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linux/drivers/ide/ide-dma.c
Tejun Heo dd8717da6d ide: clean up timed out request handling 
8f6205cd57 introduced a bug where a
timed out DMA request is never requeued and lost.
6072f7491f fixed this by making
ide_dma_timeout_retry() requeue the request itself.  While the fix is
correct, it makes DMA and non-DMA paths asymmetric regarding how the
in flight request is requeued.

As long as hwif->rq is set, the IDE driver is assuming ownership of
the request and the request should either be completed or requeued
when clearing hwif->rq.  In the timeout path, the ide driver holds
onto the request as long as the recovery action (ie. reset) is in
progress and clears it after the state machine is stopped (ide_stopped
return), so the existing requeueing logic is correct.  The bug
occurred because ide_dma_timeout_retry() explicitly clears hwif->rq
without requeueing it.

ide_dma_timeout_retry() is called only by ide_timer_expiry() and
returns ide_started only when ide_error() would return it - ie. after
reset state machine has started in which case the state machine will
eventually end up executing the ide_stopped path in ide_timer_expiry()
after reset protocol is complete.  So, there is no need to clear
hwif->rq from ide_dma_timeout_retry().  ide_timer_expiry() will handle
it the same way as PIO timeout path.

Kill hwif->rq clearing and requeueing from ide_dma_timeout_retry() and
let ide_timer_expiry() deal with it.  The end result should remain the
same.

grepping shows ide_dma_timeout_retry() is the only site which clears
hwif->rq without taking care of the request, so there shouldn't be
similar fallouts.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-10-26 10:17:30 -07:00

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/*
* IDE DMA support (including IDE PCI BM-DMA).
*
* Copyright (C) 1995-1998 Mark Lord
* Copyright (C) 1999-2000 Andre Hedrick <andre@linux-ide.org>
* Copyright (C) 2004, 2007 Bartlomiej Zolnierkiewicz
*
* May be copied or modified under the terms of the GNU General Public License
*
* DMA is supported for all IDE devices (disk drives, cdroms, tapes, floppies).
*/
/*
* Special Thanks to Mark for his Six years of work.
*/
/*
* Thanks to "Christopher J. Reimer" <reimer@doe.carleton.ca> for
* fixing the problem with the BIOS on some Acer motherboards.
*
* Thanks to "Benoit Poulot-Cazajous" <poulot@chorus.fr> for testing
* "TX" chipset compatibility and for providing patches for the "TX" chipset.
*
* Thanks to Christian Brunner <chb@muc.de> for taking a good first crack
* at generic DMA -- his patches were referred to when preparing this code.
*
* Most importantly, thanks to Robert Bringman <rob@mars.trion.com>
* for supplying a Promise UDMA board & WD UDMA drive for this work!
