[PATCH] firewire: reread config ROM when device reset the bus

From: Stefan Richter
Date: Sun Mar 02 2008 - 19:50:58 EST

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@xxxxxxxxxxxxxxxxx>
---

Applies after "firewire: replace static ROM cache by allocated cache".

drivers/firewire/fw-cdev.c | 18 ++--
drivers/firewire/fw-device.c | 147 ++++++++++++++++++++++++++++++---
drivers/firewire/fw-topology.c | 3
drivers/firewire/fw-topology.h | 11 +-
4 files changed, 158 insertions(+), 21 deletions(-)

Index: linux/drivers/firewire/fw-cdev.c
===================================================================
--- linux.orig/drivers/firewire/fw-cdev.c
+++ linux/drivers/firewire/fw-cdev.c
@@ -32,6 +32,7 @@
#include <linux/idr.h>
#include <linux/compat.h>
#include <linux/firewire-cdev.h>
+#include <asm/semaphore.h>
#include <asm/system.h>
#include <asm/uaccess.h>
#include "fw-transaction.h"
@@ -269,20 +270,25 @@ static int ioctl_get_info(struct client
{
struct fw_cdev_get_info *get_info = buffer;
struct fw_cdev_event_bus_reset bus_reset;
+ struct fw_device *device = client->device;
+ unsigned long ret = 0;

client->version = get_info->version;
get_info->version = FW_CDEV_VERSION;

+ down(&device->device.sem);
if (get_info->rom != 0) {
void __user *uptr = u64_to_uptr(get_info->rom);
size_t want = get_info->rom_length;
- size_t have = client->device->config_rom_length * 4;
+ size_t have;

- if (copy_to_user(uptr, client->device->config_rom,
- min(want, have)))
- return -EFAULT;
+ have = device->config_rom_length * 4;
+ ret = copy_to_user(uptr, device->config_rom, min(want, have));
}
- get_info->rom_length = client->device->config_rom_length * 4;
+ get_info->rom_length = device->config_rom_length * 4;
+ up(&device->device.sem);
+ if (ret != 0)
+ return -EFAULT;

client->bus_reset_closure = get_info->bus_reset_closure;
if (get_info->bus_reset != 0) {
@@ -293,7 +299,7 @@ static int ioctl_get_info(struct client
return -EFAULT;
}

- get_info->card = client->device->card->index;
+ get_info->card = device->card->index;

return 0;
}
Index: linux/drivers/firewire/fw-device.c
===================================================================
--- linux.orig/drivers/firewire/fw-device.c
+++ linux/drivers/firewire/fw-device.c
@@ -26,6 +26,7 @@
#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 +161,9 @@ static void fw_device_release(struct 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);
@@ -337,10 +338,14 @@ 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(&dev->sem);
+ length = device->config_rom_length * 4;
+ memcpy(buf, device->config_rom, length);
+ up(&dev->sem);

- return device->config_rom_length * 4;
+ return length;
}

static ssize_t
@@ -412,7 +417,7 @@ read_rom(struct fw_device *device, int g
*/
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;

@@ -527,11 +532,18 @@ static int read_bus_info_block(struct fw
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);
+
+ /* serialize with readers via sysfs or ioctl */
+ down(&device->device.sem);
+ device->config_rom = new_rom;
device->config_rom_length = length;
+ up(&device->device.sem);
+
+ kfree(old_rom);
ret = 0;
out:
kfree(rom);
@@ -724,7 +736,7 @@ static void fw_device_init(struct work_s
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 +750,7 @@ static void fw_device_init(struct work_s
device->device.bus_id,
device->config_rom[3], device->config_rom[4],
1 << device->max_speed);
+ device->config_rom_retries = 0;
}

/*
@@ -784,6 +797,104 @@ static void fw_device_update(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;
+
+ return;
+ }
+
+ /*
+ * 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 +904,7 @@ void fw_node_event(struct fw_card *card,
case FW_NODE_LINK_ON:
if (!node->link_on)
break;
-
+ create:
device = kzalloc(sizeof(*device), GFP_ATOMIC);
if (device == NULL)
break;
@@ -832,6 +943,22 @@ void fw_node_event(struct fw_card *card,
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, INITIAL_DELAY);
+ }
+ break;
+
case FW_NODE_UPDATED:
if (!node->link_on || node->data == NULL)
break;
Index: linux/drivers/firewire/fw-topology.c
===================================================================
--- linux.orig/drivers/firewire/fw-topology.c
+++ linux/drivers/firewire/fw-topology.c
@@ -107,6 +107,7 @@ static struct fw_node *fw_node_create(u3
node->node_id = LOCAL_BUS | SELF_ID_PHY_ID(sid);
node->link_on = SELF_ID_LINK_ON(sid);
node->phy_speed = SELF_ID_PHY_SPEED(sid);
+ node->initiated_reset = SELF_ID_PHY_INITIATOR(sid);
node->port_count = port_count;

atomic_set(&node->ref_count, 1);
@@ -430,6 +431,8 @@ update_tree(struct fw_card *card, struct
event = FW_NODE_LINK_OFF;
else if (!node0->link_on && node1->link_on)
event = FW_NODE_LINK_ON;
+ else if (node1->initiated_reset && node1->link_on)
+ event = FW_NODE_INITIATED_RESET;
else
event = FW_NODE_UPDATED;

Index: linux/drivers/firewire/fw-topology.h
===================================================================
--- linux.orig/drivers/firewire/fw-topology.h
+++ linux/drivers/firewire/fw-topology.h
@@ -20,11 +20,12 @@
#define __fw_topology_h

enum {
- FW_NODE_CREATED = 0x00,
- FW_NODE_UPDATED = 0x01,
- FW_NODE_DESTROYED = 0x02,
- FW_NODE_LINK_ON = 0x03,
- FW_NODE_LINK_OFF = 0x04,
+ FW_NODE_CREATED,
+ FW_NODE_UPDATED,
+ FW_NODE_DESTROYED,
+ FW_NODE_LINK_ON,
+ FW_NODE_LINK_OFF,
+ FW_NODE_INITIATED_RESET,
};

struct fw_node {

--
Stefan Richter
-=====-==--- --== ---==
http://arcgraph.de/sr/

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