_lock_lhb1, flags);
}
}
int smux_assert_lch_id(uint32_t lcid)
{
if (lcid >= SMUX_NUM_LOGICAL_CHANNELS)
return -ENXIO;
else
return 0;
}
/**
* Log packet information for debug purposes.
*
* @pkt Packet to log
* @is_recv 1 = RX packet; 0 = TX Packet
*
* [DIR][LCID] [LOCAL_STATE][LOCAL_MODE]:[REMOTE_STATE][REMOTE_MODE] PKT Info
*
* PKT Info:
* [CMD] flags [flags] len [PAYLOAD_LEN]:[PAD_LEN] [Payload hex bytes]
*
* Direction: R = Receive, S = Send
* Local State: C = Closed; c = closing; o = opening; O = Opened
* Local Mode: L = Local loopback; R = Remote loopback; N = Normal
* Remote State: C = Closed; O = Opened
* Remote Mode: R = Remote loopback; N = Normal
*/
static void smux_log_pkt(struct smux_pkt_t *pkt, int is_recv)
{
char logbuf[SMUX_PKT_LOG_SIZE];
char cmd_extra[16];
int i = 0;
int count;
int len;
char local_state;
char local_mode;
char remote_state;
char remote_mode;
struct smux_lch_t *ch = NULL;
unsigned char *data;
if (!smux_assert_lch_id(pkt->hdr.lcid))
ch = &smux_lch[pkt->hdr.lcid];
if (ch) {
switch (ch->local_state) {
case SMUX_LCH_LOCAL_CLOSED:
local_state = 'C';
break;
case SMUX_LCH_LOCAL_OPENING:
local_state = 'o';
break;
case SMUX_LCH_LOCAL_OPENED:
local_state = 'O';
break;
case SMUX_LCH_LOCAL_CLOSING:
local_state = 'c';
break;
default:
local_state = 'U';
break;
}
switch (ch->local_mode) {
case SMUX_LCH_MODE_LOCAL_LOOPBACK:
local_mode = 'L';
break;
case SMUX_LCH_MODE_REMOTE_LOOPBACK:
local_mode = 'R';
break;
case SMUX_LCH_MODE_NORMAL:
local_mode = 'N';
break;
default:
local_mode = 'U';
break;
}
switch (ch->remote_state) {
case SMUX_LCH_REMOTE_CLOSED:
remote_state = 'C';
break;
case SMUX_LCH_REMOTE_OPENED:
remote_state = 'O';
break;
default:
remote_state = 'U';
break;
}
switch (ch->remote_mode) {
case SMUX_LCH_MODE_REMOTE_LOOPBACK:
remote_mode = 'R';
break;
case SMUX_LCH_MODE_NORMAL:
remote_mode = 'N';
break;
default:
remote_mode = 'U';
break;
}
} else {
/* broadcast channel */
local_state = '-';
local_mode = '-';
remote_state = '-';
remote_mode = '-';
}
/* determine command type (ACK, etc) */
cmd_extra[0] = '\0';
switch (pkt->hdr.cmd) {
case SMUX_CMD_OPEN_LCH:
if (pkt->hdr.flags & SMUX_CMD_OPEN_ACK)
snprintf(cmd_extra, sizeof(cmd_extra), " ACK");
break;
case SMUX_CMD_CLOSE_LCH:
if (pkt->hdr.flags & SMUX_CMD_CLOSE_ACK)
snprintf(cmd_extra, sizeof(cmd_extra), " ACK");
break;
case SMUX_CMD_PWR_CTL:
if (pkt->hdr.flags & SMUX_CMD_PWR_CTL_ACK)
snprintf(cmd_extra, sizeof(cmd_extra), " ACK");
break;
};
i += snprintf(logbuf + i, SMUX_PKT_LOG_SIZE - i,
"smux: %c%d %c%c:%c%c %s%s flags %x len %d:%d ",
is_recv ? 'R' : 'S', pkt->hdr.lcid,
local_state, local_mode,
remote_state, remote_mode,
cmd_to_str(pkt->hdr.cmd), cmd_extra, pkt->hdr.flags,
pkt->hdr.payload_len, pkt->hdr.pad_len);
len = (pkt->hdr.payload_len > 16) ? 16 : pkt->hdr.payload_len;
data = (unsigned char *)pkt->payload;
for (count = 0; count < len; count++)
i += snprintf(logbuf + i, SMUX_PKT_LOG_SIZE - i,
"%02x ", (unsigned)data[count]);
IPC_LOG_STR(logbuf);
}
static void smux_notify_local_fn(struct work_struct *work)
{
struct smux_notify_handle *notify_handle = NULL;
union notifier_metadata *metadata = NULL;
unsigned long flags;
int i;
for (;;) {
/* retrieve notification */
spin_lock_irqsave(&notify_lock_lhc1, flags);
if (kfifo_len(&smux_notify_fifo) >= handle_size) {
i = kfifo_out(&smux_notify_fifo,
&notify_handle,
handle_size);
if (i != handle_size) {
SMUX_ERR(
"%s: unable to retrieve handle %d expected %d\n",
__func__, i, handle_size);
spin_unlock_irqrestore(&notify_lock_lhc1, flags);
break;
}
} else {
spin_unlock_irqrestore(&notify_lock_lhc1, flags);
break;
}
--queued_fifo_notifications;
spin_unlock_irqrestore(&notify_lock_lhc1, flags);
/* notify client */
metadata = notify_handle->metadata;
notify_handle->notify(notify_handle->priv,
notify_handle->event_type,
metadata);
kfree(metadata);
kfree(notify_handle);
}
}
/**
* Initialize existing packet.
*/
void smux_init_pkt(struct smux_pkt_t *pkt)
{
memset(pkt, 0x0, sizeof(*pkt));
pkt->hdr.magic = SMUX_MAGIC;
INIT_LIST_HEAD(&pkt->list);
}
/**
* Allocate and initialize packet.
*
* If a payload is needed, either set it directly and ensure that it's freed or
* use smd_alloc_pkt_payload() to allocate a packet and it will be freed
* automatically when smd_free_pkt() is called.
*/
struct smux_pkt_t *smux_alloc_pkt(void)
{
struct smux_pkt_t *pkt;
/* Consider a free list implementation instead of kmalloc */
pkt = kmalloc(sizeof(struct smux_pkt_t), GFP_ATOMIC);
if (!pkt) {
SMUX_ERR("%s: out of memory\n", __func__);
return NULL;
}
smux_init_pkt(pkt);
pkt->allocated = 1;
return pkt;
}
/**
* Free packet.
*
* @pkt Packet to free (may be NULL)
*
* If payload was allocated using smux_alloc_pkt_payload(), then it is freed as
* well. Otherwise, the caller is responsible for freeing the payload.
*/
void smux_free_pkt(struct smux_pkt_t *pkt)
{
if (pkt) {
if (pkt->free_payload)
kfree(pkt->payload);
if (pkt->allocated)
kfree(pkt);
}
}
/**
* Allocate packet payload.
*
* @pkt Packet to add payload to
*
* @returns 0 on success, <0 upon error
*
* A flag is set to signal smux_free_pkt() to free the payload.
*/
int smux_alloc_pkt_payload(struct smux_pkt_t *pkt)
{
if (!pkt)
return -EINVAL;
pkt->payload = kmalloc(pkt->hdr.payload_len, GFP_ATOMIC);
pkt->free_payload = 1;
if (!pkt->payload) {
SMUX_ERR("%s: unable to malloc %d bytes for payload\n",
__func__, pkt->hdr.payload_len);
return -ENOMEM;
}
return 0;
}
static int schedule_notify(uint8_t lcid, int event,
const union notifier_metadata *metadata)
{
struct smux_notify_handle *notify_handle = 0;
union notifier_metadata *meta_copy = 0;
struct smux_lch_t *ch;
int i;
unsigned long flags;
int ret = 0;
IPC_LOG_STR("smux: %s ch:%d\n", event_to_str(event), lcid);
ch = &smux_lch[lcid];
notify_handle = kzalloc(sizeof(struct smux_notify_handle),
GFP_ATOMIC);
if (!notify_handle) {
SMUX_ERR("%s: out of memory\n", __func__);
ret = -ENOMEM;
goto free_out;
}
notify_handle->notify = ch->notify;
notify_handle->priv = ch->priv;
notify_handle->event_type = event;
if (metadata) {
meta_copy = kzalloc(sizeof(union notifier_metadata),
GFP_ATOMIC);
if (!meta_copy) {
SMUX_ERR("%s: out of memory\n", __func__);
ret = -ENOMEM;
goto free_out;
}
*meta_copy = *metadata;
notify_handle->metadata = meta_copy;
} else {
notify_handle->metadata = NULL;
}
spin_lock_irqsave(&notify_lock_lhc1, flags);
i = kfifo_avail(&smux_notify_fifo);
if (i < handle_size) {
SMUX_ERR("%s: fifo full error %d expected %d\n",
__func__, i, handle_size);
ret = -ENOMEM;
goto unlock_out;
}
i = kfifo_in(&smux_notify_fifo, &notify_handle, handle_size);
if (i < 0 || i != handle_size) {
SMUX_ERR("%s: fifo not available error %d (expected %d)\n",
__func__, i, handle_size);
ret = -ENOSPC;
goto unlock_out;
}
++queued_fifo_notifications;
unlock_out:
spin_unlock_irqrestore(&notify_lock_lhc1, flags);
free_out:
queue_work(smux_notify_wq, &smux_notify_local);
if (ret < 0 && notify_handle) {
kfree(notify_handle->metadata);
kfree(notify_handle);
}
return ret;
}
/**
* Returns the serialized size of a packet.
*
* @pkt Packet to serialize
*
* @returns Serialized length of packet
*/
static unsigned int smux_serialize_size(struct smux_pkt_t *pkt)
{
unsigned int size;
size = sizeof(struct smux_hdr_t);
size += pkt->hdr.payload_len;
size += pkt->hdr.pad_len;
return size;
}
/**
* Serialize packet @pkt into output buffer @data.
*
* @pkt Packet to serialize
* @out Destination buffer pointer
* @out_len Size of serialized packet
*
* @returns 0 for success
*/
int smux_serialize(struct smux_pkt_t *pkt, char *out,
unsigned int *out_len)
{
char *data_start = out;
if (smux_serialize_size(pkt) > SMUX_MAX_PKT_SIZE) {
SMUX_ERR("%s: packet size %d too big\n",
__func__, smux_serialize_size(pkt));
return -E2BIG;
}
memcpy(out, &pkt->hdr, sizeof(struct smux_hdr_t));
out += sizeof(struct smux_hdr_t);
if (pkt->payload) {
memcpy(out, pkt->payload, pkt->hdr.payload_len);
out += pkt->hdr.payload_len;
}
if (pkt->hdr.pad_len) {
memset(out, 0x0, pkt->hdr.pad_len);
out += pkt->hdr.pad_len;
}
*out_len = out - data_start;
return 0;
}
/**
* Serialize header and provide pointer to the data.
*
* @pkt Packet
* @out[out] Pointer to the serialized header data
* @out_len[out] Pointer to the serialized header length
*/
static void smux_serialize_hdr(struct smux_pkt_t *pkt, char **out,
unsigned int *out_len)
{
*out = (char *)&pkt->hdr;
*out_len = sizeof(struct smux_hdr_t);
}
/**
* Serialize payload and provide pointer to the data.
*
* @pkt Packet
* @out[out] Pointer to the serialized payload data
* @out_len[out] Pointer to the serialized payload length
*/
static void smux_serialize_payload(struct smux_pkt_t *pkt, char **out,
unsigned int *out_len)
{
*out = pkt->payload;
*out_len = pkt->hdr.payload_len;
}
/**
* Serialize padding and provide pointer to the data.
*
* @pkt Packet
* @out[out] Pointer to the serialized padding (always NULL)
* @out_len[out] Pointer to the serialized payload length
*
* Since the padding field value is undefined, only the size of the patting
* (@out_len) is set and the buffer pointer (@out) will always be NULL.
*/
static void smux_serialize_padding(struct smux_pkt_t *pkt, char **out,
unsigned int *out_len)
{
*out = NULL;
*out_len = pkt->hdr.pad_len;
}
/**
* Write data to TTY framework and handle breaking the writes up if needed.
*
* @data Data to write
* @len Length of data
*
* @returns 0 for success, < 0 for failure
*/
static int write_to_tty(char *data, unsigned len)
{
int data_written;
if (!data)
return 0;
while (len > 0 && !smux.in_reset) {
data_written = smux.tty->ops->write(smux.tty, data, len);
if (data_written >= 0) {
len -= data_written;
data += data_written;
} else {
SMUX_ERR("%s: TTY write returned error %d\n",
__func__, data_written);
return data_written;
}
if (len)
tty_wait_until_sent(smux.tty,
msecs_to_jiffies(TTY_BUFFER_FULL_WAIT_MS));
}
return 0;
}
/**
* Write packet to TTY.
