nodemgr.c

来自「Linux Kernel 2.6.9 for OMAP1710」· C语言 代码 · 共 1,745 行 · 第 1/4 页

}


static void nodemgr_probe_ne(struct host_info *hi, struct node_entry *ne, int generation)
{
	struct device *dev;

	if (ne->host != hi->host || ne->in_limbo)
		return;

	dev = get_device(&ne->device);
	if (!dev)
		return;

	/* If "needs_probe", then this is either a new or changed node we
	 * rescan totally. If the generation matches for an existing node
	 * (one that existed prior to the bus reset) we send update calls
	 * down to the drivers. Otherwise, this is a dead node and we
	 * suspend it. */
	if (ne->needs_probe)
		nodemgr_process_root_directory(hi, ne);
	else if (ne->generation == generation)
		nodemgr_update_pdrv(ne);
	else
		nodemgr_suspend_ne(ne);

	put_device(dev);
}


static void nodemgr_node_probe(struct host_info *hi, int generation)
{
	struct hpsb_host *host = hi->host;
	struct class *class = &nodemgr_ne_class;
	struct class_device *cdev;

	/* Do some processing of the nodes we've probed. This pulls them
	 * into the sysfs layer if needed, and can result in processing of
	 * unit-directories, or just updating the node and it's
	 * unit-directories. */
	down_read(&class->subsys.rwsem);
	list_for_each_entry(cdev, &class->children, node)
		nodemgr_probe_ne(hi, container_of(cdev, struct node_entry, class_dev), generation);
        up_read(&class->subsys.rwsem);


	/* If we had a bus reset while we were scanning the bus, it is
	 * possible that we did not probe all nodes.  In that case, we
	 * skip the clean up for now, since we could remove nodes that
	 * were still on the bus.  The bus reset increased hi->reset_sem,
	 * so there's a bus scan pending which will do the clean up
	 * eventually.
	 *
	 * Now let's tell the bus to rescan our devices. This may seem
	 * like overhead, but the driver-model core will only scan a
	 * device for a driver when either the device is added, or when a
	 * new driver is added. A bus reset is a good reason to rescan
	 * devices that were there before.  For example, an sbp2 device
	 * may become available for login, if the host that held it was
	 * just removed.  */

	if (generation == get_hpsb_generation(host))
		bus_rescan_devices(&ieee1394_bus_type);

	return;
}

/* Because we are a 1394a-2000 compliant IRM, we need to inform all the other
 * nodes of the broadcast channel.  (Really we're only setting the validity
 * bit). Other IRM responsibilities go in here as well. */
static int nodemgr_do_irm_duties(struct hpsb_host *host, int cycles)
{
	quadlet_t bc;

	/* if irm_id == -1 then there is no IRM on this bus */
	if (!host->is_irm || host->irm_id == (nodeid_t)-1)
		return 1;

	host->csr.broadcast_channel |= 0x40000000;  /* set validity bit */

	bc = cpu_to_be32(host->csr.broadcast_channel);

	hpsb_write(host, LOCAL_BUS | ALL_NODES, get_hpsb_generation(host),
		   (CSR_REGISTER_BASE | CSR_BROADCAST_CHANNEL),
		   &bc, sizeof(quadlet_t));

	/* If there is no bus manager then we should set the root node's
	 * force_root bit to promote bus stability per the 1394
	 * spec. (8.4.2.6) */
	if (host->busmgr_id == 0xffff && host->node_count > 1)
	{
		u16 root_node = host->node_count - 1;
		struct node_entry *ne = find_entry_by_nodeid(host, root_node | LOCAL_BUS);

		if (ne && ne->busopt.cmc)
			hpsb_send_phy_config(host, root_node, -1);
		else {
			HPSB_DEBUG("The root node is not cycle master capable; "
				   "selecting a new root node and resetting...");

			if (cycles >= 5) {
				/* Oh screw it! Just leave the bus as it is */
				HPSB_DEBUG("Stopping reset loop for IRM sanity");
				return 1;
			}

			hpsb_send_phy_config(host, NODEID_TO_NODE(host->node_id), -1);
			hpsb_reset_bus(host, LONG_RESET_FORCE_ROOT);

			return 0;
		}
	}

	return 1;
}

/* We need to ensure that if we are not the IRM, that the IRM node is capable of
 * everything we can do, otherwise issue a bus reset and try to become the IRM
 * ourselves. */
static int nodemgr_check_irm_capability(struct hpsb_host *host, int cycles)
{
	quadlet_t bc;
	int status;

	if (host->is_irm)
		return 1;

