ahci: kill @force_restart and refine CLO for ahci_kick_engine()

This patch refines ahci_kick_engine() after discussion with Tejun about
FBS(FIS-based switching) support preparation:
a. Kill @force_restart and always kick the engine. The only case where
   @force_restart is zero is when it's called from ahci_p5wdh_hardreset()
   Actually at that point, BSY is pretty much guaranteed to be set.
b. If PMP is attached, ignore busy and always do CLO. (AHCI-1.3 9.2)

Signed-off-by: Shane Huang <shane.huang@amd.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

diff --git a/drivers/ata/ahci.c b/drivers/ata/ahci.c
index 5fb9c3a..d4cd9c2 100644 (file)
--- a/drivers/ata/ahci.c
+++ b/drivers/ata/ahci.c
@@ -1634,7 +1634,7 @@ 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_kick_engine(struct ata_port *ap, int force_restart)
+static int ahci_kick_engine(struct ata_port *ap)
 {
        void __iomem *port_mmio = ahci_port_base(ap);
        struct ahci_host_priv *hpriv = ap->host->private_data;
@@ -1642,18 +1642,16 @@ static int ahci_kick_engine(struct ata_port *ap, int force_restart)
        u32 tmp;
        int busy, rc;
 
-       /* do we need to kick the port? */
-       busy = status & (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) {
+       /* need to do CLO?
+        * always do CLO if PMP is attached (AHCI-1.3 9.2)
+        */
+       busy = status & (ATA_BUSY | ATA_DRQ);
+       if (!busy && !sata_pmp_attached(ap)) {
                rc = 0;
                goto out_restart;
        }
@@ -1701,7 +1699,7 @@ static int ahci_exec_polled_cmd(struct ata_port *ap, int pmp,
                tmp = ata_wait_register(port_mmio + PORT_CMD_ISSUE, 0x1, 0x1,
                                        1, timeout_msec);
                if (tmp & 0x1) {
-                       ahci_kick_engine(ap, 1);
+                       ahci_kick_engine(ap);
                        return -EBUSY;
                }
        } else
@@ -1724,7 +1722,7 @@ static int ahci_do_softreset(struct ata_link *link, unsigned int *class,
        DPRINTK("ENTER\n");
 
        /* prepare for SRST (AHCI-1.1 10.4.1) */
-       rc = ahci_kick_engine(ap, 1);
+       rc = ahci_kick_engine(ap);
        if (rc && rc != -EOPNOTSUPP)
                ata_link_printk(link, KERN_WARNING,
                                "failed to reset engine (errno=%d)\n", rc);
@@ -1940,7 +1938,7 @@ static int ahci_p5wdh_hardreset(struct ata_link *link, unsigned int *class,
                rc = ata_wait_after_reset(link, jiffies + 2 * HZ,
                                          ahci_check_ready);
                if (rc)
-                       ahci_kick_engine(ap, 0);
+                       ahci_kick_engine(ap);
        }
        return rc;
 }
@@ -2321,7 +2319,7 @@ static void ahci_post_internal_cmd(struct ata_queued_cmd *qc)
 
        /* make DMA engine forget about the failed command */
        if (qc->flags & ATA_QCFLAG_FAILED)
-               ahci_kick_engine(ap, 1);
+               ahci_kick_engine(ap);
 }
 
 static void ahci_pmp_attach(struct ata_port *ap)