*
* @pkt packet to write
*
* @returns 0 on success
*/
static int smux_tx_tty(struct smux_pkt_t *pkt)
{
char *data;
unsigned int len;
int ret;
if (!smux.tty) {
SMUX_ERR("%s: TTY not initialized", __func__);
return -ENOTTY;
}
if (pkt->hdr.cmd == SMUX_CMD_BYTE) {
SMUX_DBG("smux: %s: tty send single byte\n", __func__);
ret = write_to_tty(&pkt->hdr.flags, 1);
return ret;
}
smux_serialize_hdr(pkt, &data, &len);
ret = write_to_tty(data, len);
if (ret) {
SMUX_ERR("%s: failed %d to write header %d\n",
__func__, ret, len);
return ret;
}
smux_serialize_payload(pkt, &data, &len);
ret = write_to_tty(data, len);
if (ret) {
SMUX_ERR("%s: failed %d to write payload %d\n",
__func__, ret, len);
return ret;
}
smux_serialize_padding(pkt, &data, &len);
while (len > 0) {
char zero = 0x0;
ret = write_to_tty(&zero, 1);
if (ret) {
SMUX_ERR("%s: failed %d to write padding %d\n",
__func__, ret, len);
return ret;
}
--len;
}
return 0;
}
/**
* Send a single character.
*
* @ch Character to send
*/
static void smux_send_byte(char ch)
{
struct smux_pkt_t *pkt;
pkt = smux_alloc_pkt();
if (!pkt) {
SMUX_ERR("%s: alloc failure for byte %x\n", __func__, ch);
return;
}
pkt->hdr.cmd = SMUX_CMD_BYTE;
pkt->hdr.flags = ch;
pkt->hdr.lcid = SMUX_BROADCAST_LCID;
list_add_tail(&pkt->list, &smux.power_queue);
queue_work(smux_tx_wq, &smux_tx_work);
}
/**
* Receive a single-character packet (used for internal testing).
*
* @ch Character to receive
* @lcid Logical channel ID for packet
*
* @returns 0 for success
*/
static int smux_receive_byte(char ch, int lcid)
{
struct smux_pkt_t pkt;
smux_init_pkt(&pkt);
pkt.hdr.lcid = lcid;
pkt.hdr.cmd = SMUX_CMD_BYTE;
pkt.hdr.flags = ch;
return smux_dispatch_rx_pkt(&pkt);
}
/**
* Queue packet for transmit.
*
* @pkt_ptr Packet to queue
* @ch Channel to queue packet on
* @queue Queue channel on ready list
*/
static void smux_tx_queue(struct smux_pkt_t *pkt_ptr, struct smux_lch_t *ch,
int queue)
{
unsigned long flags;
SMUX_DBG("smux: %s: queuing pkt %p\n", __func__, pkt_ptr);
spin_lock_irqsave(&ch->tx_lock_lhb2, flags);
list_add_tail(&pkt_ptr->list, &ch->tx_queue);
spin_unlock_irqrestore(&ch->tx_lock_lhb2, flags);
if (queue)
list_channel(ch);
}
/**
* Handle receive OPEN ACK command.
*
* @pkt Received packet
*
* @returns 0 for success
*/
static int smux_handle_rx_open_ack(struct smux_pkt_t *pkt)
{
uint8_t lcid;
int ret;
struct smux_lch_t *ch;
int enable_powerdown = 0;
lcid = pkt->hdr.lcid;
ch = &smux_lch[lcid];
spin_lock(&ch->state_lock_lhb1);
if (ch->local_state == SMUX_LCH_LOCAL_OPENING) {
SMUX_DBG("smux: lcid %d local state 0x%x -> 0x%x\n", lcid,
ch->local_state,
SMUX_LCH_LOCAL_OPENED);
if (pkt->hdr.flags & SMUX_CMD_OPEN_POWER_COLLAPSE)
enable_powerdown = 1;
ch->local_state = SMUX_LCH_LOCAL_OPENED;
if (ch->remote_state == SMUX_LCH_REMOTE_OPENED)
schedule_notify(lcid, SMUX_CONNECTED, NULL);
ret = 0;
} else if (ch->remote_mode == SMUX_LCH_MODE_REMOTE_LOOPBACK) {
SMUX_DBG("smux: Remote loopback OPEN ACK received\n");
ret = 0;
} else {
SMUX_ERR("%s: lcid %d state 0x%x open ack invalid\n",
__func__, lcid, ch->local_state);
ret = -EINVAL;
}
spin_unlock(&ch->state_lock_lhb1);
if (enable_powerdown) {
spin_lock(&smux.tx_lock_lha2);
if (!smux.powerdown_enabled) {
smux.powerdown_enabled = 1;
SMUX_DBG("smux: %s: enabling power-collapse support\n",
__func__);
}
spin_unlock(&smux.tx_lock_lha2);
}
return ret;
}
static int smux_handle_close_ack(struct smux_pkt_t *pkt)
{
uint8_t lcid;
int ret;
struct smux_lch_t *ch;
union notifier_metadata meta_disconnected;
unsigned long flags;
lcid = pkt->hdr.lcid;
ch = &smux_lch[lcid];
meta_disconnected.disconnected.is_ssr = 0;
spin_lock_irqsave(&ch->state_lock_lhb1, flags);
if (ch->local_state == SMUX_LCH_LOCAL_CLOSING) {
SMUX_DBG("smux: lcid %d local state 0x%x -> 0x%x\n", lcid,
SMUX_LCH_LOCAL_CLOSING,
SMUX_LCH_LOCAL_CLOSED);
ch->local_state = SMUX_LCH_LOCAL_CLOSED;
if (ch->remote_state == SMUX_LCH_REMOTE_CLOSED)
schedule_notify(lcid, SMUX_DISCONNECTED,
&meta_disconnected);
ret = 0;
} else if (ch->remote_mode == SMUX_LCH_MODE_REMOTE_LOOPBACK) {
SMUX_DBG("smux: Remote loopback CLOSE ACK received\n");
ret = 0;
} else {
SMUX_ERR("%s: lcid %d state 0x%x close ack invalid\n",
__func__, lcid, ch->local_state);
ret = -EINVAL;
}
spin_unlock_irqrestore(&ch->state_lock_lhb1, flags);
return ret;
}
/**
* Handle receive OPEN command.
*
* @pkt Received packet
*
* @returns 0 for success
*/
static int smux_handle_rx_open_cmd(struct smux_pkt_t *pkt)
{
uint8_t lcid;
int ret;
struct smux_lch_t *ch;
struct smux_pkt_t *ack_pkt;
unsigned long flags;
int tx_ready = 0;
int enable_powerdown = 0;
if (pkt->hdr.flags & SMUX_CMD_OPEN_ACK)
return smux_handle_rx_open_ack(pkt);
lcid = pkt->hdr.lcid;
ch = &smux_lch[lcid];
spin_lock_irqsave(&ch->state_lock_lhb1, flags);
if (ch->remote_state == SMUX_LCH_REMOTE_CLOSED) {
SMUX_DBG("smux: lcid %d remote state 0x%x -> 0x%x\n", lcid,
SMUX_LCH_REMOTE_CLOSED,
SMUX_LCH_REMOTE_OPENED);
ch->remote_state = SMUX_LCH_REMOTE_OPENED;
if (pkt->hdr.flags & SMUX_CMD_OPEN_POWER_COLLAPSE)
enable_powerdown = 1;
/* Send Open ACK */
ack_pkt = smux_alloc_pkt();
if (!ack_pkt) {
/* exit out to allow retrying this later */
ret = -ENOMEM;
goto out;
}
ack_pkt->hdr.cmd = SMUX_CMD_OPEN_LCH;
ack_pkt->hdr.flags = SMUX_CMD_OPEN_ACK
| SMUX_CMD_OPEN_POWER_COLLAPSE;
ack_pkt->hdr.lcid = lcid;
ack_pkt->hdr.payload_len = 0;
ack_pkt->hdr.pad_len = 0;
if (pkt->hdr.flags & SMUX_CMD_OPEN_REMOTE_LOOPBACK) {
ch->remote_mode = SMUX_LCH_MODE_REMOTE_LOOPBACK;
ack_pkt->hdr.flags |= SMUX_CMD_OPEN_REMOTE_LOOPBACK;
}
smux_tx_queue(ack_pkt, ch, 0);
tx_ready = 1;
if (ch->remote_mode == SMUX_LCH_MODE_REMOTE_LOOPBACK) {
/*
* Send an Open command to the remote side to
* simulate our local client doing it.
*/
ack_pkt = smux_alloc_pkt();
if (ack_pkt) {
ack_pkt->hdr.lcid = lcid;
ack_pkt->hdr.cmd = SMUX_CMD_OPEN_LCH;
ack_pkt->hdr.flags =
SMUX_CMD_OPEN_POWER_COLLAPSE;
ack_pkt->hdr.payload_len = 0;
ack_pkt->hdr.pad_len = 0;
smux_tx_queue(ack_pkt, ch, 0);
tx_ready = 1;
} else {
SMUX_ERR(
"%s: Remote loopack allocation failure\n",
__func__);
}
} else if (ch->local_state == SMUX_LCH_LOCAL_OPENED) {
schedule_notify(lcid, SMUX_CONNECTED, NULL);
}
ret = 0;
} else {
SMUX_ERR("%s: lcid %d remote state 0x%x open invalid\n",
__func__, lcid, ch->remote_state);
ret = -EINVAL;
}
out:
spin_unlock_irqrestore(&ch->state_lock_lhb1, flags);
if (enable_powerdown) {
spin_lock_irqsave(&smux.tx_lock_lha2, flags);
if (!smux.powerdown_enabled) {
smux.powerdown_enabled = 1;
SMUX_DBG("smux: %s: enabling power-collapse support\n",
__func__);
}
spin_unlock_irqrestore(&smux.tx_lock_lha2, flags);
}
if (tx_ready)
list_channel(ch);
return ret;
}
/**
* Handle receive CLOSE command.
*
* @pkt Received packet
*
* @returns 0 for success
*/
static int smux_handle_rx_close_cmd(struct smux_pkt_t *pkt)
{
uint8_t lcid;
int ret;
struct smux_lch_t *ch;
struct smux_pkt_t *ack_pkt;
union notifier_metadata meta_disconnected;
unsigned long flags;
int tx_ready = 0;
if (pkt->hdr.flags & SMUX_CMD_CLOSE_ACK)
return smux_handle_close_ack(pkt);
lcid = pkt->hdr.lcid;
ch = &smux_lch[lcid];
meta_disconnected.disconnected.is_ssr = 0;
spin_lock_irqsave(&ch->state_lock_lhb1, flags);
if (ch->remote_state == SMUX_LCH_REMOTE_OPENED) {
SMUX_DBG("smux: lcid %d remote state 0x%x -> 0x%x\n", lcid,
SMUX_LCH_REMOTE_OPENED,
SMUX_LCH_REMOTE_CLOSED);
ack_pkt = smux_alloc_pkt();
if (!ack_pkt) {
/* exit out to allow retrying this later */
ret = -ENOMEM;
goto out;
}
ch->remote_state = SMUX_LCH_REMOTE_CLOSED;
ack_pkt->hdr.cmd = SMUX_CMD_CLOSE_LCH;
ack_pkt->hdr.flags = SMUX_CMD_CLOSE_ACK;
ack_pkt->hdr.lcid = lcid;
ack_pkt->hdr.payload_len = 0;
ack_pkt->hdr.pad_len = 0;
smux_tx_queue(ack_pkt, ch, 0);
tx_ready = 1;
if (ch->remote_mode == SMUX_LCH_MODE_REMOTE_LOOPBACK) {
/*
* Send a Close command to the remote side to simulate
* our local client doing it.
*/
ack_pkt = smux_alloc_pkt();
if (ack_pkt) {
ack_pkt->hdr.lcid = lcid;
ack_pkt->hdr.cmd = SMUX_CMD_CLOSE_LCH;
ack_pkt->hdr.flags = 0;
ack_pkt->hdr.payload_len = 0;
ack_pkt->hdr.pad_len = 0;
smux_tx_queue(ack_pkt, ch, 0);
tx_ready = 1;
} else {
SMUX_ERR(
"%s: Remote loopack allocation failure\n",
__func__);
}
}
if (ch->local_state == SMUX_LCH_LOCAL_CLOSED)
schedule_notify(lcid, SMUX_DISCONNECTED,
&meta_disconnected);
ret = 0;
} else {
SMUX_ERR("%s: lcid %d remote state 0x%x close invalid\n",
__func__, lcid, ch->remote_state);
ret = -EINVAL;
}
out:
spin_unlock_irqrestore(&ch->state_lock_lhb1, flags);
if (tx_ready)
list_channel(ch);
return ret;
}
/*
* Handle receive DATA command.
