[libata] ACPI: Properly handle bay devices in dock stations

* Differentiate between bay devices in dock stations and others:

 - When an ACPI_NOTIFY_EJECT_REQUEST appears, just signal uevent to
   userspace (that is when the optional eject button on a bay device is
   pressed/pulled) giving the possibility to unmount file systems and to
   clean up. Also, only send uevent in case we get an EJECT_REQUEST
   without doing anything else. In other cases, you'll get an add/remove
   event because libata attaches/detaches the device.

 - In case of a dock event, which in turn signals an
   ACPI_NOTIFY_EJECT_REQUEST, immediately detach the device, because it
   may already have been gone

* In case of an ACPI_NOTIFY_DEVICE/BUS_CHECK, evaluate _STA to check if
  the device has been plugged or unplugged. If plugged, hotplug it, if
  unplugged, just signal event to userspace
  (initial patch by Matthew Garrett <mjg59@srcf.ucam.org>)

* Call ACPI _EJ0 for detached devices

Signed-off-by: Holger Macht <hmacht@suse.de>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

1 files changed, 114 insertions, 51 deletions

diff --git a/drivers/ata/libata-acpi.c b/drivers/ata/libata-acpi.c
index dbf6ca781f66..3ff8b14420d9 100644
--- a/drivers/ata/libata-acpi.c
+++ b/drivers/ata/libata-acpi.c
@@ -118,12 +118,62 @@ static void ata_acpi_associate_ide_port(struct ata_port *ap)
                 ap->pflags |= ATA_PFLAG_INIT_GTM_VALID;
 }
 
-static void ata_acpi_handle_hotplug(struct ata_port *ap, struct ata_device
-                                    *dev, u32 event)
+static void ata_acpi_eject_device(acpi_handle handle)
+{
+        struct acpi_object_list arg_list;
+        union acpi_object arg;
+
+        arg_list.count = 1;
+        arg_list.pointer = &arg;
+        arg.type = ACPI_TYPE_INTEGER;
+        arg.integer.value = 1;
+
+        if (ACPI_FAILURE(acpi_evaluate_object(handle, "_EJ0",
+                                              &arg_list, NULL)))
+                printk(KERN_ERR "Failed to evaluate _EJ0!\n");
+}
+
+/* @ap and @dev are the same as ata_acpi_handle_hotplug() */
+static void ata_acpi_detach_device(struct ata_port *ap, struct ata_device *dev)
+{
+        if (dev)
+                dev->flags |= ATA_DFLAG_DETACH;
+        else {
+                struct ata_link *tlink;
+                struct ata_device *tdev;
+
+                ata_port_for_each_link(tlink, ap)
+                        ata_link_for_each_dev(tdev, tlink)
+                                tdev->flags |= ATA_DFLAG_DETACH;
+        }
+
+        ata_port_schedule_eh(ap);
+}
+
+/**
+ * ata_acpi_handle_hotplug - ACPI event handler backend
+ * @ap: ATA port ACPI event occurred
+ * @dev: ATA device ACPI event occurred (can be NULL)
+ * @event: ACPI event which occurred
+ * @is_dock_event: boolean indicating whether the event was a dock one
+ *
+ * All ACPI bay / device realted events end up in this function.  If
+ * the event is port-wide @dev is NULL.  If the event is specific to a
+ * device, @dev points to it.
+ *
+ * Hotplug (as opposed to unplug) notification is always handled as
+ * port-wide while unplug only kills the target device on device-wide
+ * event.
+ *
+ * LOCKING:
+ * ACPI notify handler context.  May sleep.
+ */
+static void ata_acpi_handle_hotplug(struct ata_port *ap, struct ata_device *dev,
+                                    u32 event, int is_dock_event)
 {
         char event_string[12];
         char *envp[] = { event_string, NULL };
-        struct ata_eh_info *ehi;
+        struct ata_eh_info *ehi = &ap->link.eh_info;
         struct kobject *kobj = NULL;
         int wait = 0;
         unsigned long flags;
@@ -131,87 +181,100 @@ static void ata_acpi_handle_hotplug(struct ata_port *ap, struct ata_device
         unsigned long sta;
         acpi_status status;
 
-        if (!ap)
-                ap = dev->link->ap;
-        ehi = &ap->link.eh_info;
-
-        spin_lock_irqsave(ap->lock, flags);
-
-        if (dev)
+        if (dev) {
+                if (dev->sdev)
+                        kobj = &dev->sdev->sdev_gendev.kobj;
                 handle = dev->acpi_handle;
-        else
+        } else {
+                kobj = &ap->dev->kobj;
                 handle = ap->acpi_handle;
+        }
 
         status = acpi_get_handle(handle, "_EJ0", &tmphandle);
-        if (ACPI_FAILURE(status)) {
-                /* This device is not ejectable */
-                spin_unlock_irqrestore(ap->lock, flags);
+        if (ACPI_FAILURE(status))
+                /* This device does not support hotplug */
                 return;
-        }
 
