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/*
* Basic HP/COMPAQ MSA 1000 support. This is only needed if your HW cannot be
* upgraded.
*
* Copyright (C) 2006 Red Hat, Inc. All rights reserved.
* Copyright (C) 2006 Mike Christie
* Copyright (C) 2008 Hannes Reinecke <hare@suse.de>
*
* 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; see the file COPYING. If not, write to
* the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <linux/slab.h>
#include <linux/module.h>
#include <scsi/scsi.h>
#include <scsi/scsi_dbg.h>
#include <scsi/scsi_eh.h>
#include <scsi/scsi_dh.h>
#define HP_SW_NAME "hp_sw"
#define HP_SW_TIMEOUT (60 * HZ)
#define HP_SW_RETRIES 3
#define HP_SW_PATH_UNINITIALIZED -1
#define HP_SW_PATH_ACTIVE 0
#define HP_SW_PATH_PASSIVE 1
struct hp_sw_dh_data {
int path_state;
int retries;
int retry_cnt;
struct scsi_device *sdev;
};
static int hp_sw_start_stop(struct hp_sw_dh_data *);
/*
* tur_done - Handle TEST UNIT READY return status
* @sdev: sdev the command has been sent to
* @errors: blk error code
*
* Returns SCSI_DH_DEV_OFFLINED if the sdev is on the passive path
*/
static int tur_done(struct scsi_device *sdev, struct hp_sw_dh_data *h,
struct scsi_sense_hdr *sshdr)
{
int ret = SCSI_DH_IO;
switch (sshdr->sense_key) {
case UNIT_ATTENTION:
ret = SCSI_DH_IMM_RETRY;
break;
case NOT_READY:
if (sshdr->asc == 0x04 && sshdr->ascq == 2) {
/*
* LUN not ready - Initialization command required
*
* This is the passive path
*/
h->path_state = HP_SW_PATH_PASSIVE;
ret = SCSI_DH_OK;
break;
}
/* Fallthrough */
default:
sdev_printk(KERN_WARNING, sdev,
"%s: sending tur failed, sense %x/%x/%x\n",
HP_SW_NAME, sshdr->sense_key, sshdr->asc,
sshdr->ascq);
break;
}
return ret;
}
/*
* hp_sw_tur - Send TEST UNIT READY
* @sdev: sdev command should be sent to
*
* Use the TEST UNIT READY command to determine
* the path state.
*/
static int hp_sw_tur(struct scsi_device *sdev, struct hp_sw_dh_data *h)
{
unsigned char cmd[6] = { TEST_UNIT_READY };
struct scsi_sense_hdr sshdr;
int ret = SCSI_DH_OK, res;
u64 req_flags = REQ_FAILFAST_DEV | REQ_FAILFAST_TRANSPORT |
REQ_FAILFAST_DRIVER;
retry:
res = scsi_execute_req_flags(sdev, cmd, DMA_NONE, NULL, 0, &sshdr,
HP_SW_TIMEOUT, HP_SW_RETRIES,
NULL, req_flags, 0);
if (res) {
if (scsi_sense_valid(&sshdr))
ret = tur_done(sdev, h, &sshdr);
else {
sdev_printk(KERN_WARNING, sdev,
"%s: sending tur failed with %x\n",
HP_SW_NAME, res);
ret = SCSI_DH_IO;
}
} else {
h->path_state = HP_SW_PATH_ACTIVE;
ret = SCSI_DH_OK;
}
if (ret == SCSI_DH_IMM_RETRY)
goto retry;
return ret;
}
/*
* hp_sw_start_stop - Send START STOP UNIT command
* @sdev: sdev command should be sent to
*
* Sending START STOP UNIT activates the SP.
