[PATCH] libata irq-pio: add read/write multiple support

   - add is_multi_taskfile() to ata.h
   - initialize ata_device->multi_count with device identify data
   - use ata_pio_sectors() to support r/w multiple commands

Signed-off-by: Albert Lee <albertcc@tw.ibm.com>

========
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>

2 files changed, 46 insertions, 6 deletions

diff --git a/drivers/scsi/libata-core.c b/drivers/scsi/libata-core.c
index 2e0e6cca327c..59a4a26bc13f 100644
--- a/drivers/scsi/libata-core.c
+++ b/drivers/scsi/libata-core.c
@@ -1261,6 +1261,12 @@ retry:
 
                 }
 
+                if (dev->id[59] & 0x100) {
+                        dev->multi_count = dev->id[59] & 0xff;
+                        DPRINTK("ata%u: dev %u multi count %u\n",
+                                ap->id, device, dev->multi_count);
+                }
+
                 ap->host->max_cmd_len = 16;
         }
 
@@ -2804,7 +2810,7 @@ static int ata_pio_complete (struct ata_port *ap)
          * we enter, BSY will be cleared in a chk-status or two.  If not,
          * the drive is probably seeking or something.  Snooze for a couple
          * msecs, then chk-status again.  If still busy, fall back to
-         * HSM_ST_POLL state.
+         * HSM_ST_LAST_POLL state.
          */
         drv_stat = ata_busy_wait(ap, ATA_BUSY | ATA_DRQ, 10);
         if (drv_stat & (ATA_BUSY | ATA_DRQ)) {
@@ -3021,6 +3027,32 @@ static void ata_pio_sector(struct ata_queued_cmd *qc)
 }
 
 /**
+ *      ata_pio_sectors - Transfer one or many 512-byte sectors.
+ *      @qc: Command on going
+ *
+ *      Transfer one or many ATA_SECT_SIZE of data from/to the 
+ *      ATA device for the DRQ request.
+ *
+ *      LOCKING:
+ *      Inherited from caller.
+ */
+
+static void ata_pio_sectors(struct ata_queued_cmd *qc)
+{
+        if (is_multi_taskfile(&qc->tf)) {
+                /* READ/WRITE MULTIPLE */
+                unsigned int nsect;
+
+                assert(qc->dev->multi_count);
+
+                nsect = min(qc->nsect - qc->cursect, qc->dev->multi_count);
+                while (nsect--)
+                        ata_pio_sector(qc);
+        } else
+                ata_pio_sector(qc);
+}
+
+/**
  *      atapi_send_cdb - Write CDB bytes to hardware
  *      @ap: Port to which ATAPI device is attached.
  *      @qc: Taskfile currently active
@@ -3118,11 +3150,11 @@ static int ata_pio_first_block(struct ata_port *ap)
                  * send first data block.
                  */
 
-                /* ata_pio_sector() might change the state to HSM_ST_LAST.
-                 * so, the state is changed here before ata_pio_sector().
+                /* ata_pio_sectors() might change the state to HSM_ST_LAST.
+                 * so, the state is changed here before ata_pio_sectors().
                  */
                 ap->hsm_task_state = HSM_ST;
-                ata_pio_sector(qc);
+                ata_pio_sectors(qc);
                 ata_altstatus(ap); /* flush */
         } else
                 /* send CDB */
@@ -3327,7 +3359,7 @@ static void ata_pio_block(struct ata_port *ap)
                         return;
                 }
 
-                ata_pio_sector(qc);
+                ata_pio_sectors(qc);
         }
 
         ata_altstatus(ap); /* flush */
@@ -4213,7 +4245,7 @@ fsm_start:
                                 goto fsm_start;
                         }
 
-                        ata_pio_sector(qc);
+                        ata_pio_sectors(qc);
 
                         if (ap->hsm_task_state == HSM_ST_LAST &&
                             (!(qc->tf.flags & ATA_TFLAG_WRITE))) {
diff --git a/include/linux/ata.h b/include/linux/ata.h
index d54da3306d2c..f512104a1a3f 100644
--- a/include/linux/ata.h
+++ b/include/linux/ata.h
@@ -293,6 +293,14 @@ static inline int is_atapi_taskfile(const struct ata_taskfile *tf)
                (tf->protocol == ATA_PROT_ATAPI_DMA);
 }
 
+static inline int is_multi_taskfile(struct ata_taskfile *tf)
+{
+        return (tf->command == ATA_CMD_READ_MULTI) ||
+               (tf->command == ATA_CMD_WRITE_MULTI) ||
+               (tf->command == ATA_CMD_READ_MULTI_EXT) ||
+               (tf->command == ATA_CMD_WRITE_MULTI_EXT);
+}
+
 static inline int ata_ok(u8 status)
 {
         return ((status & (ATA_BUSY | ATA_DRDY | ATA_DF | ATA_DRQ | ATA_ERR))