*
* @pkt Received packet
*
* @returns 0 for success
*/
static int smux_handle_rx_data_cmd(struct smux_pkt_t *pkt)
{
uint8_t lcid;
int ret = 0;
int do_retry = 0;
int tx_ready = 0;
int tmp;
int rx_len;
struct smux_lch_t *ch;
union notifier_metadata metadata;
int remote_loopback;
struct smux_pkt_t *ack_pkt;
unsigned long flags;
if (!pkt || smux_assert_lch_id(pkt->hdr.lcid)) {
ret = -ENXIO;
goto out;
}
rx_len = pkt->hdr.payload_len;
if (rx_len == 0) {
ret = -EINVAL;
goto out;
}
lcid = pkt->hdr.lcid;
ch = &smux_lch[lcid];
spin_lock_irqsave(&ch->state_lock_lhb1, flags);
remote_loopback = ch->remote_mode == SMUX_LCH_MODE_REMOTE_LOOPBACK;
if (ch->local_state != SMUX_LCH_LOCAL_OPENED
&& !remote_loopback) {
SMUX_ERR("smux: ch %d error data on local state 0x%x",
lcid, ch->local_state);
ret = -EIO;
spin_unlock_irqrestore(&ch->state_lock_lhb1, flags);
goto out;
}
if (ch->remote_state != SMUX_LCH_REMOTE_OPENED) {
SMUX_ERR("smux: ch %d error data on remote state 0x%x",
lcid, ch->remote_state);
ret = -EIO;
spin_unlock_irqrestore(&ch->state_lock_lhb1, flags);
goto out;
}
if (!list_empty(&ch->rx_retry_queue)) {
do_retry = 1;
if ((ch->options & SMUX_CH_OPTION_AUTO_REMOTE_TX_STOP) &&
!ch->rx_flow_control_auto &&
((ch->rx_retry_queue_cnt + 1) >= SMUX_RX_WM_HIGH)) {
/* need to flow control RX */
ch->rx_flow_control_auto = 1;
tx_ready |= smux_rx_flow_control_updated(ch);
schedule_notify(ch->lcid, SMUX_RX_RETRY_HIGH_WM_HIT,
NULL);
}
if ((ch->rx_retry_queue_cnt + 1) > SMUX_RX_RETRY_MAX_PKTS) {
/* retry queue full */
SMUX_ERR(
"%s: ch %d RX retry queue full; rx flow=%d\n",
__func__, lcid, ch->rx_flow_control_auto);
schedule_notify(lcid, SMUX_READ_FAIL, NULL);
ret = -ENOMEM;
spin_unlock_irqrestore(&ch->state_lock_lhb1, flags);
goto out;
}
}
spin_unlock_irqrestore(&ch->state_lock_lhb1, flags);
if (remote_loopback) {
/* Echo the data back to the remote client. */
ack_pkt = smux_alloc_pkt();
if (ack_pkt) {
ack_pkt->hdr.lcid = lcid;
ack_pkt->hdr.cmd = SMUX_CMD_DATA;
ack_pkt->hdr.flags = 0;
ack_pkt->hdr.payload_len = pkt->hdr.payload_len;
if (ack_pkt->hdr.payload_len) {
smux_alloc_pkt_payload(ack_pkt);
memcpy(ack_pkt->payload, pkt->payload,
ack_pkt->hdr.payload_len);
}
ack_pkt->hdr.pad_len = pkt->hdr.pad_len;
smux_tx_queue(ack_pkt, ch, 0);
tx_ready = 1;
} else {
SMUX_ERR("%s: Remote loopack allocation failure\n",
__func__);
}
} else if (!do_retry) {
/* request buffer from client */
metadata.read.pkt_priv = 0;
metadata.read.buffer = 0;
tmp = ch->get_rx_buffer(ch->priv,
(void **)&metadata.read.pkt_priv,
(void **)&metadata.read.buffer,
rx_len);
if (tmp == 0 && metadata.read.buffer) {
/* place data into RX buffer */
memcpy(metadata.read.buffer, pkt->payload,
rx_len);
metadata.read.len = rx_len;
schedule_notify(lcid, SMUX_READ_DONE,
&metadata);
} else if (tmp == -EAGAIN ||
(tmp == 0 && !metadata.read.buffer)) {
/* buffer allocation failed - add to retry queue */
do_retry = 1;
} else if (tmp < 0) {
SMUX_ERR("%s: ch %d Client RX buffer alloc failed %d\n",
__func__, lcid, tmp);
schedule_notify(lcid, SMUX_READ_FAIL, NULL);
ret = -ENOMEM;
}
}
if (do_retry) {
struct smux_rx_pkt_retry *retry;
retry = kmalloc(sizeof(struct smux_rx_pkt_retry), GFP_KERNEL);
if (!retry) {
SMUX_ERR("%s: retry alloc failure\n", __func__);
ret = -ENOMEM;
schedule_notify(lcid, SMUX_READ_FAIL, NULL);
goto out;
}
INIT_LIST_HEAD(&retry->rx_retry_list);
retry->timeout_in_ms = SMUX_RX_RETRY_MIN_MS;
/* copy packet */
retry->pkt = smux_alloc_pkt();
if (!retry->pkt) {
kfree(retry);
SMUX_ERR("%s: pkt alloc failure\n", __func__);
ret = -ENOMEM;
schedule_notify(lcid, SMUX_READ_FAIL, NULL);
goto out;
}
retry->pkt->hdr.lcid = lcid;
retry->pkt->hdr.payload_len = pkt->hdr.payload_len;
retry->pkt->hdr.pad_len = pkt->hdr.pad_len;
if (retry->pkt->hdr.payload_len) {
smux_alloc_pkt_payload(retry->pkt);
memcpy(retry->pkt->payload, pkt->payload,
retry->pkt->hdr.payload_len);
}
/* add to retry queue */
spin_lock_irqsave(&ch->state_lock_lhb1, flags);
list_add_tail(&retry->rx_retry_list, &ch->rx_retry_queue);
++ch->rx_retry_queue_cnt;
if (ch->rx_retry_queue_cnt == 1)
queue_delayed_work(smux_rx_wq, &ch->rx_retry_work,
msecs_to_jiffies(retry->timeout_in_ms));
spin_unlock_irqrestore(&ch->state_lock_lhb1, flags);
}
if (tx_ready)
list_channel(ch);
out:
return ret;
}
/**
* Handle receive byte command for testing purposes.
*
* @pkt Received packet
*
* @returns 0 for success
*/
static int smux_handle_rx_byte_cmd(struct smux_pkt_t *pkt)
{
uint8_t lcid;
int ret;
struct smux_lch_t *ch;
union notifier_metadata metadata;
unsigned long flags;
if (!pkt || smux_assert_lch_id(pkt->hdr.lcid)) {
SMUX_ERR("%s: invalid packet or channel id\n", __func__);
return -ENXIO;
}
lcid = pkt->hdr.lcid;
ch = &smux_lch[lcid];
spin_lock_irqsave(&ch->state_lock_lhb1, flags);
if (ch->local_state != SMUX_LCH_LOCAL_OPENED) {
SMUX_ERR("smux: ch %d error data on local state 0x%x",
lcid, ch->local_state);
ret = -EIO;
goto out;
}
if (ch->remote_state != SMUX_LCH_REMOTE_OPENED) {
SMUX_ERR("smux: ch %d error data on remote state 0x%x",
lcid, ch->remote_state);
ret = -EIO;
goto out;
}
metadata.read.pkt_priv = (void *)(int)pkt->hdr.flags;
metadata.read.buffer = 0;
schedule_notify(lcid, SMUX_READ_DONE, &metadata);
ret = 0;
out:
spin_unlock_irqrestore(&ch->state_lock_lhb1, flags);
return ret;
}
/**
* Handle receive status command.
*
* @pkt Received packet
*
* @returns 0 for success
*/
static int smux_handle_rx_status_cmd(struct smux_pkt_t *pkt)
{
uint8_t lcid;
int ret;
struct smux_lch_t *ch;
union notifier_metadata meta;
unsigned long flags;
int tx_ready = 0;
lcid = pkt->hdr.lcid;
ch = &smux_lch[lcid];
spin_lock_irqsave(&ch->state_lock_lhb1, flags);
meta.tiocm.tiocm_old = ch->remote_tiocm;
meta.tiocm.tiocm_new = pkt->hdr.flags;
/* update logical channel flow control */
if ((meta.tiocm.tiocm_old & SMUX_CMD_STATUS_FLOW_CNTL) ^
(meta.tiocm.tiocm_new & SMUX_CMD_STATUS_FLOW_CNTL)) {
/* logical channel flow control changed */
if (pkt->hdr.flags & SMUX_CMD_STATUS_FLOW_CNTL) {
/* disabled TX */
SMUX_DBG("smux: TX Flow control enabled\n");
ch->tx_flow_control = 1;
} else {
/* re-enable channel */
SMUX_DBG("smux: TX Flow control disabled\n");
ch->tx_flow_control = 0;
tx_ready = 1;
}
}
meta.tiocm.tiocm_old = msm_smux_tiocm_get_atomic(ch);
ch->remote_tiocm = pkt->hdr.flags;
meta.tiocm.tiocm_new = msm_smux_tiocm_get_atomic(ch);
/* client notification for status change */
if (IS_FULLY_OPENED(ch)) {
if (meta.tiocm.tiocm_old != meta.tiocm.tiocm_new)
schedule_notify(lcid, SMUX_TIOCM_UPDATE, &meta);
ret = 0;
}
spin_unlock_irqrestore(&ch->state_lock_lhb1, flags);
if (tx_ready)
list_channel(ch);
return ret;
}
/**
* Handle receive power command.
*
* @pkt Received packet
*
* @returns 0 for success
*/
static int smux_handle_rx_power_cmd(struct smux_pkt_t *pkt)
{
struct smux_pkt_t *ack_pkt = NULL;
int power_down = 0;
unsigned long flags;
SMUX_PWR_PKT_RX(pkt);
spin_lock_irqsave(&smux.tx_lock_lha2, flags);
if (pkt->hdr.flags & SMUX_CMD_PWR_CTL_ACK) {
/* local sleep request ack */
if (smux.power_state == SMUX_PWR_TURNING_OFF)
/* Power-down complete, turn off UART */
power_down = 1;
else
SMUX_ERR("%s: sleep request ack invalid in state %d\n",
__func__, smux.power_state);
} else {
/*
* Remote sleep request
*
* Even if we have data pending, we need to transition to the
* POWER_OFF state and then perform a wakeup since the remote
* side has requested a power-down.
*
* The state here is set to SMUX_PWR_TURNING_OFF_FLUSH and
* the TX thread will set the state to SMUX_PWR_TURNING_OFF
* when it sends the packet.
*
* If we are already powering down, then no ACK is sent.
*/
if (smux.power_state == SMUX_PWR_ON) {
ack_pkt = smux_alloc_pkt();
if (ack_pkt) {
SMUX_PWR("smux: %s: Power %d->%d\n", __func__,
smux.power_state,
SMUX_PWR_TURNING_OFF_FLUSH);
smux.power_state = SMUX_PWR_TURNING_OFF_FLUSH;
/* send power-down ack */
ack_pkt->hdr.cmd = SMUX_CMD_PWR_CTL;
ack_pkt->hdr.flags = SMUX_CMD_PWR_CTL_ACK;
ack_pkt->hdr.lcid = SMUX_BROADCAST_LCID;
list_add_tail(&ack_pkt->list,
&smux.power_queue);
queue_work(smux_tx_wq, &smux_tx_work);
}
} else if (smux.power_state == SMUX_PWR_TURNING_OFF_FLUSH) {
/* Local power-down request still in TX queue */
SMUX_PWR("smux: %s: Power-down shortcut - no ack\n",
__func__);
smux.power_ctl_remote_req_received = 1;
} else if (smux.power_state == SMUX_PWR_TURNING_OFF) {
/*
* Local power-down request already sent to remote
* side, so this request gets treated as an ACK.
*/
SMUX_PWR("smux: %s: Power-down shortcut - no ack\n",
__func__);
power_down = 1;
} else {
SMUX_ERR("%s: sleep request invalid in state %d\n",
__func__, smux.power_state);
}
}
if (power_down) {
SMUX_PWR("smux: %s: Power %d->%d\n", __func__,
smux.power_state, SMUX_PWR_OFF_FLUSH);
smux.power_state = SMUX_PWR_OFF_FLUSH;
queue_work(smux_tx_wq, &smux_inactivity_work);
}
spin_unlock_irqrestore(&smux.tx_lock_lha2, flags);
return 0;
}
/**
* Handle dispatching a completed packet for receive processing.
