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path: root/drivers/tty/serdev/core.c
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Diffstat (limited to 'drivers/tty/serdev/core.c')
-rw-r--r--drivers/tty/serdev/core.c111
1 files changed, 99 insertions, 12 deletions
diff --git a/drivers/tty/serdev/core.c b/drivers/tty/serdev/core.c
index a0ac16ee6575..226adeec2aed 100644
--- a/drivers/tty/serdev/core.c
+++ b/drivers/tty/serdev/core.c
@@ -552,16 +552,97 @@ static int of_serdev_register_devices(struct serdev_controller *ctrl)
}
#ifdef CONFIG_ACPI
+
+#define SERDEV_ACPI_MAX_SCAN_DEPTH 32
+
+struct acpi_serdev_lookup {
+ acpi_handle device_handle;
+ acpi_handle controller_handle;
+ int n;
+ int index;
+};
+
+static int acpi_serdev_parse_resource(struct acpi_resource *ares, void *data)
+{
+ struct acpi_serdev_lookup *lookup = data;
+ struct acpi_resource_uart_serialbus *sb;
+ acpi_status status;
+
+ if (ares->type != ACPI_RESOURCE_TYPE_SERIAL_BUS)
+ return 1;
+
+ if (ares->data.common_serial_bus.type != ACPI_RESOURCE_SERIAL_TYPE_UART)
+ return 1;
+
+ if (lookup->index != -1 && lookup->n++ != lookup->index)
+ return 1;
+
+ sb = &ares->data.uart_serial_bus;
+
+ status = acpi_get_handle(lookup->device_handle,
+ sb->resource_source.string_ptr,
+ &lookup->controller_handle);
+ if (ACPI_FAILURE(status))
+ return 1;
+
+ /*
+ * NOTE: Ideally, we would also want to retreive other properties here,
+ * once setting them before opening the device is supported by serdev.
+ */
+
+ return 1;
+}
+
+static int acpi_serdev_do_lookup(struct acpi_device *adev,
+ struct acpi_serdev_lookup *lookup)
+{
+ struct list_head resource_list;
+ int ret;
+
+ lookup->device_handle = acpi_device_handle(adev);
+ lookup->controller_handle = NULL;
+ lookup->n = 0;
+
+ INIT_LIST_HEAD(&resource_list);
+ ret = acpi_dev_get_resources(adev, &resource_list,
+ acpi_serdev_parse_resource, lookup);
+ acpi_dev_free_resource_list(&resource_list);
+
+ if (ret < 0)
+ return -EINVAL;
+
+ return 0;
+}
+
+static int acpi_serdev_check_resources(struct serdev_controller *ctrl,
+ struct acpi_device *adev)
+{
+ struct acpi_serdev_lookup lookup;
+ int ret;
+
+ if (acpi_bus_get_status(adev) || !adev->status.present)
+ return -EINVAL;
+
+ /* Look for UARTSerialBusV2 resource */
+ lookup.index = -1; // we only care for the last device
+
+ ret = acpi_serdev_do_lookup(adev, &lookup);
+ if (ret)
+ return ret;
+
+ /* Make sure controller and ResourceSource handle match */
+ if (ACPI_HANDLE(ctrl->dev.parent) != lookup.controller_handle)
+ return -ENODEV;
+
+ return 0;
+}
+
static acpi_status acpi_serdev_register_device(struct serdev_controller *ctrl,
- struct acpi_device *adev)
+ struct acpi_device *adev)
{
- struct serdev_device *serdev = NULL;
+ struct serdev_device *serdev;
int err;
- if (acpi_bus_get_status(adev) || !adev->status.present ||
- acpi_device_enumerated(adev))
- return AE_OK;
-
serdev = serdev_device_alloc(ctrl);
if (!serdev) {
dev_err(&ctrl->dev, "failed to allocate serdev device for %s\n",
@@ -583,7 +664,7 @@ static acpi_status acpi_serdev_register_device(struct serdev_controller *ctrl,
}
static acpi_status acpi_serdev_add_device(acpi_handle handle, u32 level,
- void *data, void **return_value)
+ void *data, void **return_value)
{
struct serdev_controller *ctrl = data;
struct acpi_device *adev;
@@ -591,22 +672,28 @@ static acpi_status acpi_serdev_add_device(acpi_handle handle, u32 level,
if (acpi_bus_get_device(handle, &adev))
return AE_OK;
+ if (acpi_device_enumerated(adev))
+ return AE_OK;
+
+ if (acpi_serdev_check_resources(ctrl, adev))
+ return AE_OK;
+
return acpi_serdev_register_device(ctrl, adev);
}
+
static int acpi_serdev_register_devices(struct serdev_controller *ctrl)
{
acpi_status status;
- acpi_handle handle;
- handle = ACPI_HANDLE(ctrl->dev.parent);
- if (!handle)
+ if (!has_acpi_companion(ctrl->dev.parent))
return -ENODEV;
- status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1,
+ status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
+ SERDEV_ACPI_MAX_SCAN_DEPTH,
acpi_serdev_add_device, NULL, ctrl, NULL);
if (ACPI_FAILURE(status))
- dev_dbg(&ctrl->dev, "failed to enumerate serdev slaves\n");
+ dev_warn(&ctrl->dev, "failed to enumerate serdev slaves\n");
if (!ctrl->serdev)
return -ENODEV;