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authorSergei Shtylyov <sshtylyov@ru.mvista.com>2006-10-03 01:14:17 -0700
committerLinus Torvalds <torvalds@g5.osdl.org>2006-10-03 08:04:07 -0700
commit0750508ae6479d4ac6154b35c5b82929f31efb03 (patch)
tree28df59ad1701c407ecdd3b08295093dffc678eb2 /drivers/ide/ide-lib.c
parent83d7dbc4095a0c314b191c573be5fb4fa6ce0897 (diff)
[PATCH] ide_dma_speed() fixes
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>
Diffstat (limited to 'drivers/ide/ide-lib.c')
-rw-r--r--drivers/ide/ide-lib.c125
1 files changed, 73 insertions, 52 deletions
diff --git a/drivers/ide/ide-lib.c b/drivers/ide/ide-lib.c
index 850ef63cc98..8237d89eec6 100644
--- a/drivers/ide/ide-lib.c
+++ b/drivers/ide/ide-lib.c
@@ -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;
+
+ 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;
-// printk("%s: %s: mode 0x%02x, speed 0x%02x\n",
-// __FUNCTION__, drive->name, mode, speed);
+ 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);