libertas: convert libertas driver to use an event/cmdresp queue
This patch (co-developed by Dan Williams and Holger Schurig) uses a kfifo
object for events and a swapping buffer scheme for the command response to
preserve the zero-copy semantics of the CF driver and keep memory usage low.
The main thread should only ever touch the buffer indexed by priv->resp_idx,
while the interface code is free to write to the second buffer, then swap
priv->resp_idx under the driver spinlock. The firmware specs only permit
one in-flight command, so there will only ever be one command response to
process at a time.
Signed-off-by: Holger Schurig <hs4233@mail.mn-solutions.de>
Signed-off-by: Dan Williams <dcbw@redhat.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/libertas/main.c b/drivers/net/wireless/libertas/main.c
index 8f11226..406f54d 100644
--- a/drivers/net/wireless/libertas/main.c
+++ b/drivers/net/wireless/libertas/main.c
@@ -10,6 +10,7 @@
#include <linux/netdevice.h>
#include <linux/if_arp.h>
#include <linux/kthread.h>
+#include <linux/kfifo.h>
#include <net/iw_handler.h>
#include <net/ieee80211.h>
@@ -480,10 +481,9 @@
dev->trans_start = jiffies;
- if (priv->currenttxskb) {
- priv->eventcause = 0x01000000;
- lbs_send_tx_feedback(priv);
- }
+ if (priv->currenttxskb)
+ lbs_send_tx_feedback(priv, 0);
+
/* XX: Shouldn't we also call into the hw-specific driver
to kick it somehow? */
lbs_host_to_card_done(priv);
@@ -659,7 +659,6 @@
struct net_device *dev = data;
struct lbs_private *priv = dev->priv;
wait_queue_t wait;
- u8 ireg = 0;
lbs_deb_enter(LBS_DEB_THREAD);
@@ -667,9 +666,10 @@
for (;;) {
int shouldsleep;
+ u8 resp_idx;
- lbs_deb_thread( "main-thread 111: intcounter=%d currenttxskb=%p dnld_sent=%d\n",
- priv->intcounter, priv->currenttxskb, priv->dnld_sent);
+ lbs_deb_thread("1: currenttxskb %p, dnld_sent %d\n",
+ priv->currenttxskb, priv->dnld_sent);
add_wait_queue(&priv->waitq, &wait);
set_current_state(TASK_INTERRUPTIBLE);
@@ -681,8 +681,6 @@
shouldsleep = 1; /* We need to wait until we're _told_ to die */
else if (priv->psstate == PS_STATE_SLEEP)
shouldsleep = 1; /* Sleep mode. Nothing we can do till it wakes */
- else if (priv->intcounter)
- shouldsleep = 0; /* Interrupt pending. Deal with it now */
else if (priv->cmd_timed_out)
shouldsleep = 0; /* Command timed out. Recover */
else if (!priv->fw_ready)
@@ -695,29 +693,34 @@
shouldsleep = 1; /* Can't send a command; one already running */
else if (!list_empty(&priv->cmdpendingq))
shouldsleep = 0; /* We have a command to send */
+ else if (__kfifo_len(priv->event_fifo))
+ shouldsleep = 0; /* We have an event to process */
+ else if (priv->resp_len[priv->resp_idx])
+ shouldsleep = 0; /* We have a command response */
else
shouldsleep = 1; /* No command */
if (shouldsleep) {
- lbs_deb_thread("main-thread sleeping... Conn=%d IntC=%d PS_mode=%d PS_State=%d\n",
- priv->connect_status, priv->intcounter,
- priv->psmode, priv->psstate);
