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>

diff --git a/drivers/ata/pata_ali.c b/drivers/ata/pata_ali.c
index d2ea2db..a4f9e39 100644 (file)
--- 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 = {