ACPI: Add _OST support for sysfs eject

Changed acpi_bus_hot_remove_device() to support _OST. This function is
also changed to global so that it can be called from hotplug notify
handlers to perform hot-remove operation.

Changed acpi_eject_store(), which is the sysfs eject handler. It checks
eject_pending to see if the request was originated from ACPI eject
notification. If not, it calls _OST(0x103,84,) per Figure 6-37 in ACPI
5.0 spec.

Added eject_pending bit to acpi_device_flags. This bit is set when the
kernel has received an ACPI eject notification, but does not initiate
its hot-remove operation by itself.

Added struct acpi_eject_event. This structure is used to pass extended
information to acpi_bus_hot_remove_device(), which has a single argument
to support asynchronous call

Signed-off-by: Toshi Kani <toshi.kani@hp.com>
Signed-off-by: Len Brown <len.brown@intel.com>

1 files changed, 49 insertions, 9 deletions

diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index 85cbfdccc97c..bea3ab6b524f 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -83,19 +83,29 @@ acpi_device_modalias_show(struct device *dev, struct device_attribute *attr, cha
 }
 static DEVICE_ATTR(modalias, 0444, acpi_device_modalias_show, NULL);
 
-static void acpi_bus_hot_remove_device(void *context)
+/**
+ * acpi_bus_hot_remove_device: hot-remove a device and its children
+ * @context: struct acpi_eject_event pointer (freed in this func)
+ *
+ * Hot-remove a device and its children. This function frees up the
+ * memory space passed by arg context, so that the caller may call
+ * this function asynchronously through acpi_os_hotplug_execute().
+ */
+void acpi_bus_hot_remove_device(void *context)
 {
+        struct acpi_eject_event *ej_event = (struct acpi_eject_event *) context;
         struct acpi_device *device;
-        acpi_handle handle = context;
+        acpi_handle handle = ej_event->handle;
         struct acpi_object_list arg_list;
         union acpi_object arg;
         acpi_status status = AE_OK;
+        u32 ost_code = ACPI_OST_SC_NON_SPECIFIC_FAILURE; /* default */
 
         if (acpi_bus_get_device(handle, &device))
-                return;
+                goto err_out;
 
         if (!device)
-                return;
+                goto err_out;
 
         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
                 "Hot-removing device %s...\n", dev_name(&device->dev)));
@@ -103,7 +113,7 @@ static void acpi_bus_hot_remove_device(void *context)
         if (acpi_bus_trim(device, 1)) {
                 printk(KERN_ERR PREFIX
                                 "Removing device failed\n");
-                return;
+                goto err_out;
         }
 
         /* power off device */
@@ -129,10 +139,21 @@ static void acpi_bus_hot_remove_device(void *context)
          * TBD: _EJD support.
          */
         status = acpi_evaluate_object(handle, "_EJ0", &arg_list, NULL);
-        if (ACPI_FAILURE(status))
-                printk(KERN_WARNING PREFIX
-                                "Eject device failed\n");
+        if (ACPI_FAILURE(status)) {
+                if (status != AE_NOT_FOUND)
+                        printk(KERN_WARNING PREFIX
+                                        "Eject device failed\n");
+                goto err_out;
+        }
+
+        kfree(context);
+        return;
 
+err_out:
+        /* Inform firmware the hot-remove operation has completed w/ error */
+        (void) acpi_evaluate_hotplug_ost(handle,
+                                ej_event->event, ost_code, NULL);
+        kfree(context);
         return;
 }
 
@@ -144,6 +165,7 @@ acpi_eject_store(struct device *d, struct device_attribute *attr,
         acpi_status status;
         acpi_object_type type = 0;
         struct acpi_device *acpi_device = to_acpi_device(d);
+        struct acpi_eject_event *ej_event;
 
         if ((!count) || (buf[0] != '1')) {
                 return -EINVAL;
@@ -160,7 +182,25 @@ acpi_eject_store(struct device *d, struct device_attribute *attr,
                 goto err;
         }
 
-        acpi_os_hotplug_execute(acpi_bus_hot_remove_device, acpi_device->handle);
+        ej_event = kmalloc(sizeof(*ej_event), GFP_KERNEL);
+        if (!ej_event) {
+                ret = -ENOMEM;
+                goto err;
+        }
+
+        ej_event->handle = acpi_device->handle;
+        if (acpi_device->flags.eject_pending) {
+                /* event originated from ACPI eject notification */
+                ej_event->event = ACPI_NOTIFY_EJECT_REQUEST;
+                acpi_device->flags.eject_pending = 0;
+        } else {
+                /* event originated from user */
+                ej_event->event = ACPI_OST_EC_OSPM_EJECT;
+                (void) acpi_evaluate_hotplug_ost(ej_event->handle,
+                        ej_event->event, ACPI_OST_SC_EJECT_IN_PROGRESS, NULL);
+        }
+
+        acpi_os_hotplug_execute(acpi_bus_hot_remove_device, (void *)ej_event);
 err:
         return ret;
 }