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path: root/drivers/ide/ide-dma.c
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Diffstat (limited to 'drivers/ide/ide-dma.c')
-rw-r--r--drivers/ide/ide-dma.c94
1 files changed, 94 insertions, 0 deletions
diff --git a/drivers/ide/ide-dma.c b/drivers/ide/ide-dma.c
index fd213088b06..5fe85191d49 100644
--- a/drivers/ide/ide-dma.c
+++ b/drivers/ide/ide-dma.c
@@ -705,6 +705,100 @@ int ide_use_dma(ide_drive_t *drive)
EXPORT_SYMBOL_GPL(ide_use_dma);
+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)
+{
+ struct hd_driveid *id = drive->id;
+ ide_hwif_t *hwif = drive->hwif;
+ unsigned int mask = 0;
+
+ switch(base) {
+ case XFER_UDMA_0:
+ if ((id->field_valid & 4) == 0)
+ break;
+
+ mask = id->dma_ultra & hwif->ultra_mask;
+
+ if (hwif->udma_filter)
+ mask &= hwif->udma_filter(drive);
+
+ if ((mask & 0x78) && (eighty_ninty_three(drive) == 0))
+ mask &= 0x07;
+ break;
+ case XFER_MW_DMA_0:
+ mask = id->dma_mword & hwif->mwdma_mask;
+ break;
+ case XFER_SW_DMA_0:
+ mask = id->dma_1word & hwif->swdma_mask;
+ break;
+ default:
+ BUG();
+ break;
+ }
+
+ return mask;
+}
+
+/**
+ * ide_max_dma_mode - compute DMA speed
+ * @drive: IDE device
+ *
+ * Checks the drive capabilities and returns the speed to use
+ * for the DMA transfer. Returns 0 if the drive is incapable
+ * of DMA transfers.
+ */
+
+u8 ide_max_dma_mode(ide_drive_t *drive)
+{
+ ide_hwif_t *hwif = drive->hwif;
+ unsigned int mask;
+ int x, i;
+ u8 mode = 0;
+
+ if (drive->media != ide_disk && hwif->atapi_dma == 0)
+ return 0;
+
+ for (i = 0; i < ARRAY_SIZE(xfer_mode_bases); i++) {
+ mask = ide_get_mode_mask(drive, xfer_mode_bases[i]);
+ x = fls(mask) - 1;
+ if (x >= 0) {
+ mode = xfer_mode_bases[i] + x;
+ break;
+ }
+ }
+
+ printk(KERN_DEBUG "%s: selected mode 0x%x\n", drive->name, mode);
+
+ return mode;
+}
+
+EXPORT_SYMBOL_GPL(ide_max_dma_mode);
+
+int ide_tune_dma(ide_drive_t *drive)
+{
+ u8 speed;
+
+ /* TODO: use only ide_max_dma_mode() */
+ if (!ide_use_dma(drive))
+ return 0;
+
+ speed = ide_max_dma_mode(drive);
+
+ if (!speed)
+ return 0;
+
+ drive->hwif->speedproc(drive, speed);
+
+ return ide_dma_enable(drive);
+}
+
+EXPORT_SYMBOL_GPL(ide_tune_dma);
+
void ide_dma_verbose(ide_drive_t *drive)
{
struct hd_driveid *id = drive->id;