libata-pmp: hook PMP support and enable it

Hook PMP support into libata and enable it.  Connect SCR and probing
functions, and update ata_dev_classify() to detect PMP.

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

1 files changed, 80 insertions, 31 deletions

diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index 9e7f55b71044..d3e78d97529d 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -670,29 +670,49 @@ static unsigned int ata_devchk(struct ata_port *ap, unsigned int device)
  *      None.
  *
  *      RETURNS:
- *      Device type, %ATA_DEV_ATA, %ATA_DEV_ATAPI, or %ATA_DEV_UNKNOWN
- *      the event of failure.
+ *      Device type, %ATA_DEV_ATA, %ATA_DEV_ATAPI, %ATA_DEV_PMP or
+ *      %ATA_DEV_UNKNOWN the event of failure.
  */
-
 unsigned int ata_dev_classify(const struct ata_taskfile *tf)
 {
         /* Apple's open source Darwin code hints that some devices only
          * put a proper signature into the LBA mid/high registers,
          * So, we only check those.  It's sufficient for uniqueness.
+         *
+         * ATA/ATAPI-7 (d1532v1r1: Feb. 19, 2003) specified separate
+         * signatures for ATA and ATAPI devices attached on SerialATA,
+         * 0x3c/0xc3 and 0x69/0x96 respectively.  However, SerialATA
+         * spec has never mentioned about using different signatures
+         * for ATA/ATAPI devices.  Then, Serial ATA II: Port
+         * Multiplier specification began to use 0x69/0x96 to identify
+         * port multpliers and 0x3c/0xc3 to identify SEMB device.
+         * ATA/ATAPI-7 dropped descriptions about 0x3c/0xc3 and
+         * 0x69/0x96 shortly and described them as reserved for
+         * SerialATA.
+         *
+         * We follow the current spec and consider that 0x69/0x96
+         * identifies a port multiplier and 0x3c/0xc3 a SEMB device.
          */
-
-        if (((tf->lbam == 0) && (tf->lbah == 0)) ||
-            ((tf->lbam == 0x3c) && (tf->lbah == 0xc3))) {
+        if ((tf->lbam == 0) && (tf->lbah == 0)) {
                 DPRINTK("found ATA device by sig\n");
                 return ATA_DEV_ATA;
         }
 
-        if (((tf->lbam == 0x14) && (tf->lbah == 0xeb)) ||
-            ((tf->lbam == 0x69) && (tf->lbah == 0x96))) {
+        if ((tf->lbam == 0x14) && (tf->lbah == 0xeb)) {
                 DPRINTK("found ATAPI device by sig\n");
                 return ATA_DEV_ATAPI;
         }
 
+        if ((tf->lbam == 0x69) && (tf->lbah == 0x96)) {
+                DPRINTK("found PMP device by sig\n");
+                return ATA_DEV_PMP;
+        }
+
+        if ((tf->lbam == 0x3c) && (tf->lbah == 0xc3)) {
+                printk("ata: SEMB device ignored\n");
+                return ATA_DEV_SEMB_UNSUP; /* not yet */
+        }
+
         DPRINTK("unknown device\n");
         return ATA_DEV_UNKNOWN;
 }
@@ -3426,6 +3446,12 @@ int ata_std_prereset(struct ata_link *link, unsigned long deadline)
             (link->flags & ATA_LFLAG_HRST_TO_RESUME))
                 ehc->i.action |= ATA_EH_HARDRESET;
 
+        /* Some PMPs don't work with only SRST, force hardreset if PMP
+         * is supported.
+         */
+        if (ap->flags & ATA_FLAG_PMP)
+                ehc->i.action |= ATA_EH_HARDRESET;
+
         /* if we're about to do hardreset, nothing more to do */
         if (ehc->i.action & ATA_EH_HARDRESET)
                 return 0;
@@ -3616,6 +3642,16 @@ int sata_std_hardreset(struct ata_link *link, unsigned int *class,
         /* wait a while before checking status, see SRST for more info */
         msleep(150);
 
