diff options
| -rw-r--r-- | drivers/scsi/libata-core.c | 147 |
1 files changed, 147 insertions, 0 deletions
diff --git a/drivers/scsi/libata-core.c b/drivers/scsi/libata-core.c index 18418c82d6f..9946618f1a3 100644 --- a/drivers/scsi/libata-core.c +++ b/drivers/scsi/libata-core.c @@ -231,6 +231,108 @@ int ata_rwcmd_protocol(struct ata_queued_cmd *qc) return -1; } +/** + * ata_pack_xfermask - Pack pio, mwdma and udma masks into xfer_mask + * @pio_mask: pio_mask + * @mwdma_mask: mwdma_mask + * @udma_mask: udma_mask + * + * Pack @pio_mask, @mwdma_mask and @udma_mask into a single + * unsigned int xfer_mask. + * + * LOCKING: + * None. + * + * RETURNS: + * Packed xfer_mask. + */ +static unsigned int ata_pack_xfermask(unsigned int pio_mask, + unsigned int mwdma_mask, + unsigned int udma_mask) +{ + return ((pio_mask << ATA_SHIFT_PIO) & ATA_MASK_PIO) | + ((mwdma_mask << ATA_SHIFT_MWDMA) & ATA_MASK_MWDMA) | + ((udma_mask << ATA_SHIFT_UDMA) & ATA_MASK_UDMA); +} + +static const struct ata_xfer_ent { + unsigned int shift, bits; + u8 base; +} ata_xfer_tbl[] = { + { ATA_SHIFT_PIO, ATA_BITS_PIO, XFER_PIO_0 }, + { ATA_SHIFT_MWDMA, ATA_BITS_MWDMA, XFER_MW_DMA_0 }, + { ATA_SHIFT_UDMA, ATA_BITS_UDMA, XFER_UDMA_0 }, + { -1, }, +}; + +/** + * ata_xfer_mask2mode - Find matching XFER_* for the given xfer_mask + * @xfer_mask: xfer_mask of interest + * + * Return matching XFER_* value for @xfer_mask. Only the highest + * bit of @xfer_mask is considered. + * + * LOCKING: + * None. + * + * RETURNS: + * Matching XFER_* value, 0 if no match found. + */ +static u8 ata_xfer_mask2mode(unsigned int xfer_mask) +{ + int highbit = fls(xfer_mask) - 1; + const struct ata_xfer_ent *ent; + + for (ent = ata_xfer_tbl; ent->shift >= 0; ent++) + if (highbit >= ent->shift && highbit < ent->shift + ent->bits) + return ent->base + highbit - ent->shift; + return 0; +} + +/** + * ata_xfer_mode2mask - Find matching xfer_mask for XFER_* + * @xfer_mode: XFER_* of interest + * + * Return matching xfer_mask for @xfer_mode. + * + * LOCKING: + * None. + * + * RETURNS: + * Matching xfer_mask, 0 if no match found. + */ +static unsigned int ata_xfer_mode2mask(u8 xfer_mode) +{ + const struct ata_xfer_ent *ent; + + for (ent = ata_xfer_tbl; ent->shift >= 0; ent++) + if (xfer_mode >= ent->base && xfer_mode < ent->base + ent->bits) + return 1 << (ent->shift + xfer_mode - ent->base); + return 0; +} + +/** + * ata_xfer_mode2shift - Find matching xfer_shift for XFER_* + * @xfer_mode: XFER_* of interest + * + * Return matching xfer_shift for @xfer_mode. + * + * LOCKING: + * None. + * + * RETURNS: + * Matching xfer_shift, -1 if no match found. + */ +static int ata_xfer_mode2shift(unsigned int xfer_mode) +{ + const struct ata_xfer_ent *ent; + + for (ent = ata_xfer_tbl; ent->shift >= 0; ent++) + if (xfer_mode >= ent->base && xfer_mode < ent->base + ent->bits) + return ent->shift; + return -1; +} + static const char * const xfer_mode_str[] = { "PIO0", "PIO1", @@ -682,6 +784,51 @@ static inline void ata_dump_id(const u16 *id) id[93]); } +/** + * ata_id_xfermask - Compute xfermask from the given IDENTIFY data + * @id: IDENTIFY data to compute xfer mask from + * + * Compute the xfermask for this device. This is not as trivial + * as it seems if we must consider early devices correctly. + * + * FIXME: pre IDE drive timing (do we care ?). + * + * LOCKING: + * None. + * + * RETURNS: + * Computed xfermask + */ +static unsigned int ata_id_xfermask(const u16 *id) +{ + unsigned int pio_mask, mwdma_mask, udma_mask; + + /* Usual case. Word 53 indicates word 64 is valid */ + if (id[ATA_ID_FIELD_VALID] & (1 << 1)) { + pio_mask = id[ATA_ID_PIO_MODES] & 0x03; + pio_mask <<= 3; + pio_mask |= 0x7; + } else { + /* If word 64 isn't valid then Word 51 high byte holds + * the PIO timing number for the maximum. Turn it into + * a mask. + */ + pio_mask = (2 << (id[ATA_ID_OLD_PIO_MODES] & 0xFF)) - 1 ; + + /* But wait.. there's more. Design your standards by + * committee and you too can get a free iordy field to + * process. However its the speeds not the modes that + * are supported... Note drivers using the timing API + * will get this right anyway + */ + } + + mwdma_mask = id[ATA_ID_MWDMA_MODES] & 0x07; + udma_mask = id[ATA_ID_UDMA_MODES] & 0xff; + + return ata_pack_xfermask(pio_mask, mwdma_mask, udma_mask); +} + /* * Compute the PIO modes available for this device. This is not as * trivial as it seems if we must consider early devices correctly. |