path: root/drivers/s390/char/sclp.c

/*
 * core function to access sclp interface
 *
 * Copyright IBM Corp. 1999, 2009
 *
 * Author(s): Martin Peschke <mpeschke@de.ibm.com>
 *	      Martin Schwidefsky <schwidefsky@de.ibm.com>
 */

#include <linux/module.h>
#include <linux/err.h>
#include <linux/spinlock.h>
#include <linux/interrupt.h>
#include <linux/timer.h>
#include <linux/reboot.h>
#include <linux/jiffies.h>
#include <linux/init.h>
#include <linux/suspend.h>
#include <linux/completion.h>
#include <linux/platform_device.h>
#include <asm/types.h>
#include <asm/s390_ext.h>

#include "sclp.h"

#define SCLP_HEADER		"sclp: "

/* Structure for register_early_external_interrupt. */
static ext_int_info_t ext_int_info_hwc;

/* Lock to protect internal data consistency. */
static DEFINE_SPINLOCK(sclp_lock);

/* Mask of events that we can send to the sclp interface. */
static sccb_mask_t sclp_receive_mask;

/* Mask of events that we can receive from the sclp interface. */
static sccb_mask_t sclp_send_mask;

/* List of registered event listeners and senders. */
static struct list_head sclp_reg_list;

/* List of queued requests. */
static struct list_head sclp_req_queue;

/* Data for read and and init requests. */
static struct sclp_req sclp_read_req;
static struct sclp_req sclp_init_req;
static char sclp_read_sccb[PAGE_SIZE] __attribute__((__aligned__(PAGE_SIZE)));
static char sclp_init_sccb[PAGE_SIZE] __attribute__((__aligned__(PAGE_SIZE)));

/* Suspend request */
static DECLARE_COMPLETION(sclp_request_queue_flushed);

static void sclp_suspend_req_cb(struct sclp_req *req, void *data)
{
	complete(&sclp_request_queue_flushed);
}

static struct sclp_req sclp_suspend_req;

/* Timer for request retries. */
static struct timer_list sclp_request_timer;

/* Internal state: is the driver initialized? */
static volatile enum sclp_init_state_t {
	sclp_init_state_uninitialized,
	sclp_init_state_initializing,
	sclp_init_state_initialized
} sclp_init_state = sclp_init_state_uninitialized;

/* Internal state: is a request active at the sclp? */
static volatile enum sclp_running_state_t {
	sclp_running_state_idle,
	sclp_running_state_running,
	sclp_running_state_reset_pending
} sclp_running_state = sclp_running_state_idle;

/* Internal state: is a read request pending? */
static volatile enum sclp_reading_state_t {
	sclp_reading_state_idle,
	sclp_reading_state_reading
} sclp_reading_state = sclp_reading_state_idle;

/* Internal state: is the driver currently serving requests? */
static volatile enum sclp_activation_state_t {
	sclp_activation_state_active,
	sclp_activation_state_deactivating,
	sclp_activation_state_inactive,
	sclp_activation_state_activating
} sclp_activation_state = sclp_activation_state_active;

/* Internal state: is an init mask request pending? */
static volatile enum sclp_mask_state_t {
	sclp_mask_state_idle,
	sclp_mask_state_initializing
} sclp_mask_state = sclp_mask_state_idle;

/* Internal state: is the driver suspended? */
static enum sclp_suspend_state_t {
	sclp_suspend_state_running,
	sclp_suspend_state_suspended,
} sclp_suspend_state = sclp_suspend_state_running;

/* Maximum retry counts */
#define SCLP_INIT_RETRY		3
#define SCLP_MASK_RETRY		3

/* Timeout intervals in seconds.*/
#define SCLP_BUSY_INTERVAL	10
#define SCLP_RETRY_INTERVAL	30

static void sclp_process_queue(void);
static void __sclp_make_read_req(void);
static int sclp_init_mask(int calculate);
static int sclp_init(void);

/* Perform service call. Return 0 on success, non-zero otherwise. */
int
sclp_service_call(sclp_cmdw_t command, void *sccb)
{
	int cc;

	asm volatile(
		"	.insn	rre,0xb2200000,%1,%2\n"  /* servc %1,%2 */
		"	ipm	%0\n"
		"	srl	%0,28"
		: "=&d" (cc) : "d" (command), "a" (__pa(sccb))
		: "cc", "memory");
	if (cc == 3)
		return -EIO;
	if (cc == 2)
		return -EBUSY;
	return 0;
}


static void
__sclp_queue_read_req(void)
{
	if (sclp_reading_state == sclp_reading_state_idle) {
		sclp_reading_state = sclp_reading_state_reading;
		__sclp_make_read_req();
		/* Add request to head of queue */
		list_add(&sclp_read_req.list, &sclp_req_queue);
	}
}

/* Set up request retry timer. Called while sclp_lock is locked. */
static inline void
__sclp_set_request_timer(unsigned long time, void (*function)(unsigned long),
			 unsigned long data)
{
	del_timer(&sclp_request_timer);
	sclp_request_timer.function = function;
	sclp_request_timer.data = data