*/
#include <linux/types.h>
#include <linux/gfp.h>
#include <linux/kernel.h>
#include <linux/ide.h>
#include <linux/scatterlist.h>
#include <linux/dma-mapping.h>
static const struct drive_list_entry drive_whitelist[] = {
{ "Micropolis 2112A" , NULL },
{ "CONNER CTMA 4000" , NULL },
{ "CONNER CTT8000-A" , NULL },
{ "ST34342A" , NULL },
{ NULL , NULL }
};
static const struct drive_list_entry drive_blacklist[] = {
{ "WDC AC11000H" , NULL },
{ "WDC AC22100H" , NULL },
{ "WDC AC32500H" , NULL },
{ "WDC AC33100H" , NULL },
{ "WDC AC31600H" , NULL },
{ "WDC AC32100H" , "24.09P07" },
{ "WDC AC23200L" , "21.10N21" },
{ "Compaq CRD-8241B" , NULL },
{ "CRD-8400B" , NULL },
{ "CRD-8480B", NULL },
{ "CRD-8482B", NULL },
{ "CRD-84" , NULL },
{ "SanDisk SDP3B" , NULL },
{ "SanDisk SDP3B-64" , NULL },
{ "SANYO CD-ROM CRD" , NULL },
{ "HITACHI CDR-8" , NULL },
{ "HITACHI CDR-8335" , NULL },
{ "HITACHI CDR-8435" , NULL },
{ "Toshiba CD-ROM XM-6202B" , NULL },
{ "TOSHIBA CD-ROM XM-1702BC", NULL },
{ "CD-532E-A" , NULL },
{ "E-IDE CD-ROM CR-840", NULL },
{ "CD-ROM Drive/F5A", NULL },
{ "WPI CDD-820", NULL },
{ "SAMSUNG CD-ROM SC-148C", NULL },
{ "SAMSUNG CD-ROM SC", NULL },
{ "ATAPI CD-ROM DRIVE 40X MAXIMUM", NULL },
{ "_NEC DV5800A", NULL },
{ "SAMSUNG CD-ROM SN-124", "N001" },
{ "Seagate STT20000A", NULL },
{ "CD-ROM CDR_U200", "1.09" },
{ NULL , NULL }
};
/**
* ide_dma_intr - IDE DMA interrupt handler
* @drive: the drive the interrupt is for
*
* Handle an interrupt completing a read/write DMA transfer on an
* IDE device
*/
ide_startstop_t ide_dma_intr(ide_drive_t *drive)
{
ide_hwif_t *hwif = drive->hwif;
struct ide_cmd *cmd = &hwif->cmd;
u8 stat = 0, dma_stat = 0;
drive->waiting_for_dma = 0;
dma_stat = hwif->dma_ops->dma_end(drive);
ide_dma_unmap_sg(drive, cmd);
stat = hwif->tp_ops->read_status(hwif);
if (OK_STAT(stat, DRIVE_READY, drive->bad_wstat | ATA_DRQ)) {
if (!dma_stat) {
if ((cmd->tf_flags & IDE_TFLAG_FS) == 0)
ide_finish_cmd(drive, cmd, stat);
else
ide_complete_rq(drive, 0,
blk_rq_sectors(cmd->rq) << 9);
return ide_stopped;
}
printk(KERN_ERR "%s: %s: bad DMA status (0x%02x)\n",
drive->name, __func__, dma_stat);
}
return ide_error(drive, "dma_intr", stat);
}
int ide_dma_good_drive(ide_drive_t *drive)
{
return ide_in_drive_list(drive->id, drive_whitelist);
}
/**
* ide_dma_map_sg - map IDE scatter gather for DMA I/O
* @drive: the drive to map the DMA table for
* @cmd: command
*
* Perform the DMA mapping magic necessary to access the source or
* target buffers of a request via DMA. The lower layers of the
* kernel provide the necessary cache management so that we can
* operate in a portable fashion.
*/
static int ide_dma_map_sg(ide_drive_t *drive, struct ide_cmd *cmd)
{
ide_hwif_t *hwif = drive->hwif;
struct scatterlist *sg = hwif->sg_table;
int i;
if (cmd->tf_flags & IDE_TFLAG_WRITE)
cmd->sg_dma_direction = DMA_TO_DEVICE;
else
cmd->sg_dma_direction = DMA_FROM_DEVICE;
i = dma_map_sg(hwif->dev, sg, cmd->sg_nents, cmd->sg_dma_direction);
if (i) {
cmd->orig_sg_nents = cmd->sg_nents;
cmd->sg_nents = i;
}
return i;
}
/**
* ide_dma_unmap_sg - clean up DMA mapping
* @drive: The drive to unmap
*
* Teardown mappings after DMA has completed. This must be called
* after the completion of each use of ide_build_dmatable and before
* the next use of ide_build_dmatable. Failure to do so will cause
* an oops as only one mapping can be live for each target at a given
* time.
