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[PATCH] ide_dma_speed() fixes

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ide_dma_speed() fails to actually honor the IDE drivers' mode support
masks) because of the bogus checks -- thus, selecting the DMA transfer mode
that the driver explicitly refuses to support is possible.  Additionally,
there is no check for validity of the UltraDMA mode data in the drive ID,
and the function is misdocumented.

Signed-off-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Cc: Bartlomiej Zolnierkiewicz <B.Zolnierkiewicz@elka.pw.edu.pl>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Sergei Shtylyov 2006-10-03 01:14:17 -07:00 committed by Linus Torvalds
parent 83d7dbc409
commit 0750508ae6
1 changed files with 73 additions and 52 deletions
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125
drivers/ide/ide-lib.c
View File

@ -71,75 +71,96 @@ EXPORT_SYMBOL(ide_xfer_verbose);
/**
* ide_dma_speed - compute DMA speed
* @drive: drive
* @mode; intended mode
* @mode: modes available
*
* Checks the drive capabilities and returns the speed to use
* for the transfer. Returns -1 if the requested mode is unknown
* (eg PIO)
* for the DMA transfer. Returns 0 if the drive is incapable
* of DMA transfers.
*/
u8 ide_dma_speed(ide_drive_t *drive, u8 mode)
{
struct hd_driveid *id = drive->id;
ide_hwif_t *hwif = HWIF(drive);
u8 ultra_mask, mwdma_mask, swdma_mask;
u8 speed = 0;
if (drive->media != ide_disk && hwif->atapi_dma == 0)
return 0;
switch(mode) {
case 0x04:
if ((id->dma_ultra & 0x0040) &&
(id->dma_ultra & hwif->ultra_mask))
{ speed = XFER_UDMA_6; break; }
case 0x03:
if ((id->dma_ultra & 0x0020) &&
(id->dma_ultra & hwif->ultra_mask))
{ speed = XFER_UDMA_5; break; }
case 0x02:
if ((id->dma_ultra & 0x0010) &&
(id->dma_ultra & hwif->ultra_mask))
{ speed = XFER_UDMA_4; break; }
if ((id->dma_ultra & 0x0008) &&
(id->dma_ultra & hwif->ultra_mask))
{ speed = XFER_UDMA_3; break; }
case 0x01:
if ((id->dma_ultra & 0x0004) &&
(id->dma_ultra & hwif->ultra_mask))
{ speed = XFER_UDMA_2; break; }
if ((id->dma_ultra & 0x0002) &&
(id->dma_ultra & hwif->ultra_mask))
{ speed = XFER_UDMA_1; break; }
if ((id->dma_ultra & 0x0001) &&
(id->dma_ultra & hwif->ultra_mask))
{ speed = XFER_UDMA_0; break; }
case 0x00:
if ((id->dma_mword & 0x0004) &&
(id->dma_mword & hwif->mwdma_mask))
{ speed = XFER_MW_DMA_2; break; }
if ((id->dma_mword & 0x0002) &&
(id->dma_mword & hwif->mwdma_mask))
{ speed = XFER_MW_DMA_1; break; }
if ((id->dma_mword & 0x0001) &&
(id->dma_mword & hwif->mwdma_mask))
{ speed = XFER_MW_DMA_0; break; }
if ((id->dma_1word & 0x0004) &&
(id->dma_1word & hwif->swdma_mask))
{ speed = XFER_SW_DMA_2; break; }
if ((id->dma_1word & 0x0002) &&
(id->dma_1word & hwif->swdma_mask))
{ speed = XFER_SW_DMA_1; break; }
if ((id->dma_1word & 0x0001) &&
(id->dma_1word & hwif->swdma_mask))
{ speed = XFER_SW_DMA_0; break; }
}
/* Capable of UltraDMA modes? */
ultra_mask = id->dma_ultra & hwif->ultra_mask;
// printk("%s: %s: mode 0x%02x, speed 0x%02x\n",
// __FUNCTION__, drive->name, mode, speed);
if (!(id->field_valid & 4))
mode = 0; /* fallback to MW/SW DMA if no UltraDMA */
switch (mode) {
case 4:
if (ultra_mask & 0x40) {
speed = XFER_UDMA_6;
break;
}
case 3:
if (ultra_mask & 0x20) {
speed = XFER_UDMA_5;
break;
}
case 2:
if (ultra_mask & 0x10) {
speed = XFER_UDMA_4;
break;
}
if (ultra_mask & 0x08) {
speed = XFER_UDMA_3;
break;
}
case 1:
if (ultra_mask & 0x04) {
speed = XFER_UDMA_2;
break;
}
if (ultra_mask & 0x02) {
speed = XFER_UDMA_1;
break;
}
if (ultra_mask & 0x01) {
speed = XFER_UDMA_0;
break;
}
case 0:
mwdma_mask = id->dma_mword & hwif->mwdma_mask;
if (mwdma_mask & 0x04) {
speed = XFER_MW_DMA_2;
break;
}
if (mwdma_mask & 0x02) {
speed = XFER_MW_DMA_1;
break;
}
if (mwdma_mask & 0x01) {
speed = XFER_MW_DMA_0;
break;
}
swdma_mask = id->dma_1word & hwif->swdma_mask;
if (swdma_mask & 0x04) {
speed = XFER_SW_DMA_2;
break;
}
if (swdma_mask & 0x02) {
speed = XFER_SW_DMA_1;
break;
}
if (swdma_mask & 0x01) {
speed = XFER_SW_DMA_0;
break;
}
}
return speed;
}
EXPORT_SYMBOL(ide_dma_speed);