firewire: reread config ROM when device reset the bus
When a device changes its configuration ROM, it announces this with a
bus reset. firewire-core has to check which node initiated a bus reset
and whether any unit directories went away or were added on this node.
Tested with an IOI FWB-IDE01AB which has its link-on bit set if bus
power is available but does not respond to ROM read requests if self
power is off. This implements
- recognition of the units if self power is switched on after fw-core
gave up the initial attempt to read the config ROM,
- shutdown of the units when self power is switched off.
Also tested with a second PC running Linux/ieee1394. When the eth1394
driver is inserted and removed on that node, fw-core now notices the
addition and removal of the IPv4 unit on the ieee1394 node.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
diff --git a/drivers/firewire/fw-device.c b/drivers/firewire/fw-device.c
index 20ac9a5..75365cd 100644
--- a/drivers/firewire/fw-device.c
+++ b/drivers/firewire/fw-device.c
@@ -25,7 +25,7 @@
#include <linux/device.h>
#include <linux/delay.h>
#include <linux/idr.h>
-#include <linux/rwsem.h>
+#include <linux/string.h>
#include <asm/semaphore.h>
#include <asm/system.h>
#include <linux/ctype.h>
@@ -160,9 +160,9 @@
* Take the card lock so we don't set this to NULL while a
* FW_NODE_UPDATED callback is being handled.
*/
- spin_lock_irqsave(&device->card->lock, flags);
+ spin_lock_irqsave(&card->lock, flags);
device->node->data = NULL;
- spin_unlock_irqrestore(&device->card->lock, flags);
+ spin_unlock_irqrestore(&card->lock, flags);
fw_node_put(device->node);
kfree(device->config_rom);
@@ -195,7 +195,9 @@
container_of(dattr, struct config_rom_attribute, attr);
struct fw_csr_iterator ci;
u32 *dir;
- int key, value;
+ int key, value, ret = -ENOENT;
+
+ down_read(&fw_device_rwsem);
if (is_fw_unit(dev))
dir = fw_unit(dev)->directory;
@@ -204,11 +206,15 @@
fw_csr_iterator_init(&ci, dir);
while (fw_csr_iterator_next(&ci, &key, &value))
- if (attr->key == key)
- return snprintf(buf, buf ? PAGE_SIZE : 0,
- "0x%06x\n", value);
+ if (attr->key == key) {
+ ret = snprintf(buf, buf ? PAGE_SIZE : 0,
+ "0x%06x\n", value);
+ break;
+ }
- return -ENOENT;
+ up_read(&fw_device_rwsem);
+
+ return ret;
}
#define IMMEDIATE_ATTR(name, key) \
@@ -221,9 +227,11 @@
container_of(dattr, struct config_rom_attribute, attr);
struct fw_csr_iterator ci;
u32 *dir, *block = NULL, *p, *end;
- int length, key, value, last_key = 0;
+ int length, key, value, last_key = 0, ret = -ENOENT;
char *b;
+ down_read(&fw_device_rwsem);
+
if (is_fw_unit(dev))
dir = fw_unit(dev)->directory;
else
@@ -238,18 +246,20 @@
}
if (block == NULL)
- return -ENOENT;
+ goto out;
length = min(block[0] >> 16, 256U);
if (length < 3)
- return -ENOENT;
+ goto out;
if (block[1] != 0 || block[2] != 0)
/* Unknown encoding. */
- return -ENOENT;
+ goto out;
- if (buf == NULL)
- return length * 4;
+ if (buf == NULL) {
+ ret = length * 4;
+ goto out;
+ }
b = buf;
end = &block[length + 1];
@@ -259,8 +269,11 @@
/* Strip trailing whitespace and add newline. */
while (b--, (isspace(*b) || *b == '\0') && b > buf);
strcpy(b + 1, "\n");
+ ret = b + 2 - buf;
+ out:
+ up_read(&fw_device_rwsem);
- return b + 2 - buf;
+ return ret;
}
#define TEXT_LEAF_ATTR(name, key) \
@@ -337,19 +350,28 @@
config_rom_show(struct device *dev, struct device_attribute *attr, char *buf)
{
struct fw_device *device = fw_device(dev);