*
* @pkt Packet to process
*
* @returns 0 for success
*/
static int smux_dispatch_rx_pkt(struct smux_pkt_t *pkt)
{
int ret = -ENXIO;
switch (pkt->hdr.cmd) {
case SMUX_CMD_OPEN_LCH:
SMUX_LOG_PKT_RX(pkt);
if (smux_assert_lch_id(pkt->hdr.lcid)) {
SMUX_ERR("%s: invalid channel id %d\n",
__func__, pkt->hdr.lcid);
break;
}
ret = smux_handle_rx_open_cmd(pkt);
break;
case SMUX_CMD_DATA:
SMUX_LOG_PKT_RX(pkt);
if (smux_assert_lch_id(pkt->hdr.lcid)) {
SMUX_ERR("%s: invalid channel id %d\n",
__func__, pkt->hdr.lcid);
break;
}
ret = smux_handle_rx_data_cmd(pkt);
break;
case SMUX_CMD_CLOSE_LCH:
SMUX_LOG_PKT_RX(pkt);
if (smux_assert_lch_id(pkt->hdr.lcid)) {
SMUX_ERR("%s: invalid channel id %d\n",
__func__, pkt->hdr.lcid);
break;
}
ret = smux_handle_rx_close_cmd(pkt);
break;
case SMUX_CMD_STATUS:
SMUX_LOG_PKT_RX(pkt);
if (smux_assert_lch_id(pkt->hdr.lcid)) {
SMUX_ERR("%s: invalid channel id %d\n",
__func__, pkt->hdr.lcid);
break;
}
ret = smux_handle_rx_status_cmd(pkt);
break;
case SMUX_CMD_PWR_CTL:
ret = smux_handle_rx_power_cmd(pkt);
break;
case SMUX_CMD_BYTE:
SMUX_LOG_PKT_RX(pkt);
ret = smux_handle_rx_byte_cmd(pkt);
break;
default:
SMUX_LOG_PKT_RX(pkt);
SMUX_ERR("%s: command %d unknown\n", __func__, pkt->hdr.cmd);
ret = -EINVAL;
}
return ret;
}
/**
* Deserializes a packet and dispatches it to the packet receive logic.
*
* @data Raw data for one packet
* @len Length of the data
*
* @returns 0 for success
*/
static int smux_deserialize(unsigned char *data, int len)
{
struct smux_pkt_t recv;
smux_init_pkt(&recv);
/*
* It may be possible to optimize this to not use the
* temporary buffer.
*/
memcpy(&recv.hdr, data, sizeof(struct smux_hdr_t));
if (recv.hdr.magic != SMUX_MAGIC) {
SMUX_ERR("%s: invalid header magic\n", __func__);
return -EINVAL;
}
if (recv.hdr.payload_len)
recv.payload = data + sizeof(struct smux_hdr_t);
return smux_dispatch_rx_pkt(&recv);
}
/**
* Handle wakeup request byte.
*/
static void smux_handle_wakeup_req(void)
{
unsigned long flags;
spin_lock_irqsave(&smux.tx_lock_lha2, flags);
if (smux.power_state == SMUX_PWR_OFF
|| smux.power_state == SMUX_PWR_TURNING_ON) {
/* wakeup system */
SMUX_PWR("smux: %s: Power %d->%d\n", __func__,
smux.power_state, SMUX_PWR_ON);
smux.power_state = SMUX_PWR_ON;
queue_work(smux_tx_wq, &smux_wakeup_work);
queue_work(smux_tx_wq, &smux_tx_work);
queue_delayed_work(smux_tx_wq, &smux_delayed_inactivity_work,
msecs_to_jiffies(SMUX_INACTIVITY_TIMEOUT_MS));
smux_send_byte(SMUX_WAKEUP_ACK);
} else if (smux.power_state == SMUX_PWR_ON) {
smux_send_byte(SMUX_WAKEUP_ACK);
} else {
/* stale wakeup request from previous wakeup */
SMUX_PWR("smux: %s: stale Wakeup REQ in state %d\n",
__func__, smux.power_state);
}
spin_unlock_irqrestore(&smux.tx_lock_lha2, flags);
}
/**
* Handle wakeup request ack.
*/
static void smux_handle_wakeup_ack(void)
{
unsigned long flags;
spin_lock_irqsave(&smux.tx_lock_lha2, flags);
if (smux.power_state == SMUX_PWR_TURNING_ON) {
/* received response to wakeup request */
SMUX_PWR("smux: %s: Power %d->%d\n", __func__,
smux.power_state, SMUX_PWR_ON);
smux.power_state = SMUX_PWR_ON;
queue_work(smux_tx_wq, &smux_tx_work);
queue_delayed_work(smux_tx_wq, &smux_delayed_inactivity_work,
msecs_to_jiffies(SMUX_INACTIVITY_TIMEOUT_MS));
} else if (smux.power_state != SMUX_PWR_ON) {
/* invalid message */
SMUX_PWR("smux: %s: stale Wakeup REQ ACK in state %d\n",
__func__, smux.power_state);
}
spin_unlock_irqrestore(&smux.tx_lock_lha2, flags);
}
/**
* RX State machine - IDLE state processing.
*
* @data New RX data to process
* @len Length of the data
* @used Return value of length processed
* @flag Error flag - TTY_NORMAL 0 for no failure
*/
static void smux_rx_handle_idle(const unsigned char *data,
int len, int *used, int flag)
{
int i;
if (flag) {
if (smux_byte_loopback)
smux_receive_byte(SMUX_UT_ECHO_ACK_FAIL,
smux_byte_loopback);
SMUX_ERR("%s: TTY error 0x%x - ignoring\n", __func__, flag);
++*used;
return;
}
for (i = *used; i < len && smux.rx_state == SMUX_RX_IDLE; i++) {
switch (data[i]) {
case SMUX_MAGIC_WORD1:
smux.rx_state = SMUX_RX_MAGIC;
break;
case SMUX_WAKEUP_REQ:
SMUX_PWR("smux: smux: RX Wakeup REQ\n");
if (unlikely(!smux.remote_is_alive)) {
mutex_lock(&smux.mutex_lha0);
smux.remote_is_alive = 1;
mutex_unlock(&smux.mutex_lha0);
}
smux_handle_wakeup_req();
break;
case SMUX_WAKEUP_ACK:
SMUX_PWR("smux: smux: RX Wakeup ACK\n");
if (unlikely(!smux.remote_is_alive)) {
mutex_lock(&smux.mutex_lha0);
smux.remote_is_alive = 1;
mutex_unlock(&smux.mutex_lha0);
}
smux_handle_wakeup_ack();
break;
default:
/* unexpected character */
if (smux_byte_loopback && data[i] == SMUX_UT_ECHO_REQ)
smux_receive_byte(SMUX_UT_ECHO_ACK_OK,
smux_byte_loopback);
SMUX_ERR("%s: parse error 0x%02x - ignoring\n",
__func__, (unsigned)data[i]);
break;
}
}
*used = i;
}
/**
* RX State machine - Header Magic state processing.
*
* @data New RX data to process
* @len Length of the data
* @used Return value of length processed
* @flag Error flag - TTY_NORMAL 0 for no failure
*/
static void smux_rx_handle_magic(const unsigned char *data,
int len, int *used, int flag)
{
int i;
if (flag) {
SMUX_ERR("%s: TTY RX error %d\n", __func__, flag);
smux_enter_reset();
smux.rx_state = SMUX_RX_FAILURE;
++*used;
return;
}
for (i = *used; i < len && smux.rx_state == SMUX_RX_MAGIC; i++) {
/* wait for completion of the magic */
if (data[i] == SMUX_MAGIC_WORD2) {
smux.recv_len = 0;
smux.recv_buf[smux.recv_len++] = SMUX_MAGIC_WORD1;
smux.recv_buf[smux.recv_len++] = SMUX_MAGIC_WORD2;
smux.rx_state = SMUX_RX_HDR;
} else {
/* unexpected / trash character */
SMUX_ERR(
"%s: rx parse error for char %c; *used=%d, len=%d\n",
__func__, data[i], *used, len);
smux.rx_state = SMUX_RX_IDLE;
}
}
*used = i;
}
/**
* RX State machine - Packet Header state processing.
*
* @data New RX data to process
* @len Length of the data
* @used Return value of length processed
* @flag Error flag - TTY_NORMAL 0 for no failure
*/
static void smux_rx_handle_hdr(const unsigned char *data,
int len, int *used, int flag)
{
int i;
struct smux_hdr_t *hdr;
if (flag) {
SMUX_ERR("%s: TTY RX error %d\n", __func__, flag);
smux_enter_reset();
smux.rx_state = SMUX_RX_FAILURE;
++*used;
return;
}
for (i = *used; i < len && smux.rx_state == SMUX_RX_HDR; i++) {
smux.recv_buf[smux.recv_len++] = data[i];
if (smux.recv_len == sizeof(struct smux_hdr_t)) {
/* complete header received */
hdr = (struct smux_hdr_t *)smux.recv_buf;
smux.pkt_remain = hdr->payload_len + hdr->pad_len;
smux.rx_state = SMUX_RX_PAYLOAD;
}
}
*used = i;
}
/**
* RX State machine - Packet Payload state processing.
*
* @data New RX data to process
* @len Length of the data
* @used Return value of length processed
* @flag Error flag - TTY_NORMAL 0 for no failure
*/
static void smux_rx_handle_pkt_payload(const unsigned char *data,
int len, int *used, int flag)
{
int remaining;
if (flag) {
SMUX_ERR("%s: TTY RX error %d\n", __func__, flag);
smux_enter_reset();
smux.rx_state = SMUX_RX_FAILURE;
++*used;
return;
}
/* copy data into rx buffer */
if (smux.pkt_remain < (len - *used))
remaining = smux.pkt_remain;
else
remaining = len - *used;
memcpy(&smux.recv_buf[smux.recv_len], &data[*used], remaining);
smux.recv_len += remaining;
smux.pkt_remain -= remaining;
*used += remaining;
if (smux.pkt_remain == 0) {
/* complete packet received */
smux_deserialize(smux.recv_buf, smux.recv_len);
smux.rx_state = SMUX_RX_IDLE;
}
}
/**
* Feed data to the receive state machine.
*
* @data Pointer to data block
* @len Length of data
* @flag TTY_NORMAL (0) for no error, otherwise TTY Error Flag
*/
void smux_rx_state_machine(const unsigned char *data,
int len, int flag)
{
struct smux_rx_worker_data work;
work.data = data;
work.len = len;
work.flag = flag;
INIT_WORK_ONSTACK(&work.work, smux_rx_worker);
work.work_complete = COMPLETION_INITIALIZER_ONSTACK(work.work_complete);
queue_work(smux_rx_wq, &work.work);
wait_for_completion(&work.work_complete);
}
/**
* Returns true if the remote side has acknowledged a wakeup
* request previously, so we know that the link is alive and active.
*
* @returns true for is alive, false for not alive
*/
bool smux_remote_is_active(void)
{
bool is_active = false;
mutex_lock(&smux.mutex_lha0);
if (smux.remote_is_alive)
is_active = true;
mutex_unlock(&smux.mutex_lha0);
return is_active;
}
/**
* Add channel to transmit-ready list and trigger transmit worker.
*
* @ch Channel to add
*/
static void list_channel(struct smux_lch_t *ch)
{
unsigned long flags;
SMUX_DBG("smux: %s: listing channel %d\n",
__func__, ch->lcid);
spin_lock_irqsave(&smux.tx_lock_lha2, flags);
spin_lock(&ch->tx_lock_lhb2);
smux.tx_activity_flag = 1;
if (list_empty(&ch->tx_ready_list))
list_add_tail(&ch->tx_ready_list, &smux.lch_tx_ready_list);
spin_unlock(&ch->tx_lock_lhb2);
spin_unlock_irqrestore(&smux.tx_lock_lha2, flags);
queue_work(smux_tx_wq, &smux_tx_work);
}
/**
* Transmit packet on correct transport and then perform client
* notification.
*
* @ch Channel to transmit on
* @pkt Packet to transmit
*/
static void smux_tx_pkt(struct smux_lch_t *ch, struct smux_pkt_t *pkt)
{
union notifier_metadata meta_write;
int ret;
if (ch && pkt) {
SMUX_LOG_PKT_TX(pkt);
if (ch->local_mode == SMUX_LCH_MODE_LOCAL_LOOPBACK)
ret = smux_tx_loopback(pkt);
else
ret = smux_tx_tty(pkt);
if (pkt->hdr.cmd == SMUX_CMD_DATA) {
/* notify write-done */
meta_write.write.pkt_priv = pkt->priv;
meta_write.write.buffer = pkt->payload;
meta_write.write.len = pkt->hdr.payload_len;
if (ret >= 0) {
SMUX_DBG("smux: %s: PKT write done", __func__);
schedule_notify(ch->lcid, SMUX_WRITE_DONE,
&meta_write);
} else {
SMUX_ERR("%s: failed to write pkt %d\n",
__func__, ret);
schedule_notify(ch->lcid, SMUX_WRITE_FAIL,
&meta_write);
}
}
}
}
/**
* Flush pending TTY TX data.
*/
static void smux_flush_tty(void)
{
mutex_lock(&smux.mutex_lha0);
if (!smux.tty) {
SMUX_ERR("%s: ldisc not loaded\n", __func__);
mutex_unlock(&smux.mutex_lha0);
return;
}
tty_wait_until_sent(smux.tty,
msecs_to_jiffies(TTY_BUFFER_FULL_WAIT_MS));
if (tty_chars_in_buffer(smux.tty) > 0)
SMUX_ERR("%s: unable to flush UART queue\n", __func__);
mutex_unlock(&smux.mutex_lha0);
}
/**
* Purge TX queue for logical channel.
