On Thu, Jun 30, 2022 at 5:01 PM Stefan Binding sbinding@opensource.cirrus.com wrote:
Add a wrapper function to read the _SUB string from ACPI.
Signed-off-by: Stefan Binding sbinding@opensource.cirrus.com
drivers/acpi/utils.c | 38 ++++++++++++++++++++++++++++++++++++++ include/linux/acpi.h | 6 ++++++ 2 files changed, 44 insertions(+)
diff --git a/drivers/acpi/utils.c b/drivers/acpi/utils.c index 3a9773a09e19..394954f4b6ef 100644 --- a/drivers/acpi/utils.c +++ b/drivers/acpi/utils.c @@ -291,6 +291,44 @@ int acpi_get_local_address(acpi_handle handle, u32 *addr) } EXPORT_SYMBOL(acpi_get_local_address);
+#define ACPI_MAX_SUB_BUF_SIZE 9
+const char *acpi_get_subsystem_id(acpi_handle handle) +{
struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };union acpi_object *obj;acpi_status status;const char *sub;status = acpi_evaluate_object(handle, METHOD_NAME__SUB, NULL, &buffer);if (ACPI_FAILURE(status)) {acpi_handle_debug(handle, "Reading ACPI _SUB failed: %#x\n", status);return ERR_PTR(-ENODATA);}obj = buffer.pointer;if (obj->type == ACPI_TYPE_STRING) {if (strlen(obj->string.pointer) < ACPI_MAX_SUB_BUF_SIZE &&strlen(obj->string.pointer) > 0) {sub = kstrdup(obj->string.pointer, GFP_KERNEL);if (!sub)sub = ERR_PTR(-ENOMEM);
The error codes below are somewhat questionable.
} else {acpi_handle_err(handle, "ACPI _SUB Length %zu is Invalid\n",strlen(obj->string.pointer));sub = ERR_PTR(-EINVAL);
This is as good as failure, so why not use -ENODATA here?
}} else {acpi_handle_warn(handle, "Warning ACPI _SUB did not return a string\n");sub = ERR_PTR(-EINVAL);
Likewise.
}acpi_os_free(buffer.pointer);return sub;+} +EXPORT_SYMBOL_GPL(acpi_get_subsystem_id);
acpi_status acpi_evaluate_reference(acpi_handle handle, acpi_string pathname, diff --git a/include/linux/acpi.h b/include/linux/acpi.h index 7b96a8bff6d2..7651198ad6f5 100644 --- a/include/linux/acpi.h +++ b/include/linux/acpi.h @@ -762,6 +762,7 @@ static inline u64 acpi_arch_get_root_pointer(void) #endif
int acpi_get_local_address(acpi_handle handle, u32 *addr); +const char *acpi_get_subsystem_id(acpi_handle handle);
#else /* !CONFIG_ACPI */
@@ -1023,6 +1024,11 @@ static inline int acpi_get_local_address(acpi_handle handle, u32 *addr) return -ENODEV; }
+static inline const char *acpi_get_subsystem_id(acpi_handle handle) +{
return ERR_PTR(-ENODEV);+}
static inline int acpi_register_wakeup_handler(int wake_irq, bool (*wakeup)(void *context), void *context) { -- 2.25.1