+ lbs_deb_thread("sleeping, connect_status %d, "
+ "ps_mode %d, ps_state %d\n",
+ priv->connect_status,
+ priv->psmode, priv->psstate);
spin_unlock_irq(&priv->driver_lock);
schedule();
} else
spin_unlock_irq(&priv->driver_lock);
- lbs_deb_thread("main-thread 222 (waking up): intcounter=%d currenttxskb=%p dnld_sent=%d\n",
- priv->intcounter, priv->currenttxskb, priv->dnld_sent);
+ lbs_deb_thread("2: currenttxskb %p, dnld_send %d\n",
+ priv->currenttxskb, priv->dnld_sent);
set_current_state(TASK_RUNNING);
remove_wait_queue(&priv->waitq, &wait);
- lbs_deb_thread("main-thread 333: intcounter=%d currenttxskb=%p dnld_sent=%d\n",
- priv->intcounter, priv->currenttxskb, priv->dnld_sent);
+ lbs_deb_thread("3: currenttxskb %p, dnld_sent %d\n",
+ priv->currenttxskb, priv->dnld_sent);
if (kthread_should_stop()) {
- lbs_deb_thread("main-thread: break from main thread\n");
+ lbs_deb_thread("break from main thread\n");
break;
}
@@ -726,35 +729,23 @@
continue;
}
+ lbs_deb_thread("4: currenttxskb %p, dnld_sent %d\n",
+ priv->currenttxskb, priv->dnld_sent);
+
spin_lock_irq(&priv->driver_lock);
-
- if (priv->intcounter) {
- u8 int_status;
-
- priv->intcounter = 0;
- int_status = priv->hw_get_int_status(priv, &ireg);
-
- if (int_status) {
- lbs_deb_thread("main-thread: reading HOST_INT_STATUS_REG failed\n");
- spin_unlock_irq(&priv->driver_lock);
- continue;
- }
- priv->hisregcpy |= ireg;
- }
-
- lbs_deb_thread("main-thread 444: intcounter=%d currenttxskb=%p dnld_sent=%d\n",
- priv->intcounter, priv->currenttxskb, priv->dnld_sent);
-
- /* command response? */
- if (priv->hisregcpy & MRVDRV_CMD_UPLD_RDY) {
- lbs_deb_thread("main-thread: cmd response ready\n");
-
- priv->hisregcpy &= ~MRVDRV_CMD_UPLD_RDY;
+ /* Process any pending command response */
+ resp_idx = priv->resp_idx;
+ if (priv->resp_len[resp_idx]) {
spin_unlock_irq(&priv->driver_lock);
- lbs_process_rx_command(priv);
+ lbs_process_command_response(priv,
+ priv->resp_buf[resp_idx],
+ priv->resp_len[resp_idx]);
spin_lock_irq(&priv->driver_lock);
+ priv->resp_len[resp_idx] = 0;
}
+ spin_unlock_irq(&priv->driver_lock);
+ /* command timeout stuff */
if (priv->cmd_timed_out && priv->cur_cmd) {
struct cmd_ctrl_node *cmdnode = priv->cur_cmd;
@@ -775,21 +766,18 @@
}
priv->cmd_timed_out = 0;
- /* Any Card Event */
- if (priv->hisregcpy & MRVDRV_CARDEVENT) {
- lbs_deb_thread("main-thread: Card Event Activity\n");
+ /* Process hardware events, e.g. card removed, link lost */
+ spin_lock_irq(&priv->driver_lock);
+ while (__kfifo_len(priv->event_fifo)) {
+ u32 event;
- priv->hisregcpy &= ~MRVDRV_CARDEVENT;
-
- if (priv->hw_read_event_cause(priv)) {
- lbs_pr_alert("main-thread: hw_read_event_cause failed\n");
- spin_unlock_irq(&priv->driver_lock);
- continue;
- }
+ __kfifo_get(priv->event_fifo, (unsigned char *) &event,
+ sizeof(event));
spin_unlock_irq(&priv->driver_lock);
- lbs_process_event(priv);
- } else
- spin_unlock_irq(&priv->driver_lock);
+ lbs_process_event(priv, event);
