sata_promise: ATAPI cleanup

Here's a cleanup for yesterday's sata_promise ATAPI patch:
- add and use a symbolic constant for the altstatus register
- check return status from ata_busy_wait()
- add missing newline in a warning printk()
- update comment in pdc_issue_atapi_pkt_cmd() to clarify
  that the maybe-wait-for-INT issue cannot occur in the
  current driver, but may occur if the driver starts issuing
  ATAPI non-DMA commands as PDC packets

Signed-off-by: Mikael Pettersson <mikpe@it.uu.se>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

1 files changed, 16 insertions, 11 deletions

diff --git a/drivers/ata/sata_promise.c b/drivers/ata/sata_promise.c
index 9bd195fbd88..4c09d6504f0 100644
--- a/drivers/ata/sata_promise.c
+++ b/drivers/ata/sata_promise.c
@@ -59,6 +59,7 @@ enum {
         PDC_CYLINDER_HIGH       = 0x14, /* Cylinder high reg (per port) */
         PDC_DEVICE              = 0x18, /* Device/Head reg (per port) */
         PDC_COMMAND             = 0x1C, /* Command/status reg (per port) */
+        PDC_ALTSTATUS           = 0x38, /* Alternate-status/device-control reg (per port) */
         PDC_PKT_SUBMIT          = 0x40, /* Command packet pointer addr */
         PDC_INT_SEQMASK         = 0x40, /* Mask of asserted SEQ INTs */
         PDC_FLASH_CTL           = 0x44, /* Flash control register */
@@ -728,7 +729,7 @@ static unsigned int pdc_wait_for_drq(struct ata_port *ap)
          * know when to time out the outer loop.
          */
         for(i = 0; i < 1000; ++i) {
-                status = readb(port_mmio + 0x38); /* altstatus */
+                status = readb(port_mmio + PDC_ALTSTATUS);
                 if (status == 0xFF)
                         break;
                 if (status & ATA_BUSY)
@@ -738,7 +739,15 @@ static unsigned int pdc_wait_for_drq(struct ata_port *ap)
                 mdelay(1);
         }
         if (i >= 1000)
-                ata_port_printk(ap, KERN_WARNING, "%s timed out", __FUNCTION__);
+                ata_port_printk(ap, KERN_WARNING, "%s timed out\n", __FUNCTION__);
+        return status;
+}
+
+static unsigned int pdc_wait_on_busy(struct ata_port *ap)
+{
+        unsigned int status = ata_busy_wait(ap, ATA_BUSY, 1000);
+        if (status != 0xff && (status & ATA_BUSY))
+                ata_port_printk(ap, KERN_WARNING, "%s timed out\n", __FUNCTION__);
         return status;
 }
 
@@ -762,7 +771,7 @@ static void pdc_issue_atapi_pkt_cmd(struct ata_queued_cmd *qc)
                         tmp |= ATA_DEV1;
         }
         writeb(tmp, port_mmio + PDC_DEVICE);
-        ata_busy_wait(ap, ATA_BUSY, 1000);
+        pdc_wait_on_busy(ap);
 
         writeb(0x00, port_mmio + PDC_SECTOR_COUNT);
         writeb(0x00, port_mmio + PDC_SECTOR_NUMBER);
@@ -788,14 +797,10 @@ static void pdc_issue_atapi_pkt_cmd(struct ata_queued_cmd *qc)
         /* send ATAPI packet command 0xA0 */
         writeb(ATA_CMD_PACKET, port_mmio + PDC_COMMAND);
 
-        /*
-         * At this point in the issuing of a packet command, the Promise
-         * driver busy-waits for INT (CTLSTAT bit 27) if it detected
-         * (at port init time) that the device interrupts with assertion
-         * of DRQ after receiving a packet command.
-         *
-         * XXX: Do we need to handle this case as well? Does libata detect
-         * this case for us, or do we have to do our own per-port init?
+        /* pdc_qc_issue_prot() currently sends ATAPI PIO packets back
+         * to libata. If we start handling those packets ourselves,
+         * then we must busy-wait for INT (CTLSTAT bit 27) at this point
+         * if the device has ATA_DFLAG_CDB_INTR set.
          */
 
         pdc_wait_for_drq(ap);