ap_bus.c

linux 内核源代码

/*
 * linux/drivers/s390/crypto/ap_bus.c
 *
 * Copyright (C) 2006 IBM Corporation
 * Author(s): Cornelia Huck <[e-mail]>
 *	      Martin Schwidefsky <[e-mail]>
 *	      Ralph Wuerthner <[e-mail]>
 *
 * Adjunct processor bus.
 *
 * 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, or (at your option)
 * any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/err.h>
#include <linux/interrupt.h>
#include <linux/workqueue.h>
#include <linux/notifier.h>
#include <linux/kthread.h>
#include <linux/mutex.h>
#include <asm/s390_rdev.h>
#include <asm/reset.h>

#include "ap_bus.h"

/* Some prototypes. */
static void ap_scan_bus(struct work_struct *);
static void ap_poll_all(unsigned long);
static void ap_poll_timeout(unsigned long);
static int ap_poll_thread_start(void);
static void ap_poll_thread_stop(void);
static void ap_request_timeout(unsigned long);

/**
 * Module description.
 */
MODULE_AUTHOR("IBM Corporation");
MODULE_DESCRIPTION("Adjunct Processor Bus driver, "
		   "Copyright 2006 IBM Corporation");
MODULE_LICENSE("GPL");

/**
 * Module parameter
 */
int ap_domain_index = -1;	/* Adjunct Processor Domain Index */
module_param_named(domain, ap_domain_index, int, 0000);
MODULE_PARM_DESC(domain, "domain index for ap devices");
EXPORT_SYMBOL(ap_domain_index);

static int ap_thread_flag = 1;
module_param_named(poll_thread, ap_thread_flag, int, 0000);
MODULE_PARM_DESC(poll_thread, "Turn on/off poll thread, default is 1 (on).");

static struct device *ap_root_device = NULL;
static DEFINE_SPINLOCK(ap_device_lock);
static LIST_HEAD(ap_device_list);

/**
 * Workqueue & timer for bus rescan.
 */
static struct workqueue_struct *ap_work_queue;
static struct timer_list ap_config_timer;
static int ap_config_time = AP_CONFIG_TIME;
static DECLARE_WORK(ap_config_work, ap_scan_bus);

/**
 * Tasklet & timer for AP request polling.
 */
static struct timer_list ap_poll_timer = TIMER_INITIALIZER(ap_poll_timeout,0,0);
static DECLARE_TASKLET(ap_tasklet, ap_poll_all, 0);
static atomic_t ap_poll_requests = ATOMIC_INIT(0);
static DECLARE_WAIT_QUEUE_HEAD(ap_poll_wait);
static struct task_struct *ap_poll_kthread = NULL;
static DEFINE_MUTEX(ap_poll_thread_mutex);

/**
 * Test if ap instructions are available.
 *
 * Returns 0 if the ap instructions are installed.
 */
static inline int ap_instructions_available(void)
{
	register unsigned long reg0 asm ("0") = AP_MKQID(0,0);
	register unsigned long reg1 asm ("1") = -ENODEV;
	register unsigned long reg2 asm ("2") = 0UL;

	asm volatile(
		"   .long 0xb2af0000\n"		/* PQAP(TAPQ) */
		"0: la    %1,0\n"
		"1:\n"
		EX_TABLE(0b, 1b)
		: "+d" (reg0), "+d" (reg1), "+d" (reg2) : : "cc" );
	return reg1;
}

/**
 * Test adjunct processor queue.
 * @qid: the ap queue number
 * @queue_depth: pointer to queue depth value
 * @device_type: pointer to device type value
 *
 * Returns ap queue status structure.
 */
static inline struct ap_queue_status
ap_test_queue(ap_qid_t qid, int *queue_depth, int *device_type)
{
	register unsigned long reg0 asm ("0") = qid;
	register struct ap_queue_status reg1 asm ("1");
	register unsigned long reg2 asm ("2") = 0UL;

	asm volatile(".long 0xb2af0000"		/* PQAP(TAPQ) */
		     : "+d" (reg0), "=d" (reg1), "+d" (reg2) : : "cc");
	*device_type = (int) (reg2 >> 24);
	*queue_depth = (int) (reg2 & 0xff);
	return reg1;
}

/**
 * Reset adjunct processor queue.
 * @qid: the ap queue number
 *
 * Returns ap queue status structure.
 */
static inline struct ap_queue_status ap_reset_queue(ap_qid_t qid)
{
	register unsigned long reg0 asm ("0") = qid | 0x01000000UL;
	register struct ap_queue_status reg1 asm ("1");
	register unsigned long reg2 asm ("2") = 0UL;

	asm volatile(
		".long 0xb2af0000"		/* PQAP(RAPQ) */
		: "+d" (reg0), "=d" (reg1), "+d" (reg2) : : "cc");
	return reg1;
}

