dasd_diag.c

linux-2.6.15.6

/* 
 * File...........: linux/drivers/s390/block/dasd_diag.c
 * Author(s)......: Holger Smolinski <[e-mail]>
 * Based on.......: linux/drivers/s390/block/mdisk.c
 * ...............: by Hartmunt Penner <[e-mail]>
 * Bugreports.to..: <[e-mail]>
 * (C) IBM Corporation, IBM Deutschland Entwicklung GmbH, 1999,2000
 *
 * $Revision: 1.51 $
 */

#include <linux/config.h>
#include <linux/stddef.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/hdreg.h>
#include <linux/bio.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/jiffies.h>

#include <asm/dasd.h>
#include <asm/debug.h>
#include <asm/ebcdic.h>
#include <asm/io.h>
#include <asm/s390_ext.h>
#include <asm/todclk.h>

#include "dasd_int.h"
#include "dasd_diag.h"

#define PRINTK_HEADER "dasd(diag):"

MODULE_LICENSE("GPL");

/* The maximum number of blocks per request (max_blocks) is dependent on the
 * amount of storage that is available in the static I/O buffer for each
 * device. Currently each device gets 2 pages. We want to fit two requests
 * into the available memory so that we can immediately start the next if one
 * finishes. */
#define DIAG_MAX_BLOCKS	(((2 * PAGE_SIZE - sizeof(struct dasd_ccw_req) - \
			   sizeof(struct dasd_diag_req)) / \
		           sizeof(struct dasd_diag_bio)) / 2)
#define DIAG_MAX_RETRIES	32
#define DIAG_TIMEOUT		50 * HZ

struct dasd_discipline dasd_diag_discipline;

struct dasd_diag_private {
	struct dasd_diag_characteristics rdc_data;
	struct dasd_diag_rw_io iob;
	struct dasd_diag_init_io iib;
	blocknum_t pt_block;
};

struct dasd_diag_req {
	unsigned int block_count;
	struct dasd_diag_bio bio[0];
};

static const u8 DASD_DIAG_CMS1[] = { 0xc3, 0xd4, 0xe2, 0xf1 };/* EBCDIC CMS1 */

/* Perform DIAG250 call with block I/O parameter list iob (input and output)
 * and function code cmd.
 * In case of an exception return 3. Otherwise return result of bitwise OR of
 * resulting condition code and DIAG return code. */
static __inline__ int
dia250(void *iob, int cmd)
{
	typedef union {
		struct dasd_diag_init_io init_io;
		struct dasd_diag_rw_io rw_io;
	} addr_type;
	int rc;

	__asm__ __volatile__(
#ifdef CONFIG_ARCH_S390X
		"	lghi	%0,3\n"
		"	lgr	0,%3\n"
		"	diag	0,%2,0x250\n"
		"0:	ipm	%0\n"
		"	srl	%0,28\n"
		"	or	%0,1\n"
		"1:\n"
		".section __ex_table,\"a\"\n"
		"	.align 8\n"
		"	.quad  0b,1b\n"
		".previous\n"
#else
		"	lhi	%0,3\n"
		"	lr	0,%3\n"
		"	diag	0,%2,0x250\n"
		"0:	ipm	%0\n"
		"	srl	%0,28\n"
		"	or	%0,1\n"
		"1:\n"
		".section __ex_table,\"a\"\n"
		"	.align 4\n"
		"	.long 0b,1b\n"
		".previous\n"
#endif
		: "=&d" (rc), "=m" (*(addr_type *) iob)
		: "d" (cmd), "d" (iob), "m" (*(addr_type *) iob)
		: "0", "1", "cc");
	return rc;
}

/* Initialize block I/O to DIAG device using the specified blocksize and
 * block offset. On success, return zero and set end_block to contain the
 * number of blocks on the device minus the specified offset. Return non-zero
 * otherwise. */
static __inline__ int
mdsk_init_io(struct dasd_device *device, unsigned int blocksize,
	     blocknum_t offset, blocknum_t *end_block)
{
	struct dasd_diag_private *private;
	struct dasd_diag_init_io *iib;
	int rc;

	private = (struct dasd_diag_private *) device->private;
	iib = &private->iib;
	memset(iib, 0, sizeof (struct dasd_diag_init_io));

	iib->dev_nr = _ccw_device_get_device_number(device->cdev);
	iib->block_size = blocksize;
	iib->offset = offset;
	iib->flaga = DASD_DIAG_FLAGA_DEFAULT;

	rc = dia250(iib, INIT_BIO);

	if ((rc & 3) == 0 && end_block)
		*end_block = iib->end_block;

	return rc;
}

/* Remove block I/O environment for device. Return zero on success, non-zero
 * otherwise. */
static __inline__ int
mdsk_term_io(struct dasd_device * device)
{
	struct dasd_diag_private *private;
	struct dasd_diag_init_io *iib;
	int rc;

	private = (struct dasd_diag_private *) device->private;
	iib = &private->iib;
	memset(iib, 0, sizeof (struct dasd_diag_init_io));
	iib->dev_nr = _ccw_device_get_device_number(device->cdev);
	rc = dia250(iib, TERM_BIO);
	return rc;
}

/* Error recovery for failed DIAG requests - try to reestablish the DIAG
 * environment. */
static void
dasd_diag_erp(struct dasd_device *device)
{
	int rc;

	mdsk_term_io(device);
	rc = mdsk_init_io(device, device->bp_block, 0, NULL);
	if (rc)
		DEV_MESSAGE(KERN_WARNING, device, "DIAG ERP unsuccessful, "
			    "rc=%d", rc);
}

