device.c

h内核

/*
 *	Functions to handle I2O devices
 *
 *	Copyright (C) 2004	Markus Lidel <[e-mail]>
 *
 *	This program is free software; you can redistribute it and/or modify it
 *	under the terms of the GNU General Public License as published by the
 *	Free Software Foundation; either version 2 of the License, or (at your
 *	option) any later version.
 *
 *	Fixes/additions:
 *		Markus Lidel <[e-mail]>
 *			initial version.
 */

#include <linux/module.h>
#include <linux/i2o.h>
#include <linux/delay.h>

/* Exec OSM functions */
extern struct bus_type i2o_bus_type;

/**
 *	i2o_device_issue_claim - claim or release a device
 *	@dev: I2O device to claim or release
 *	@cmd: claim or release command
 *	@type: type of claim
 *
 *	Issue I2O UTIL_CLAIM or UTIL_RELEASE messages. The message to be sent
 *	is set by cmd. dev is the I2O device which should be claim or
 *	released and the type is the claim type (see the I2O spec).
 *
 *	Returs 0 on success or negative error code on failure.
 */
static inline int i2o_device_issue_claim(struct i2o_device *dev, u32 cmd,
					 u32 type)
{
	struct i2o_message __iomem *msg;
	u32 m;

	m = i2o_msg_get_wait(dev->iop, &msg, I2O_TIMEOUT_MESSAGE_GET);
	if (m == I2O_QUEUE_EMPTY)
		return -ETIMEDOUT;

	writel(FIVE_WORD_MSG_SIZE | SGL_OFFSET_0, &msg->u.head[0]);
	writel(cmd << 24 | HOST_TID << 12 | dev->lct_data.tid, &msg->u.head[1]);
	writel(type, &msg->body[0]);

	return i2o_msg_post_wait(dev->iop, m, 60);
};

/**
 * 	i2o_device_claim - claim a device for use by an OSM
 *	@dev: I2O device to claim
 *	@drv: I2O driver which wants to claim the device
 *
 *	Do the leg work to assign a device to a given OSM. If the claim succeed
 *	the owner of the rimary. If the attempt fails a negative errno code
 *	is returned. On success zero is returned.
 */
int i2o_device_claim(struct i2o_device *dev)
{
	int rc = 0;

	down(&dev->lock);

	rc = i2o_device_issue_claim(dev, I2O_CMD_UTIL_CLAIM, I2O_CLAIM_PRIMARY);
	if (!rc)
		pr_debug("i2o: claim of device %d succeded\n",
			 dev->lct_data.tid);
	else
		pr_debug("i2o: claim of device %d failed %d\n",
			 dev->lct_data.tid, rc);

	up(&dev->lock);

	return rc;
};

/**
 *	i2o_device_claim_release - release a device that the OSM is using
 *	@dev: device to release
 *	@drv: driver which claimed the device
 *
 *	Drop a claim by an OSM on a given I2O device.
 *
 *	AC - some devices seem to want to refuse an unclaim until they have
 *	finished internal processing. It makes sense since you don't want a
 *	new device to go reconfiguring the entire system until you are done.
 *	Thus we are prepared to wait briefly.
 *
 *	Returns 0 on success or negative error code on failure.
 */
int i2o_device_claim_release(struct i2o_device *dev)
{
	int tries;
	int rc = 0;

	down(&dev->lock);

	/*
	 *      If the controller takes a nonblocking approach to
	 *      releases we have to sleep/poll for a few times.
	 */
	for (tries = 0; tries < 10; tries++) {
		rc = i2o_device_issue_claim(dev, I2O_CMD_UTIL_RELEASE,
					    I2O_CLAIM_PRIMARY);
		if (!rc)
			break;

		ssleep(1);
	}

	if (!rc)
		pr_debug("i2o: claim release of device %d succeded\n",
			 dev->lct_data.tid);
	else
		pr_debug("i2o: claim release of device %d failed %d\n",
			 dev->lct_data.tid, rc);

	up(&dev->lock);

	return rc;
};

/**
 *	i2o_device_release - release the memory for a I2O device
 *	@dev: I2O device which should be released
 *
 *	Release the allocated memory. This function is called if refcount of
 *	device reaches 0 automatically.
 */
static void i2o_device_release(struct device *dev)
{
	struct i2o_device *i2o_dev = to_i2o_device(dev);

	pr_debug("i2o: device %s released\n", dev->bus_id);

	kfree(i2o_dev);
};

/**
 *	i2o_device_class_release - Remove I2O device attributes
 *	@cd: I2O class device which is added to the I2O device class
 *
 *	Removes attributes from the I2O device again. Also search each device
 *	on the controller for I2O devices which refert to this device as parent
 *	or user and remove this links also.
 */
static void i2o_device_class_release(struct class_device *cd)
{
	struct i2o_device *i2o_dev, *tmp;
	struct i2o_controller *c;

	i2o_dev = to_i2o_device(cd->dev);
	c = i2o_dev->iop;

	sysfs_remove_link(&i2o_dev->device.kobj, "parent");
	sysfs_remove_link(&i2o_dev->device.kobj, "user");

	list_for_each_entry(tmp, &c->devices, list) {
		if (tmp->lct_data.parent_tid == i2o_dev->lct_data.tid)
			sysfs_remove_link(&tmp->device.kobj, "parent");
		if (tmp->lct_data.user_tid == i2o_dev->lct_data.tid)
			sysfs_remove_link(&tmp->device.kobj, "user");
	}
};