*
* @ch Logical channel pointer
* @is_ssr 1 = this is a subsystem restart purge
*
* Must be called with the following spinlocks locked:
* state_lock_lhb1
* tx_lock_lhb2
*/
static void smux_purge_ch_tx_queue(struct smux_lch_t *ch, int is_ssr)
{
struct smux_pkt_t *pkt;
int send_disconnect = 0;
struct smux_pkt_t *pkt_tmp;
int is_state_pkt;
list_for_each_entry_safe(pkt, pkt_tmp, &ch->tx_queue, list) {
is_state_pkt = 0;
if (pkt->hdr.cmd == SMUX_CMD_OPEN_LCH) {
if (pkt->hdr.flags & SMUX_CMD_OPEN_ACK) {
/* Open ACK must still be sent */
is_state_pkt = 1;
} else {
/* Open never sent -- force to closed state */
ch->local_state = SMUX_LCH_LOCAL_CLOSED;
send_disconnect = 1;
}
} else if (pkt->hdr.cmd == SMUX_CMD_CLOSE_LCH) {
if (pkt->hdr.flags & SMUX_CMD_CLOSE_ACK)
is_state_pkt = 1;
if (!send_disconnect)
is_state_pkt = 1;
} else if (pkt->hdr.cmd == SMUX_CMD_DATA) {
/* Notify client of failed write */
union notifier_metadata meta_write;
meta_write.write.pkt_priv = pkt->priv;
meta_write.write.buffer = pkt->payload;
meta_write.write.len = pkt->hdr.payload_len;
schedule_notify(ch->lcid, SMUX_WRITE_FAIL, &meta_write);
}
if (!is_state_pkt || is_ssr) {
list_del(&pkt->list);
smux_free_pkt(pkt);
}
}
if (send_disconnect) {
union notifier_metadata meta_disconnected;
meta_disconnected.disconnected.is_ssr = smux.in_reset;
schedule_notify(ch->lcid, SMUX_DISCONNECTED,
&meta_disconnected);
}
}
/**
* Power-up the UART.
*
* Must be called with smux.mutex_lha0 already locked.
*/
static void smux_uart_power_on_atomic(void)
{
struct uart_state *state;
if (!smux.tty || !smux.tty->driver_data) {
SMUX_ERR("%s: unable to find UART port for tty %p\n",
__func__, smux.tty);
return;
}
state = smux.tty->driver_data;
msm_hs_request_clock_on(state->uart_port);
}
/**
* Power-up the UART.
*/
static void smux_uart_power_on(void)
{
mutex_lock(&smux.mutex_lha0);
smux_uart_power_on_atomic();
mutex_unlock(&smux.mutex_lha0);
}
/**
* Power down the UART.
*
* Must be called with mutex_lha0 locked.
*/
static void smux_uart_power_off_atomic(void)
{
struct uart_state *state;
if (!smux.tty || !smux.tty->driver_data) {
SMUX_ERR("%s: unable to find UART port for tty %p\n",
__func__, smux.tty);
mutex_unlock(&smux.mutex_lha0);
return;
}
state = smux.tty->driver_data;
msm_hs_request_clock_off(state->uart_port);
}
/**
* Power down the UART.
*/
static void smux_uart_power_off(void)
{
mutex_lock(&smux.mutex_lha0);
smux_uart_power_off_atomic();
mutex_unlock(&smux.mutex_lha0);
}
/**
* TX Wakeup Worker
*
* @work Not used
*
* Do an exponential back-off wakeup sequence with a maximum period
* of approximately 1 second (1 << 20 microseconds).
*/
static void smux_wakeup_worker(struct work_struct *work)
{
unsigned long flags;
unsigned wakeup_delay;
if (smux.in_reset)
return;
spin_lock_irqsave(&smux.tx_lock_lha2, flags);
if (smux.power_state == SMUX_PWR_ON) {
/* wakeup complete */
smux.pwr_wakeup_delay_us = 1;
spin_unlock_irqrestore(&smux.tx_lock_lha2, flags);
SMUX_DBG("smux: %s: wakeup complete\n", __func__);
/*
* Cancel any pending retry. This avoids a race condition with
* a new power-up request because:
* 1) this worker doesn't modify the state
* 2) this worker is processed on the same single-threaded
* workqueue as new TX wakeup requests
*/
cancel_delayed_work(&smux_wakeup_delayed_work);
queue_work(smux_tx_wq, &smux_tx_work);
} else if (smux.power_state == SMUX_PWR_TURNING_ON) {
/* retry wakeup */
wakeup_delay = smux.pwr_wakeup_delay_us;
smux.pwr_wakeup_delay_us <<= 1;
if (smux.pwr_wakeup_delay_us > SMUX_WAKEUP_DELAY_MAX)
smux.pwr_wakeup_delay_us =
SMUX_WAKEUP_DELAY_MAX;
spin_unlock_irqrestore(&smux.tx_lock_lha2, flags);
SMUX_PWR("smux: %s: triggering wakeup\n", __func__);
smux_send_byte(SMUX_WAKEUP_REQ);
if (wakeup_delay < SMUX_WAKEUP_DELAY_MIN) {
SMUX_DBG("smux: %s: sleeping for %u us\n", __func__,
wakeup_delay);
usleep_range(wakeup_delay, 2*wakeup_delay);
queue_work(smux_tx_wq, &smux_wakeup_work);
} else {
/* schedule delayed work */
SMUX_DBG(
"smux: %s: scheduling delayed wakeup in %u ms\n",
__func__, wakeup_delay / 1000);
queue_delayed_work(smux_tx_wq,
&smux_wakeup_delayed_work,
msecs_to_jiffies(wakeup_delay / 1000));
}
} else {
/* wakeup aborted */
smux.pwr_wakeup_delay_us = 1;
spin_unlock_irqrestore(&smux.tx_lock_lha2, flags);
SMUX_PWR("smux: %s: wakeup aborted\n", __func__);
cancel_delayed_work(&smux_wakeup_delayed_work);
}
}
/**
* Inactivity timeout worker. Periodically scheduled when link is active.
* When it detects inactivity, it will power-down the UART link.
*
* @work Work structure (not used)
*/
static void smux_inactivity_worker(struct work_struct *work)
{
struct smux_pkt_t *pkt;
unsigned long flags;
if (smux.in_reset)
return;
spin_lock_irqsave(&smux.rx_lock_lha1, flags);
spin_lock(&smux.tx_lock_lha2);
if (!smux.tx_activity_flag && !smux.rx_activity_flag) {
/* no activity */
if (smux.powerdown_enabled) {
if (smux.power_state == SMUX_PWR_ON) {
/* start power-down sequence */
pkt = smux_alloc_pkt();
if (pkt) {
SMUX_PWR(
"smux: %s: Power %d->%d\n", __func__,
smux.power_state,
SMUX_PWR_TURNING_OFF_FLUSH);
smux.power_state =
SMUX_PWR_TURNING_OFF_FLUSH;
/* send power-down request */
pkt->hdr.cmd = SMUX_CMD_PWR_CTL;
pkt->hdr.flags = 0;
pkt->hdr.lcid = SMUX_BROADCAST_LCID;
list_add_tail(&pkt->list,
&smux.power_queue);
queue_work(smux_tx_wq, &smux_tx_work);
} else {
SMUX_ERR("%s: packet alloc failed\n",
__func__);
}
}
}
}
smux.tx_activity_flag = 0;
smux.rx_activity_flag = 0;
if (smux.power_state == SMUX_PWR_OFF_FLUSH) {
/* ready to power-down the UART */
SMUX_PWR("smux: %s: Power %d->%d\n", __func__,
smux.power_state, SMUX_PWR_OFF);
smux.power_state = SMUX_PWR_OFF;
/* if data is pending, schedule a new wakeup */
if (!list_empty(&smux.lch_tx_ready_list) ||
!list_empty(&smux.power_queue))
queue_work(smux_tx_wq, &smux_tx_work);
spin_unlock(&smux.tx_lock_lha2);
spin_unlock_irqrestore(&smux.rx_lock_lha1, flags);
/* flush UART output queue and power down */
smux_flush_tty();
smux_uart_power_off();
} else {
spin_unlock(&smux.tx_lock_lha2);
spin_unlock_irqrestore(&smux.rx_lock_lha1, flags);
}
/* reschedule inactivity worker */
if (smux.power_state != SMUX_PWR_OFF)
queue_delayed_work(smux_tx_wq, &smux_delayed_inactivity_work,
msecs_to_jiffies(SMUX_INACTIVITY_TIMEOUT_MS));
}
/**
* Remove RX retry packet from channel and free it.
*
* @ch Channel for retry packet
* @retry Retry packet to remove
*
* @returns 1 if flow control updated; 0 otherwise
*
* Must be called with state_lock_lhb1 locked.
*/
int smux_remove_rx_retry(struct smux_lch_t *ch,
struct smux_rx_pkt_retry *retry)
{
int tx_ready = 0;
list_del(&retry->rx_retry_list);
--ch->rx_retry_queue_cnt;
smux_free_pkt(retry->pkt);
kfree(retry);
if ((ch->options & SMUX_CH_OPTION_AUTO_REMOTE_TX_STOP) &&
(ch->rx_retry_queue_cnt <= SMUX_RX_WM_LOW) &&
ch->rx_flow_control_auto) {
ch->rx_flow_control_auto = 0;
smux_rx_flow_control_updated(ch);
schedule_notify(ch->lcid, SMUX_RX_RETRY_LOW_WM_HIT, NULL);
tx_ready = 1;
}
return tx_ready;
}
/**
* RX worker handles all receive operations.
*
* @work Work structure contained in TBD structure
*/
static void smux_rx_worker(struct work_struct *work)
{
unsigned long flags;
int used;
int initial_rx_state;
struct smux_rx_worker_data *w;
const unsigned char *data;
int len;
int flag;
w = container_of(work, struct smux_rx_worker_data, work);
data = w->data;
len = w->len;
flag = w->flag;
spin_lock_irqsave(&smux.rx_lock_lha1, flags);
smux.rx_activity_flag = 1;
spin_unlock_irqrestore(&smux.rx_lock_lha1, flags);
SMUX_DBG("smux: %s: %p, len=%d, flag=%d\n", __func__, data, len, flag);
used = 0;
do {
if (smux.in_reset) {
SMUX_DBG("smux: %s: abort RX due to reset\n", __func__);
smux.rx_state = SMUX_RX_IDLE;
break;
}
SMUX_DBG("smux: %s: state %d; %d of %d\n",
__func__, smux.rx_state, used, len);
initial_rx_state = smux.rx_state;
switch (smux.rx_state) {
case SMUX_RX_IDLE:
smux_rx_handle_idle(data, len, &used, flag);
break;
case SMUX_RX_MAGIC:
smux_rx_handle_magic(data, len, &used, flag);
break;
case SMUX_RX_HDR:
smux_rx_handle_hdr(data, len, &used, flag);
break;
case SMUX_RX_PAYLOAD:
smux_rx_handle_pkt_payload(data, len, &used, flag);
break;
default:
SMUX_DBG("smux: %s: invalid state %d\n",
__func__, smux.rx_state);
smux.rx_state = SMUX_RX_IDLE;
break;
}
} while (used < len || smux.rx_state != initial_rx_state);
complete(&w->work_complete);
}
/**
* RX Retry worker handles retrying get_rx_buffer calls that previously failed
* because the client was not ready (-EAGAIN).
