/*
 * Sclp "store data in absolut storage"
 *
 * Copyright IBM Corp. 2003,2007
 * Author(s): Michael Holzheu
 */

#include <linux/sched.h>
#include <asm/sclp.h>
#include <asm/debug.h>
#include <asm/ipl.h>
#include "sclp.h"
#include "sclp_rw.h"

#define TRACE(x...) debug_sprintf_event(sdias_dbf, 1, x)
#define ERROR_MSG(x...) printk ( KERN_ALERT "SDIAS: " x )

#define SDIAS_RETRIES 300
#define SDIAS_SLEEP_TICKS 50

#define EQ_STORE_DATA	0x0
#define EQ_SIZE		0x1
#define DI_FCP_DUMP	0x0
#define ASA_SIZE_32	0x0
#define ASA_SIZE_64	0x1
#define EVSTATE_ALL_STORED	0x0
#define EVSTATE_NO_DATA		0x3
#define EVSTATE_PART_STORED	0x10

static struct debug_info *sdias_dbf;

static struct sclp_register sclp_sdias_register = {
	.send_mask = EVTYP_SDIAS_MASK,
};

struct sdias_evbuf {
	struct	evbuf_header hdr;
	u8	event_qual;
	u8	data_id;
	u64	reserved2;
	u32	event_id;
	u16	reserved3;
	u8	asa_size;
	u8	event_status;
	u32	reserved4;
	u32	blk_cnt;
	u64	asa;
	u32	reserved5;
	u32	fbn;
	u32	reserved6;
	u32	lbn;
	u16	reserved7;
	u16	dbs;
} __attribute__((packed));

struct sdias_sccb {
	struct sccb_header  hdr;
	struct sdias_evbuf  evbuf;
} __attribute__((packed));

static struct sdias_sccb sccb __attribute__((aligned(4096)));

static int sclp_req_done;
static wait_queue_head_t sdias_wq;
static DEFINE_MUTEX(sdias_mutex);

static void sdias_callback(struct sclp_req *request, void *data)
{
	struct sdias_sccb *sccb;

	sccb = (struct sdias_sccb *) request->sccb;
	sclp_req_done = 1;
	wake_up(&sdias_wq); /* Inform caller, that request is complete */
	TRACE("callback done\n");
}

static int sdias_sclp_send(struct sclp_req *req)
{
	int retries;
	int rc;

	for (retries = SDIAS_RETRIES; retries; retries--) {
		sclp_req_done = 0;
		TRACE("add request\n");
		rc = sclp_add_request(req);
		if (rc) {
			/* not initiated, wait some time and retry */
			set_current_state(TASK_INTERRUPTIBLE);
			TRACE("add request failed: rc = %i\n",rc);
			schedule_timeout(SDIAS_SLEEP_TICKS);
			continue;
		}
		/* initiated, wait for completion of service call */
		wait_event(sdias_wq, (sclp_req_done == 1));
		if (req->status == SCLP_REQ_FAILED) {
			TRACE("sclp request failed\n");
			rc = -EIO;
			continue;
		}
		TRACE("request done\n");
		break;
	}
	return rc;
}

/*
 * Get number of blocks (4K) available in the HSA
 */
int sclp_sdias_blk_count(void)
{
	struct sclp_req request;
	int rc;

	mutex_lock(&sdias_mutex);

	memset(&sccb, 0, sizeof(sccb));
	memset(&request, 0, sizeof(request));

	sccb.hdr.length = sizeof(sccb);
	sccb.evbuf.hdr.length = sizeof(struct sdias_evbuf);
	sccb.evbuf.hdr.type = EVTYP_SDIAS;
	sccb.evbuf.event_qual = EQ_SIZE;
	sccb.evbuf.data_id = DI_FCP_DUMP;
	sccb.evbuf.event_id = 4712;
	sccb.evbuf.dbs = 1;

	request.sccb = &sccb;
	request.command = SCLP_CMDW_WRITE_EVENT_DATA;
	request.status = SCLP_REQ_FILLED;
	request.callback = sdias_callback;