*/
void ide_dma_unmap_sg(ide_drive_t *drive, struct ide_cmd *cmd)
{
ide_hwif_t *hwif = drive->hwif;
dma_unmap_sg(hwif->dev, hwif->sg_table, cmd->orig_sg_nents,
cmd->sg_dma_direction);
}
EXPORT_SYMBOL_GPL(ide_dma_unmap_sg);
/**
* ide_dma_off_quietly - Generic DMA kill
* @drive: drive to control
*
* Turn off the current DMA on this IDE controller.
*/
void ide_dma_off_quietly(ide_drive_t *drive)
{
drive->dev_flags &= ~IDE_DFLAG_USING_DMA;
ide_toggle_bounce(drive, 0);
drive->hwif->dma_ops->dma_host_set(drive, 0);
}
EXPORT_SYMBOL(ide_dma_off_quietly);
/**
* ide_dma_off - disable DMA on a device
* @drive: drive to disable DMA on
*
* Disable IDE DMA for a device on this IDE controller.
* Inform the user that DMA has been disabled.
*/
void ide_dma_off(ide_drive_t *drive)
{
printk(KERN_INFO "%s: DMA disabled\n", drive->name);
ide_dma_off_quietly(drive);
}
EXPORT_SYMBOL(ide_dma_off);
/**
* ide_dma_on - Enable DMA on a device
* @drive: drive to enable DMA on
*
* Enable IDE DMA for a device on this IDE controller.
*/
void ide_dma_on(ide_drive_t *drive)
{
drive->dev_flags |= IDE_DFLAG_USING_DMA;
ide_toggle_bounce(drive, 1);
drive->hwif->dma_ops->dma_host_set(drive, 1);
}
int __ide_dma_bad_drive(ide_drive_t *drive)
{
u16 *id = drive->id;
int blacklist = ide_in_drive_list(id, drive_blacklist);
if (blacklist) {
printk(KERN_WARNING "%s: Disabling (U)DMA for %s (blacklisted)\n",
drive->name, (char *)&id[ATA_ID_PROD]);
return blacklist;
}
return 0;
}
EXPORT_SYMBOL(__ide_dma_bad_drive);
static const u8 xfer_mode_bases[] = {
XFER_UDMA_0,
XFER_MW_DMA_0,
XFER_SW_DMA_0,
};
static unsigned int ide_get_mode_mask(ide_drive_t *drive, u8 base, u8 req_mode)
{
u16 *id = drive->id;
ide_hwif_t *hwif = drive->hwif;
const struct ide_port_ops *port_ops = hwif->port_ops;
unsigned int mask = 0;
switch (base) {
case XFER_UDMA_0:
if ((id[ATA_ID_FIELD_VALID] & 4) == 0)
break;
mask = id[ATA_ID_UDMA_MODES];
if (port_ops && port_ops->udma_filter)
mask &= port_ops->udma_filter(drive);
else
mask &= hwif->ultra_mask;
/*
* avoid false cable warning from eighty_ninty_three()
*/
if (req_mode > XFER_UDMA_2) {
if ((mask & 0x78) && (eighty_ninty_three(drive) == 0))
mask &= 0x07;
}
break;
case XFER_MW_DMA_0:
mask = id[ATA_ID_MWDMA_MODES];
/* Also look for the CF specific MWDMA modes... */
if (ata_id_is_cfa(id) && (id[ATA_ID_CFA_MODES] & 0x38)) {
u8 mode = ((id[ATA_ID_CFA_MODES] & 0x38) >> 3) - 1;
mask |= ((2 << mode) - 1) << 3;
}
if (port_ops && port_ops->mdma_filter)
mask &= port_ops->mdma_filter(drive);
else
mask &= hwif->mwdma_mask;
break;
case XFER_SW_DMA_0:
mask = id[ATA_ID_SWDMA_MODES];
if (!(mask & ATA_SWDMA2) && (id[ATA_ID_OLD_DMA_MODES] >> 8)) {
u8 mode = id[ATA_ID_OLD_DMA_MODES] >> 8;
/*
* if the mode is valid convert it to the mask
* (the maximum allowed mode is XFER_SW_DMA_2)
*/
if (mode <= 2)
mask = (2 << mode) - 1;
}
mask &= hwif->swdma_mask;
break;
default:
BUG();
break;
}
return mask;
}
/**
* ide_find_dma_mode - compute DMA speed
* @drive: IDE device
* @req_mode: requested mode
*
* Checks the drive/host capabilities and finds the speed to use for
* the DMA transfer. The speed is then limited by the requested mode.
