device.c

linux 内核源代码

/*
 *  drivers/s390/cio/device.c
 *  bus driver for ccw devices
 *
 *    Copyright (C) 2002 IBM Deutschland Entwicklung GmbH,
 *			 IBM Corporation
 *    Author(s): Arnd Bergmann ([e-mail])
 *		 Cornelia Huck ([e-mail])
 *		 Martin Schwidefsky ([e-mail])
 */
#include <linux/module.h>
#include <linux/init.h>
#include <linux/spinlock.h>
#include <linux/errno.h>
#include <linux/err.h>
#include <linux/slab.h>
#include <linux/list.h>
#include <linux/device.h>
#include <linux/workqueue.h>

#include <asm/ccwdev.h>
#include <asm/cio.h>
#include <asm/param.h>		/* HZ */
#include <asm/cmb.h>

#include "cio.h"
#include "cio_debug.h"
#include "css.h"
#include "device.h"
#include "ioasm.h"

/******************* bus type handling ***********************/

/* The Linux driver model distinguishes between a bus type and
 * the bus itself. Of course we only have one channel
 * subsystem driver and one channel system per machine, but
 * we still use the abstraction. T.R. says it's a good idea. */
static int
ccw_bus_match (struct device * dev, struct device_driver * drv)
{
	struct ccw_device *cdev = to_ccwdev(dev);
	struct ccw_driver *cdrv = to_ccwdrv(drv);
	const struct ccw_device_id *ids = cdrv->ids, *found;

	if (!ids)
		return 0;

	found = ccw_device_id_match(ids, &cdev->id);
	if (!found)
		return 0;

	cdev->id.driver_info = found->driver_info;

	return 1;
}

/* Store modalias string delimited by prefix/suffix string into buffer with
 * specified size. Return length of resulting string (excluding trailing '\0')
 * even if string doesn't fit buffer (snprintf semantics). */
static int snprint_alias(char *buf, size_t size,
			 struct ccw_device_id *id, const char *suffix)
{
	int len;

	len = snprintf(buf, size, "ccw:t%04Xm%02X", id->cu_type, id->cu_model);
	if (len > size)
		return len;
	buf += len;
	size -= len;

	if (id->dev_type != 0)
		len += snprintf(buf, size, "dt%04Xdm%02X%s", id->dev_type,
				id->dev_model, suffix);
	else
		len += snprintf(buf, size, "dtdm%s", suffix);

	return len;
}

/* Set up environment variables for ccw device uevent. Return 0 on success,
 * non-zero otherwise. */
static int ccw_uevent(struct device *dev, struct kobj_uevent_env *env)
{
	struct ccw_device *cdev = to_ccwdev(dev);
	struct ccw_device_id *id = &(cdev->id);
	int ret;
	char modalias_buf[30];

	/* CU_TYPE= */
	ret = add_uevent_var(env, "CU_TYPE=%04X", id->cu_type);
	if (ret)
		return ret;

	/* CU_MODEL= */
	ret = add_uevent_var(env, "CU_MODEL=%02X", id->cu_model);
	if (ret)
		return ret;

	/* The next two can be zero, that's ok for us */
	/* DEV_TYPE= */
	ret = add_uevent_var(env, "DEV_TYPE=%04X", id->dev_type);
	if (ret)
		return ret;

	/* DEV_MODEL= */
	ret = add_uevent_var(env, "DEV_MODEL=%02X", id->dev_model);
	if (ret)
		return ret;

	/* MODALIAS=  */
	snprint_alias(modalias_buf, sizeof(modalias_buf), id, "");
	ret = add_uevent_var(env, "MODALIAS=%s", modalias_buf);
	return ret;
}

struct bus_type ccw_bus_type;

static int io_subchannel_probe (struct subchannel *);
static int io_subchannel_remove (struct subchannel *);
static int io_subchannel_notify(struct device *, int);
static void io_subchannel_verify(struct device *);
static void io_subchannel_ioterm(struct device *);
static void io_subchannel_shutdown(struct subchannel *);

