ahci: separate out ahci_kick_engine()

Separate out stop_engine - CLO - start_engine sequence from
ahci_softreset() and ahci_clo() into ahci_reset_engine() and use it in
ahci_softreset() and ahci_post_internal_cmd().  The function will also
be used to prepare for and clean up after PMP register access
commands.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

diff --git a/drivers/ata/ahci.c b/drivers/ata/ahci.c
index 0451600..1be238d 100644 (file)
--- a/drivers/ata/ahci.c
+++ b/drivers/ata/ahci.c
@@ -948,25 +948,49 @@ static void ahci_fill_cmd_slot(struct ahci_port_priv *pp, unsigned int tag,
        pp->cmd_slot[tag].tbl_addr_hi = cpu_to_le32((cmd_tbl_dma >> 16) >> 16);
 }
 
-static int ahci_clo(struct ata_port *ap)
+static int ahci_kick_engine(struct ata_port *ap, int force_restart)
 {
        void __iomem *port_mmio = ap->ioaddr.cmd_addr;
        struct ahci_host_priv *hpriv = ap->host->private_data;
        u32 tmp;
+       int busy, rc;
 
-       if (!(hpriv->cap & HOST_CAP_CLO))
-               return -EOPNOTSUPP;
+       /* do we need to kick the port? */
+       busy = ahci_check_status(ap) & (ATA_BUSY | ATA_DRQ);
+       if (!busy && !force_restart)
+               return 0;
+
+       /* stop engine */
+       rc = ahci_stop_engine(ap);
+       if (rc)
+               goto out_restart;
+
+       /* need to do CLO? */
+       if (!busy) {
+               rc = 0;
+               goto out_restart;
+       }
+
+       if (!(hpriv->cap & HOST_CAP_CLO)) {
+               rc = -EOPNOTSUPP;
+               goto out_restart;
+       }
 
+       /* perform CLO */
        tmp = readl(port_mmio + PORT_CMD);
        tmp |= PORT_CMD_CLO;
        writel(tmp, port_mmio + PORT_CMD);
 
+       rc = 0;
        tmp = ata_wait_register(port_mmio + PORT_CMD,
                                PORT_CMD_CLO, PORT_CMD_CLO, 1, 500);
        if (tmp & PORT_CMD_CLO)
-               return -EIO;
+               rc = -EIO;
 
-       return 0;
+       /* restart engine */
+ out_restart:
+       ahci_start_engine(ap);
+       return rc;
 }
 
 static int ahci_softreset(struct ata_port *ap, unsigned int *class,
@@ -991,27 +1015,10 @@ static int ahci_softreset(struct ata_port *ap, unsigned int *class,
        }
 
        /* prepare for SRST (AHCI-1.1 10.4.1) */
-       rc = ahci_stop_engine(ap);
-       if (rc) {
-               reason = "failed to stop engine";
-               goto fail_restart;
-       }
-
-       /* check BUSY/DRQ, perform Command List Override if necessary */
-       if (ahci_check_status(ap) & (ATA_BUSY | ATA_DRQ)) {
-               rc = ahci_clo(ap);
-
-               if (rc == -EOPNOTSUPP) {
-                       reason = "port busy but CLO unavailable";
-                       goto fail_restart;
-               } else if (rc) {
-                       reason = "port busy but CLO failed";
-                       goto fail_restart;
-               }
-       }
-
-       /* restart engine */
-       ahci_start_engine(ap);
+       rc = ahci_kick_engine(ap, 1);
+       if (rc)
+               ata_port_printk(ap, KERN_WARNING,
+                               "failed to reset engine (errno=%d)", rc);
 
        ata_tf_init(ap->device, &tf);
        fis = pp->cmd_tbl;
@@ -1070,8 +1077,6 @@ static int ahci_softreset(struct ata_port *ap, unsigned int *class,
        DPRINTK("EXIT, class=%u\n", *class);
        return 0;
 
- fail_restart:
-       ahci_start_engine(ap);
  fail:
        ata_port_printk(ap, KERN_ERR, "softreset failed (%s)\n", reason);
        return rc;
@@ -1516,11 +1521,9 @@ static void ahci_post_internal_cmd(struct ata_queued_cmd *qc)
 {
        struct ata_port *ap = qc->ap;
 
-       if (qc->flags & ATA_QCFLAG_FAILED) {
-               /* make DMA engine forget about the failed command */
-               ahci_stop_engine(ap);
-               ahci_start_engine(ap);
-       }
+       /* make DMA engine forget about the failed command */
+       if (qc->flags & ATA_QCFLAG_FAILED)
+               ahci_kick_engine(ap, 1);
 }
 
 static int ahci_port_resume(struct ata_port *ap)