diff options
Diffstat (limited to 'drivers/acpi')
| -rw-r--r-- | drivers/acpi/utils.c | 38 |
1 files changed, 38 insertions, 0 deletions
diff --git a/drivers/acpi/utils.c b/drivers/acpi/utils.c index 3a9773a09e19..5a7b8065e77f 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; + size_t len; + + 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) { + len = strlen(obj->string.pointer); + if (len < ACPI_MAX_SUB_BUF_SIZE && len > 0) { + sub = kstrdup(obj->string.pointer, GFP_KERNEL); + if (!sub) + sub = ERR_PTR(-ENOMEM); + } else { + acpi_handle_err(handle, "ACPI _SUB Length %zu is Invalid\n", len); + sub = ERR_PTR(-ENODATA); + } + } else { + acpi_handle_warn(handle, "Warning ACPI _SUB did not return a string\n"); + sub = ERR_PTR(-ENODATA); + } + + 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, |