static struct css_driver io_subchannel_driver = {
	.subchannel_type = SUBCHANNEL_TYPE_IO,
	.drv = {
		.name = "io_subchannel",
		.bus  = &css_bus_type,
	},
	.irq = io_subchannel_irq,
	.notify = io_subchannel_notify,
	.verify = io_subchannel_verify,
	.termination = io_subchannel_ioterm,
	.probe = io_subchannel_probe,
	.remove = io_subchannel_remove,
	.shutdown = io_subchannel_shutdown,
};

struct workqueue_struct *ccw_device_work;
struct workqueue_struct *ccw_device_notify_work;
wait_queue_head_t ccw_device_init_wq;
atomic_t ccw_device_init_count;

static int __init
init_ccw_bus_type (void)
{
	int ret;

	init_waitqueue_head(&ccw_device_init_wq);
	atomic_set(&ccw_device_init_count, 0);

	ccw_device_work = create_singlethread_workqueue("cio");
	if (!ccw_device_work)
		return -ENOMEM; /* FIXME: better errno ? */
	ccw_device_notify_work = create_singlethread_workqueue("cio_notify");
	if (!ccw_device_notify_work) {
		ret = -ENOMEM; /* FIXME: better errno ? */
		goto out_err;
	}
	slow_path_wq = create_singlethread_workqueue("kslowcrw");
	if (!slow_path_wq) {
		ret = -ENOMEM; /* FIXME: better errno ? */
		goto out_err;
	}
	if ((ret = bus_register (&ccw_bus_type)))
		goto out_err;

	if ((ret = driver_register(&io_subchannel_driver.drv)))
		goto out_err;

	wait_event(ccw_device_init_wq,
		   atomic_read(&ccw_device_init_count) == 0);
	flush_workqueue(ccw_device_work);
	return 0;
out_err:
	if (ccw_device_work)
		destroy_workqueue(ccw_device_work);
	if (ccw_device_notify_work)
		destroy_workqueue(ccw_device_notify_work);
	if (slow_path_wq)
		destroy_workqueue(slow_path_wq);
	return ret;
}

static void __exit
cleanup_ccw_bus_type (void)
{
	driver_unregister(&io_subchannel_driver.drv);
	bus_unregister(&ccw_bus_type);
	destroy_workqueue(ccw_device_notify_work);
	destroy_workqueue(ccw_device_work);
}

subsys_initcall(init_ccw_bus_type);
module_exit(cleanup_ccw_bus_type);

/************************ device handling **************************/

/*
 * A ccw_device has some interfaces in sysfs in addition to the
 * standard ones.
 * The following entries are designed to export the information which
 * resided in 2.4 in /proc/subchannels. Subchannel and device number
 * are obvious, so they don't have an entry :)
 * TODO: Split chpids and pimpampom up? Where is "in use" in the tree?
 */
static ssize_t
chpids_show (struct device * dev, struct device_attribute *attr, char * buf)
{
	struct subchannel *sch = to_subchannel(dev);
	struct chsc_ssd_info *ssd = &sch->ssd_info;
	ssize_t ret = 0;
	int chp;
	int mask;

	for (chp = 0; chp < 8; chp++) {
		mask = 0x80 >> chp;
		if (ssd->path_mask & mask)
			ret += sprintf(buf + ret, "%02x ", ssd->chpid[chp].id);
		else
			ret += sprintf(buf + ret, "00 ");
	}
	ret += sprintf (buf+ret, "\n");
	return min((ssize_t)PAGE_SIZE, ret);
}

static ssize_t
pimpampom_show (struct device * dev, struct device_attribute *attr, char * buf)
{
	struct subchannel *sch = to_subchannel(dev);
	struct pmcw *pmcw = &sch->schib.pmcw;

	return sprintf (buf, "%02x %02x %02x\n",
			pmcw->pim, pmcw->pam, pmcw->pom);
}

static ssize_t
devtype_show (struct device *dev, struct device_attribute *attr, char *buf)
{
	struct ccw_device *cdev = to_ccwdev(dev);
	struct ccw_device_id *id = &(cdev->id);

	if (id->dev_type != 0)
		return sprintf(buf, "%04x/%02x\n",
				id->dev_type, id->dev_model);
	else
		return sprintf(buf, "n/a\n");
}

