]> www.pilppa.org Git - linux-2.6-omap-h63xx.git/blobdiff - drivers/firewire/fw-device.c
firewire: reread config ROM when device reset the bus
[linux-2.6-omap-h63xx.git] / drivers / firewire / fw-device.c
index 20ac9a5afc370d36b7940ef2636b85e02cb58e73..75365cd0008a3f0ee6d5b3e9752e4cc86ae9afcc 100644 (file)
@@ -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 @@ static void fw_device_release(struct device *dev)
         * 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 @@ show_immediate(struct device *dev, struct device_attribute *dattr, char *buf)
                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 @@ show_immediate(struct device *dev, struct device_attribute *dattr, char *buf)
 
        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;
+               }
+
+       up_read(&fw_device_rwsem);
 
-       return -ENOENT;
+       return ret;
 }
 
 #define IMMEDIATE_ATTR(name, key)                              \
@@ -221,9 +227,11 @@ show_text_leaf(struct device *dev, struct device_attribute *dattr, char *buf)
                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 @@ show_text_leaf(struct device *dev, struct device_attribute *dattr, char *buf)
        }
 
        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 @@ show_text_leaf(struct device *dev, struct device_attribute *dattr, char *buf)
        /* 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 @@ static ssize_t
 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;
+
+       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 snprintf(buf, PAGE_SIZE, "0x%08x%08x\n",
-                       device->config_rom[3], device->config_rom[4]);
+       return ret;
 }
 
 static struct device_attribute fw_device_attributes[] = {
@@ -412,7 +434,7 @@ read_rom(struct fw_device *device, int generation, int index, u32 *data)
  */
 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 @@ static int read_bus_info_block(struct fw_device *device, int generation)
                        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 @@ static int shutdown_unit(struct device *device, void *data)
        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 *fw_device_get_by_devt(dev_t devt)
 {
        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 @@ static void fw_device_shutdown(struct work_struct *work)
        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 @@ static void fw_device_init(struct work_struct *work)
        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 @@ static void fw_device_init(struct work_struct *work)
        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 @@ static void fw_device_init(struct work_struct *work)
                                  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 @@ static void fw_device_init(struct work_struct *work)
        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 @@ static void fw_device_update(struct work_struct *work)
        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 @@ void fw_node_event(struct fw_card *card, struct fw_node *node, int event)
        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 @@ void fw_node_event(struct fw_card *card, struct fw_node *node, int event)
                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;