*
* @work Work structure contained in smux_lch_t structure
*/
static void smux_rx_retry_worker(struct work_struct *work)
{
struct smux_lch_t *ch;
struct smux_rx_pkt_retry *retry;
union notifier_metadata metadata;
int tmp;
unsigned long flags;
int immediate_retry = 0;
int tx_ready = 0;
ch = container_of(work, struct smux_lch_t, rx_retry_work.work);
/* get next retry packet */
spin_lock_irqsave(&ch->state_lock_lhb1, flags);
if ((ch->local_state != SMUX_LCH_LOCAL_OPENED) || smux.in_reset) {
/* port has been closed - remove all retries */
while (!list_empty(&ch->rx_retry_queue)) {
retry = list_first_entry(&ch->rx_retry_queue,
struct smux_rx_pkt_retry,
rx_retry_list);
(void)smux_remove_rx_retry(ch, retry);
}
}
if (list_empty(&ch->rx_retry_queue)) {
SMUX_DBG("smux: %s: retry list empty for channel %d\n",
__func__, ch->lcid);
spin_unlock_irqrestore(&ch->state_lock_lhb1, flags);
return;
}
retry = list_first_entry(&ch->rx_retry_queue,
struct smux_rx_pkt_retry,
rx_retry_list);
spin_unlock_irqrestore(&ch->state_lock_lhb1, flags);
SMUX_DBG("smux: %s: ch %d retrying rx pkt %p\n",
__func__, ch->lcid, retry);
metadata.read.pkt_priv = 0;
metadata.read.buffer = 0;
tmp = ch->get_rx_buffer(ch->priv,
(void **)&metadata.read.pkt_priv,
(void **)&metadata.read.buffer,
retry->pkt->hdr.payload_len);
if (tmp == 0 && metadata.read.buffer) {
/* have valid RX buffer */
memcpy(metadata.read.buffer, retry->pkt->payload,
retry->pkt->hdr.payload_len);
metadata.read.len = retry->pkt->hdr.payload_len;
spin_lock_irqsave(&ch->state_lock_lhb1, flags);
tx_ready = smux_remove_rx_retry(ch, retry);
spin_unlock_irqrestore(&ch->state_lock_lhb1, flags);
schedule_notify(ch->lcid, SMUX_READ_DONE, &metadata);
if (tx_ready)
list_channel(ch);
immediate_retry = 1;
} else if (tmp == -EAGAIN ||
(tmp == 0 && !metadata.read.buffer)) {
/* retry again */
retry->timeout_in_ms <<= 1;
if (retry->timeout_in_ms > SMUX_RX_RETRY_MAX_MS) {
/* timed out */
SMUX_ERR("%s: ch %d RX retry client timeout\n",
__func__, ch->lcid);
spin_lock_irqsave(&ch->state_lock_lhb1, flags);
tx_ready = smux_remove_rx_retry(ch, retry);
spin_unlock_irqrestore(&ch->state_lock_lhb1, flags);
schedule_notify(ch->lcid, SMUX_READ_FAIL, NULL);
if (tx_ready)
list_channel(ch);
}
} else {
/* client error - drop packet */
SMUX_ERR("%s: ch %d RX retry client failed (%d)\n",
__func__, ch->lcid, tmp);
spin_lock_irqsave(&ch->state_lock_lhb1, flags);
tx_ready = smux_remove_rx_retry(ch, retry);
spin_unlock_irqrestore(&ch->state_lock_lhb1, flags);
schedule_notify(ch->lcid, SMUX_READ_FAIL, NULL);
if (tx_ready)
list_channel(ch);
}
/* schedule next retry */
spin_lock_irqsave(&ch->state_lock_lhb1, flags);
if (!list_empty(&ch->rx_retry_queue)) {
retry = list_first_entry(&ch->rx_retry_queue,
struct smux_rx_pkt_retry,
rx_retry_list);
if (immediate_retry)
queue_delayed_work(smux_rx_wq, &ch->rx_retry_work, 0);
else
queue_delayed_work(smux_rx_wq, &ch->rx_retry_work,
msecs_to_jiffies(retry->timeout_in_ms));
}
spin_unlock_irqrestore(&ch->state_lock_lhb1, flags);
}
/**
* Transmit worker handles serializing and transmitting packets onto the
* underlying transport.
*
* @work Work structure (not used)
*/
static void smux_tx_worker(struct work_struct *work)
{
struct smux_pkt_t *pkt;
struct smux_lch_t *ch;
unsigned low_wm_notif;
unsigned lcid;
unsigned long flags;
/*
* Transmit packets in round-robin fashion based upon ready
* channels.
*
* To eliminate the need to hold a lock for the entire
* iteration through the channel ready list, the head of the
* ready-channel list is always the next channel to be
* processed. To send a packet, the first valid packet in
* the head channel is removed and the head channel is then
* rescheduled at the end of the queue by removing it and
* inserting after the tail. The locks can then be released
* while the packet is processed.
*/
while (!smux.in_reset) {
pkt = NULL;
low_wm_notif = 0;
spin_lock_irqsave(&smux.tx_lock_lha2, flags);
/* handle wakeup if needed */
if (smux.power_state == SMUX_PWR_OFF) {
if (!list_empty(&smux.lch_tx_ready_list) ||
!list_empty(&smux.power_queue)) {
/* data to transmit, do wakeup */
SMUX_PWR("smux: %s: Power %d->%d\n", __func__,
smux.power_state,
SMUX_PWR_TURNING_ON);
smux.power_state = SMUX_PWR_TURNING_ON;
spin_unlock_irqrestore(&smux.tx_lock_lha2,
flags);
queue_work(smux_tx_wq, &smux_wakeup_work);
} else {
/* no activity -- stay asleep */
spin_unlock_irqrestore(&smux.tx_lock_lha2,
flags);
}
break;
}
/* process any pending power packets */
if (!list_empty(&smux.power_queue)) {
pkt = list_first_entry(&smux.power_queue,
struct smux_pkt_t, list);
list_del(&pkt->list);
spin_unlock_irqrestore(&smux.tx_lock_lha2, flags);
/* Adjust power state if this is a flush command */
spin_lock_irqsave(&smux.tx_lock_lha2, flags);
if (smux.power_state == SMUX_PWR_TURNING_OFF_FLUSH &&
pkt->hdr.cmd == SMUX_CMD_PWR_CTL) {
if (pkt->hdr.flags & SMUX_CMD_PWR_CTL_ACK ||
smux.power_ctl_remote_req_received) {
/*
* Sending remote power-down request ACK
* or sending local power-down request
* and we already received a remote
* power-down request.
*/
SMUX_PWR(
"smux: %s: Power %d->%d\n", __func__,
smux.power_state,
SMUX_PWR_OFF_FLUSH);
smux.power_state = SMUX_PWR_OFF_FLUSH;
smux.power_ctl_remote_req_received = 0;
queue_work(smux_tx_wq,
&smux_inactivity_work);
} else {
/* sending local power-down request */
SMUX_PWR(
"smux: %s: Power %d->%d\n", __func__,
smux.power_state,
SMUX_PWR_TURNING_OFF);
smux.power_state = SMUX_PWR_TURNING_OFF;
}
}
spin_unlock_irqrestore(&smux.tx_lock_lha2, flags);
/* send the packet */
smux_uart_power_on();
smux.tx_activity_flag = 1;
SMUX_PWR_PKT_TX(pkt);
if (!smux_byte_loopback) {
smux_tx_tty(pkt);
smux_flush_tty();
} else {
smux_tx_loopback(pkt);
}
smux_free_pkt(pkt);
continue;
}
/* get the next ready channel */
if (list_empty(&smux.lch_tx_ready_list)) {
/* no ready channels */
SMUX_DBG("smux: %s: no more ready channels, exiting\n",
__func__);
spin_unlock_irqrestore(&smux.tx_lock_lha2, flags);
break;
}
smux.tx_activity_flag = 1;
if (smux.power_state != SMUX_PWR_ON) {
/* channel not ready to transmit */
SMUX_DBG("smux: %s: waiting for link up (state %d)\n",
__func__,
smux.power_state);
spin_unlock_irqrestore(&smux.tx_lock_lha2, flags);
break;
}
/* get the next packet to send and rotate channel list */
ch = list_first_entry(&smux.lch_tx_ready_list,
struct smux_lch_t,
tx_ready_list);
spin_lock(&ch->state_lock_lhb1);
spin_lock(&ch->tx_lock_lhb2);
if (!list_empty(&ch->tx_queue)) {
/*
* If remote TX flow control is enabled or
* the channel is not fully opened, then only
* send command packets.
*/
if (ch->tx_flow_control || !IS_FULLY_OPENED(ch)) {
struct smux_pkt_t *curr;
list_for_each_entry(curr, &ch->tx_queue, list) {
if (curr->hdr.cmd != SMUX_CMD_DATA) {
pkt = curr;
break;
}
}
} else {
/* get next cmd/data packet to send */
pkt = list_first_entry(&ch->tx_queue,
struct smux_pkt_t, list);
}
}
if (pkt) {
list_del(&pkt->list);
/* update packet stats */
if (pkt->hdr.cmd == SMUX_CMD_DATA) {
--ch->tx_pending_data_cnt;
if (ch->notify_lwm &&
ch->tx_pending_data_cnt
<= SMUX_TX_WM_LOW) {
ch->notify_lwm = 0;
low_wm_notif = 1;
}
}
/* advance to the next ready channel */
list_rotate_left(&smux.lch_tx_ready_list);
} else {
/* no data in channel to send, remove from ready list */
list_del(&ch->tx_ready_list);
INIT_LIST_HEAD(&ch->tx_ready_list);
}
lcid = ch->lcid;
spin_unlock(&ch->tx_lock_lhb2);
spin_unlock(&ch->state_lock_lhb1);
spin_unlock_irqrestore(&smux.tx_lock_lha2, flags);
if (low_wm_notif)
schedule_notify(lcid, SMUX_LOW_WM_HIT, NULL);
/* send the packet */
smux_tx_pkt(ch, pkt);
smux_free_pkt(pkt);
}
}
/**
* Update the RX flow control (sent in the TIOCM Status command).
*
* @ch Channel for update
*
* @returns 1 for updated, 0 for not updated
*
* Must be called with ch->state_lock_lhb1 locked.
*/
static int smux_rx_flow_control_updated(struct smux_lch_t *ch)
{
int updated = 0;
int prev_state;
prev_state = ch->local_tiocm & SMUX_CMD_STATUS_FLOW_CNTL;
if (ch->rx_flow_control_client || ch->rx_flow_control_auto)
ch->local_tiocm |= SMUX_CMD_STATUS_FLOW_CNTL;
else
ch->local_tiocm &= ~SMUX_CMD_STATUS_FLOW_CNTL;
if (prev_state != (ch->local_tiocm & SMUX_CMD_STATUS_FLOW_CNTL)) {
smux_send_status_cmd(ch);
updated = 1;
}
return updated;
}
/**
* Flush all SMUX workqueues.
*
* This sets the reset bit to abort any processing loops and then
* flushes the workqueues to ensure that no new pending work is
* running. Do not call with any locks used by workers held as
* this will result in a deadlock.
*/
static void smux_flush_workqueues(void)
{
smux.in_reset = 1;
SMUX_DBG("smux: %s: flushing tx wq\n", __func__);
flush_workqueue(smux_tx_wq);
SMUX_DBG("smux: %s: flushing rx wq\n", __func__);
flush_workqueue(smux_rx_wq);
SMUX_DBG("smux: %s: flushing notify wq\n", __func__);
flush_workqueue(smux_notify_wq);
}
/**********************************************************************/
/* Kernel API */
/**********************************************************************/
/**
* Set or clear channel option using the SMUX_CH_OPTION_* channel
* flags.
*
* @lcid Logical channel ID
* @set Options to set
* @clear Options to clear
*
* @returns 0 for success, < 0 for failure
*/
int msm_smux_set_ch_option(uint8_t lcid, uint32_t set, uint32_t clear)
{
unsigned long flags;
struct smux_lch_t *ch;
int tx_ready = 0;
int ret = 0;
if (smux_assert_lch_id(lcid))
return -ENXIO;
ch = &smux_lch[lcid];
spin_lock_irqsave(&ch->state_lock_lhb1, flags);
/* Local loopback mode */
if (set & SMUX_CH_OPTION_LOCAL_LOOPBACK)
ch->local_mode = SMUX_LCH_MODE_LOCAL_LOOPBACK;
if (clear & SMUX_CH_OPTION_LOCAL_LOOPBACK)
ch->local_mode = SMUX_LCH_MODE_NORMAL;
/* Remote loopback mode */
if (set & SMUX_CH_OPTION_REMOTE_LOOPBACK)
ch->local_mode = SMUX_LCH_MODE_REMOTE_LOOPBACK;
if (clear & SMUX_CH_OPTION_REMOTE_LOOPBACK)
ch->local_mode = SMUX_LCH_MODE_NORMAL;
/* RX Flow control */
if (set & SMUX_CH_OPTION_REMOTE_TX_STOP) {
ch->rx_flow_control_client = 1;
tx_ready |= smux_rx_flow_control_updated(ch);
}
if (clear & SMUX_CH_OPTION_REMOTE_TX_STOP) {
ch->rx_flow_control_client = 0;
tx_ready |= smux_rx_flow_control_updated(ch);
}
/* Auto RX Flow Control */
if (set & SMUX_CH_OPTION_AUTO_REMOTE_TX_STOP) {
SMUX_DBG("smux: %s: auto rx flow control option enabled\n",
__func__);
ch->options |= SMUX_CH_OPTION_AUTO_REMOTE_TX_STOP;
}
if (clear & SMUX_CH_OPTION_AUTO_REMOTE_TX_STOP) {
SMUX_DBG("smux: %s: auto rx flow control option disabled\n",
__func__);
ch->options &= ~SMUX_CH_OPTION_AUTO_REMOTE_TX_STOP;
ch->rx_flow_control_auto = 0;
tx_ready |= smux_rx_flow_control_updated(ch);
}
spin_unlock_irqrestore(&ch->state_lock_lhb1, flags);
if (tx_ready)
list_channel(ch);
return ret;
}
/**
* Starts the opening sequence for a logical channel.