+ spin_lock_irq(&priv->driver_lock);
+ }
+ spin_unlock_irq(&priv->driver_lock);
if (!priv->fw_ready)
continue;
@@ -798,8 +786,10 @@
if (priv->psstate == PS_STATE_PRE_SLEEP &&
!priv->dnld_sent && !priv->cur_cmd) {
if (priv->connect_status == LBS_CONNECTED) {
- lbs_deb_thread("main_thread: PRE_SLEEP--intcounter=%d currenttxskb=%p dnld_sent=%d cur_cmd=%p, confirm now\n",
- priv->intcounter, priv->currenttxskb, priv->dnld_sent, priv->cur_cmd);
+ lbs_deb_thread("pre-sleep, currenttxskb %p, "
+ "dnld_sent %d, cur_cmd %p\n",
+ priv->currenttxskb, priv->dnld_sent,
+ priv->cur_cmd);
lbs_ps_confirm_sleep(priv);
} else {
@@ -809,7 +799,8 @@
* after firmware fixes it
*/
priv->psstate = PS_STATE_AWAKE;
- lbs_pr_alert("main-thread: ignore PS_SleepConfirm in non-connected state\n");
+ lbs_pr_alert("ignore PS_SleepConfirm in "
+ "non-connected state\n");
}
}
@@ -1046,7 +1037,18 @@
/* Allocate the command buffers */
if (lbs_allocate_cmd_buffer(priv)) {
lbs_pr_err("Out of memory allocating command buffers\n");
- ret = -1;
+ ret = -ENOMEM;
+ goto out;
+ }
+ priv->resp_idx = 0;
+ priv->resp_len[0] = priv->resp_len[1] = 0;
+
+ /* Create the event FIFO */
+ priv->event_fifo = kfifo_alloc(sizeof(u32) * 16, GFP_KERNEL, NULL);
+ if (IS_ERR(priv->event_fifo)) {
+ lbs_pr_err("Out of memory allocating event FIFO buffer\n");
+ ret = -ENOMEM;
+ goto out;
}
out:
@@ -1060,6 +1062,8 @@
lbs_deb_enter(LBS_DEB_MAIN);
lbs_free_cmd_buffer(priv);
+ if (priv->event_fifo)
+ kfifo_free(priv->event_fifo);
del_timer(&priv->command_timer);
kfree(priv->networks);
priv->networks = NULL;
@@ -1434,27 +1438,41 @@
return ret;
}
-/**
- * @brief This function handles the interrupt. it will change PS
- * state if applicable. it will wake up main_thread to handle
- * the interrupt event as well.
- *
- * @param dev A pointer to net_device structure
- * @return n/a
- */
-void lbs_interrupt(struct lbs_private *priv)
+void lbs_queue_event(struct lbs_private *priv, u32 event)
+{
+ unsigned long flags;
+
+ lbs_deb_enter(LBS_DEB_THREAD);
+ spin_lock_irqsave(&priv->driver_lock, flags);
+
+ if (priv->psstate == PS_STATE_SLEEP)
+ priv->psstate = PS_STATE_AWAKE;
+
+ __kfifo_put(priv->event_fifo, (unsigned char *) &event, sizeof(u32));
+
+ wake_up_interruptible(&priv->waitq);
+
+ spin_unlock_irqrestore(&priv->driver_lock, flags);
+ lbs_deb_leave(LBS_DEB_THREAD);
+}
+EXPORT_SYMBOL_GPL(lbs_queue_event);
+
+void lbs_notify_command_response(struct lbs_private *priv, u8 resp_idx)
{
lbs_deb_enter(LBS_DEB_THREAD);
- lbs_deb_thread("lbs_interrupt: intcounter=%d\n", priv->intcounter);
- priv->intcounter++;
if (priv->psstate == PS_STATE_SLEEP)
priv->psstate = PS_STATE_AWAKE;
+
+ /* Swap buffers by flipping the response index */
+ BUG_ON(resp_idx > 1);
+ priv->resp_idx = resp_idx;
+
wake_up_interruptible(&priv->waitq);
lbs_deb_leave(LBS_DEB_THREAD);
}
-EXPORT_SYMBOL_GPL(lbs_interrupt);
+EXPORT_SYMBOL_GPL(lbs_notify_command_response);
static int __init lbs_init_module(void)
{