acpi_memhotplug.c: auto bind the memory device which is hotplugged before the driver...

If the memory device is hotplugged before the driver is loaded, the user
cannot see this device under the directory /sys/bus/acpi/devices/, and the
user cannot bind it by hand after the driver is loaded.  This patch
introduces a new feature to bind such device when the driver is being
loaded.

Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
Cc: Len Brown <lenb@kernel.org>
Cc: "Brown, Len" <len.brown@intel.com>
Cc: Yasuaki ISIMATU <isimatu.yasuaki@jp.fujitsu.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/drivers/acpi/acpi_memhotplug.c b/drivers/acpi/acpi_memhotplug.c
index 669e140e81bcebe624db1b4fec035c1dde072a26..05be17ada0a21b88ec8c601c012695c9a5307467 100644 (file)
--- a/drivers/acpi/acpi_memhotplug.c
+++ b/drivers/acpi/acpi_memhotplug.c
@@ -52,6 +52,9 @@ MODULE_LICENSE("GPL");
 #define MEMORY_POWER_ON_STATE  1
 #define MEMORY_POWER_OFF_STATE 2
 
+static bool auto_probe;
+module_param(auto_probe, bool, S_IRUGO | S_IWUSR);
+
 static int acpi_memory_device_add(struct acpi_device *device);
 static int acpi_memory_device_remove(struct acpi_device *device, int type);
 
@@ -543,12 +546,44 @@ acpi_memory_register_notify_handler(acpi_handle handle,
                                    u32 level, void *ctxt, void **retv)
 {
        acpi_status status;
-
+       struct acpi_memory_device *mem_device = NULL;
+       unsigned long long current_status;
 
        status = is_memory_device(handle);
        if (ACPI_FAILURE(status))
                return AE_OK;   /* continue */
 
+       if (auto_probe) {
+               /* Get device present/absent information from the _STA */
+               status = acpi_evaluate_integer(handle, "_STA", NULL,
+                                              &current_status);
+               if (ACPI_FAILURE(status))
+                       goto install;
+
+               /*
+                * Check for device status. Device should be
+                * present/enabled/functioning.
+                */
+               if (!(current_status &
+                     (ACPI_STA_DEVICE_PRESENT | ACPI_STA_DEVICE_ENABLED |
+                      ACPI_STA_DEVICE_FUNCTIONING)))
+                       goto install;
+
+               if (acpi_memory_get_device(handle, &mem_device))
+                       goto install;
+
+               /* We have bound this device while we register the driver */
+               if (mem_device->state == MEMORY_POWER_ON_STATE)
+                       goto install;
+
+               ACPI_DEBUG_PRINT((ACPI_DB_INFO,
+                                 "\nauto probe memory device\n"));
+
+               if (acpi_memory_enable_device(mem_device))
+                       pr_err(PREFIX "Cannot enable memory device\n");
+       }
+
+install:
        status = acpi_install_notify_handler(handle, ACPI_SYSTEM_NOTIFY,
                                             acpi_memory_device_notify, NULL);
        /* continue */