*/
static int hp_sw_start_stop(struct hp_sw_dh_data *h)
{
unsigned char cmd[6] = { START_STOP, 0, 0, 0, 1, 0 };
struct scsi_sense_hdr sshdr;
struct scsi_device *sdev = h->sdev;
int res, rc = SCSI_DH_OK;
int retry_cnt = HP_SW_RETRIES;
u64 req_flags = REQ_FAILFAST_DEV | REQ_FAILFAST_TRANSPORT |
REQ_FAILFAST_DRIVER;
retry:
res = scsi_execute_req_flags(sdev, cmd, DMA_NONE, NULL, 0, &sshdr,
HP_SW_TIMEOUT, HP_SW_RETRIES,
NULL, req_flags, 0);
if (res) {
if (!scsi_sense_valid(&sshdr)) {
sdev_printk(KERN_WARNING, sdev,
"%s: sending start_stop_unit failed, "
"no sense available\n", HP_SW_NAME);
return SCSI_DH_IO;
}
switch (sshdr.sense_key) {
case NOT_READY:
if (sshdr.asc == 0x04 && sshdr.ascq == 3) {
/*
* LUN not ready - manual intervention required
*
* Switch-over in progress, retry.
*/
if (--retry_cnt)
goto retry;
rc = SCSI_DH_RETRY;
break;
}
/* fall through */
default:
sdev_printk(KERN_WARNING, sdev,
"%s: sending start_stop_unit failed, "
"sense %x/%x/%x\n", HP_SW_NAME,
sshdr.sense_key, sshdr.asc, sshdr.ascq);
rc = SCSI_DH_IO;
}
}
return rc;
}
static int hp_sw_prep_fn(struct scsi_device *sdev, struct request *req)
{
struct hp_sw_dh_data *h = sdev->handler_data;
int ret = BLKPREP_OK;
if (h->path_state != HP_SW_PATH_ACTIVE) {
ret = BLKPREP_KILL;
req->rq_flags |= RQF_QUIET;
}
return ret;
}
/*
* hp_sw_activate - Activate a path
* @sdev: sdev on the path to be activated
*
* The HP Active/Passive firmware is pretty simple;
* the passive path reports NOT READY with sense codes
* 0x04/0x02; a START STOP UNIT command will then
* activate the passive path (and deactivate the
* previously active one).
*/
static int hp_sw_activate(struct scsi_device *sdev,
activate_complete fn, void *data)
{
int ret = SCSI_DH_OK;
struct hp_sw_dh_data *h = sdev->handler_data;
ret = hp_sw_tur(sdev, h);
if (ret == SCSI_DH_OK && h->path_state == HP_SW_PATH_PASSIVE)
ret = hp_sw_start_stop(h);
if (fn)
fn(data, ret);
return 0;
}
static int hp_sw_bus_attach(struct scsi_device *sdev)
{
struct hp_sw_dh_data *h;
int ret;
h = kzalloc(sizeof(*h), GFP_KERNEL);
if (!h)
return -ENOMEM;
h->path_state = HP_SW_PATH_UNINITIALIZED;
h->retries = HP_SW_RETRIES;
h->sdev = sdev;
ret = hp_sw_tur(sdev, h);
if (ret != SCSI_DH_OK || h->path_state == HP_SW_PATH_UNINITIALIZED)
goto failed;
sdev_printk(KERN_INFO, sdev, "%s: attached to %s path\n",
HP_SW_NAME, h->path_state == HP_SW_PATH_ACTIVE?
"active":"passive");
sdev->handler_data = h;
return 0;
failed:
kfree(h);
return -EINVAL;
}
static void hp_sw_bus_detach( struct scsi_device *sdev )
{
kfree(sdev->handler_data);
sdev->handler_data = NULL;
}
static struct scsi_device_handler hp_sw_dh = {
.name = HP_SW_NAME,
.module = THIS_MODULE,
.attach = hp_sw_bus_attach,
.detach = hp_sw_bus_detach,
.activate = hp_sw_activate,
.prep_fn = hp_sw_prep_fn,
};
static int __init hp_sw_init(void)
{
return scsi_register_device_handler(&hp_sw_dh);
}
static void __exit hp_sw_exit(void)
{
scsi_unregister_device_handler(&hp_sw_dh);
}
module_init(hp_sw_init);
module_exit(hp_sw_exit);
MODULE_DESCRIPTION("HP Active/Passive driver");
MODULE_AUTHOR("Mike Christie <michaelc@cs.wisc.edu");
MODULE_LICENSE("GPL");
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