[PATCH] ahci: add softreset

Now that libata is smart enought to handle both soft and hard resets,
add softreset method.

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

diff --git a/drivers/scsi/ahci.c b/drivers/scsi/ahci.c
index a1ddbba..ffba656 100644 (file)
--- a/drivers/scsi/ahci.c
+++ b/drivers/scsi/ahci.c
@@ -513,6 +513,138 @@ 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_poll_register(void __iomem *reg, u32 mask, u32 val,
+                             unsigned long interval_msec,
+                             unsigned long timeout_msec)
+{
+       unsigned long timeout;
+       u32 tmp;
+
+       timeout = jiffies + (timeout_msec * HZ) / 1000;
+       do {
+               tmp = readl(reg);
+               if ((tmp & mask) == val)
+                       return 0;
+               msleep(interval_msec);
+       } while (time_before(jiffies, timeout));
+
+       return -1;
+}
+
+static int ahci_softreset(struct ata_port *ap, int verbose, unsigned int *class)
+{
+       struct ahci_host_priv *hpriv = ap->host_set->private_data;
+       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);
+       const u32 cmd_fis_len = 5; /* five dwords */
+       const char *reason = NULL;
+       struct ata_taskfile tf;
+       u8 *fis;
+       int rc;
+
+       DPRINTK("ENTER\n");
+
+       /* 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 */
+       ahci_tf_read(ap, &tf);
+       if (tf.command & (ATA_BUSY | ATA_DRQ)) {
+               u32 tmp;
+
+               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);
+               readl(port_mmio + PORT_CMD); /* flush */
+
+               if (ahci_poll_register(port_mmio + PORT_CMD, PORT_CMD_CLO, 0x0,
+                                      1, 500)) {
+                       rc = -EIO;
+                       reason = "CLO failed";
+                       goto fail_restart;
+               }
+       }
+
+       /* restart engine */
+       ahci_start_engine(ap);
+
+       ata_tf_init(ap, &tf, 0);
+       fis = pp->cmd_tbl;
+
+       /* issue the first D2H Register FIS */
+       ahci_fill_cmd_slot(pp, cmd_fis_len | AHCI_CMD_RESET | AHCI_CMD_CLR_BUSY);
+
+       tf.ctl |= ATA_SRST;
+       ata_tf_to_fis(&tf, fis, 0);
+       fis[1] &= ~(1 << 7);    /* turn off Command FIS bit */
+
+       writel(1, port_mmio + PORT_CMD_ISSUE);
+       readl(port_mmio + PORT_CMD_ISSUE);      /* flush */
+
+       if (ahci_poll_register(port_mmio + PORT_CMD_ISSUE, 0x1, 0x0, 1, 500)) {
+               rc = -EIO;
+               reason = "1st FIS failed";
+               goto fail;
+       }
+
+       /* spec says at least 5us, but be generous and sleep for 1ms */
+       msleep(1);
+
+       /* issue the second D2H Register FIS */
+       ahci_fill_cmd_slot(pp, cmd_fis_len);
+
+       tf.ctl &= ~ATA_SRST;
+       ata_tf_to_fis(&tf, fis, 0);
+       fis[1] &= ~(1 << 7);    /* turn off Command FIS bit */
+
+       writel(1, port_mmio + PORT_CMD_ISSUE);
+       readl(port_mmio + PORT_CMD_ISSUE);      /* flush */
+
+       /* spec mandates ">= 2ms" before checking status.
+        * We wait 150ms, because that was the magic delay used for
+        * ATAPI devices in Hale Landis's ATADRVR, for the period of time
+        * between when the ATA command register is written, and then
+        * status is checked.  Because waiting for "a while" before
+        * checking status is fine, post SRST, we perform this magic
+        * delay here as well.
+        */
+       msleep(150);
+
+       *class = ATA_DEV_NONE;
+       if (sata_dev_present(ap)) {
+               if (ata_busy_sleep(ap, ATA_TMOUT_BOOT_QUICK, ATA_TMOUT_BOOT)) {
+                       rc = -EIO;
+                       reason = "device not ready";
+                       goto fail;
+               }
+               *class = ahci_dev_classify(ap);
+       }
+
+       DPRINTK("EXIT, class=%u\n", *class);
+       return 0;
+
+ fail_restart:
+       ahci_start_engine(ap);
+ fail:
+       if (verbose)
+               printk(KERN_ERR "ata%u: softreset failed (%s)\n",
+                      ap->id, reason);
+       else
+               DPRINTK("EXIT, rc=%d reason=\"%s\"\n", rc, reason);
+       return rc;
+}
+
 static int ahci_hardreset(struct ata_port *ap, int verbose, unsigned int *class)
 {
        int rc;
@@ -553,7 +685,8 @@ static void ahci_postreset(struct ata_port *ap, unsigned int *class)
 
 static int ahci_probe_reset(struct ata_port *ap, unsigned int *classes)
 {
-       return ata_drive_probe_reset(ap, NULL, NULL, ahci_hardreset,
+       return ata_drive_probe_reset(ap, ata_std_probeinit,
+                                    ahci_softreset, ahci_hardreset,
                                     ahci_postreset, classes);
 }