-        status = acpi_evaluate_integer(handle, "_STA", NULL, &sta);
-        if (ACPI_FAILURE(status)) {
-                printk ("Unable to determine bay status\n");
-                spin_unlock_irqrestore(ap->lock, flags);
-                return;
-        }
+        spin_lock_irqsave(ap->lock, flags);
 
         switch (event) {
         case ACPI_NOTIFY_BUS_CHECK:
         case ACPI_NOTIFY_DEVICE_CHECK:
                 ata_ehi_push_desc(ehi, "ACPI event");
-                if (!sta) {
-                /* Device has been unplugged */
-                        if (dev)
-                                dev->flags |= ATA_DFLAG_DETACH;
-                        else {
-                                struct ata_link *tlink;
-                                struct ata_device *tdev;
-
-                                ata_port_for_each_link(tlink, ap) {
-                                        ata_link_for_each_dev(tdev, tlink) {
-                                                tdev->flags |=
-                                                        ATA_DFLAG_DETACH;
-                                        }
-                                }
-                        }
-                        ata_port_schedule_eh(ap);
-                        wait = 1;
-                } else {
+
+                status = acpi_evaluate_integer(handle, "_STA", NULL, &sta);
+                if (ACPI_FAILURE(status)) {
+                        ata_port_printk(ap, KERN_ERR,
+                                "acpi: failed to determine bay status (0x%x)\n",
+                                status);
+                        break;
+                }
+
+                if (sta) {
                         ata_ehi_hotplugged(ehi);
                         ata_port_freeze(ap);
+                } else {
+                        /* The device has gone - unplug it */
+                        ata_acpi_detach_device(ap, dev);
+                        wait = 1;
                 }
+                break;
+        case ACPI_NOTIFY_EJECT_REQUEST:
+                ata_ehi_push_desc(ehi, "ACPI event");
+
+                if (!is_dock_event)
+                        break;
+
+                /* undock event - immediate unplug */
+                ata_acpi_detach_device(ap, dev);
+                wait = 1;
+                break;
         }
 
+        /* make sure kobj doesn't go away while ap->lock is released */
+        kobject_get(kobj);
+
         spin_unlock_irqrestore(ap->lock, flags);
 
-        if (wait)
+        if (wait) {
                 ata_port_wait_eh(ap);
+                ata_acpi_eject_device(handle);
+        }
 
-        if (dev) {
-                if (dev->sdev)
-                        kobj = &dev->sdev->sdev_gendev.kobj;
-        } else
-                kobj = &ap->dev->kobj;
-
-        if (kobj) {
+        if (kobj && !is_dock_event) {
                 sprintf(event_string, "BAY_EVENT=%d", event);
                 kobject_uevent_env(kobj, KOBJ_CHANGE, envp);
         }
+
+        kobject_put(kobj);
+}
+
+static void ata_acpi_dev_notify_dock(acpi_handle handle, u32 event, void *data)
+{
+        struct ata_device *dev = data;
+
+        ata_acpi_handle_hotplug(dev->link->ap, dev, event, 1);
+}
+
+static void ata_acpi_ap_notify_dock(acpi_handle handle, u32 event, void *data)
+{
+        struct ata_port *ap = data;
+
+        ata_acpi_handle_hotplug(ap, NULL, event, 1);
 }
 
 static void ata_acpi_dev_notify(acpi_handle handle, u32 event, void *data)
 {
         struct ata_device *dev = data;
 
-        ata_acpi_handle_hotplug(NULL, dev, event);
+        ata_acpi_handle_hotplug(dev->link->ap, dev, event, 0);
 }
 
 static void ata_acpi_ap_notify(acpi_handle handle, u32 event, void *data)
 {
         struct ata_port *ap = data;
 
-        ata_acpi_handle_hotplug(ap, NULL, event);
+        ata_acpi_handle_hotplug(ap, NULL, event, 0);
 }
 
 /**
@@ -252,7 +315,7 @@ void ata_acpi_associate(struct ata_host *host)
                                                     ata_acpi_ap_notify, ap);
                         /* we might be on a docking station */
                         register_hotplug_dock_device(ap->acpi_handle,
-                                                     ata_acpi_ap_notify, ap);
+                                             ata_acpi_ap_notify_dock, ap);
                 }
 
                 for (j = 0; j < ata_link_max_devices(&ap->link); j++) {
@@ -264,7 +327,7 @@ void ata_acpi_associate(struct ata_host *host)
                                                 ata_acpi_dev_notify, dev);
                                 /* we might be on a docking station */
                                 register_hotplug_dock_device(dev->acpi_handle,
-                                                ata_acpi_dev_notify, dev);
+                                             ata_acpi_dev_notify_dock, dev);
                         }
                 }
         }