- * ide_dma_speed - compute DMA speed
- * @drive: drive
- * @mode: modes available
- *
- * 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_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;
-
- /* 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;
-
- 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);
-
-
-/**
- * ide_rate_filter - return best speed for mode
- * @mode: modes available