/* I2O device class */
static struct class i2o_device_class = {
	.name = "i2o_device",
	.release = i2o_device_class_release
};

/**
 *	i2o_device_alloc - Allocate a I2O device and initialize it
 *
 *	Allocate the memory for a I2O device and initialize locks and lists
 *
 *	Returns the allocated I2O device or a negative error code if the device
 *	could not be allocated.
 */
static struct i2o_device *i2o_device_alloc(void)
{
	struct i2o_device *dev;

	dev = kmalloc(sizeof(*dev), GFP_KERNEL);
	if (!dev)
		return ERR_PTR(-ENOMEM);

	memset(dev, 0, sizeof(*dev));

	INIT_LIST_HEAD(&dev->list);
	init_MUTEX(&dev->lock);

	dev->device.bus = &i2o_bus_type;
	dev->device.release = &i2o_device_release;
	dev->classdev.class = &i2o_device_class;
	dev->classdev.dev = &dev->device;

	return dev;
};

/**
 *	i2o_device_add - allocate a new I2O device and add it to the IOP
 *	@iop: I2O controller where the device is on
 *	@entry: LCT entry of the I2O device
 *
 *	Allocate a new I2O device and initialize it with the LCT entry. The
 *	device is appended to the device list of the controller.
 *
 *	Returns a pointer to the I2O device on success or negative error code
 *	on failure.
 */
static struct i2o_device *i2o_device_add(struct i2o_controller *c,
					 i2o_lct_entry * entry)
{
	struct i2o_device *dev;

	dev = i2o_device_alloc();
	if (IS_ERR(dev)) {
		printk(KERN_ERR "i2o: unable to allocate i2o device\n");
		return dev;
	}

	dev->lct_data = *entry;

	snprintf(dev->device.bus_id, BUS_ID_SIZE, "%d:%03x", c->unit,
		 dev->lct_data.tid);

	snprintf(dev->classdev.class_id, BUS_ID_SIZE, "%d:%03x", c->unit,
		 dev->lct_data.tid);

	dev->iop = c;
	dev->device.parent = &c->device;

	device_register(&dev->device);

	list_add_tail(&dev->list, &c->devices);

	class_device_register(&dev->classdev);

	i2o_driver_notify_device_add_all(dev);

	pr_debug("i2o: device %s added\n", dev->device.bus_id);

	return dev;
};

/**
 *	i2o_device_remove - remove an I2O device from the I2O core
 *	@dev: I2O device which should be released
 *
 *	Is used on I2O controller removal or LCT modification, when the device
 *	is removed from the system. Note that the device could still hang
 *	around until the refcount reaches 0.
 */
void i2o_device_remove(struct i2o_device *i2o_dev)
{
	i2o_driver_notify_device_remove_all(i2o_dev);
	class_device_unregister(&i2o_dev->classdev);
	list_del(&i2o_dev->list);
	device_unregister(&i2o_dev->device);
};

/**
 *	i2o_device_parse_lct - Parse a previously fetched LCT and create devices
 *	@c: I2O controller from which the LCT should be parsed.
 *
 *	The Logical Configuration Table tells us what we can talk to on the
 *	board. For every entry we create an I2O device, which is registered in
 *	the I2O core.
 *
 *	Returns 0 on success or negative error code on failure.
 */
int i2o_device_parse_lct(struct i2o_controller *c)
{
	struct i2o_device *dev, *tmp;
	i2o_lct *lct;
	int i;
	int max;

	down(&c->lct_lock);

	if (c->lct)
		kfree(c->lct);

	lct = c->dlct.virt;

	c->lct = kmalloc(lct->table_size * 4, GFP_KERNEL);
	if (!c->lct) {
		up(&c->lct_lock);
		return -ENOMEM;
	}

	if (lct->table_size * 4 > c->dlct.len) {
		memcpy_fromio(c->lct, c->dlct.virt, c->dlct.len);
		up(&c->lct_lock);
		return -EAGAIN;
	}

	memcpy_fromio(c->lct, c->dlct.virt, lct->table_size * 4);

	lct = c->lct;

	max = (lct->table_size - 3) / 9;

	pr_debug("%s: LCT has %d entries (LCT size: %d)\n", c->name, max,
		 lct->table_size);

	/* remove devices, which are not in the LCT anymore */
	list_for_each_entry_safe(dev, tmp, &c->devices, list) {
		int found = 0;

		for (i = 0; i < max; i++) {
			if (lct->lct_entry[i].tid == dev->lct_data.tid) {
				found = 1;
				break;