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>

1 files changed, 10 insertions, 12 deletions

diff --git a/drivers/ata/ahci.c b/drivers/ata/ahci.c
index 5fb9c3a1f404..d4cd9c203314 100644
--- 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)