libata-acpi: implement _GTM/_STM support

Implement _GTM/_STM support.  acpi_gtm is added to ata_port which
stores _GTM parameters over suspend/resume cycle.  A new hook
ata_acpi_on_suspend() is responsible for storing _GTM parameters
during suspend.  _STM is executed in ata_acpi_on_resume().  With this
change, invoking _GTF is safe on IDE hierarchy and acpi_sata check
before _GTF is removed.

ata_acpi_gtm() and ata_acpi_stm() implementation is taken from Alan
Cox's pata_acpi implementation.  ata_acpi_gtm() is fixed such that the
result parameter is not shifted by sizeof(union acpi_object).

Signed-off-by: Tejun Heo <htejun@gmail.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

1 files changed, 149 insertions, 4 deletions

diff --git a/drivers/ata/libata-acpi.c b/drivers/ata/libata-acpi.c
index 78db2e67d7c7..c059f78ad944 100644
--- a/drivers/ata/libata-acpi.c
+++ b/drivers/ata/libata-acpi.c
@@ -101,6 +101,108 @@ void ata_acpi_associate(struct ata_host *host)
 }
 
 /**
+ * ata_acpi_gtm - execute _GTM
+ * @ap: target ATA port
+ * @gtm: out parameter for _GTM result
+ *
+ * Evaluate _GTM and store the result in @gtm.
+ *
+ * LOCKING:
+ * EH context.
+ *
+ * RETURNS:
+ * 0 on success, -ENOENT if _GTM doesn't exist, -errno on failure.
+ */
+static int ata_acpi_gtm(const struct ata_port *ap, struct ata_acpi_gtm *gtm)
+{
+        struct acpi_buffer output = { .length = ACPI_ALLOCATE_BUFFER };
+        union acpi_object *out_obj;
+        acpi_status status;
+        int rc = 0;
+
+        status = acpi_evaluate_object(ap->acpi_handle, "_GTM", NULL, &output);
+
+        rc = -ENOENT;
+        if (status == AE_NOT_FOUND)
+                goto out_free;
+
+        rc = -EINVAL;
+        if (ACPI_FAILURE(status)) {
+                ata_port_printk(ap, KERN_ERR,
+                                "ACPI get timing mode failed (AE 0x%x)\n",
+                                status);
+                goto out_free;
+        }
+
+        out_obj = output.pointer;
+        if (out_obj->type != ACPI_TYPE_BUFFER) {
+                ata_port_printk(ap, KERN_WARNING,
+                                "_GTM returned unexpected object type 0x%x\n",
+                                out_obj->type);
+
+                goto out_free;
+        }
+
+        if (out_obj->buffer.length != sizeof(struct ata_acpi_gtm)) {
+                ata_port_printk(ap, KERN_ERR,
+                                "_GTM returned invalid length %d\n",
+                                out_obj->buffer.length);
+                goto out_free;
+        }
+
+        memcpy(gtm, out_obj->buffer.pointer, sizeof(struct ata_acpi_gtm));
+        rc = 0;
+ out_free:
+        kfree(output.pointer);
+        return rc;
+}
+
+/**
+ * ata_acpi_stm - execute _STM
+ * @ap: target ATA port
+ * @stm: timing parameter to _STM
+ *
+ * Evaluate _STM with timing parameter @stm.
+ *
+ * LOCKING:
+ * EH context.
+ *
+ * RETURNS:
+ * 0 on success, -ENOENT if _STM doesn't exist, -errno on failure.
+ */
+static int ata_acpi_stm(const struct ata_port *ap, struct ata_acpi_gtm *stm)
+{
+        acpi_status status;
+        struct acpi_object_list         input;
+        union acpi_object               in_params[3];
+
+        in_params[0].type = ACPI_TYPE_BUFFER;
+        in_params[0].buffer.length = sizeof(struct ata_acpi_gtm);
+        in_params[0].buffer.pointer = (u8 *)stm;
+        /* Buffers for id may need byteswapping ? */
+        in_params[1].type = ACPI_TYPE_BUFFER;
+        in_params[1].buffer.length = 512;
+        in_params[1].buffer.pointer = (u8 *)ap->device[0].id;
+        in_params[2].type = ACPI_TYPE_BUFFER;
+        in_params[2].buffer.length = 512;
+        in_params[2].buffer.pointer = (u8 *)ap->device[1].id;
+
+        input.count = 3;
+        input.pointer = in_params;
+
+        status = acpi_evaluate_object(ap->acpi_handle, "_STM", &input, NULL);
+
+        if (status == AE_NOT_FOUND)
+                return -ENOENT;
+        if (ACPI_FAILURE(status)) {
+                ata_port_printk(ap, KERN_ERR,
+                        "ACPI set timing mode failed (status=0x%x)\n", status);
+                return -EINVAL;
+        }
+        return 0;
+}
+
+/**
  * ata_dev_get_GTF - get the drive bootup default taskfile settings
  * @dev: target ATA device
  * @gtf: output parameter for buffer containing _GTF taskfile arrays
@@ -355,6 +457,46 @@ static int ata_acpi_push_id(struct ata_device *dev)
 }
 
 /**
+ * ata_acpi_on_suspend - ATA ACPI hook called on suspend
+ * @ap: target ATA port
+ *
+ * This function is called when @ap is about to be suspended.  All
+ * devices are already put to sleep but the port_suspend() callback
+ * hasn't been executed yet.  Error return from this function aborts
+ * suspend.
+ *
+ * LOCKING:
+ * EH context.
+ *
+ * RETURNS:
+ * 0 on success, -errno on failure.
+ */
+int ata_acpi_on_suspend(struct ata_port *ap)
+{
+        unsigned long flags;
+        int rc;
+
+        /* proceed iff per-port acpi_handle is valid */
+        if (!ap->acpi_handle)
+                return 0;
+        BUG_ON(ap->flags & ATA_FLAG_ACPI_SATA);
+
+        /* store timing parameters */
+        rc = ata_acpi_gtm(ap, &ap->acpi_gtm);
+
+        spin_lock_irqsave(ap->lock, flags);
+        if (rc == 0)
+                ap->pflags |= ATA_PFLAG_GTM_VALID;
+        else
+                ap->pflags &= ~ATA_PFLAG_GTM_VALID;
+        spin_unlock_irqrestore(ap->lock, flags);
+
+        if (rc == -ENOENT)
+                rc = 0;
+        return rc;
+}
+
+/**
  * ata_acpi_on_resume - ATA ACPI hook called on resume
  * @ap: target ATA port
  *
@@ -368,6 +510,13 @@ void ata_acpi_on_resume(struct ata_port *ap)
 {
         int i;
 
+        if (ap->acpi_handle && (ap->pflags & ATA_PFLAG_GTM_VALID)) {
+                BUG_ON(ap->flags & ATA_FLAG_ACPI_SATA);
+
+                /* restore timing parameters */
+                ata_acpi_stm(ap, &ap->acpi_gtm);
+        }
+
         /* schedule _GTF */
         for (i = 0; i < ATA_MAX_DEVICES; i++)
                 ap->device[i].flags |= ATA_DFLAG_ACPI_PENDING;
@@ -394,10 +543,6 @@ int ata_acpi_on_devcfg(struct ata_device *dev)
         int acpi_sata = ap->flags & ATA_FLAG_ACPI_SATA;
         int rc;
 
-        /* XXX: _STM isn't implemented yet, skip if IDE for now */
-        if (!acpi_sata)
-                return 0;
-
         if (!dev->acpi_handle)
                 return 0;