*
* Returns 0 if the drive/host combination is incapable of DMA transfers
* or if the requested mode is not a DMA mode.
*/
u8 ide_find_dma_mode(ide_drive_t *drive, u8 req_mode)
{
ide_hwif_t *hwif = drive->hwif;
unsigned int mask;
int x, i;
u8 mode = 0;
if (drive->media != ide_disk) {
if (hwif->host_flags & IDE_HFLAG_NO_ATAPI_DMA)
return 0;
}
for (i = 0; i < ARRAY_SIZE(xfer_mode_bases); i++) {
if (req_mode < xfer_mode_bases[i])
continue;
mask = ide_get_mode_mask(drive, xfer_mode_bases[i], req_mode);
x = fls(mask) - 1;
if (x >= 0) {
mode = xfer_mode_bases[i] + x;
break;
}
}
if (hwif->chipset == ide_acorn && mode == 0) {
/*
* is this correct?
*/
if (ide_dma_good_drive(drive) &&
drive->id[ATA_ID_EIDE_DMA_TIME] < 150)
mode = XFER_MW_DMA_1;
}
mode = min(mode, req_mode);
printk(KERN_INFO "%s: %s mode selected\n", drive->name,
mode ? ide_xfer_verbose(mode) : "no DMA");
return mode;
}
static int ide_tune_dma(ide_drive_t *drive)
{
ide_hwif_t *hwif = drive->hwif;
u8 speed;
if (ata_id_has_dma(drive->id) == 0 ||
(drive->dev_flags & IDE_DFLAG_NODMA))
return 0;
/* consult the list of known "bad" drives */
if (__ide_dma_bad_drive(drive))
return 0;
if (hwif->host_flags & IDE_HFLAG_TRUST_BIOS_FOR_DMA)
return config_drive_for_dma(drive);
speed = ide_max_dma_mode(drive);
if (!speed)
return 0;
if (ide_set_dma_mode(drive, speed))
return 0;
return 1;
}
static int ide_dma_check(ide_drive_t *drive)
{
ide_hwif_t *hwif = drive->hwif;
if (ide_tune_dma(drive))
return 0;
/* TODO: always do PIO fallback */
if (hwif->host_flags & IDE_HFLAG_TRUST_BIOS_FOR_DMA)
return -1;
ide_set_max_pio(drive);
return -1;
}
int ide_set_dma(ide_drive_t *drive)
{
int rc;
/*
* Force DMAing for the beginning of the check.
* Some chipsets appear to do interesting
* things, if not checked and cleared.
* PARANOIA!!!
*/
ide_dma_off_quietly(drive);
rc = ide_dma_check(drive);
if (rc)
return rc;
ide_dma_on(drive);
return 0;
}
void ide_check_dma_crc(ide_drive_t *drive)
{
u8 mode;
ide_dma_off_quietly(drive);
drive->crc_count = 0;
mode = drive->current_speed;
/*
* Don't try non Ultra-DMA modes without iCRC's. Force the
* device to PIO and make the user enable SWDMA/MWDMA modes.
