On Thu, Aug 30, 2012 at 1:16 PM, Toshi Kani <toshi.kani@xxxxxx> wrote:
> Added acpi_lookup_driver(), which looks up an associated driver
> for the notified ACPI device object by walking through the list
> of ACPI drivers.
>
> Signed-off-by: Toshi Kani <toshi.kani@xxxxxx>
> ---
> drivers/acpi/scan.c | 65 +++++++++++++++++++++++++++++++++++++++++++++++
> include/acpi/acpi_bus.h | 2 +
> 2 files changed, 67 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
> index d1ecca2..d0e0d18 100644
> --- a/drivers/acpi/scan.c
> +++ b/drivers/acpi/scan.c
> @@ -1630,3 +1630,68 @@ int __init acpi_scan_init(void)
>
> return result;
> }
> +
> +static int acpi_match_driver(struct device_driver *drv, void *data)
> +{
> + struct acpi_driver *driver = to_acpi_driver(drv);
> + struct acpi_device *device = (struct acpi_device *) data;
> + int ret;
> +
> + ret = acpi_match_device_ids(device, driver->ids);
> + if (!ret)
> + device->driver = driver;
> +
> + return !ret;
> +}
> +
> +/**
> + * acpi_lookup_driver: Look up a driver for the notified ACPI device
> + * @handle: ACPI handle of the notified device object
> + * @event: Notify event
> + *
> + * Look up an associated driver for the notified ACPI device object
> + * by walking through the list of ACPI drivers.
> + */
> +struct acpi_driver *acpi_lookup_driver(acpi_handle handle, u32 event)
> +{
> + struct acpi_device *device;
> + struct acpi_driver *driver = NULL;
> + unsigned long long sta;
> + int type;
> + int ret;
> +
> + /* allocate a temporary device object */
> + device = kzalloc(sizeof(struct acpi_device), GFP_KERNEL);
> + if (!device) {
> + pr_err(PREFIX "No memory to allocate a tmp device\n");
> + return NULL;
> + }
> +
> + ret = acpi_bus_type_and_status(handle, &type, &sta);
> + if (ret) {
> + pr_err(PREFIX "Failed to get type of device\n");
> + goto out;
> + }
> +
> + /* setup this temporary device object */
> + INIT_LIST_HEAD(&device->pnp.ids);
> + device->device_type = type;
> + device->handle = handle;
> + device->parent = acpi_bus_get_parent(handle);
> + device->dev.bus = &acpi_bus_type;
> + device->driver = NULL;
> + STRUCT_TO_INT(device->status) = sta;
> + device->status.present = 1;
> +
> + /* set HID to this device object */
> + acpi_device_set_id(device);
> +
> + /* lookup a matching driver */
> + (void) bus_for_each_drv(device->dev.bus, NULL,
> + device, acpi_match_driver);
> + driver = device->driver;
This path is used when we receive a Notify to a device and a matching
driver has been registered, but the driver is not bound to the device.
For example, it may be a newly-added device where we haven't bound a
driver to it yet.
Is there anything that prevents us from unloading the driver between
here (the point where we capture the "struct acpi_driver *") and the
point where we call "driver->ops.sys_notify"?
> +
> +out:
> + kfree(device);
> + return driver;
> +}
> diff --git a/include/acpi/acpi_bus.h b/include/acpi/acpi_bus.h
> index bde976e..a773b46 100644
> --- a/include/acpi/acpi_bus.h
> +++ b/include/acpi/acpi_bus.h
> @@ -345,6 +345,8 @@ extern int unregister_acpi_notifier(struct notifier_block *);
>
> extern int register_acpi_bus_notifier(struct notifier_block *nb);
> extern void unregister_acpi_bus_notifier(struct notifier_block *nb);
> +extern struct acpi_driver *acpi_lookup_driver(acpi_handle handle, u32 event);
> +
> /*
> * External Functions
> */
> --
> 1.7.7.6
>
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