*
* @lcid Logical channel ID
* @priv Free for client usage
* @notify Event notification function
* @get_rx_buffer Function used to provide a receive buffer to SMUX
*
* @returns 0 for success, <0 otherwise
*
* A channel must be fully closed (either not previously opened or
* msm_smux_close() has been called and the SMUX_DISCONNECTED has been
* received.
*
* One the remote side is opened, the client will receive a SMUX_CONNECTED
* event.
*/
int msm_smux_open(uint8_t lcid, void *priv,
void (*notify)(void *priv, int event_type, const void *metadata),
int (*get_rx_buffer)(void *priv, void **pkt_priv, void **buffer,
int size))
{
int ret;
struct smux_lch_t *ch;
struct smux_pkt_t *pkt;
int tx_ready = 0;
unsigned long flags;
if (smux_assert_lch_id(lcid))
return -ENXIO;
ch = &smux_lch[lcid];
spin_lock_irqsave(&ch->state_lock_lhb1, flags);
if (ch->local_state == SMUX_LCH_LOCAL_CLOSING) {
ret = -EAGAIN;
goto out;
}
if (ch->local_state != SMUX_LCH_LOCAL_CLOSED) {
SMUX_ERR("%s: open lcid %d local state %x invalid\n",
__func__, lcid, ch->local_state);
ret = -EINVAL;
goto out;
}
SMUX_DBG("smux: lcid %d local state 0x%x -> 0x%x\n", lcid,
ch->local_state,
SMUX_LCH_LOCAL_OPENING);
ch->rx_flow_control_auto = 0;
ch->local_state = SMUX_LCH_LOCAL_OPENING;
ch->priv = priv;
ch->notify = notify;
ch->get_rx_buffer = get_rx_buffer;
ret = 0;
/* Send Open Command */
pkt = smux_alloc_pkt();
if (!pkt) {
ret = -ENOMEM;
goto out;
}
pkt->hdr.magic = SMUX_MAGIC;
pkt->hdr.cmd = SMUX_CMD_OPEN_LCH;
pkt->hdr.flags = SMUX_CMD_OPEN_POWER_COLLAPSE;
if (ch->local_mode == SMUX_LCH_MODE_REMOTE_LOOPBACK)
pkt->hdr.flags |= SMUX_CMD_OPEN_REMOTE_LOOPBACK;
pkt->hdr.lcid = lcid;
pkt->hdr.payload_len = 0;
pkt->hdr.pad_len = 0;
smux_tx_queue(pkt, ch, 0);
tx_ready = 1;
out:
spin_unlock_irqrestore(&ch->state_lock_lhb1, flags);
smux_rx_flow_control_updated(ch);
if (tx_ready)
list_channel(ch);
return ret;
}
/**
* Starts the closing sequence for a logical channel.
*
* @lcid Logical channel ID
*
* @returns 0 for success, <0 otherwise
*
* Once the close event has been acknowledge by the remote side, the client
* will receive a SMUX_DISCONNECTED notification.
*/
int msm_smux_close(uint8_t lcid)
{
int ret = 0;
struct smux_lch_t *ch;
struct smux_pkt_t *pkt;
int tx_ready = 0;
unsigned long flags;
if (smux_assert_lch_id(lcid))
return -ENXIO;
ch = &smux_lch[lcid];
spin_lock_irqsave(&ch->state_lock_lhb1, flags);
ch->local_tiocm = 0x0;
ch->remote_tiocm = 0x0;
ch->tx_pending_data_cnt = 0;
ch->notify_lwm = 0;
ch->tx_flow_control = 0;
/* Purge TX queue */
spin_lock(&ch->tx_lock_lhb2);
smux_purge_ch_tx_queue(ch, 0);
spin_unlock(&ch->tx_lock_lhb2);
/* Send Close Command */
if (ch->local_state == SMUX_LCH_LOCAL_OPENED ||
ch->local_state == SMUX_LCH_LOCAL_OPENING) {
SMUX_DBG("smux: lcid %d local state 0x%x -> 0x%x\n", lcid,
ch->local_state,
SMUX_LCH_LOCAL_CLOSING);
ch->local_state = SMUX_LCH_LOCAL_CLOSING;
pkt = smux_alloc_pkt();
if (pkt) {
pkt->hdr.cmd = SMUX_CMD_CLOSE_LCH;
pkt->hdr.flags = 0;
pkt->hdr.lcid = lcid;
pkt->hdr.payload_len = 0;
pkt->hdr.pad_len = 0;
smux_tx_queue(pkt, ch, 0);
tx_ready = 1;
} else {
SMUX_ERR("%s: pkt allocation failed\n", __func__);
ret = -ENOMEM;
}
/* Purge RX retry queue */
if (ch->rx_retry_queue_cnt)
queue_delayed_work(smux_rx_wq, &ch->rx_retry_work, 0);
}
spin_unlock_irqrestore(&ch->state_lock_lhb1, flags);
if (tx_ready)
list_channel(ch);
return ret;
}
/**
* Write data to a logical channel.
*
* @lcid Logical channel ID
* @pkt_priv Client data that will be returned with the SMUX_WRITE_DONE or
* SMUX_WRITE_FAIL notification.
* @data Data to write
* @len Length of @data
*
* @returns 0 for success, <0 otherwise
*
* Data may be written immediately after msm_smux_open() is called,
* but the data will wait in the transmit queue until the channel has
* been fully opened.
*
* Once the data has been written, the client will receive either a completion
* (SMUX_WRITE_DONE) or a failure notice (SMUX_WRITE_FAIL).
*/
int msm_smux_write(uint8_t lcid, void *pkt_priv, const void *data, int len)
{
struct smux_lch_t *ch;
struct smux_pkt_t *pkt;
int tx_ready = 0;
unsigned long flags;
int ret;
if (smux_assert_lch_id(lcid))
return -ENXIO;
ch = &smux_lch[lcid];
spin_lock_irqsave(&ch->state_lock_lhb1, flags);
if (ch->local_state != SMUX_LCH_LOCAL_OPENED &&
ch->local_state != SMUX_LCH_LOCAL_OPENING) {
SMUX_ERR("%s: hdr.invalid local state %d channel %d\n",
__func__, ch->local_state, lcid);
ret = -EINVAL;
goto out;
}
if (len > SMUX_MAX_PKT_SIZE - sizeof(struct smux_hdr_t)) {
SMUX_ERR("%s: payload %d too large\n",
__func__, len);
ret = -E2BIG;
goto out;
}
pkt = smux_alloc_pkt();
if (!pkt) {
ret = -ENOMEM;
goto out;
}
pkt->hdr.cmd = SMUX_CMD_DATA;
pkt->hdr.lcid = lcid;
pkt->hdr.flags = 0;
pkt->hdr.payload_len = len;
pkt->payload = (void *)data;
pkt->priv = pkt_priv;
pkt->hdr.pad_len = 0;
spin_lock(&ch->tx_lock_lhb2);
/* verify high watermark */
SMUX_DBG("smux: %s: pending %d", __func__, ch->tx_pending_data_cnt);
if (ch->tx_pending_data_cnt >= SMUX_TX_WM_HIGH) {
SMUX_ERR("%s: ch %d high watermark %d exceeded %d\n",
__func__, lcid, SMUX_TX_WM_HIGH,
ch->tx_pending_data_cnt);
ret = -EAGAIN;
goto out_inner;
}
/* queue packet for transmit */
if (++ch->tx_pending_data_cnt == SMUX_TX_WM_HIGH) {
ch->notify_lwm = 1;
SMUX_ERR("%s: high watermark hit\n", __func__);
schedule_notify(lcid, SMUX_HIGH_WM_HIT, NULL);
}
list_add_tail(&pkt->list, &ch->tx_queue);
/* add to ready list */
if (IS_FULLY_OPENED(ch))
tx_ready = 1;
ret = 0;
out_inner:
spin_unlock(&ch->tx_lock_lhb2);
out:
if (ret)
smux_free_pkt(pkt);
spin_unlock_irqrestore(&ch->state_lock_lhb1, flags);
if (tx_ready)
list_channel(ch);
return ret;
}
/**
* Returns true if the TX queue is currently full (high water mark).
*
* @lcid Logical channel ID
* @returns 0 if channel is not full
* 1 if it is full
* < 0 for error
*/
int msm_smux_is_ch_full(uint8_t lcid)
{
struct smux_lch_t *ch;
unsigned long flags;
int is_full = 0;
if (smux_assert_lch_id(lcid))
return -ENXIO;
ch = &smux_lch[lcid];
spin_lock_irqsave(&ch->tx_lock_lhb2, flags);
if (ch->tx_pending_data_cnt >= SMUX_TX_WM_HIGH)
is_full = 1;
spin_unlock_irqrestore(&ch->tx_lock_lhb2, flags);
return is_full;
}
/**
* Returns true if the TX queue has space for more packets it is at or
* below the low water mark).
*
* @lcid Logical channel ID
* @returns 0 if channel is above low watermark
* 1 if it's at or below the low watermark
* < 0 for error
*/
int msm_smux_is_ch_low(uint8_t lcid)
{
struct smux_lch_t *ch;
unsigned long flags;
int is_low = 0;
if (smux_assert_lch_id(lcid))
return -ENXIO;
ch = &smux_lch[lcid];
spin_lock_irqsave(&ch->tx_lock_lhb2, flags);
if (ch->tx_pending_data_cnt <= SMUX_TX_WM_LOW)
is_low = 1;
spin_unlock_irqrestore(&ch->tx_lock_lhb2, flags);
return is_low;
}
/**
* Send TIOCM status update.
*
* @ch Channel for update
*
* @returns 0 for success, <0 for failure
*
* Channel lock must be held before calling.
*/
static int smux_send_status_cmd(struct smux_lch_t *ch)
{
struct smux_pkt_t *pkt;
if (!ch)
return -EINVAL;
pkt = smux_alloc_pkt();
if (!pkt)
return -ENOMEM;
pkt->hdr.lcid = ch->lcid;
pkt->hdr.cmd = SMUX_CMD_STATUS;
pkt->hdr.flags = ch->local_tiocm;
pkt->hdr.payload_len = 0;
pkt->hdr.pad_len = 0;
smux_tx_queue(pkt, ch, 0);
return 0;
}
/**
* Internal helper function for getting the TIOCM status with
* state_lock_lhb1 already locked.
*
* @ch Channel pointer
*
* @returns TIOCM status
*/
long msm_smux_tiocm_get_atomic(struct smux_lch_t *ch)
{
long status = 0x0;
status |= (ch->remote_tiocm & SMUX_CMD_STATUS_RTC) ? TIOCM_DSR : 0;
status |= (ch->remote_tiocm & SMUX_CMD_STATUS_RTR) ? TIOCM_CTS : 0;
status |= (ch->remote_tiocm & SMUX_CMD_STATUS_RI) ? TIOCM_RI : 0;
status |= (ch->remote_tiocm & SMUX_CMD_STATUS_DCD) ? TIOCM_CD : 0;
status |= (ch->local_tiocm & SMUX_CMD_STATUS_RTC) ? TIOCM_DTR : 0;
status |= (ch->local_tiocm & SMUX_CMD_STATUS_RTR) ? TIOCM_RTS : 0;
return status;
}
/**
* Get the TIOCM status bits.
*
* @lcid Logical channel ID
*
* @returns >= 0 TIOCM status bits
* < 0 Error condition
*/
long msm_smux_tiocm_get(uint8_t lcid)
{
struct smux_lch_t *ch;
unsigned long flags;
long status = 0x0;
if (smux_assert_lch_id(lcid))
return -ENXIO;
ch = &smux_lch[lcid];
spin_lock_irqsave(&ch->state_lock_lhb1, flags);
status = msm_smux_tiocm_get_atomic(ch);
spin_unlock_irqrestore(&ch->state_lock_lhb1, flags);
return status;
}
/**
* Set/clear the TIOCM status bits.
*
* @lcid Logical channel ID
* @set Bits to set
* @clear Bits to clear
*
* @returns 0 for success; < 0 for failure
*
* If a bit is specified in both the @set and @clear masks, then the clear bit
* definition will dominate and the bit will be cleared.