/**
 * Send message to adjunct processor queue.
 * @qid: the ap queue number
 * @psmid: the program supplied message identifier
 * @msg: the message text
 * @length: the message length
 *
 * Returns ap queue status structure.
 *
 * Condition code 1 on NQAP can't happen because the L bit is 1.
 *
 * Condition code 2 on NQAP also means the send is incomplete,
 * because a segment boundary was reached. The NQAP is repeated.
 */
static inline struct ap_queue_status
__ap_send(ap_qid_t qid, unsigned long long psmid, void *msg, size_t length)
{
	typedef struct { char _[length]; } msgblock;
	register unsigned long reg0 asm ("0") = qid | 0x40000000UL;
	register struct ap_queue_status reg1 asm ("1");
	register unsigned long reg2 asm ("2") = (unsigned long) msg;
	register unsigned long reg3 asm ("3") = (unsigned long) length;
	register unsigned long reg4 asm ("4") = (unsigned int) (psmid >> 32);
	register unsigned long reg5 asm ("5") = (unsigned int) psmid;

	asm volatile (
		"0: .long 0xb2ad0042\n"		/* DQAP */
		"   brc   2,0b"
		: "+d" (reg0), "=d" (reg1), "+d" (reg2), "+d" (reg3)
		: "d" (reg4), "d" (reg5), "m" (*(msgblock *) msg)
		: "cc" );
	return reg1;
}

int ap_send(ap_qid_t qid, unsigned long long psmid, void *msg, size_t length)
{
	struct ap_queue_status status;

	status = __ap_send(qid, psmid, msg, length);
	switch (status.response_code) {
	case AP_RESPONSE_NORMAL:
		return 0;
	case AP_RESPONSE_Q_FULL:
	case AP_RESPONSE_RESET_IN_PROGRESS:
		return -EBUSY;
	default:	/* Device is gone. */
		return -ENODEV;
	}
}
EXPORT_SYMBOL(ap_send);

/*
 * Receive message from adjunct processor queue.
 * @qid: the ap queue number
 * @psmid: pointer to program supplied message identifier
 * @msg: the message text
 * @length: the message length
 *
 * Returns ap queue status structure.
 *
 * Condition code 1 on DQAP means the receive has taken place
 * but only partially.	The response is incomplete, hence the
 * DQAP is repeated.
 *
 * Condition code 2 on DQAP also means the receive is incomplete,
 * this time because a segment boundary was reached. Again, the
 * DQAP is repeated.
 *
 * Note that gpr2 is used by the DQAP instruction to keep track of
 * any 'residual' length, in case the instruction gets interrupted.
 * Hence it gets zeroed before the instruction.
 */
static inline struct ap_queue_status
__ap_recv(ap_qid_t qid, unsigned long long *psmid, void *msg, size_t length)
{
	typedef struct { char _[length]; } msgblock;
	register unsigned long reg0 asm("0") = qid | 0x80000000UL;
	register struct ap_queue_status reg1 asm ("1");
	register unsigned long reg2 asm("2") = 0UL;
	register unsigned long reg4 asm("4") = (unsigned long) msg;
	register unsigned long reg5 asm("5") = (unsigned long) length;
	register unsigned long reg6 asm("6") = 0UL;
	register unsigned long reg7 asm("7") = 0UL;


	asm volatile(
		"0: .long 0xb2ae0064\n"
		"   brc   6,0b\n"
		: "+d" (reg0), "=d" (reg1), "+d" (reg2),
		"+d" (reg4), "+d" (reg5), "+d" (reg6), "+d" (reg7),
		"=m" (*(msgblock *) msg) : : "cc" );
	*psmid = (((unsigned long long) reg6) << 32) + reg7;
	return reg1;
}

int ap_recv(ap_qid_t qid, unsigned long long *psmid, void *msg, size_t length)
{
	struct ap_queue_status status;

	status = __ap_recv(qid, psmid, msg, length);
	switch (status.response_code) {
	case AP_RESPONSE_NORMAL:
		return 0;
	case AP_RESPONSE_NO_PENDING_REPLY:
		if (status.queue_empty)
			return -ENOENT;
		return -EBUSY;
	case AP_RESPONSE_RESET_IN_PROGRESS:
		return -EBUSY;
	default:
		return -ENODEV;
	}
}
EXPORT_SYMBOL(ap_recv);

/**
 * Check if an AP queue is available. The test is repeated for
 * AP_MAX_RESET times.
 * @qid: the ap queue number
 * @queue_depth: pointer to queue depth value
 * @device_type: pointer to device type value
 */
static int ap_query_queue(ap_qid_t qid, int *queue_depth, int *device_type)
{
	struct ap_queue_status status;
	int t_depth, t_device_type, rc, i;

	rc = -EBUSY;
	for (i = 0; i < AP_MAX_RESET; i++) {
		status = ap_test_queue(qid, &t_depth, &t_device_type);
		switch (status.response_code) {
		case AP_RESPONSE_NORMAL:
			*queue_depth = t_depth + 1;
			*device_type = t_device_type;
			rc = 0;
			break;
		case AP_RESPONSE_Q_NOT_AVAIL:
			rc = -ENODEV;
			break;
		case AP_RESPONSE_RESET_IN_PROGRESS:
			break;
		case AP_RESPONSE_DECONFIGURED:
			rc = -ENODEV;
			break;
		case AP_RESPONSE_CHECKSTOPPED:
			rc = -ENODEV;
			break;
		case AP_RESPONSE_BUSY:
			break;
		default:
			BUG();
		}
		if (rc != -EBUSY)
			break;
		if (i < AP_MAX_RESET - 1)
			udelay(5);
	}
	return rc;
}

