android_kernel_motorola_sm6225/drivers/scsi/libata-eh.c
Tejun Heo e318049949 [PATCH] libata-eh-fw: implement freeze/thaw
Freezing is performed atomic w.r.t. host_set->lock and once frozen
LLDD is not allowed to access the port or any qc on it.  Also, libata
makes sure that no new qc gets issued to a frozen port.

A frozen port is thawed after a reset operation completes
successfully, so reset methods must do its job while the port is
frozen.  During initialization all ports get frozen before requesting
IRQ, so reset methods are always invoked on a frozen port.

Optional ->freeze and ->thaw operations notify LLDD that the port is
being frozen and thawed, respectively.  LLDD can disable/enable
hardware interrupt in these callbacks if the controller's IRQ mask can
be changed dynamically.  If the controller doesn't allow such
operation, LLDD can check for frozen state in the interrupt handler
and ack/clear interrupts unconditionally while frozen.

Signed-off-by: Tejun Heo <htejun@gmail.com>
2006-05-15 20:58:09 +09:00

448 lines
11 KiB
C

/*
* 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);
}
/**
* ata_port_schedule_eh - schedule error handling without a qc
* @ap: ATA port to schedule EH for
*
* Schedule error handling for @ap. EH will kick in as soon as
* all commands are drained.
*
* LOCKING:
* spin_lock_irqsave(host_set lock)
*/
void ata_port_schedule_eh(struct ata_port *ap)
{
WARN_ON(!ap->ops->error_handler);
ap->flags |= ATA_FLAG_EH_PENDING;
ata_schedule_scsi_eh(ap->host);
DPRINTK("port EH scheduled\n");
}
/**
* ata_port_abort - abort all qc's on the port
* @ap: ATA port to abort qc's for
*
* Abort all active qc's of @ap and schedule EH.
*
* LOCKING:
* spin_lock_irqsave(host_set lock)
*
* RETURNS:
* Number of aborted qc's.
*/
int ata_port_abort(struct ata_port *ap)
{
int tag, nr_aborted = 0;
WARN_ON(!ap->ops->error_handler);
for (tag = 0; tag < ATA_MAX_QUEUE; tag++) {
struct ata_queued_cmd *qc = ata_qc_from_tag(ap, tag);
if (qc) {
qc->flags |= ATA_QCFLAG_FAILED;
ata_qc_complete(qc);
nr_aborted++;
}
}
if (!nr_aborted)
ata_port_schedule_eh(ap);
return nr_aborted;
}
/**
* __ata_port_freeze - freeze port
* @ap: ATA port to freeze
*
* This function is called when HSM violation or some other
* condition disrupts normal operation of the port. Frozen port
* is not allowed to perform any operation until the port is
* thawed, which usually follows a successful reset.
*
* ap->ops->freeze() callback can be used for freezing the port
* hardware-wise (e.g. mask interrupt and stop DMA engine). If a
* port cannot be frozen hardware-wise, the interrupt handler
* must ack and clear interrupts unconditionally while the port
* is frozen.
*
* LOCKING:
* spin_lock_irqsave(host_set lock)
*/
static void __ata_port_freeze(struct ata_port *ap)
{
WARN_ON(!ap->ops->error_handler);
if (ap->ops->freeze)
ap->ops->freeze(ap);
ap->flags |= ATA_FLAG_FROZEN;
DPRINTK("ata%u port frozen\n", ap->id);
}
/**
* ata_port_freeze - abort & freeze port
* @ap: ATA port to freeze
*
* Abort and freeze @ap.
*
* LOCKING:
* spin_lock_irqsave(host_set lock)
*
* RETURNS:
* Number of aborted commands.
*/
int ata_port_freeze(struct ata_port *ap)
{
int nr_aborted;
WARN_ON(!ap->ops->error_handler);
nr_aborted = ata_port_abort(ap);
__ata_port_freeze(ap);
return nr_aborted;
}
/**
* ata_eh_freeze_port - EH helper to freeze port
* @ap: ATA port to freeze
*
* Freeze @ap.
*
* LOCKING:
* None.
*/
void ata_eh_freeze_port(struct ata_port *ap)
{
unsigned long flags;
if (!ap->ops->error_handler)
return;
spin_lock_irqsave(&ap->host_set->lock, flags);
__ata_port_freeze(ap);
spin_unlock_irqrestore(&ap->host_set->lock, flags);
}
/**
* ata_port_thaw_port - EH helper to thaw port
* @ap: ATA port to thaw
*
* Thaw frozen port @ap.
*
* LOCKING:
* None.
*/
void ata_eh_thaw_port(struct ata_port *ap)
{
unsigned long flags;
if (!ap->ops->error_handler)
return;
spin_lock_irqsave(&ap->host_set->lock, flags);
ap->flags &= ~ATA_FLAG_FROZEN;
if (ap->ops->thaw)
ap->ops->thaw(ap);
spin_unlock_irqrestore(&ap->host_set->lock, flags);
DPRINTK("ata%u port thawed\n", ap->id);
}
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);
}