*/
int msm_smux_tiocm_set(uint8_t lcid, uint32_t set, uint32_t clear)
{
struct smux_lch_t *ch;
unsigned long flags;
uint8_t old_status;
uint8_t status_set = 0x0;
uint8_t status_clear = 0x0;
int tx_ready = 0;
int ret = 0;
if (smux_assert_lch_id(lcid))
return -ENXIO;
ch = &smux_lch[lcid];
spin_lock_irqsave(&ch->state_lock_lhb1, flags);
status_set |= (set & TIOCM_DTR) ? SMUX_CMD_STATUS_RTC : 0;
status_set |= (set & TIOCM_RTS) ? SMUX_CMD_STATUS_RTR : 0;
status_set |= (set & TIOCM_RI) ? SMUX_CMD_STATUS_RI : 0;
status_set |= (set & TIOCM_CD) ? SMUX_CMD_STATUS_DCD : 0;
status_clear |= (clear & TIOCM_DTR) ? SMUX_CMD_STATUS_RTC : 0;
status_clear |= (clear & TIOCM_RTS) ? SMUX_CMD_STATUS_RTR : 0;
status_clear |= (clear & TIOCM_RI) ? SMUX_CMD_STATUS_RI : 0;
status_clear |= (clear & TIOCM_CD) ? SMUX_CMD_STATUS_DCD : 0;
old_status = ch->local_tiocm;
ch->local_tiocm |= status_set;
ch->local_tiocm &= ~status_clear;
if (ch->local_tiocm != old_status) {
ret = smux_send_status_cmd(ch);
tx_ready = 1;
}
spin_unlock_irqrestore(&ch->state_lock_lhb1, flags);
if (tx_ready)
list_channel(ch);
return ret;
}
/**********************************************************************/
/* Subsystem Restart */
/**********************************************************************/
static struct notifier_block ssr_notifier = {
.notifier_call = ssr_notifier_cb,
};
/**
* Handle Subsystem Restart (SSR) notifications.
*
* @this Pointer to ssr_notifier
* @code SSR Code
* @data Data pointer (not used)
*/
static int ssr_notifier_cb(struct notifier_block *this,
unsigned long code,
void *data)
{
unsigned long flags;
int i;
int tmp;
int power_off_uart = 0;
if (code == SUBSYS_BEFORE_SHUTDOWN) {
SMUX_DBG("smux: %s: ssr - before shutdown\n", __func__);
mutex_lock(&smux.mutex_lha0);
smux.in_reset = 1;
smux.remote_is_alive = 0;
mutex_unlock(&smux.mutex_lha0);
return NOTIFY_DONE;
} else if (code == SUBSYS_AFTER_POWERUP) {
/* re-register platform devices */
SMUX_DBG("smux: %s: ssr - after power-up\n", __func__);
mutex_lock(&smux.mutex_lha0);
if (smux.ld_open_count > 0
&& !smux.platform_devs_registered) {
for (i = 0; i < ARRAY_SIZE(smux_devs); ++i) {
SMUX_DBG("smux: %s: register pdev '%s'\n",
__func__, smux_devs[i].name);
smux_devs[i].dev.release = smux_pdev_release;
tmp = platform_device_register(&smux_devs[i]);
if (tmp)
SMUX_ERR(
"%s: error %d registering device %s\n",
__func__, tmp, smux_devs[i].name);
}
smux.platform_devs_registered = 1;
}
mutex_unlock(&smux.mutex_lha0);
return NOTIFY_DONE;
} else if (code != SUBSYS_AFTER_SHUTDOWN) {
return NOTIFY_DONE;
}
SMUX_DBG("smux: %s: ssr - after shutdown\n", __func__);
/* Cleanup channels */
smux_flush_workqueues();
mutex_lock(&smux.mutex_lha0);
if (smux.ld_open_count > 0) {
smux_lch_purge();
if (smux.tty)
tty_driver_flush_buffer(smux.tty);
/* Unregister platform devices */
if (smux.platform_devs_registered) {
for (i = 0; i < ARRAY_SIZE(smux_devs); ++i) {
SMUX_DBG("smux: %s: unregister pdev '%s'\n",
__func__, smux_devs[i].name);
platform_device_unregister(&smux_devs[i]);
}
smux.platform_devs_registered = 0;
}
/* Power-down UART */
spin_lock_irqsave(&smux.tx_lock_lha2, flags);
if (smux.power_state != SMUX_PWR_OFF) {
SMUX_PWR("smux: %s: SSR - turning off UART\n",
__func__);
smux.power_state = SMUX_PWR_OFF;
power_off_uart = 1;
}
smux.powerdown_enabled = 0;
spin_unlock_irqrestore(&smux.tx_lock_lha2, flags);
if (power_off_uart)
smux_uart_power_off_atomic();
}
smux.tx_activity_flag = 0;
smux.rx_activity_flag = 0;
smux.rx_state = SMUX_RX_IDLE;
smux.in_reset = 0;
smux.remote_is_alive = 0;
mutex_unlock(&smux.mutex_lha0);
return NOTIFY_DONE;
}
/**********************************************************************/
/* Line Discipline Interface */
/**********************************************************************/
static void smux_pdev_release(struct device *dev)
{
struct platform_device *pdev;
pdev = container_of(dev, struct platform_device, dev);
SMUX_DBG("smux: %s: releasing pdev %p '%s'\n",
__func__, pdev, pdev->name);
memset(&pdev->dev, 0x0, sizeof(pdev->dev));
}
static int smuxld_open(struct tty_struct *tty)
{
int i;
int tmp;
unsigned long flags;
if (!smux.is_initialized)
return -ENODEV;
mutex_lock(&smux.mutex_lha0);
if (smux.ld_open_count) {
SMUX_ERR("%s: %p multiple instances not supported\n",
__func__, tty);
mutex_unlock(&smux.mutex_lha0);
return -EEXIST;
}
if (tty->ops->write == NULL) {
SMUX_ERR("%s: tty->ops->write already NULL\n", __func__);
mutex_unlock(&smux.mutex_lha0);
return -EINVAL;
}
/* connect to TTY */
++smux.ld_open_count;
smux.in_reset = 0;
smux.tty = tty;
tty->disc_data = &smux;
tty->receive_room = TTY_RECEIVE_ROOM;
tty_driver_flush_buffer(tty);
/* power-down the UART if we are idle */
spin_lock_irqsave(&smux.tx_lock_lha2, flags);
if (smux.power_state == SMUX_PWR_OFF) {
SMUX_PWR("smux: %s: powering off uart\n", __func__);
smux.power_state = SMUX_PWR_OFF_FLUSH;
spin_unlock_irqrestore(&smux.tx_lock_lha2, flags);
queue_work(smux_tx_wq, &smux_inactivity_work);
} else {
spin_unlock_irqrestore(&smux.tx_lock_lha2, flags);
}
/* register platform devices */
for (i = 0; i < ARRAY_SIZE(smux_devs); ++i) {
SMUX_DBG("smux: %s: register pdev '%s'\n",
__func__, smux_devs[i].name);
smux_devs[i].dev.release = smux_pdev_release;
tmp = platform_device_register(&smux_devs[i]);
if (tmp)
SMUX_ERR("%s: error %d registering device %s\n",
__func__, tmp, smux_devs[i].name);
}
smux.platform_devs_registered = 1;
mutex_unlock(&smux.mutex_lha0);
return 0;
}
static void smuxld_close(struct tty_struct *tty)
{
unsigned long flags;
int power_up_uart = 0;
int i;
SMUX_DBG("smux: %s: ldisc unload\n", __func__);
smux_flush_workqueues();
mutex_lock(&smux.mutex_lha0);
if (smux.ld_open_count <= 0) {
SMUX_ERR("%s: invalid ld count %d\n", __func__,
smux.ld_open_count);
mutex_unlock(&smux.mutex_lha0);
return;
}
--smux.ld_open_count;
/* Cleanup channels */
smux_lch_purge();
/* Unregister platform devices */
if (smux.platform_devs_registered) {
for (i = 0; i < ARRAY_SIZE(smux_devs); ++i) {
SMUX_DBG("smux: %s: unregister pdev '%s'\n",
__func__, smux_devs[i].name);
platform_device_unregister(&smux_devs[i]);
}
smux.platform_devs_registered = 0;
}
/* Schedule UART power-up if it's down */
spin_lock_irqsave(&smux.tx_lock_lha2, flags);
if (smux.power_state == SMUX_PWR_OFF)
power_up_uart = 1;
smux.power_state = SMUX_PWR_OFF;
smux.powerdown_enabled = 0;
smux.tx_activity_flag = 0;
smux.rx_activity_flag = 0;
spin_unlock_irqrestore(&smux.tx_lock_lha2, flags);
if (power_up_uart)
smux_uart_power_on_atomic();
smux.rx_state = SMUX_RX_IDLE;
/* Disconnect from TTY */
smux.tty = NULL;
smux.remote_is_alive = 0;
mutex_unlock(&smux.mutex_lha0);
SMUX_DBG("smux: %s: ldisc complete\n", __func__);
}
/**
* Receive data from TTY Line Discipline.
*
* @tty TTY structure
* @cp Character data
* @fp Flag data
* @count Size of character and flag data
*/
void smuxld_receive_buf(struct tty_struct *tty, const unsigned char *cp,
char *fp, int count)
{
int i;
int last_idx = 0;
const char *tty_name = NULL;
char *f;
/* verify error flags */
for (i = 0, f = fp; i < count; ++i, ++f) {
if (*f != TTY_NORMAL) {
if (tty)
tty_name = tty->name;
SMUX_ERR("%s: TTY %s Error %d (%s)\n", __func__,
tty_name, *f, tty_flag_to_str(*f));
/* feed all previous valid data to the parser */
smux_rx_state_machine(cp + last_idx, i - last_idx,
TTY_NORMAL);
/* feed bad data to parser */
smux_rx_state_machine(cp + i, 1, *f);
last_idx = i + 1;
}
}
/* feed data to RX state machine */
smux_rx_state_machine(cp + last_idx, count - last_idx, TTY_NORMAL);
}
static void smuxld_flush_buffer(struct tty_struct *tty)
{
SMUX_ERR("%s: not supported\n", __func__);
}
static ssize_t smuxld_chars_in_buffer(struct tty_struct *tty)
{
SMUX_ERR("%s: not supported\n", __func__);
return -ENODEV;
}
static ssize_t smuxld_read(struct tty_struct *tty, struct file *file,
unsigned char __user *buf, size_t nr)
{
SMUX_ERR("%s: not supported\n", __func__);
return -ENODEV;
}
static ssize_t smuxld_write(struct tty_struct *tty, struct file *file,
const unsigned char *buf, size_t nr)
{
SMUX_ERR("%s: not supported\n", __func__);
return -ENODEV;
}
static int smuxld_ioctl(struct tty_struct *tty, struct file *file,
unsigned int cmd, unsigned long arg)
{
SMUX_ERR("%s: not supported\n", __func__);
return -ENODEV;
}
static unsigned int smuxld_poll(struct tty_struct *tty, struct file *file,
struct poll_table_struct *tbl)
{
SMUX_ERR("%s: not supported\n", __func__);
return -ENODEV;
}
static void smuxld_write_wakeup(struct tty_struct *tty)
{
SMUX_ERR("%s: not supported\n", __func__);
}
static struct tty_ldisc_ops smux_ldisc_ops = {
.owner = THIS_MODULE,
.magic = TTY_LDISC_MAGIC,
.name = "n_smux",
.open = smuxld_open,
.close = smuxld_close,
.flush_buffer = smuxld_flush_buffer,
.chars_in_buffer = smuxld_chars_in_buffer,
.read = smuxld_read,
.write = smuxld_write,
.ioctl = smuxld_ioctl,
.poll = smuxld_poll,
.receive_buf = smuxld_receive_buf,
.write_wakeup = smuxld_write_wakeup
};
static int __init smux_init(void)
{
int ret;
mutex_init(&smux.mutex_lha0);
spin_lock_init(&smux.rx_lock_lha1);
smux.rx_state = SMUX_RX_IDLE;
smux.power_state = SMUX_PWR_OFF;
smux.pwr_wakeup_delay_us = 1;
smux.powerdown_enabled = 0;
smux.power_ctl_remote_req_received = 0;
INIT_LIST_HEAD(&smux.power_queue);
smux.rx_activity_flag = 0;
smux.tx_activity_flag = 0;
smux.recv_len = 0;
smux.tty = NULL;
smux.ld_open_count = 0;
smux.in_reset = 0;
smux.remote_is_alive = 0;
smux.is_initialized = 1;
smux.platform_devs_registered = 0;
smux_byte_loopback = 0;
spin_lock_init(&smux.tx_lock_lha2);
INIT_LIST_HEAD(&smux.lch_tx_ready_list);
ret = tty_register_ldisc(N_SMUX, &smux_ldisc_ops);
if (ret != 0) {
SMUX_ERR("%s: error %d registering line discipline\n",
__func__, ret);
return ret;
}
subsys_notif_register_notifier("external_modem", &ssr_notifier);
ret = lch_init();
if (ret != 0) {
SMUX_ERR("%s: lch_init failed\n", __func__);
return ret;
}
log_ctx = ipc_log_context_create(1, "smux");
if (!log_ctx) {
SMUX_ERR("%s: unable to create log context\n", __func__);
disable_ipc_logging = 1;
}
return 0;
}
static void __exit smux_exit(void)
{
int ret;
ret = tty_unregister_ldisc(N_SMUX);
if (ret != 0) {
SMUX_ERR("%s error %d unregistering line discipline\n",
__func__, ret);
return;
}
}
module_init(smux_init);
module_exit(smux_exit);
MODULE_DESCRIPTION("Serial Mux TTY Line Discipline");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS_LDISC(N_SMUX);