path: root/drivers/s390/crypto/ap_bus.c

/*
 * linux/drivers/s390/crypto/ap_bus.c
 *
 * Copyright (C) 2006 IBM Corporation
 * Author(s): Cornelia Huck <cornelia.huck@de.ibm.com>
 *	      Martin Schwidefsky <schwidefsky@de.ibm.com>
 *	      Ralph Wuerthner <rwuerthn@de.ibm.com>
 *
 * 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);

/**
 * 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;

/**
 * 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" (</