device.c

linux-2.6.15.6

/*
 *  drivers/s390/cio/device.c
 *  bus driver for ccw devices
 *   $Revision: 1.131 $
 *
 *    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/config.h>
#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 "cio.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;
}

/*
 * Hotplugging interface for ccw devices.
 * Heavily modeled on pci and usb hotplug.
 */
static int
ccw_hotplug (struct device *dev, char **envp, int num_envp,
	     char *buffer, int buffer_size)
{
	struct ccw_device *cdev = to_ccwdev(dev);
	int i = 0;
	int length = 0;

	if (!cdev)
		return -ENODEV;

	/* what we want to pass to /sbin/hotplug */

	envp[i++] = buffer;
	length += scnprintf(buffer, buffer_size - length, "CU_TYPE=%04X",
			   cdev->id.cu_type);
	if ((buffer_size - length <= 0) || (i >= num_envp))
		return -ENOMEM;
	++length;
	buffer += length;

	envp[i++] = buffer;
	length += scnprintf(buffer, buffer_size - length, "CU_MODEL=%02X",
			   cdev->id.cu_model);
	if ((buffer_size - length <= 0) || (i >= num_envp))
		return -ENOMEM;
	++length;
	buffer += length;

	/* The next two can be zero, that's ok for us */
	envp[i++] = buffer;
	length += scnprintf(buffer, buffer_size - length, "DEV_TYPE=%04X",
			   cdev->id.dev_type);
	if ((buffer_size - length <= 0) || (i >= num_envp))
		return -ENOMEM;
	++length;
	buffer += length;

	envp[i++] = buffer;
	length += scnprintf(buffer, buffer_size - length, "DEV_MODEL=%02X",
			   cdev->id.dev_model);
	if ((buffer_size - length <= 0) || (i >= num_envp))
		return -ENOMEM;

	envp[i] = 0;

	return 0;
}

struct bus_type ccw_bus_type = {
	.name  = "ccw",
	.match = &ccw_bus_match,
	.hotplug = &ccw_hotplug,
};

static int io_subchannel_probe (struct device *);
static int io_subchannel_remove (struct device *);
void io_subchannel_irq (struct device *);
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 device *);

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

struct workqueue_struct *ccw_device_work;
struct workqueue_struct *ccw_device_notify_work;
static wait_queue_head_t ccw_device_init_wq;
static 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 ssd_info *ssd = &sch->ssd_info;
	ssize_t ret = 0;
	int chp;

	for (chp = 0; chp < 8; chp++)
		ret += sprintf (buf+ret, "%02x ", ssd->chpid[chp]);

	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 ret;

	ret = sprintf(buf, "ccw:t%04Xm%02x",
			id->cu_type, id->cu_model);
	if (id->dev_type != 0)
		ret += sprintf(buf + ret, "dt%04Xdm%02X\n",
				id->dev_type, id->dev_model);
	else
		ret += sprintf(buf + ret, "dtdm\n");
	return ret;
}

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");
}

static void
ccw_device_remove_disconnected(struct ccw_device *cdev)
{
	struct subchannel *sch;
	/*
	 * Forced offline in disconnected state means
	 * 'throw away device'.
	 */
	sch = to_subchannel(cdev->dev.parent);
	device_unregister(&sch->dev);
	/* Reset intparm to zeroes. */
	sch->schib.pmcw.intparm = 0;
	cio_modify(sch);
	put_device(&sch->dev);
}

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 {
		pr_debug("ccw_device_offline returned %d, device %s\n",
			 ret, cdev->dev.bus_id);
		cdev->online = 1;
	}
 	return ret;
}

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 {
		pr_debug("ccw_device_online returned %d, device %s\n",
			 ret, cdev->dev.bus_id);
		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 
		pr_debug("ccw_device_offline returned %d, device %s\n",
			 ret, cdev->dev.bus_id);
	return (ret = 0) ? -ENODEV : ret;
}

static ssize_t
online_store (struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
{
	struct ccw_device *cdev = to_ccwdev(dev);
	int i, force, ret;
	char *tmp;

	if (atomic_compare_and_swap(0, 1, &cdev->private->onoff))
		return -EAGAIN;