	status = hpsb_read(host, LOCAL_BUS | (host->irm_id),
			   get_hpsb_generation(host),
			   (CSR_REGISTER_BASE | CSR_BROADCAST_CHANNEL),
			   &bc, sizeof(quadlet_t));

	if (status < 0 || !(be32_to_cpu(bc) & 0x80000000)) {
		/* The current irm node does not have a valid BROADCAST_CHANNEL
		 * register and we do, so reset the bus with force_root set */
		HPSB_DEBUG("Current remote IRM is not 1394a-2000 compliant, resetting...");

		if (cycles >= 5) {
			/* Oh screw it! Just leave the bus as it is */
			HPSB_DEBUG("Stopping reset loop for IRM sanity");
			return 1;
		}

		hpsb_send_phy_config(host, NODEID_TO_NODE(host->node_id), -1);
		hpsb_reset_bus(host, LONG_RESET_FORCE_ROOT);

		return 0;
	}

	return 1;
}

static int nodemgr_host_thread(void *__hi)
{
	struct host_info *hi = (struct host_info *)__hi;
	struct hpsb_host *host = hi->host;
	int reset_cycles = 0;

	/* No userlevel access needed */
	daemonize(hi->daemon_name);

	/* Setup our device-model entries */
	nodemgr_create_host_dev_files(host);

	/* Sit and wait for a signal to probe the nodes on the bus. This
	 * happens when we get a bus reset. */
	while (1) {
		unsigned int generation = 0;
		int i;

		if (down_interruptible(&hi->reset_sem) ||
		    down_interruptible(&nodemgr_serialize)) {
			if (current->flags & PF_FREEZE) {
				refrigerator(0);
				continue;
			}
			printk("NodeMgr: received unexpected signal?!\n" );
			break;
		}

		if (hi->kill_me)
			break;

		/* Pause for 1/4 second in 1/16 second intervals,
		 * to make sure things settle down. */
		for (i = 0; i < 4 ; i++) {
			set_current_state(TASK_INTERRUPTIBLE);
			if (schedule_timeout(HZ/16)) {
				up(&nodemgr_serialize);
				goto caught_signal;
			}

			/* Now get the generation in which the node ID's we collect
			 * are valid.  During the bus scan we will use this generation
			 * for the read transactions, so that if another reset occurs
			 * during the scan the transactions will fail instead of
			 * returning bogus data. */
			generation = get_hpsb_generation(host);

			/* If we get a reset before we are done waiting, then
			 * start the the waiting over again */
			while (!down_trylock(&hi->reset_sem))
				i = 0;

			/* Check the kill_me again */
			if (hi->kill_me)
				goto caught_signal;
		}

		if (!nodemgr_check_irm_capability(host, reset_cycles)) {
			reset_cycles++;
			up(&nodemgr_serialize);
			continue;
		}

		/* Scan our nodes to get the bus options and create node
		 * entries. This does not do the sysfs stuff, since that
		 * would trigger hotplug callbacks and such, which is a
		 * bad idea at this point. */
		nodemgr_node_scan(hi, generation);
		if (!nodemgr_do_irm_duties(host, reset_cycles)) {
			reset_cycles++;
			up(&nodemgr_serialize);
			continue;
		}

		reset_cycles = 0;

		/* This actually does the full probe, with sysfs
		 * registration. */
		nodemgr_node_probe(hi, generation);

		/* Update some of our sysfs symlinks */
		nodemgr_update_host_dev_links(host);

		up(&nodemgr_serialize);
	}

caught_signal:
	HPSB_VERBOSE("NodeMgr: Exiting thread");

	complete_and_exit(&hi->exited, 0);
}

struct node_entry *hpsb_guid_get_entry(u64 guid)
{
        struct node_entry *ne;

	down(&nodemgr_serialize);
        ne = find_entry_by_guid(guid);
	up(&nodemgr_serialize);

        return ne;
}

struct node_entry *hpsb_nodeid_get_entry(struct hpsb_host *host, nodeid_t nodeid)
{
	struct node_entry *ne;

	down(&nodemgr_serialize);
	ne = find_entry_by_nodeid(host, nodeid);
	up(&nodemgr_serialize);

	return ne;
}


int nodemgr_for_each_host(void *__data, int (*cb)(struct hpsb_host *, void *))
{
	struct class *class = &hpsb_host_class;
	struct class_device *cdev;
	struct hpsb_host *host;
	int error = 0;

	down_read(&class->subsys.rwsem);
	list_for_each_entry(cdev, &class->children, node) {
		host = container_of(cdev, struct hpsb_host, class_dev);

