diff options
Diffstat (limited to 'drivers/ide/ide-lib.c')
| -rw-r--r-- | drivers/ide/ide-lib.c | 125 |
1 files changed, 73 insertions, 52 deletions
diff --git a/drivers/ide/ide-lib.c b/drivers/ide/ide-lib.c index 850ef63cc986..8237d89eec6e 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); |