libata: automatically use DMADIR if drive/bridge requires it

Back in 2.6.17-rc2, a libata module parameter was added for atapi_dmadir.

That's nice, but most SATA devices which need it will tell us about it
in their IDENTIFY PACKET response, as bit-15 of word-62 of the
returned data (as per ATA7, ATA8 specifications).

So for those which specify it, we should automatically use the DMADIR bit.
Otherwise, disc writing will fail by default on many SATA-ATAPI drives.

This patch adds ATA_DFLAG_DMADIR and make ata_dev_configure() set it
if atapi_dmadir is set or identify data indicates DMADIR is necessary.
atapi_xlat() is converted to check ATA_DFLAG_DMADIR before setting
DMADIR.

Original patch is from Mark Lord.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Cc: Mark Lord <mlord@pobox.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index 9812bbf05e622ed20c7cbc14c479b3b929679b87..1845119cc7f01f8104df815162fd0d7d4502a530 100644 (file)
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -2396,6 +2396,7 @@ int ata_dev_configure(struct ata_device *dev)
        else if (dev->class == ATA_DEV_ATAPI) {
                const char *cdb_intr_string = "";
                const char *atapi_an_string = "";
+               const char *dma_dir_string = "";
                u32 sntf;
 
                rc = atapi_cdb_len(id);
@@ -2436,13 +2437,19 @@ int ata_dev_configure(struct ata_device *dev)
                        cdb_intr_string = ", CDB intr";
                }
 
+               if (atapi_dmadir || atapi_id_dmadir(dev->id)) {
+                       dev->flags |= ATA_DFLAG_DMADIR;
+                       dma_dir_string = ", DMADIR";
+               }
+
                /* print device info to dmesg */
                if (ata_msg_drv(ap) && print_info)
                        ata_dev_printk(dev, KERN_INFO,
-                                      "ATAPI: %s, %s, max %s%s%s\n",
+                                      "ATAPI: %s, %s, max %s%s%s%s\n",
                                       modelbuf, fwrevbuf,
                                       ata_mode_string(xfer_mask),
-                                      cdb_intr_string, atapi_an_string);
+                                      cdb_intr_string, atapi_an_string,
+                                      dma_dir_string);
        }
 
        /* determine max_sectors */

diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
index f888babc8283cc3512c2932769ff9bfc50a570de..0562b0a49f3b2acc474c3145ee0f48911eefe349 100644 (file)
--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -2582,7 +2582,8 @@ static unsigned int atapi_xlat(struct ata_queued_cmd *qc)
                qc->tf.protocol = ATAPI_PROT_DMA;
                qc->tf.feature |= ATAPI_PKT_DMA;
 
-               if (atapi_dmadir && (scmd->sc_data_direction != DMA_TO_DEVICE))
+               if ((dev->flags & ATA_DFLAG_DMADIR) &&
+                   (scmd->sc_data_direction != DMA_TO_DEVICE))
                        /* some SATA bridges need us to indicate data xfer direction */
                        qc->tf.feature |= ATAPI_DMADIR;
        }

diff --git a/include/linux/ata.h b/include/linux/ata.h
index 78bbacaed8c4a4f2521f552432d2b4baf2dfc226..1c622e2b0504749e7fdc59b7406a12a1819f6651 100644 (file)
--- a/include/linux/ata.h
+++ b/include/linux/ata.h
@@ -659,6 +659,11 @@ static inline int atapi_command_packet_set(const u16 *dev_id)
        return (dev_id[0] >> 8) & 0x1f;
 }
 
+static inline int atapi_id_dmadir(const u16 *dev_id)
+{
+       return ata_id_major_version(dev_id) >= 7 && (dev_id[62] & 0x8000);
+}
+
 static inline int is_multi_taskfile(struct ata_taskfile *tf)
 {
        return (tf->command == ATA_CMD_READ_MULTI) ||

diff --git a/include/linux/libata.h b/include/linux/libata.h
index ce7603a73156b15490d054e4374fe1560d04a57f..a05f600136426c74455f2739169be4fec4c9497f 100644 (file)
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -138,6 +138,7 @@ enum {
        ATA_DFLAG_AN            = (1 << 7), /* AN configured */
        ATA_DFLAG_HIPM          = (1 << 8), /* device supports HIPM */
        ATA_DFLAG_DIPM          = (1 << 9), /* device supports DIPM */
+       ATA_DFLAG_DMADIR        = (1 << 10), /* device requires DMADIR */
        ATA_DFLAG_CFG_MASK      = (1 << 12) - 1,
 
        ATA_DFLAG_PIO           = (1 << 12), /* device limited to PIO mode */