		if ((error = cb(host, __data)))
			break;
	}
	up_read(&class->subsys.rwsem);

	return error;
}

/* The following four convenience functions use a struct node_entry
 * for addressing a node on the bus.  They are intended for use by any
 * process context, not just the nodemgr thread, so we need to be a
 * little careful when reading out the node ID and generation.  The
 * thing that can go wrong is that we get the node ID, then a bus
 * reset occurs, and then we read the generation.  The node ID is
 * possibly invalid, but the generation is current, and we end up
 * sending a packet to a the wrong node.
 *
 * The solution is to make sure we read the generation first, so that
 * if a reset occurs in the process, we end up with a stale generation
 * and the transactions will fail instead of silently using wrong node
 * ID's.
 */

void hpsb_node_fill_packet(struct node_entry *ne, struct hpsb_packet *pkt)
{
        pkt->host = ne->host;
        pkt->generation = ne->generation;
	barrier();
        pkt->node_id = ne->nodeid;
}

int hpsb_node_read(struct node_entry *ne, u64 addr,
		   quadlet_t *buffer, size_t length)
{
	unsigned int generation = ne->generation;

	barrier();
	return hpsb_read(ne->host, ne->nodeid, generation,
			 addr, buffer, length);
}

int hpsb_node_write(struct node_entry *ne, u64 addr,
		    quadlet_t *buffer, size_t length)
{
	unsigned int generation = ne->generation;

	barrier();
	return hpsb_write(ne->host, ne->nodeid, generation,
			  addr, buffer, length);
}

int hpsb_node_lock(struct node_entry *ne, u64 addr,
		   int extcode, quadlet_t *data, quadlet_t arg)
{
	unsigned int generation = ne->generation;

	barrier();
	return hpsb_lock(ne->host, ne->nodeid, generation,
			 addr, extcode, data, arg);
}

static void nodemgr_add_host(struct hpsb_host *host)
{
	struct host_info *hi;

	hi = hpsb_create_hostinfo(&nodemgr_highlevel, host, sizeof(*hi));

	if (!hi) {
		HPSB_ERR ("NodeMgr: out of memory in add host");
		return;
	}

	hi->host = host;
	init_completion(&hi->exited);
        sema_init(&hi->reset_sem, 0);

	sprintf(hi->daemon_name, "knodemgrd_%d", host->id);

	hi->pid = kernel_thread(nodemgr_host_thread, hi, CLONE_KERNEL);

	if (hi->pid < 0) {
		HPSB_ERR ("NodeMgr: failed to start %s thread for %s",
			  hi->daemon_name, host->driver->name);
		hpsb_destroy_hostinfo(&nodemgr_highlevel, host);
		return;
	}

	return;
}

static void nodemgr_host_reset(struct hpsb_host *host)
{
	struct host_info *hi = hpsb_get_hostinfo(&nodemgr_highlevel, host);

	if (hi != NULL) {
		HPSB_VERBOSE("NodeMgr: Processing host reset for %s", hi->daemon_name);
		up(&hi->reset_sem);
	} else
		HPSB_ERR ("NodeMgr: could not process reset of unused host");

	return;
}

static void nodemgr_remove_host(struct hpsb_host *host)
{
	struct host_info *hi = hpsb_get_hostinfo(&nodemgr_highlevel, host);

	if (hi) {
		if (hi->pid >= 0) {
			hi->kill_me = 1;
			mb();
			up(&hi->reset_sem);
			wait_for_completion(&hi->exited);
			nodemgr_remove_host_dev(&host->device);
		}
	} else
		HPSB_ERR("NodeMgr: host %s does not exist, cannot remove",
			 host->driver->name);

	return;
}

static struct hpsb_highlevel nodemgr_highlevel = {
	.name =		"Node manager",
	.add_host =	nodemgr_add_host,
	.host_reset =	nodemgr_host_reset,
	.remove_host =	nodemgr_remove_host,
};

int init_ieee1394_nodemgr(void)
{
	int ret;

	ret = class_register(&nodemgr_ne_class);
	if (ret < 0)
		return ret;

	ret = class_register(&nodemgr_ud_class);
	if (ret < 0) {
		class_unregister(&nodemgr_ne_class);
		return ret;
	}

	hpsb_register_highlevel(&nodemgr_highlevel);

	return 0;
}

void cleanup_ieee1394_nodemgr(void)
{
        hpsb_unregister_highlevel(&nodemgr_highlevel);

	class_unregister(&nodemgr_ud_class);
	class_unregister(&nodemgr_ne_class);
}