/**
 * Reset an AP queue and wait for it to become available again.
 * @qid: the ap queue number
 */
static int ap_init_queue(ap_qid_t qid)
{
	struct ap_queue_status status;
	int rc, dummy, i;

	rc = -ENODEV;
	status = ap_reset_queue(qid);
	for (i = 0; i < AP_MAX_RESET; i++) {
		switch (status.response_code) {
		case AP_RESPONSE_NORMAL:
			if (status.queue_empty)
				rc = 0;
			break;
		case AP_RESPONSE_Q_NOT_AVAIL:
		case AP_RESPONSE_DECONFIGURED:
		case AP_RESPONSE_CHECKSTOPPED:
			i = AP_MAX_RESET;	/* return with -ENODEV */
			break;
		case AP_RESPONSE_RESET_IN_PROGRESS:
			rc = -EBUSY;
		case AP_RESPONSE_BUSY:
		default:
			break;
		}
		if (rc != -ENODEV && rc != -EBUSY)
			break;
		if (i < AP_MAX_RESET - 1) {
			udelay(5);
			status = ap_test_queue(qid, &dummy, &dummy);
		}
	}
	return rc;
}

/**
 * Arm request timeout if a AP device was idle and a new request is submitted.
 */
static void ap_increase_queue_count(struct ap_device *ap_dev)
{
	int timeout = ap_dev->drv->request_timeout;

	ap_dev->queue_count++;
	if (ap_dev->queue_count == 1) {
		mod_timer(&ap_dev->timeout, jiffies + timeout);
		ap_dev->reset = AP_RESET_ARMED;
	}
}

/**
 * AP device is still alive, re-schedule request timeout if there are still
 * pending requests.
 */
static void ap_decrease_queue_count(struct ap_device *ap_dev)
{
	int timeout = ap_dev->drv->request_timeout;

	ap_dev->queue_count--;
	if (ap_dev->queue_count > 0)
		mod_timer(&ap_dev->timeout, jiffies + timeout);
	else
		/**
		 * The timeout timer should to be disabled now - since
		 * del_timer_sync() is very expensive, we just tell via the
		 * reset flag to ignore the pending timeout timer.
		 */
		ap_dev->reset = AP_RESET_IGNORE;
}

/**
 * AP device related attributes.
 */
static ssize_t ap_hwtype_show(struct device *dev,
			      struct device_attribute *attr, char *buf)
{
	struct ap_device *ap_dev = to_ap_dev(dev);
	return snprintf(buf, PAGE_SIZE, "%d\n", ap_dev->device_type);
}
static DEVICE_ATTR(hwtype, 0444, ap_hwtype_show, NULL);

static ssize_t ap_depth_show(struct device *dev, struct device_attribute *attr,
			     char *buf)
{
	struct ap_device *ap_dev = to_ap_dev(dev);
	return snprintf(buf, PAGE_SIZE, "%d\n", ap_dev->queue_depth);
}
static DEVICE_ATTR(depth, 0444, ap_depth_show, NULL);

static ssize_t ap_request_count_show(struct device *dev,
				     struct device_attribute *attr,
				     char *buf)
{
	struct ap_device *ap_dev = to_ap_dev(dev);
	int rc;

	spin_lock_bh(&ap_dev->lock);
	rc = snprintf(buf, PAGE_SIZE, "%d\n", ap_dev->total_request_count);
	spin_unlock_bh(&ap_dev->lock);
	return rc;
}

static DEVICE_ATTR(request_count, 0444, ap_request_count_show, NULL);

static ssize_t ap_modalias_show(struct device *dev,
				struct device_attribute *attr, char *buf)
{
	return sprintf(buf, "ap:t%02X", to_ap_dev(dev)->device_type);
}

static DEVICE_ATTR(modalias, 0444, ap_modalias_show, NULL);

static struct attribute *ap_dev_attrs[] = {
	&dev_attr_hwtype.attr,
	&dev_attr_depth.attr,
	&dev_attr_request_count.attr,
	&dev_attr_modalias.attr,
	NULL
};
static struct attribute_group ap_dev_attr_group = {
	.attrs = ap_dev_attrs
};

/**
 * AP bus driver registration/unregistration.
 */
static int ap_bus_match(struct device *dev, struct device_driver *drv)
{
	struct ap_device *ap_dev = to_ap_dev(dev);
	struct ap_driver *ap_drv = to_ap_drv(drv);
	struct ap_device_id *id;

	/**
	 * Compare device type of the device with the list of
	 * supported types of the device_driver.
	 */
	for (id = ap_drv->ids; id->match_flags; id++) {
		if ((id->match_flags & AP_DEVICE_ID_MATCH_DEVICE_TYPE) &&
		    (id->dev_type != ap_dev->device_type))
			continue;
		return 1;