static ssize_t
cutype_show (struct device *dev, struct device_attribute *attr, char *buf)
{
	struct ccw_device *cdev = to_ccwdev(dev);
	struct ccw_device_id *id = &(cdev->id);

	return sprintf(buf, "%04x/%02x\n",
		       id->cu_type, id->cu_model);
}

static ssize_t
modalias_show (struct device *dev, struct device_attribute *attr, char *buf)
{
	struct ccw_device *cdev = to_ccwdev(dev);
	struct ccw_device_id *id = &(cdev->id);
	int len;

	len = snprint_alias(buf, PAGE_SIZE, id, "\n");

	return len > PAGE_SIZE ? PAGE_SIZE : len;
}

static ssize_t
online_show (struct device *dev, struct device_attribute *attr, char *buf)
{
	struct ccw_device *cdev = to_ccwdev(dev);

	return sprintf(buf, cdev->online ? "1\n" : "0\n");
}

int ccw_device_is_orphan(struct ccw_device *cdev)
{
	return sch_is_pseudo_sch(to_subchannel(cdev->dev.parent));
}

static void ccw_device_unregister(struct ccw_device *cdev)
{
	if (test_and_clear_bit(1, &cdev->private->registered))
		device_del(&cdev->dev);
}

static void ccw_device_remove_orphan_cb(struct device *dev)
{
	struct ccw_device *cdev = to_ccwdev(dev);

	ccw_device_unregister(cdev);
	put_device(&cdev->dev);
}

static void ccw_device_remove_sch_cb(struct device *dev)
{
	struct subchannel *sch;

	sch = to_subchannel(dev);
	css_sch_device_unregister(sch);
	/* Reset intparm to zeroes. */
	sch->schib.pmcw.intparm = 0;
	cio_modify(sch);
	put_device(&sch->dev);
}

static void
ccw_device_remove_disconnected(struct ccw_device *cdev)
{
	unsigned long flags;
	int rc;

	/*
	 * Forced offline in disconnected state means
	 * 'throw away device'.
	 */
	if (ccw_device_is_orphan(cdev)) {
		/*
		 * Deregister ccw device.
		 * Unfortunately, we cannot do this directly from the
		 * attribute method.
		 */
		spin_lock_irqsave(cdev->ccwlock, flags);
		cdev->private->state = DEV_STATE_NOT_OPER;
		spin_unlock_irqrestore(cdev->ccwlock, flags);
		rc = device_schedule_callback(&cdev->dev,
					      ccw_device_remove_orphan_cb);
		if (rc)
			CIO_MSG_EVENT(2, "Couldn't unregister orphan "
				      "0.%x.%04x\n",
				      cdev->private->dev_id.ssid,
				      cdev->private->dev_id.devno);
		return;
	}
	/* Deregister subchannel, which will kill the ccw device. */
	rc = device_schedule_callback(cdev->dev.parent,
				      ccw_device_remove_sch_cb);
	if (rc)
		CIO_MSG_EVENT(2, "Couldn't unregister disconnected device "
			      "0.%x.%04x\n",
			      cdev->private->dev_id.ssid,
			      cdev->private->dev_id.devno);
}

/**
 * ccw_device_set_offline() - disable a ccw device for I/O
 * @cdev: target ccw device
 *
 * This function calls the driver's set_offline() function for @cdev, if
 * given, and then disables @cdev.
 * Returns:
 *   %0 on success and a negative error value on failure.
 * Context:
 *  enabled, ccw device lock not held
 */
int ccw_device_set_offline(struct ccw_device *cdev)
{
	int ret;

	if (!cdev)
		return -ENODEV;
	if (!cdev->online || !cdev->drv)
		return -EINVAL;

