summaryrefslogtreecommitdiffstats
path: root/drivers/ide/pci/piix.c
diff options
context:
space:
mode:
Diffstat (limited to 'drivers/ide/pci/piix.c')
-rw-r--r--drivers/ide/pci/piix.c17
1 files changed, 4 insertions, 13 deletions
diff --git a/drivers/ide/pci/piix.c b/drivers/ide/pci/piix.c
index 27781d294ce..bd6d3f77d30 100644
--- a/drivers/ide/pci/piix.c
+++ b/drivers/ide/pci/piix.c
@@ -203,20 +203,11 @@ static void piix_set_dma_mode(ide_drive_t *drive, const u8 speed)
pci_read_config_byte(dev, 0x54, &reg54);
pci_read_config_byte(dev, 0x55, &reg55);
- switch(speed) {
- case XFER_UDMA_4:
- case XFER_UDMA_2: u_speed = 2 << (drive->dn * 4); break;
- case XFER_UDMA_5:
- case XFER_UDMA_3:
- case XFER_UDMA_1: u_speed = 1 << (drive->dn * 4); break;
- case XFER_UDMA_0: u_speed = 0 << (drive->dn * 4); break;
- case XFER_MW_DMA_2:
- case XFER_MW_DMA_1:
- case XFER_SW_DMA_2: break;
- default: return;
- }
-
if (speed >= XFER_UDMA_0) {
+ u8 udma = speed - XFER_UDMA_0;
+
+ u_speed = min_t(u8, 2 - (udma & 1), udma) << (drive->dn * 4);
+
if (!(reg48 & u_flag))
pci_write_config_byte(dev, 0x48, reg48 | u_flag);
if (speed == XFER_UDMA_5) {