+ size_t length;
- memcpy(buf, device->config_rom, device->config_rom_length * 4);
+ down_read(&fw_device_rwsem);
+ length = device->config_rom_length * 4;
+ memcpy(buf, device->config_rom, length);
+ up_read(&fw_device_rwsem);
- return device->config_rom_length * 4;
+ return length;
}
static ssize_t
guid_show(struct device *dev, struct device_attribute *attr, char *buf)
{
struct fw_device *device = fw_device(dev);
+ int ret;
- return snprintf(buf, PAGE_SIZE, "0x%08x%08x\n",
- device->config_rom[3], device->config_rom[4]);
+ down_read(&fw_device_rwsem);
+ ret = snprintf(buf, PAGE_SIZE, "0x%08x%08x\n",
+ device->config_rom[3], device->config_rom[4]);
+ up_read(&fw_device_rwsem);
+
+ return ret;
}
static struct device_attribute fw_device_attributes[] = {
@@ -412,7 +434,7 @@
*/
static int read_bus_info_block(struct fw_device *device, int generation)
{
- u32 *rom, *stack;
+ u32 *rom, *stack, *old_rom, *new_rom;
u32 sp, key;
int i, end, length, ret = -1;
@@ -527,12 +549,19 @@
length = i;
}
- device->config_rom = kmalloc(length * 4, GFP_KERNEL);
- if (device->config_rom == NULL)
+ old_rom = device->config_rom;
+ new_rom = kmemdup(rom, length * 4, GFP_KERNEL);
+ if (new_rom == NULL)
goto out;
- memcpy(device->config_rom, rom, length * 4);
+
+ down_write(&fw_device_rwsem);
+ device->config_rom = new_rom;
device->config_rom_length = length;
+ up_write(&fw_device_rwsem);
+
+ kfree(old_rom);
ret = 0;
+ device->cmc = rom[2] & 1 << 30;
out:
kfree(rom);
@@ -605,7 +634,14 @@
return 0;
}
-static DECLARE_RWSEM(idr_rwsem);
+/*
+ * fw_device_rwsem acts as dual purpose mutex:
+ * - serializes accesses to fw_device_idr,
+ * - serializes accesses to fw_device.config_rom/.config_rom_length and
+ * fw_unit.directory, unless those accesses happen at safe occasions
+ */
+DECLARE_RWSEM(fw_device_rwsem);
+
static DEFINE_IDR(fw_device_idr);
int fw_cdev_major;
@@ -613,11 +649,11 @@
{
struct fw_device *device;
- down_read(&idr_rwsem);
+ down_read(&fw_device_rwsem);
device = idr_find(&fw_device_idr, MINOR(devt));
if (device)
fw_device_get(device);
- up_read(&idr_rwsem);
+ up_read(&fw_device_rwsem);
return device;
}
@@ -632,9 +668,9 @@
device_for_each_child(&device->device, NULL, shutdown_unit);
device_unregister(&device->device);
- down_write(&idr_rwsem);
+ down_write(&fw_device_rwsem);
idr_remove(&fw_device_idr, minor);
- up_write(&idr_rwsem);
+ up_write(&fw_device_rwsem);
fw_device_put(device);
}
@@ -687,10 +723,10 @@
err = -ENOMEM;
fw_device_get(device);
- down_write(&idr_rwsem);
+ down_write(&fw_device_rwsem);
if (idr_pre_get(&fw_device_idr, GFP_KERNEL))
err = idr_get_new(&fw_device_idr, device, &minor);
- up_write(&idr_rwsem);
+ up_write(&fw_device_rwsem);
if (err < 0)
goto error;
@@ -724,7 +760,7 @@
if (atomic_cmpxchg(&device->state,
FW_DEVICE_INITIALIZING,
FW_DEVICE_RUNNING) == FW_DEVICE_SHUTDOWN) {
- fw_device_shutdown(&device->work.work);
+ fw_device_shutdown(work);
} else {
if (device->config_rom_retries)
fw_notify("created device %s: GUID %08x%08x, S%d00, "
@@ -738,6 +774,7 @@
device->device.bus_id,
device->config_rom[3], device->config_rom[4],
1 << device->max_speed);
+ device->config_rom_retries = 0;
}
/*
@@ -752,9 +789,9 @@
return;
error_with_cdev:
- down_write(&idr_rwsem);
+ down_write(&fw_device_rwsem);
idr_remove(&fw_device_idr, minor);
- up_write(&idr_rwsem);
+ up_write(&fw_device_rwsem);
error:
fw_device_put(device); /* fw_device_idr's reference */