	if (cdev->drv->set_offline) {
		ret = cdev->drv->set_offline(cdev);
		if (ret != 0)
			return ret;
	}
	cdev->online = 0;
	spin_lock_irq(cdev->ccwlock);
	ret = ccw_device_offline(cdev);
	if (ret == -ENODEV) {
		if (cdev->private->state != DEV_STATE_NOT_OPER) {
			cdev->private->state = DEV_STATE_OFFLINE;
			dev_fsm_event(cdev, DEV_EVENT_NOTOPER);
		}
		spin_unlock_irq(cdev->ccwlock);
		return ret;
	}
	spin_unlock_irq(cdev->ccwlock);
	if (ret == 0)
		wait_event(cdev->private->wait_q, dev_fsm_final_state(cdev));
	else {
		CIO_MSG_EVENT(2, "ccw_device_offline returned %d, "
			      "device 0.%x.%04x\n",
			      ret, cdev->private->dev_id.ssid,
			      cdev->private->dev_id.devno);
		cdev->online = 1;
	}
 	return ret;
}

/**
 * ccw_device_set_online() - enable a ccw device for I/O
 * @cdev: target ccw device
 *
 * This function first enables @cdev and then calls the driver's set_online()
 * function for @cdev, if given. If set_online() returns an error, @cdev is
 * disabled again.
 * Returns:
 *   %0 on success and a negative error value on failure.
 * Context:
 *  enabled, ccw device lock not held
 */
int ccw_device_set_online(struct ccw_device *cdev)
{
	int ret;

	if (!cdev)
		return -ENODEV;
	if (cdev->online || !cdev->drv)
		return -EINVAL;

	spin_lock_irq(cdev->ccwlock);
	ret = ccw_device_online(cdev);
	spin_unlock_irq(cdev->ccwlock);
	if (ret == 0)
		wait_event(cdev->private->wait_q, dev_fsm_final_state(cdev));
	else {
		CIO_MSG_EVENT(2, "ccw_device_online returned %d, "
			      "device 0.%x.%04x\n",
			      ret, cdev->private->dev_id.ssid,
			      cdev->private->dev_id.devno);
		return ret;
	}
	if (cdev->private->state != DEV_STATE_ONLINE)
		return -ENODEV;
	if (!cdev->drv->set_online || cdev->drv->set_online(cdev) == 0) {
		cdev->online = 1;
		return 0;
	}
	spin_lock_irq(cdev->ccwlock);
	ret = ccw_device_offline(cdev);
	spin_unlock_irq(cdev->ccwlock);
	if (ret == 0)
		wait_event(cdev->private->wait_q, dev_fsm_final_state(cdev));
	else
		CIO_MSG_EVENT(2, "ccw_device_offline returned %d, "
			      "device 0.%x.%04x\n",
			      ret, cdev->private->dev_id.ssid,
			      cdev->private->dev_id.devno);
	return (ret == 0) ? -ENODEV : ret;
}

static void online_store_handle_offline(struct ccw_device *cdev)
{
	if (cdev->private->state == DEV_STATE_DISCONNECTED)
		ccw_device_remove_disconnected(cdev);
	else if (cdev->drv && cdev->drv->set_offline)
		ccw_device_set_offline(cdev);
}

static int online_store_recog_and_online(struct ccw_device *cdev)
{
	int ret;

	/* Do device recognition, if needed. */
	if (cdev->id.cu_type == 0) {
		ret = ccw_device_recognition(cdev);
		if (ret) {
			CIO_MSG_EVENT(0, "Couldn't start recognition "
				      "for device 0.%x.%04x (ret=%d)\n",
				      cdev->private->dev_id.ssid,
				      cdev->private->dev_id.devno, ret);
			return ret;
		}
		wait_event(cdev->private->wait_q,
			   cdev->private->flags.recog_done);
	}
	if (cdev->drv && cdev->drv->set_online)
		ccw_device_set_online(cdev);
	return 0;
}
static void online_store_handle_online(struct ccw_device *cdev, int force)
{
	int ret;

	ret = online_store_recog_and_online(cdev);
	if (ret)
		return;
	if (force && cdev->private->state == DEV_STATE_BOXED) {
		ret = ccw_device_stlck(cdev);
		if (ret) {
			dev_warn(&cdev->dev,
				 "ccw_device_stlck returned %d!\n", ret);
			return;
		}
		if (cdev->id.cu_type == 0)
			cdev->private->state = DEV_STATE_NOT_OPER;
		online_store_recog_and_online(cdev);
	}