+ return -EINVAL;
+ iowrite32(val, link->ap->ioaddr.scr_addr + (4 * sc_reg));
+ return 0;
+}
+
+static int vt8251_scr_read(struct ata_link *link, unsigned int scr, u32 *val)
+{
+ static const u8 ipm_tbl[] = { 1, 2, 6, 0 };
+ struct pci_dev *pdev = to_pci_dev(link->ap->host->dev);
+ int slot = 2 * link->ap->port_no + link->pmp;
+ u32 v = 0;
+ u8 raw;
+
+ switch (scr) {
+ case SCR_STATUS:
+ pci_read_config_byte(pdev, 0xA0 + slot, &raw);
+
+ /* read the DET field, bit0 and 1 of the config byte */
+ v |= raw & 0x03;
+
+ /* read the SPD field, bit4 of the configure byte */
+ if (raw & (1 << 4))
+ v |= 0x02 << 4;
+ else
+ v |= 0x01 << 4;
+
+ /* read the IPM field, bit2 and 3 of the config byte */
+ v |= ipm_tbl[(raw >> 2) & 0x3];
+ break;
+
+ case SCR_ERROR:
+ /* devices other than 5287 uses 0xA8 as base */
+ WARN_ON(pdev->device != 0x5287);
+ pci_read_config_dword(pdev, 0xB0 + slot * 4, &v);
+ break;
+
+ case SCR_CONTROL:
+ pci_read_config_byte(pdev, 0xA4 + slot, &raw);
+
+ /* read the DET field, bit0 and bit1 */
+ v |= ((raw & 0x02) << 1) | (raw & 0x01);
+
+ /* read the IPM field, bit2 and bit3 */
+ v |= ((raw >> 2) & 0x03) << 8;
+ break;
+
+ default:
+ return -EINVAL;
+ }
+
+ *val = v;
+ return 0;
+}
+
+static int vt8251_scr_write(struct ata_link *link, unsigned int scr, u32 val)
+{
+ struct pci_dev *pdev = to_pci_dev(link->ap->host->dev);
+ int slot = 2 * link->ap->port_no + link->pmp;
+ u32 v = 0;
+
+ switch (scr) {
+ case SCR_ERROR:
+ /* devices other than 5287 uses 0xA8 as base */
+ WARN_ON(pdev->device != 0x5287);
+ pci_write_config_dword(pdev, 0xB0 + slot * 4, val);
+ return 0;
+
+ case SCR_CONTROL:
+ /* set the DET field */
+ v |= ((val & 0x4) >> 1) | (val & 0x1);
+
+ /* set the IPM field */
+ v |= ((val >> 8) & 0x3) << 2;
+
+ pci_write_config_byte(pdev, 0xA4 + slot, v);
+ return 0;
+
+ default:
+ return -EINVAL;
+ }
+}
+
+/**
+ * svia_tf_load - send taskfile registers to host controller
+ * @ap: Port to which output is sent
+ * @tf: ATA taskfile register set
+ *
+ * Outputs ATA taskfile to standard ATA host controller.
+ *
+ * This is to fix the internal bug of via chipsets, which will
+ * reset the device register after changing the IEN bit on ctl
+ * register.
+ */
+static void svia_tf_load(struct ata_port *ap, const struct ata_taskfile *tf)
+{
+ struct ata_taskfile ttf;
+
+ if (tf->ctl != ap->last_ctl) {
+ ttf = *tf;
+ ttf.flags |= ATA_TFLAG_DEVICE;
+ tf = &ttf;
+ }
+ ata_sff_tf_load(ap, tf);