chp.c

linux 内核源代码

/*
 *  drivers/s390/cio/chp.c
 *
 *    Copyright IBM Corp. 1999,2007
 *    Author(s): Cornelia Huck ([e-mail])
 *		 Arnd Bergmann ([e-mail])
 *		 Peter Oberparleiter <[e-mail]>
 */

#include <linux/bug.h>
#include <linux/workqueue.h>
#include <linux/spinlock.h>
#include <linux/init.h>
#include <linux/jiffies.h>
#include <linux/wait.h>
#include <linux/mutex.h>
#include <linux/errno.h>
#include <asm/chpid.h>
#include <asm/sclp.h>

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

#define to_channelpath(device) container_of(device, struct channel_path, dev)
#define CHP_INFO_UPDATE_INTERVAL	1*HZ

enum cfg_task_t {
	cfg_none,
	cfg_configure,
	cfg_deconfigure
};

/* Map for pending configure tasks. */
static enum cfg_task_t chp_cfg_task[__MAX_CSSID + 1][__MAX_CHPID + 1];
static DEFINE_MUTEX(cfg_lock);
static int cfg_busy;

/* Map for channel-path status. */
static struct sclp_chp_info chp_info;
static DEFINE_MUTEX(info_lock);

/* Time after which channel-path status may be outdated. */
static unsigned long chp_info_expires;

/* Workqueue to perform pending configure tasks. */
static struct workqueue_struct *chp_wq;
static struct work_struct cfg_work;

/* Wait queue for configure completion events. */
static wait_queue_head_t cfg_wait_queue;

/* Return channel_path struct for given chpid. */
static inline struct channel_path *chpid_to_chp(struct chp_id chpid)
{
	return channel_subsystems[chpid.cssid]->chps[chpid.id];
}

/* Set vary state for given chpid. */
static void set_chp_logically_online(struct chp_id chpid, int onoff)
{
	chpid_to_chp(chpid)->state = onoff;
}

/* On succes return 0 if channel-path is varied offline, 1 if it is varied
 * online. Return -ENODEV if channel-path is not registered. */
int chp_get_status(struct chp_id chpid)
{
	return (chpid_to_chp(chpid) ? chpid_to_chp(chpid)->state : -ENODEV);
}

/**
 * chp_get_sch_opm - return opm for subchannel
 * @sch: subchannel
 *
 * Calculate and return the operational path mask (opm) based on the chpids
 * used by the subchannel and the status of the associated channel-paths.
 */
u8 chp_get_sch_opm(struct subchannel *sch)
{
	struct chp_id chpid;
	int opm;
	int i;

	opm = 0;
	chp_id_init(&chpid);
	for (i = 0; i < 8; i++) {
		opm <<= 1;
		chpid.id = sch->schib.pmcw.chpid[i];
		if (chp_get_status(chpid) != 0)
			opm |= 1;
	}
	return opm;
}

/**
 * chp_is_registered - check if a channel-path is registered
 * @chpid: channel-path ID
 *
 * Return non-zero if a channel-path with the given chpid is registered,
 * zero otherwise.
 */
int chp_is_registered(struct chp_id chpid)
{
	return chpid_to_chp(chpid) != NULL;
}

/*
 * Function: s390_vary_chpid
 * Varies the specified chpid online or offline
 */
static int s390_vary_chpid(struct chp_id chpid, int on)
{
	char dbf_text[15];
	int status;

	sprintf(dbf_text, on?"varyon%x.%02x":"varyoff%x.%02x", chpid.cssid,
		chpid.id);
	CIO_TRACE_EVENT(2, dbf_text);

	status = chp_get_status(chpid);
	if (!on && !status) {
		printk(KERN_ERR "cio: chpid %x.%02x is already offline\n",
		       chpid.cssid, chpid.id);
		return -EINVAL;
	}

	set_chp_logically_online(chpid, on);
	chsc_chp_vary(chpid, on);
	return 0;
}

/*
 * Channel measurement related functions
 */
static ssize_t chp_measurement_chars_read(struct kobject *kobj,
					  struct bin_attribute *bin_attr,
					  char *buf, loff_t off, size_t count)
{
	struct channel_path *chp;
	struct device *device;
	unsigned int size;

	device = container_of(kobj, struct device, kobj);
	chp = to_channelpath(device);
	if (!chp->cmg_chars)
		return 0;

	size = sizeof(struct cmg_chars);

	if (off > size)
		return 0;
	if (off + count > size)
		count = size - off;
	memcpy(buf, chp->cmg_chars + off, count);
	return count;
}

static struct bin_attribute chp_measurement_chars_attr = {
	.attr = {
		.name = "measurement_chars",
		.mode = S_IRUSR,
	},
	.size = sizeof(struct cmg_chars),
	.read = chp_measurement_chars_read,
};

