ata_piix: fix pio/mwdma programming

Fix various bugs in pio/mwdma mode programming.

* Control bits in the timing register wasn't cleared properly while
  programming PIO mode.

* MWDMA mode programming cleared the wrong part of control bits.

* MWDMA mode programming cleared udma_mask even when the controller
  doesn't support UDMA.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Cc: Art Haas <ahaas@airmail.net>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

diff --git a/drivers/ata/ata_piix.c b/drivers/ata/ata_piix.c
index 9c07b88631be6d50635d292d67fa632996c57e4f..924e4474068d3a197c853f2882d560d7218273a1 100644 (file)
--- a/drivers/ata/ata_piix.c
+++ b/drivers/ata/ata_piix.c
@@ -685,8 +685,14 @@ static void piix_set_piomode (struct ata_port *ap, struct ata_device *adev)
        if (adev->class == ATA_DEV_ATA)
                control |= 4;   /* PPE enable */
 
+       /* PIO configuration clears DTE unconditionally.  It will be
+        * programmed in set_dmamode which is guaranteed to be called
+        * after set_piomode if any DMA mode is available.
+        */
        pci_read_config_word(dev, master_port, &master_data);
        if (is_slave) {
+               /* clear TIME1|IE1|PPE1|DTE1 */
+               master_data &= 0xff0f;
                /* Enable SITRE (seperate slave timing register) */
                master_data |= 0x4000;
                /* enable PPE1, IE1 and TIME1 as needed */
@@ -694,12 +700,14 @@ static void piix_set_piomode (struct ata_port *ap, struct ata_device *adev)
                pci_read_config_byte(dev, slave_port, &slave_data);
                slave_data &= (ap->port_no ? 0x0f : 0xf0);
                /* Load the timing nibble for this slave */
-               slave_data |= ((timings[pio][0] << 2) | timings[pio][1]) << (ap->port_no ? 4 : 0);
+               slave_data |= ((timings[pio][0] << 2) | timings[pio][1])
+                                               << (ap->port_no ? 4 : 0);
        } else {
-               /* Master keeps the bits in a different format */
-               master_data &= 0xccf8;
+               /* clear ISP|RCT|TIME0|IE0|PPE0|DTE0 */
+               master_data &= 0xccf0;
                /* Enable PPE, IE and TIME as appropriate */
                master_data |= control;
+               /* load ISP and RCT */
                master_data |=
                        (timings[pio][0] << 12) |
                        (timings[pio][1] << 8);
@@ -816,7 +824,7 @@ static void do_pata_set_dmamode (struct ata_port *ap, struct ata_device *adev, i
                        master_data &= 0xFF4F;  /* Mask out IORDY|TIME1|DMAONLY */
                        master_data |= control << 4;
                        pci_read_config_byte(dev, 0x44, &slave_data);
-                       slave_data &= (0x0F + 0xE1 * ap->port_no);
+                       slave_data &= (ap->port_no ? 0x0f : 0xf0);
                        /* Load the matching timing */
                        slave_data |= ((timings[pio][0] << 2) | timings[pio][1]) << (ap->port_no ? 4 : 0);
                        pci_write_config_byte(dev, 0x44, slave_data);
@@ -828,8 +836,11 @@ static void do_pata_set_dmamode (struct ata_port *ap, struct ata_device *adev, i
                                (timings[pio][0] << 12) |
                                (timings[pio][1] << 8);
                }
-               udma_enable &= ~(1 << devid);
-               pci_write_config_word(dev, master_port, master_data);
+
+               if (ap->udma_mask) {
+                       udma_enable &= ~(1 << devid);
+                       pci_write_config_word(dev, master_port, master_data);
+               }
        }
        /* Don't scribble on 0x48 if the controller does not support UDMA */
        if (ap->udma_mask)