+        /* If PMP is supported, we have to do follow-up SRST.  Note
+         * that some PMPs don't send D2H Reg FIS after hardreset at
+         * all if the first port is empty.  Wait for it just for a
+         * second and request follow-up SRST.
+         */
+        if (ap->flags & ATA_FLAG_PMP) {
+                ata_wait_ready(ap, jiffies + HZ);
+                return -EAGAIN;
+        }
+
         rc = ata_wait_ready(ap, deadline);
         /* link occupied, -ENODEV too is an error */
         if (rc) {
@@ -5966,22 +6002,26 @@ int sata_scr_valid(struct ata_link *link)
  *      @val: Place to store read value
  *
  *      Read SCR register @reg of @link into *@val.  This function is
- *      guaranteed to succeed if the cable type of the port is SATA
- *      and the port implements ->scr_read.
+ *      guaranteed to succeed if @link is ap->link, the cable type of
+ *      the port is SATA and the port implements ->scr_read.
  *
  *      LOCKING:
- *      None.
+ *      None if @link is ap->link.  Kernel thread context otherwise.
  *
  *      RETURNS:
  *      0 on success, negative errno on failure.
  */
 int sata_scr_read(struct ata_link *link, int reg, u32 *val)
 {
-        struct ata_port *ap = link->ap;
+        if (ata_is_host_link(link)) {
+                struct ata_port *ap = link->ap;
 
-        if (sata_scr_valid(link))
-                return ap->ops->scr_read(ap, reg, val);
-        return -EOPNOTSUPP;
+                if (sata_scr_valid(link))
+                        return ap->ops->scr_read(ap, reg, val);
+                return -EOPNOTSUPP;
+        }
+
+        return sata_pmp_scr_read(link, reg, val);
 }
 
 /**
@@ -5991,22 +6031,26 @@ int sata_scr_read(struct ata_link *link, int reg, u32 *val)
  *      @val: value to write
  *
  *      Write @val to SCR register @reg of @link.  This function is
- *      guaranteed to succeed if the cable type of the port is SATA
- *      and the port implements ->scr_read.
+ *      guaranteed to succeed if @link is ap->link, the cable type of
+ *      the port is SATA and the port implements ->scr_read.
  *
  *      LOCKING:
- *      None.
+ *      None if @link is ap->link.  Kernel thread context otherwise.
  *
  *      RETURNS:
  *      0 on success, negative errno on failure.
  */
 int sata_scr_write(struct ata_link *link, int reg, u32 val)
 {
-        struct ata_port *ap = link->ap;
+        if (ata_is_host_link(link)) {
+                struct ata_port *ap = link->ap;
 
-        if (sata_scr_valid(link))
-                return ap->ops->scr_write(ap, reg, val);
-        return -EOPNOTSUPP;
+                if (sata_scr_valid(link))
+                        return ap->ops->scr_write(ap, reg, val);
+                return -EOPNOTSUPP;
+        }
+
+        return sata_pmp_scr_write(link, reg, val);
 }
 
 /**
@@ -6019,23 +6063,27 @@ int sata_scr_write(struct ata_link *link, int reg, u32 val)
  *      function performs flush after writing to the register.
  *
  *      LOCKING:
- *      None.
+ *      None if @link is ap->link.  Kernel thread context otherwise.
  *
  *      RETURNS:
  *      0 on success, negative errno on failure.
  */
 int sata_scr_write_flush(struct ata_link *link, int reg, u32 val)
 {
-        struct ata_port *ap = link->ap;
-        int rc;
+        if (ata_is_host_link(link)) {
+                struct ata_port *ap = link->ap;
+                int rc;
 
-        if (sata_scr_valid(link)) {
-                rc = ap->ops->scr_write(ap, reg, val);
-                if (rc == 0)
-                        rc = ap->ops->scr_read(ap, reg, &val);
-                return rc;
+                if (sata_scr_valid(link)) {
+                        rc = ap->ops->scr_write(ap, reg, val);
+                        if (rc == 0)
+                                rc = ap->ops->scr_read(ap, reg, &val);
+                        return rc;
+                }
+                return -EOPNOTSUPP;
         }
-        return -EOPNOTSUPP;
+
+        return sata_pmp_scr_write(link, reg, val);
 }
 
 /**
@@ -6424,6 +6472,7 @@ static void ata_host_release(struct device *gendev, void *res)
                 if (ap->scsi_host)
                         scsi_host_put(ap->scsi_host);
 
+                kfree(ap->pmp_link);
                 kfree(ap);
                 host->ports[i] = NULL;
         }