/*
* libata-eh.c - libata error handling
*
* Maintained by: Jeff Garzik <jgarzik@pobox.com>
* Please ALWAYS copy linux-ide@vger.kernel.org
* on emails.
*
* Copyright 2006 Tejun Heo <htejun@gmail.com>
*
*
* 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.
*
*
* libata documentation is available via 'make {ps|pdf}docs',
* as Documentation/DocBook/libata.*
*
* Hardware documentation available from http://www.t13.org/ and
* http://www.sata-io.org/
*
*/
#include <linux/config.h>
#include <linux/kernel.h>
#include <scsi/scsi.h>
#include <scsi/scsi_host.h>
#include <scsi/scsi_eh.h>
#include <scsi/scsi_device.h>
#include <scsi/scsi_cmnd.h>
#include <linux/libata.h>
#include "libata.h"
/**
* ata_scsi_timed_out - SCSI layer time out callback
* @cmd: timed out SCSI command
*
* Handles SCSI layer timeout. We race with normal completion of
* the qc for @cmd. If the qc is already gone, we lose and let
* the scsi command finish (EH_HANDLED). Otherwise, the qc has
* timed out and EH should be invoked. Prevent ata_qc_complete()
* from finishing it by setting EH_SCHEDULED and return
* EH_NOT_HANDLED.
*
* LOCKING:
* Called from timer context
*
* RETURNS:
* EH_HANDLED or EH_NOT_HANDLED
*/
enum scsi_eh_timer_return ata_scsi_timed_out(struct scsi_cmnd *cmd)
{
struct Scsi_Host *host = cmd->device->host;
struct ata_port *ap = ata_shost_to_port(host);
unsigned long flags;
struct ata_queued_cmd *qc;
enum scsi_eh_timer_return ret = EH_HANDLED;
DPRINTK("ENTER\n");
spin_lock_irqsave(&ap->host_set->lock, flags);
qc = ata_qc_from_tag(ap, ap->active_tag);
if (qc) {
WARN_ON(qc->scsicmd != cmd);
qc->flags |= ATA_QCFLAG_EH_SCHEDULED;
qc->err_mask |= AC_ERR_TIMEOUT;
ret = EH_NOT_HANDLED;
}
spin_unlock_irqrestore(&ap->host_set->lock, flags);
DPRINTK("EXIT, ret=%d\n", ret);
return ret;
}
/**
* ata_scsi_error - SCSI layer error handler callback
* @host: SCSI host on which error occurred
*
* Handles SCSI-layer-thrown error events.
*
* LOCKING:
* Inherited from SCSI layer (none, can sleep)
*
* RETURNS:
* Zero.
*/
void ata_scsi_error(struct Scsi_Host *host)
{
struct ata_port *ap = ata_shost_to_port(host);
DPRINTK("ENTER\n");
/* synchronize with IRQ handler and port task */
spin_unlock_wait(&ap->host_set->lock);
ata_port_flush_task(ap);
WARN_ON(ata_qc_from_tag(ap, ap->active_tag) == NULL);
ap->ops->eng_timeout(ap);
WARN_ON(host->host_failed || !list_empty(&host->eh_cmd_q));
scsi_eh_flush_done_q(&ap->eh_done_q);
DPRINTK("EXIT\n");
}
/**
* ata_qc_timeout - Handle timeout of queued command
* @qc: Command that timed out
*
* Some part of the kernel (currently, only the SCSI layer)
* has noticed that the active command on port @ap has not
* completed after a specified length of time. Handle this
* condition by disabling DMA (if necessary) and completing
* transactions, with error if necessary.
*
* This also handles the case of the "lost interrupt", where
* for some reason (possibly hardware bug, possibly driver bug)
* an interrupt was not delivered to the driver, even though the
* transaction completed successfully.