	rc = sdias_sclp_send(&request);
	if (rc) {
		ERROR_MSG("sclp_send failed for get_nr_blocks\n");
		goto out;
	}
	if (sccb.hdr.response_code != 0x0020) {
		TRACE("send failed: %x\n", sccb.hdr.response_code);
		rc = -EIO;
		goto out;
	}

	switch (sccb.evbuf.event_status) {
		case 0:
			rc = sccb.evbuf.blk_cnt;
			break;
		default:
			ERROR_MSG("SCLP error: %x\n", sccb.evbuf.event_status);
			rc = -EIO;
			goto out;
	}
	TRACE("%i blocks\n", rc);
out:
	mutex_unlock(&sdias_mutex);
	return rc;
}

/*
 * Copy from HSA to absolute storage (not reentrant):
 *
 * @dest     : Address of buffer where data should be copied
 * @start_blk: Start Block (beginning with 1)
 * @nr_blks  : Number of 4K blocks to copy
 *
 * Return Value: 0 : Requested 'number' of blocks of data copied
 *		 <0: ERROR - negative event status
 */
int sclp_sdias_copy(void *dest, int start_blk, int nr_blks)
{
	struct sclp_req request;
	int rc;

	mutex_lock(&sdias_mutex);

	memset(&sccb, 0, sizeof(sccb));
	memset(&request, 0, sizeof(request));

	sccb.hdr.length = sizeof(sccb);
	sccb.evbuf.hdr.length = sizeof(struct sdias_evbuf);
	sccb.evbuf.hdr.type = EVTYP_SDIAS;
	sccb.evbuf.hdr.flags = 0;
	sccb.evbuf.event_qual = EQ_STORE_DATA;
	sccb.evbuf.data_id = DI_FCP_DUMP;
	sccb.evbuf.event_id = 4712;
#ifdef __s390x__
	sccb.evbuf.asa_size = ASA_SIZE_64;
#else
	sccb.evbuf.asa_size = ASA_SIZE_32;
#endif
	sccb.evbuf.event_status = 0;
	sccb.evbuf.blk_cnt = nr_blks;
	sccb.evbuf.asa = (unsigned long)dest;
	sccb.evbuf.fbn = start_blk;
	sccb.evbuf.lbn = 0;
	sccb.evbuf.dbs = 1;

	request.sccb	 = &sccb;
	request.command  = SCLP_CMDW_WRITE_EVENT_DATA;
	request.status	 = SCLP_REQ_FILLED;
	request.callback = sdias_callback;

	rc = sdias_sclp_send(&request);
	if (rc) {
		ERROR_MSG("sclp_send failed: %x\n", rc);
		goto out;
	}
	if (sccb.hdr.response_code != 0x0020) {
		TRACE("copy failed: %x\n", sccb.hdr.response_code);
		rc = -EIO;
		goto out;
	}

	switch (sccb.evbuf.event_status) {
		case EVSTATE_ALL_STORED:
			TRACE("all stored\n");
		case EVSTATE_PART_STORED:
			TRACE("part stored: %i\n", sccb.evbuf.blk_cnt);
			break;
		case EVSTATE_NO_DATA:
			TRACE("no data\n");
		default:
			ERROR_MSG("Error from SCLP while copying hsa. "
				  "Event status = %x\n",
				sccb.evbuf.event_status);
			rc = -EIO;
	}
out:
	mutex_unlock(&sdias_mutex);
	return rc;
}

int __init sdias_init(void)
{
	int rc;

	if (ipl_info.type != IPL_TYPE_FCP_DUMP)
		return 0;
	sdias_dbf = debug_register("dump_sdias", 4, 1, 4 * sizeof(long));
	debug_register_view(sdias_dbf, &debug_sprintf_view);
	debug_set_level(sdias_dbf, 6);
	rc = sclp_register(&sclp_sdias_register);
	if (rc) {
		ERROR_MSG("sclp register failed\n");
		return rc;
	}
	init_waitqueue_head(&sdias_wq);
	TRACE("init done\n");
	return 0;
}

void __exit sdias_exit(void)
{
	debug_unregister(sdias_dbf);
	sclp_unregister(&sclp_sdias_register);
}