pata_ali: Fix and workaround for FIFO DMA bug

In very obscure cases this can cause problems. We need to help the hardware
out a bit to avoid DMA problems on a reset.

Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

1 files changed, 30 insertions, 2 deletions

diff --git a/drivers/ata/pata_ali.c b/drivers/ata/pata_ali.c
index d2ea2db61e5..a4f9e39442c 100644
--- a/drivers/ata/pata_ali.c
+++ b/drivers/ata/pata_ali.c
@@ -35,7 +35,7 @@
 #include <linux/dmi.h>
 
 #define DRV_NAME "pata_ali"
-#define DRV_VERSION "0.7.7"
+#define DRV_VERSION "0.7.8"
 
 static int ali_atapi_dma = 0;
 module_param_named(atapi_dma, ali_atapi_dma, int, 0644);
@@ -341,6 +341,23 @@ static int ali_check_atapi_dma(struct ata_queued_cmd *qc)
         return 0;
 }
 
+static void ali_c2_c3_postreset(struct ata_link *link, unsigned int *classes)
+{
+        u8 r;
+        int port_bit = 4 << link->ap->port_no;
+
+        /* If our bridge is an ALI 1533 then do the extra work */
+        if (isa_bridge) {
+                /* Tristate and re-enable the bus signals */
+                pci_read_config_byte(isa_bridge, 0x58, &r);
+                r &= ~port_bit;
+                pci_write_config_byte(isa_bridge, 0x58, r);
+                r |= port_bit;
+                pci_write_config_byte(isa_bridge, 0x58, r);
+        }
+        ata_sff_postreset(link, classes);
+}
+
 static struct scsi_host_template ali_sht = {
         ATA_BMDMA_SHT(DRV_NAME),
 };
@@ -381,6 +398,17 @@ static struct ata_port_operations ali_c2_port_ops = {
         .check_atapi_dma = ali_check_atapi_dma,
         .cable_detect   = ali_c2_cable_detect,
         .dev_config     = ali_lock_sectors,
+        .postreset      = ali_c2_c3_postreset,
+};
+
+/*
+ *      Port operations for DMA capable ALi with cable detect
+ */
+static struct ata_port_operations ali_c4_port_ops = {
+        .inherits       = &ali_dma_base_ops,
+        .check_atapi_dma = ali_check_atapi_dma,
+        .cable_detect   = ali_c2_cable_detect,
+        .dev_config     = ali_lock_sectors,
 };
 
 /*
@@ -504,7 +532,7 @@ static int ali_init_one(struct pci_dev *pdev, const struct pci_device_id *id)
                 .pio_mask = 0x1f,
                 .mwdma_mask = 0x07,
                 .udma_mask = ATA_UDMA5,
-                .port_ops = &ali_c2_port_ops
+                .port_ops = &ali_c4_port_ops
         };
         /* Revision 0xC5 is UDMA133 with LBA48 DMA */
         static const struct ata_port_info info_c5 = {