*
* LOCKING:
* Inherited from SCSI layer (none, can sleep)
*/
static void ata_qc_timeout(struct ata_queued_cmd *qc)
{
struct ata_port *ap = qc->ap;
struct ata_host_set *host_set = ap->host_set;
u8 host_stat = 0, drv_stat;
unsigned long flags;
DPRINTK("ENTER\n");
ap->hsm_task_state = HSM_ST_IDLE;
spin_lock_irqsave(&host_set->lock, flags);
switch (qc->tf.protocol) {
case ATA_PROT_DMA:
case ATA_PROT_ATAPI_DMA:
host_stat = ap->ops->bmdma_status(ap);
/* before we do anything else, clear DMA-Start bit */
ap->ops->bmdma_stop(qc);
/* fall through */
default:
ata_altstatus(ap);
drv_stat = ata_chk_status(ap);
/* ack bmdma irq events */
ap->ops->irq_clear(ap);
ata_dev_printk(qc->dev, KERN_ERR, "command 0x%x timeout, "
"stat 0x%x host_stat 0x%x\n",
qc->tf.command, drv_stat, host_stat);
/* complete taskfile transaction */
qc->err_mask |= ac_err_mask(drv_stat);
break;
}
spin_unlock_irqrestore(&host_set->lock, flags);
ata_eh_qc_complete(qc);
DPRINTK("EXIT\n");
}
/**
* ata_eng_timeout - Handle timeout of queued command
* @ap: Port on which timed-out command is active
*
* Some part of the kernel (currently, only the SCSI layer)
* has noticed that the active command on port @ap has not
* completed after a specified length of time. Handle this
* condition by disabling DMA (if necessary) and completing
* transactions, with error if necessary.
*
* This also handles the case of the "lost interrupt", where
* for some reason (possibly hardware bug, possibly driver bug)
* an interrupt was not delivered to the driver, even though the
* transaction completed successfully.
*
* LOCKING:
* Inherited from SCSI layer (none, can sleep)
*/
void ata_eng_timeout(struct ata_port *ap)
{
DPRINTK("ENTER\n");
ata_qc_timeout(ata_qc_from_tag(ap, ap->active_tag));
DPRINTK("EXIT\n");
}
/**
* ata_qc_schedule_eh - schedule qc for error handling
* @qc: command to schedule error handling for
*
* Schedule error handling for @qc. EH will kick in as soon as
* other commands are drained.
*
* LOCKING:
* spin_lock_irqsave(host_set lock)
*/
void ata_qc_schedule_eh(struct ata_queued_cmd *qc)
{
struct ata_port *ap = qc->ap;
WARN_ON(!ap->ops->error_handler);
qc->flags |= ATA_QCFLAG_FAILED;
qc->ap->flags |= ATA_FLAG_EH_PENDING;
/* The following will fail if timeout has already expired.
* ata_scsi_error() takes care of such scmds on EH entry.
* Note that ATA_QCFLAG_FAILED is unconditionally set after
* this function completes.
*/
scsi_req_abort_cmd(qc->scsicmd);
}
static void ata_eh_scsidone(struct scsi_cmnd *scmd)
{
/* nada */
}
static void __ata_eh_qc_complete(struct ata_queued_cmd *qc)
{
struct ata_port *ap = qc->ap;
struct scsi_cmnd *scmd = qc->scsicmd;
unsigned long flags;
spin_lock_irqsave(&ap->host_set->lock, flags);
qc->scsidone = ata_eh_scsidone;
__ata_qc_complete(qc);
WARN_ON(ata_tag_valid(qc->tag));
spin_unlock_irqrestore(&ap->host_set->lock, flags);
scsi_eh_finish_cmd(scmd, &ap->eh_done_q);
}
/**
* ata_eh_qc_complete - Complete an active ATA command from EH
* @qc: Command to complete
*
* Indicate to the mid and upper layers that an ATA command has
* completed. To be used from EH.
*/
void ata_eh_qc_complete(struct ata_queued_cmd *qc)
{
struct scsi_cmnd *scmd = qc->scsicmd;
scmd->retries = scmd->allowed;
__ata_eh_qc_complete(qc);
}
/**
* ata_eh_qc_retry - Tell midlayer to retry an ATA command after EH
* @qc: Command to retry
*
* Indicate to the mid and upper layers that an ATA command
* should be retried. To be used from EH.
*
* SCSI midlayer limits the number of retries to scmd->allowed.
* scmd->retries is decremented for commands which get retried
* due to unrelated failures (qc->err_mask is zero).
*/
void ata_eh_qc_retry(struct ata_queued_cmd *qc)
{
struct scsi_cmnd *scmd = qc->scsicmd;
if (!qc->err_mask && scmd->retries)
scmd->retries--;
__ata_eh_qc_complete(qc);
}
