[PATCH] ahci: add support for VIA VT8251

Adds AHCI support for the VIA VT8251.

Includes a workaround for a hardware bug which requires a Command List
Override before softreset.

Signed-off-by: Bastiaan Jacques <b.jacques@planet.nl>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

1 files changed, 49 insertions, 15 deletions

diff --git a/drivers/scsi/ahci.c b/drivers/scsi/ahci.c
index 1b8429cb3c96..d23f00230a76 100644
--- a/drivers/scsi/ahci.c
+++ b/drivers/scsi/ahci.c
@@ -73,6 +73,7 @@ enum {
         RX_FIS_D2H_REG          = 0x40, /* offset of D2H Register FIS data */
 
         board_ahci              = 0,
+        board_ahci_vt8251       = 1,
 
         /* global controller registers */
         HOST_CAP                = 0x00, /* host capabilities */
@@ -153,6 +154,9 @@ enum {
 
         /* hpriv->flags bits */
         AHCI_FLAG_MSI           = (1 << 0),
+
+        /* ap->flags bits */
+        AHCI_FLAG_RESET_NEEDS_CLO       = (1 << 24),
 };
 
 struct ahci_cmd_hdr {
@@ -255,6 +259,16 @@ static const struct ata_port_info ahci_port_info[] = {
                 .udma_mask      = 0x7f, /* udma0-6 ; FIXME */
                 .port_ops       = &ahci_ops,
         },
+        /* board_ahci_vt8251 */
+        {
+                .sht            = &ahci_sht,
+                .host_flags     = ATA_FLAG_SATA | ATA_FLAG_NO_LEGACY |
+                                  ATA_FLAG_MMIO | ATA_FLAG_PIO_DMA |
+                                  AHCI_FLAG_RESET_NEEDS_CLO,
+                .pio_mask       = 0x1f, /* pio0-4 */
+                .udma_mask      = 0x7f, /* udma0-6 ; FIXME */
+                .port_ops       = &ahci_ops,
+        },
 };
 
 static const struct pci_device_id ahci_pci_tbl[] = {
@@ -296,6 +310,8 @@ static const struct pci_device_id ahci_pci_tbl[] = {
           board_ahci }, /* ATI SB600 non-raid */
         { PCI_VENDOR_ID_ATI, 0x4381, PCI_ANY_ID, PCI_ANY_ID, 0, 0,
           board_ahci }, /* ATI SB600 raid */
+        { PCI_VENDOR_ID_VIA, 0x3349, PCI_ANY_ID, PCI_ANY_ID, 0, 0,
+          board_ahci_vt8251 }, /* VIA VT8251 */
         { }     /* terminate list */
 };
 
@@ -516,9 +532,29 @@ static void ahci_fill_cmd_slot(struct ahci_port_priv *pp, u32 opts)
         pp->cmd_slot[0].tbl_addr_hi = cpu_to_le32((pp->cmd_tbl_dma >> 16) >> 16);
 }
 
-static int ahci_softreset(struct ata_port *ap, unsigned int *class)
+static int ahci_clo(struct ata_port *ap)
 {
+        void __iomem *port_mmio = (void __iomem *) ap->ioaddr.cmd_addr;
         struct ahci_host_priv *hpriv = ap->host_set->private_data;
+        u32 tmp;
+
+        if (!(hpriv->cap & HOST_CAP_CLO))
+                return -EOPNOTSUPP;
+
+        tmp = readl(port_mmio + PORT_CMD);
+        tmp |= PORT_CMD_CLO;
+        writel(tmp, port_mmio + PORT_CMD);
+
+        tmp = ata_wait_register(port_mmio + PORT_CMD,
+                                PORT_CMD_CLO, PORT_CMD_CLO, 1, 500);
+        if (tmp & PORT_CMD_CLO)
+                return -EIO;
+
+        return 0;
+}
+
+static int ahci_softreset(struct ata_port *ap, unsigned int *class)
+{
         struct ahci_port_priv *pp = ap->private_data;
         void __iomem *mmio = ap->host_set->mmio_base;
         void __iomem *port_mmio = ahci_port_base(mmio, ap->port_no);
@@ -547,21 +583,13 @@ static int ahci_softreset(struct ata_port *ap, unsigned int *class)
         /* check BUSY/DRQ, perform Command List Override if necessary */
         ahci_tf_read(ap, &tf);
         if (tf.command & (ATA_BUSY | ATA_DRQ)) {
-                if (!(hpriv->cap & HOST_CAP_CLO)) {
-                        rc = -EIO;
-                        reason = "port busy but no CLO";
-                        goto fail_restart;
-                }
-
-                tmp = readl(port_mmio + PORT_CMD);
-                tmp |= PORT_CMD_CLO;
-                writel(tmp, port_mmio + PORT_CMD);
+                rc = ahci_clo(ap);
 
-                tmp = ata_wait_register(port_mmio + PORT_CMD,
-                                        PORT_CMD_CLO, PORT_CMD_CLO, 1, 500);
-                if (tmp & PORT_CMD_CLO) {
-                        rc = -EIO;
-                        reason = "CLO failed";
+                if (rc == -EOPNOTSUPP) {
+                        reason = "port busy but CLO unavailable";
+                        goto fail_restart;
+                } else if (rc) {
+                        reason = "port busy but CLO failed";
                         goto fail_restart;
                 }
         }
@@ -672,6 +700,12 @@ static void ahci_postreset(struct ata_port *ap, unsigned int *class)
 
 static int ahci_probe_reset(struct ata_port *ap, unsigned int *classes)
 {
+        if ((ap->flags & AHCI_FLAG_RESET_NEEDS_CLO) &&
+            (ata_busy_wait(ap, ATA_BUSY, 1000) & ATA_BUSY)) {
+                /* ATA_BUSY hasn't cleared, so send a CLO */
+                ahci_clo(ap);
+        }
+
         return ata_drive_probe_reset(ap, ata_std_probeinit,
                                      ahci_softreset, ahci_hardreset,
                                      ahci_postreset, classes);