/* Start a given request at the device. Return zero on success, non-zero
 * otherwise. */
static int
dasd_start_diag(struct dasd_ccw_req * cqr)
{
	struct dasd_device *device;
	struct dasd_diag_private *private;
	struct dasd_diag_req *dreq;
	int rc;

	device = cqr->device;
	if (cqr->retries < 0) {
		DEV_MESSAGE(KERN_WARNING, device, "DIAG start_IO: request %p "
			    "- no retry left)", cqr);
		cqr->status = DASD_CQR_FAILED;
		return -EIO;
	}
	private = (struct dasd_diag_private *) device->private;
	dreq = (struct dasd_diag_req *) cqr->data;

	private->iob.dev_nr = _ccw_device_get_device_number(device->cdev);
	private->iob.key = 0;
	private->iob.flags = DASD_DIAG_RWFLAG_ASYNC;
	private->iob.block_count = dreq->block_count;
	private->iob.interrupt_params = (addr_t) cqr;
	private->iob.bio_list = dreq->bio;
	private->iob.flaga = DASD_DIAG_FLAGA_DEFAULT;

	cqr->startclk = get_clock();
	cqr->starttime = jiffies;
	cqr->retries--;

	rc = dia250(&private->iob, RW_BIO);
	switch (rc) {
	case 0: /* Synchronous I/O finished successfully */
		cqr->stopclk = get_clock();
		cqr->status = DASD_CQR_DONE;
		/* Indicate to calling function that only a dasd_schedule_bh()
		   and no timer is needed */
                rc = -EACCES;
		break;
	case 8: /* Asynchronous I/O was started */
		cqr->status = DASD_CQR_IN_IO;
		rc = 0;
		break;
	default: /* Error condition */
		cqr->status = DASD_CQR_QUEUED;
		DEV_MESSAGE(KERN_WARNING, device, "dia250 returned rc=%d", rc);
		dasd_diag_erp(device);
		rc = -EIO;
		break;
	}
	return rc;
}

/* Terminate given request at the device. */
static int
dasd_diag_term_IO(struct dasd_ccw_req * cqr)
{
	struct dasd_device *device;

	device = cqr->device;
	mdsk_term_io(device);
	mdsk_init_io(device, device->bp_block, 0, NULL);
	cqr->status = DASD_CQR_CLEAR;
	cqr->stopclk = get_clock();
	dasd_schedule_bh(device);
	return 0;
}

/* Handle external interruption. */
static void
dasd_ext_handler(struct pt_regs *regs, __u16 code)
{
	struct dasd_ccw_req *cqr, *next;
	struct dasd_device *device;
	unsigned long long expires;
	unsigned long flags;
	u8 int_code, status;
	addr_t ip;
	int rc;

	int_code = *((u8 *) DASD_DIAG_LC_INT_CODE);
	status = *((u8 *) DASD_DIAG_LC_INT_STATUS);
	switch (int_code) {
	case DASD_DIAG_CODE_31BIT:
		ip = (addr_t) *((u32 *) DASD_DIAG_LC_INT_PARM_31BIT);
		break;
	case DASD_DIAG_CODE_64BIT:
		ip = (addr_t) *((u64 *) DASD_DIAG_LC_INT_PARM_64BIT);
		break;
	default:
		return;
	}
	if (!ip) {		/* no intparm: unsolicited interrupt */
		MESSAGE(KERN_DEBUG, "%s", "caught unsolicited interrupt");
		return;
	}
	cqr = (struct dasd_ccw_req *) ip;
	device = (struct dasd_device *) cqr->device;
	if (strncmp(device->discipline->ebcname, (char *) &cqr->magic, 4)) {
		DEV_MESSAGE(KERN_WARNING, device,
			    " magic number of dasd_ccw_req 0x%08X doesn't"
			    " match discipline 0x%08X",
			    cqr->magic, *(int *) (&device->discipline->name));
		return;
	}

	/* get irq lock to modify request queue */
	spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);

	/* Check for a pending clear operation */
	if (cqr->status == DASD_CQR_CLEAR) {
		cqr->status = DASD_CQR_QUEUED;
		dasd_clear_timer(device);
		dasd_schedule_bh(device);
		spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
		return;
	}

	cqr->stopclk = get_clock();

	expires = 0;
	if (status == 0) {
		cqr->status = DASD_CQR_DONE;
		/* Start first request on queue if possible -> fast_io. */
		if (!list_empty(&device->ccw_queue)) {
			next = list_entry(device->ccw_queue.next,
					  struct dasd_ccw_req, list);
			if (next->status == DASD_CQR_QUEUED) {
				rc = dasd_start_diag(next);
				if (rc == 0)
					expires = next->expires;
				else if (rc != -EACCES)
					DEV_MESSAGE(KERN_WARNING, device, "%s",
						    "Interrupt fastpath "
						    "failed!");
			}
		}
	} else {
		cqr->status = DASD_CQR_QUEUED;
		DEV_MESSAGE(KERN_WARNING, device, "interrupt status for "
			    "request %p was %d (%d retries left)", cqr, status,
			    cqr->retries);
		dasd_diag_erp(device);
	}

	if (expires != 0)
		dasd_set_timer(device, expires);
	else
		dasd_clear_timer(device);
	dasd_schedule_bh(device);

	spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);