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>

drivers/firewire/fw-card.c

@@ -331,7 +331,7 @@ fw_card_bm_work(struct work_struct *work)
 		 */
 		spin_unlock_irqrestore(&card->lock, flags);
 		goto out;
-	} else if (root_device->config_rom[2] & BIB_CMC) {
+	} else if (root_device->cmc) {
 		/*
 		 * FIXME: I suppose we should set the cmstr bit in the
 		 * STATE_CLEAR register of this node, as described in

drivers/firewire/fw-cdev.c

@@ -269,21 +269,28 @@ static int ioctl_get_info(struct client *client, void *buffer)
 {
 	struct fw_cdev_get_info *get_info = buffer;
 	struct fw_cdev_event_bus_reset bus_reset;
+	unsigned long ret = 0;
 
 	client->version = get_info->version;
 	get_info->version = FW_CDEV_VERSION;
 
+	down_read(&fw_device_rwsem);
+
 	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;
 
-		if (copy_to_user(uptr, client->device->config_rom,
-				 min(want, have)))
-			return -EFAULT;
+		ret = copy_to_user(uptr, client->device->config_rom,
+				   min(want, have));
 	}
 	get_info->rom_length = client->device->config_rom_length * 4;
 
+	up_read(&fw_device_rwsem);
+
+	if (ret != 0)
+		return -EFAULT;
+
 	client->bus_reset_closure = get_info->bus_reset_closure;
 	if (get_info->bus_reset != 0) {
 		void __user *uptr = u64_to_uptr(get_info->bus_reset);

drivers/firewire/fw-device.h

@@ -21,6 +21,7 @@
 
 #include <linux/fs.h>
 #include <linux/cdev.h>
+#include <linux/rwsem.h>
 #include <asm/atomic.h>
 
 enum fw_device_state {
@@ -46,6 +47,11 @@ struct fw_attribute_group {
  * fw_device.node_id is guaranteed to be current too.
  *
  * The same applies to fw_device.card->node_id vs. fw_device.generation.
+ *
+ * fw_device.config_rom and fw_device.config_rom_length may be accessed during
+ * the lifetime of any fw_unit belonging to the fw_device, before device_del()
+ * was called on the last fw_unit.  Alternatively, they may be accessed while
+ * holding fw_device_rwsem.
  */
 struct fw_device {
 	atomic_t state;
@@ -53,6 +59,7 @@ struct fw_device {
 	int node_id;
 	int generation;
 	unsigned max_speed;
+	bool cmc;
 	struct fw_card *card;
 	struct device device;
 	struct list_head link;
@@ -92,8 +99,12 @@ int fw_device_enable_phys_dma(struct fw_device *device);
 void fw_device_cdev_update(struct fw_device *device);
 void fw_device_cdev_remove(struct fw_device *device);
 
+extern struct rw_semaphore fw_device_rwsem;
 extern int fw_cdev_major;
 
+/*
+ * fw_unit.directory must not be accessed after device_del(&fw_unit.device).
+ */
 struct fw_unit {
 	struct device device;
 	u32 *directory;

drivers/firewire/fw-sbp2.c

@@ -153,6 +153,7 @@ struct sbp2_target {
 	struct list_head lu_list;
 
 	u64 management_agent_address;
+	u64 guid;
 	int directory_id;
 	int node_id;
 	int address_high;
@@ -1114,6 +1115,7 @@ static int sbp2_probe(struct device *dev)
 	kref_init(&tgt->kref);
 	INIT_LIST_HEAD(&tgt->lu_list);
 	tgt->bus_id = unit->device.bus_id;
+	tgt->guid = (u64)device->config_rom[3] << 32 | device->config_rom[4];
 
 	if (fw_device_enable_phys_dma(device) < 0)
 		goto fail_shost_put;
@@ -1571,16 +1573,14 @@ sbp2_sysfs_ieee1394_id_show(struct device *dev, struct device_attribute *attr,
 {
 	struct scsi_device *sdev = to_scsi_device(dev);
 	struct sbp2_logical_unit *lu;
-	struct fw_device *device;
 
 	if (!sdev)
 		return 0;
 
 	lu = sdev->hostdata;
-	device = fw_device(lu->tgt->unit->device.parent);
 
-	return sprintf(buf, "%08x%08x:%06x:%04x\n",
-			device->config_rom[3], device->config_rom[4],
+	return sprintf(buf, "%016llx:%06x:%04x\n",
+			(unsigned long long)lu->tgt->guid,
 			lu->tgt->directory_id, lu->lun);
 }
 

drivers/firewire/fw-topology.c

@@ -108,6 +108,7 @@ static struct fw_node *fw_node_create(u32 sid, int port_count, int color)
 	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);
@@ -431,6 +432,8 @@ update_tree(struct fw_card *card, struct fw_node *root)
 			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;
 

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 {