	if (cdev->drv && !try_module_get(cdev->drv->owner)) {
		atomic_set(&cdev->private->onoff, 0);
		return -EINVAL;
	}
	if (!strncmp(buf, "force\n", count)) {
		force = 1;
		i = 1;
	} else {
		force = 0;
		i = simple_strtoul(buf, &tmp, 16);
	}
	if (i == 1) {
		/* Do device recognition, if needed. */
		if (cdev->id.cu_type == 0) {
			ret = ccw_device_recognition(cdev);
			if (ret) {
				printk(KERN_WARNING"Couldn't start recognition "
				       "for device %s (ret=%d)\n",
				       cdev->dev.bus_id, ret);
				goto out;
			}
			wait_event(cdev->private->wait_q,
				   cdev->private->flags.recog_done);
		}
		if (cdev->drv && cdev->drv->set_online)
			ccw_device_set_online(cdev);
	} else if (i == 0) {
		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);
	}
	if (force && cdev->private->state == DEV_STATE_BOXED) {
		ret = ccw_device_stlck(cdev);
		if (ret) {
			printk(KERN_WARNING"ccw_device_stlck for device %s "
			       "returned %d!\n", cdev->dev.bus_id, ret);
			goto out;
		}
		/* Do device recognition, if needed. */
		if (cdev->id.cu_type == 0) {
			cdev->private->state = DEV_STATE_NOT_OPER;
			ret = ccw_device_recognition(cdev);
			if (ret) {
				printk(KERN_WARNING"Couldn't start recognition "
				       "for device %s (ret=%d)\n",
				       cdev->dev.bus_id, ret);
				goto out;
			}
			wait_event(cdev->private->wait_q,
				   cdev->private->flags.recog_done);
		}
		if (cdev->drv && cdev->drv->set_online)
			ccw_device_set_online(cdev);
	}
	out:
	if (cdev->drv)
		module_put(cdev->drv->owner);
	atomic_set(&cdev->private->onoff, 0);
	return count;
}

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

	switch (cdev->private->state) {
	case DEV_STATE_BOXED:
		return sprintf(buf, "boxed\n");
	case DEV_STATE_DISCONNECTED:
	case DEV_STATE_DISCONNECTED_SENSE_ID:
	case DEV_STATE_NOT_OPER:
		sch = to_subchannel(dev->parent);
		if (!sch->lpm)
			return sprintf(buf, "no path\n");
		else
			return sprintf(buf, "no device\n");
	default:
		/* All other states considered fine. */
		return sprintf(buf, "good\n");
	}
}

static DEVICE_ATTR(chpids, 0444, chpids_show, NULL);
static DEVICE_ATTR(pimpampom, 0444, pimpampom_show, NULL);
static DEVICE_ATTR(devtype, 0444, devtype_show, NULL);
static DEVICE_ATTR(cutype, 0444, cutype_show, NULL);
static DEVICE_ATTR(modalias, 0444, modalias_show, NULL);
static DEVICE_ATTR(online, 0644, online_show, online_store);
extern struct device_attribute dev_attr_cmb_enable;
static DEVICE_ATTR(availability, 0444, available_show, NULL);

static struct attribute * subch_attrs[] = {
	&dev_attr_chpids.attr,
	&dev_attr_pimpampom.attr,
	NULL,
};

static struct attribute_group subch_attr_group = {
	.attrs = subch_attrs,
};

static inline int
subchannel_add_files (struct device *dev)
{
	return sysfs_create_group(&dev->kobj, &subch_attr_group);
}

static struct attribute * ccwdev_attrs[] = {
	&dev_attr_devtype.attr,
	&dev_attr_cutype.attr,
	&dev_attr_modalias.attr,
	&dev_attr_online.attr,
	&dev_attr_cmb_enable.attr,
	&dev_attr_availability.attr,
	NULL,
};

static struct attribute_group ccwdev_attr_group = {
	.attrs = ccwdev_attrs,
};

static inline int
device_add_files (struct device *dev)
{
	return sysfs_create_group(&dev->kobj, &ccwdev_attr_group);
}

static inline void
device_remove_files(struct device *dev)
{
	sysfs_remove_group(&dev->kobj, &ccwdev_attr_group);
}

/* this is a simple abstraction for device_register that sets the
 * correct bus type and adds the bus specific files */
int
ccw_device_register(struct ccw_device *cdev)
{
	struct device *dev = &cdev->dev;
	int ret;

	dev->bus = &ccw_bus_type;

	if ((ret = device_add(dev)))
		return ret;

	set_bit(1, &cdev->private->registered);
	if ((ret = device_add_files(dev))) {
		if (test_and_clear_bit(1, &cdev->private->registered))
			device_del(dev);
	}
	return ret;
}

struct match_data {
	unsigned int  devno;
	struct ccw_device * sibling;
};

static int
match_devno(struct device * dev, void * data)
{
	struct match_data * d = (struct match_data *)data;
	struct ccw_device * cdev;

	cdev = to_ccwdev(dev);
	if ((cdev->private->state == DEV_STATE_DISCONNECTED) &&
	    (cdev->private->devno == d->devno) &&
	    (cdev != d->sibling)) {
		cdev->private->state = DEV_STATE_NOT_OPER;
		return 1;
	}
	return 0;
}

static struct ccw_device *
get_disc_ccwdev_by_devno(unsigned int devno, struct ccw_device *sibling)
{
	struct device *dev;
	struct match_data data = {
		.devno  = devno,
		.sibling = sibling,
	};

	dev = bus_find_device(&ccw_bus_type, NULL, &data, match_devno);

	return dev ? to_ccwdev(dev) : NULL;
}

static void
ccw_device_add_changed(void *data)
{

	struct ccw_device *cdev;

	cdev = (struct ccw_device *)data;
	if (device_add(&cdev->dev)) {