*/
if (mode > XFER_UDMA_0 && mode <= XFER_UDMA_7)
mode--;
else
mode = XFER_PIO_4;
ide_set_xfer_rate(drive, mode);
if (drive->current_speed >= XFER_SW_DMA_0)
ide_dma_on(drive);
}
void ide_dma_lost_irq(ide_drive_t *drive)
{
printk(KERN_ERR "%s: DMA interrupt recovery\n", drive->name);
}
EXPORT_SYMBOL_GPL(ide_dma_lost_irq);
/*
* un-busy the port etc, and clear any pending DMA status. we want to
* retry the current request in pio mode instead of risking tossing it
* all away
*/
ide_startstop_t ide_dma_timeout_retry(ide_drive_t *drive, int error)
{
ide_hwif_t *hwif = drive->hwif;
const struct ide_dma_ops *dma_ops = hwif->dma_ops;
struct ide_cmd *cmd = &hwif->cmd;
ide_startstop_t ret = ide_stopped;
/*
* end current dma transaction
*/
if (error < 0) {
printk(KERN_WARNING "%s: DMA timeout error\n", drive->name);
drive->waiting_for_dma = 0;
(void)dma_ops->dma_end(drive);
ide_dma_unmap_sg(drive, cmd);
ret = ide_error(drive, "dma timeout error",
hwif->tp_ops->read_status(hwif));
} else {
printk(KERN_WARNING "%s: DMA timeout retry\n", drive->name);
if (dma_ops->dma_clear)
dma_ops->dma_clear(drive);
printk(KERN_ERR "%s: timeout waiting for DMA\n", drive->name);
if (dma_ops->dma_test_irq(drive) == 0) {
ide_dump_status(drive, "DMA timeout",
hwif->tp_ops->read_status(hwif));
drive->waiting_for_dma = 0;
(void)dma_ops->dma_end(drive);
ide_dma_unmap_sg(drive, cmd);
}
}
/*
* disable dma for now, but remember that we did so because of
* a timeout -- we'll reenable after we finish this next request
* (or rather the first chunk of it) in pio.
*/
drive->dev_flags |= IDE_DFLAG_DMA_PIO_RETRY;
drive->retry_pio++;
ide_dma_off_quietly(drive);
/*
* make sure request is sane
*/
if (hwif->rq)
hwif->rq->errors = 0;
return ret;
}
void ide_release_dma_engine(ide_hwif_t *hwif)
{
if (hwif->dmatable_cpu) {
int prd_size = hwif->prd_max_nents * hwif->prd_ent_size;
dma_free_coherent(hwif->dev, prd_size,
hwif->dmatable_cpu, hwif->dmatable_dma);
hwif->dmatable_cpu = NULL;
}
}
EXPORT_SYMBOL_GPL(ide_release_dma_engine);
int ide_allocate_dma_engine(ide_hwif_t *hwif)
{
int prd_size;
if (hwif->prd_max_nents == 0)
hwif->prd_max_nents = PRD_ENTRIES;
if (hwif->prd_ent_size == 0)
hwif->prd_ent_size = PRD_BYTES;
prd_size = hwif->prd_max_nents * hwif->prd_ent_size;
hwif->dmatable_cpu = dma_alloc_coherent(hwif->dev, prd_size,
&hwif->dmatable_dma,
GFP_ATOMIC);
if (hwif->dmatable_cpu == NULL) {
printk(KERN_ERR "%s: unable to allocate PRD table\n",
hwif->name);
return -ENOMEM;
}
return 0;
}
EXPORT_SYMBOL_GPL(ide_allocate_dma_engine);
int ide_dma_prepare(ide_drive_t *drive, struct ide_cmd *cmd)
{
const struct ide_dma_ops *dma_ops = drive->hwif->dma_ops;
if ((drive->dev_flags & IDE_DFLAG_USING_DMA) == 0 ||
(dma_ops->dma_check && dma_ops->dma_check(drive, cmd)))
goto out;
ide_map_sg(drive, cmd);
if (ide_dma_map_sg(drive, cmd) == 0)
goto out_map;
if (dma_ops->dma_setup(drive, cmd))
goto out_dma_unmap;
drive->waiting_for_dma = 1;
return 0;
out_dma_unmap:
ide_dma_unmap_sg(drive, cmd);
out_map:
ide_map_sg(drive, cmd);
out:
return 1;
}
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