@@ -784,6 +821,106 @@
device_for_each_child(&device->device, NULL, update_unit);
}
+enum {
+ REREAD_BIB_ERROR,
+ REREAD_BIB_GONE,
+ REREAD_BIB_UNCHANGED,
+ REREAD_BIB_CHANGED,
+};
+
+/* Reread and compare bus info block and header of root directory */
+static int reread_bus_info_block(struct fw_device *device, int generation)
+{
+ u32 q;
+ int i;
+
+ for (i = 0; i < 6; i++) {
+ if (read_rom(device, generation, i, &q) != RCODE_COMPLETE)
+ return REREAD_BIB_ERROR;
+
+ if (i == 0 && q == 0)
+ return REREAD_BIB_GONE;
+
+ if (i > device->config_rom_length || q != device->config_rom[i])
+ return REREAD_BIB_CHANGED;
+ }
+
+ return REREAD_BIB_UNCHANGED;
+}
+
+static void fw_device_refresh(struct work_struct *work)
+{
+ struct fw_device *device =
+ container_of(work, struct fw_device, work.work);
+ struct fw_card *card = device->card;
+ int node_id = device->node_id;
+
+ switch (reread_bus_info_block(device, device->generation)) {
+ case REREAD_BIB_ERROR:
+ if (device->config_rom_retries < MAX_RETRIES / 2 &&
+ atomic_read(&device->state) == FW_DEVICE_INITIALIZING) {
+ device->config_rom_retries++;
+ schedule_delayed_work(&device->work, RETRY_DELAY / 2);
+
+ return;
+ }
+ goto give_up;
+
+ case REREAD_BIB_GONE:
+ goto gone;
+
+ case REREAD_BIB_UNCHANGED:
+ if (atomic_cmpxchg(&device->state,
+ FW_DEVICE_INITIALIZING,
+ FW_DEVICE_RUNNING) == FW_DEVICE_SHUTDOWN)
+ goto gone;
+
+ fw_device_update(work);
+ device->config_rom_retries = 0;
+ goto out;
+
+ case REREAD_BIB_CHANGED:
+ break;
+ }
+
+ /*
+ * Something changed. We keep things simple and don't investigate
+ * further. We just destroy all previous units and create new ones.
+ */
+ device_for_each_child(&device->device, NULL, shutdown_unit);
+
+ if (read_bus_info_block(device, device->generation) < 0) {
+ if (device->config_rom_retries < MAX_RETRIES &&
+ atomic_read(&device->state) == FW_DEVICE_INITIALIZING) {
+ device->config_rom_retries++;
+ schedule_delayed_work(&device->work, RETRY_DELAY);
+
+ return;
+ }
+ goto give_up;
+ }
+
+ create_units(device);
+
+ if (atomic_cmpxchg(&device->state,
+ FW_DEVICE_INITIALIZING,
+ FW_DEVICE_RUNNING) == FW_DEVICE_SHUTDOWN)
+ goto gone;
+
+ fw_notify("refreshed device %s\n", device->device.bus_id);
+ device->config_rom_retries = 0;
+ goto out;
+
+ give_up:
+ fw_notify("giving up on refresh of device %s\n", device->device.bus_id);
+ gone:
+ atomic_set(&device->state, FW_DEVICE_SHUTDOWN);
+ fw_device_shutdown(work);
+ out:
+ if (node_id == card->root_node->node_id)
+ schedule_delayed_work(&card->work, 0);
+}
+
void fw_node_event(struct fw_card *card, struct fw_node *node, int event)
{
struct fw_device *device;
@@ -793,7 +930,7 @@
case FW_NODE_LINK_ON:
if (!node->link_on)
break;
-
+ create:
device = kzalloc(sizeof(*device), GFP_ATOMIC);
if (device == NULL)
break;
@@ -832,6 +969,23 @@
schedule_delayed_work(&device->work, INITIAL_DELAY);
break;
+ case FW_NODE_INITIATED_RESET:
+ device = node->data;
+ if (device == NULL)
+ goto create;
+
+ device->node_id = node->node_id;
+ smp_wmb(); /* update node_id before generation */
+ device->generation = card->generation;
+ if (atomic_cmpxchg(&device->state,
+ FW_DEVICE_RUNNING,
+ FW_DEVICE_INITIALIZING) == FW_DEVICE_RUNNING) {
+ PREPARE_DELAYED_WORK(&device->work, fw_device_refresh);
+ schedule_delayed_work(&device->work,
+ node == card->local_node ? 0 : INITIAL_DELAY);
+ }
+ break;
+
case FW_NODE_UPDATED:
if (!node->link_on || node->data == NULL)
break;