static void chp_measurement_copy_block(struct cmg_entry *buf,
				       struct channel_subsystem *css,
				       struct chp_id chpid)
{
	void *area;
	struct cmg_entry *entry, reference_buf;
	int idx;

	if (chpid.id < 128) {
		area = css->cub_addr1;
		idx = chpid.id;
	} else {
		area = css->cub_addr2;
		idx = chpid.id - 128;
	}
	entry = area + (idx * sizeof(struct cmg_entry));
	do {
		memcpy(buf, entry, sizeof(*entry));
		memcpy(&reference_buf, entry, sizeof(*entry));
	} while (reference_buf.values[0] != buf->values[0]);
}

static ssize_t chp_measurement_read(struct kobject *kobj,
				    struct bin_attribute *bin_attr,
				    char *buf, loff_t off, size_t count)
{
	struct channel_path *chp;
	struct channel_subsystem *css;
	struct device *device;
	unsigned int size;

	device = container_of(kobj, struct device, kobj);
	chp = to_channelpath(device);
	css = to_css(chp->dev.parent);

	size = sizeof(struct cmg_entry);

	/* Only allow single reads. */
	if (off || count < size)
		return 0;
	chp_measurement_copy_block((struct cmg_entry *)buf, css, chp->chpid);
	count = size;
	return count;
}

static struct bin_attribute chp_measurement_attr = {
	.attr = {
		.name = "measurement",
		.mode = S_IRUSR,
	},
	.size = sizeof(struct cmg_entry),
	.read = chp_measurement_read,
};

void chp_remove_cmg_attr(struct channel_path *chp)
{
	device_remove_bin_file(&chp->dev, &chp_measurement_chars_attr);
	device_remove_bin_file(&chp->dev, &chp_measurement_attr);
}

int chp_add_cmg_attr(struct channel_path *chp)
{
	int ret;

	ret = device_create_bin_file(&chp->dev, &chp_measurement_chars_attr);
	if (ret)
		return ret;
	ret = device_create_bin_file(&chp->dev, &chp_measurement_attr);
	if (ret)
		device_remove_bin_file(&chp->dev, &chp_measurement_chars_attr);
	return ret;
}

/*
 * Files for the channel path entries.
 */
static ssize_t chp_status_show(struct device *dev,
			       struct device_attribute *attr, char *buf)
{
	struct channel_path *chp = to_channelpath(dev);

	if (!chp)
		return 0;
	return (chp_get_status(chp->chpid) ? sprintf(buf, "online\n") :
		sprintf(buf, "offline\n"));
}

static ssize_t chp_status_write(struct device *dev,
				struct device_attribute *attr,
				const char *buf, size_t count)
{
	struct channel_path *cp = to_channelpath(dev);
	char cmd[10];
	int num_args;
	int error;

	num_args = sscanf(buf, "%5s", cmd);
	if (!num_args)
		return count;

	if (!strnicmp(cmd, "on", 2) || !strcmp(cmd, "1"))
		error = s390_vary_chpid(cp->chpid, 1);
	else if (!strnicmp(cmd, "off", 3) || !strcmp(cmd, "0"))
		error = s390_vary_chpid(cp->chpid, 0);
	else
		error = -EINVAL;

	return error < 0 ? error : count;

}

static DEVICE_ATTR(status, 0644, chp_status_show, chp_status_write);

static ssize_t chp_configure_show(struct device *dev,
				  struct device_attribute *attr, char *buf)
{
	struct channel_path *cp;
	int status;

	cp = to_channelpath(dev);
	status = chp_info_get_status(cp->chpid);
	if (status < 0)
		return status;

	return snprintf(buf, PAGE_SIZE, "%d\n", status);
}

static int cfg_wait_idle(void);

static ssize_t chp_configure_write(struct device *dev,
				   struct device_attribute *attr,
				   const char *buf, size_t count)
{
	struct channel_path *cp;
	int val;
	char delim;

	if (sscanf(buf, "%d %c", &val, &delim) != 1)
		return -EINVAL;
	if (val != 0 && val != 1)
		return -EINVAL;
	cp = to_channelpath(dev);
	chp_cfg_schedule(cp->chpid, val);
	cfg_wait_idle();

	return count;
}

static DEVICE_ATTR(configure, 0644, chp_configure_show, chp_configure_write);

static ssize_t chp_type_show(struct device *dev, struct device_attribute *attr,
			     char *buf)
{
	struct channel_path *chp = to_channelpath(dev);

	if (!chp)
		return 0;
	return sprintf(buf, "%x\n", chp->desc.desc);
}

static DEVICE_ATTR(type, 0444, chp_type_show, NULL);

static ssize_t chp_cmg_show(struct device *dev, struct device_attribute *attr,
			    char *buf)
{
	struct channel_path *chp = to_channelpath(dev);

	if (!chp)
		return 0;