[libata] Link power management infrastructure
[linux-2.6.git] / drivers / ata / libata-scsi.c
index f752edd..93bd36c 100644 (file)
@@ -110,6 +110,74 @@ static struct scsi_transport_template ata_scsi_transport_template = {
 };
 
 
+static const struct {
+       enum link_pm    value;
+       const char      *name;
+} link_pm_policy[] = {
+       { NOT_AVAILABLE, "max_performance" },
+       { MIN_POWER, "min_power" },
+       { MAX_PERFORMANCE, "max_performance" },
+       { MEDIUM_POWER, "medium_power" },
+};
+
+const char *ata_scsi_lpm_get(enum link_pm policy)
+{
+       int i;
+
+       for (i = 0; i < ARRAY_SIZE(link_pm_policy); i++)
+               if (link_pm_policy[i].value == policy)
+                       return link_pm_policy[i].name;
+
+       return NULL;
+}
+
+static ssize_t ata_scsi_lpm_put(struct class_device *class_dev,
+       const char *buf, size_t count)
+{
+       struct Scsi_Host *shost = class_to_shost(class_dev);
+       struct ata_port *ap = ata_shost_to_port(shost);
+       enum link_pm policy = 0;
+       int i;
+
+       /*
+        * we are skipping array location 0 on purpose - this
+        * is because a value of NOT_AVAILABLE is displayed
+        * to the user as max_performance, but when the user
+        * writes "max_performance", they actually want the
+        * value to match MAX_PERFORMANCE.
+        */
+       for (i = 1; i < ARRAY_SIZE(link_pm_policy); i++) {
+               const int len = strlen(link_pm_policy[i].name);
+               if (strncmp(link_pm_policy[i].name, buf, len) == 0 &&
+                  buf[len] == '\n') {
+                       policy = link_pm_policy[i].value;
+                       break;
+               }
+       }
+       if (!policy)
+               return -EINVAL;
+
+       ata_lpm_schedule(ap, policy);
+       return count;
+}
+
+static ssize_t
+ata_scsi_lpm_show(struct class_device *class_dev, char *buf)
+{
+       struct Scsi_Host *shost = class_to_shost(class_dev);
+       struct ata_port *ap = ata_shost_to_port(shost);
+       const char *policy =
+               ata_scsi_lpm_get(ap->pm_policy);
+
+       if (!policy)
+               return -EINVAL;
+
+       return snprintf(buf, 23, "%s\n", policy);
+}
+CLASS_DEVICE_ATTR(link_power_management_policy, S_IRUGO | S_IWUSR,
+               ata_scsi_lpm_show, ata_scsi_lpm_put);
+EXPORT_SYMBOL_GPL(class_device_attr_link_power_management_policy);
+
 static void ata_scsi_invalid_field(struct scsi_cmnd *cmd,
                                   void (*done)(struct scsi_cmnd *))
 {