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Wysocki" , Len Brown , Mark Brown , Liam Girdwood CC: , , , , "Stefan Binding" Subject: [PATCH v6 1/2] ACPI: utils: Add api to read _SUB from ACPI Date: Thu, 7 Jul 2022 16:10:36 +0100 Message-ID: <20220707151037.3901050-2-sbinding@opensource.cirrus.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20220707151037.3901050-1-sbinding@opensource.cirrus.com> References: <20220707151037.3901050-1-sbinding@opensource.cirrus.com> MIME-Version: 1.0 X-Proofpoint-GUID: nXzdEGsX5TRFa1bZ1Bt_e7IGnOHN5v0e X-Proofpoint-ORIG-GUID: nXzdEGsX5TRFa1bZ1Bt_e7IGnOHN5v0e X-Proofpoint-Spam-Reason: safe Precedence: bulk List-ID: X-Mailing-List: linux-acpi@vger.kernel.org Add a wrapper function to read the _SUB string from ACPI. Signed-off-by: Stefan Binding Acked-by: Rafael J. Wysocki --- 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..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, diff --git a/include/linux/acpi.h b/include/linux/acpi.h index 2a0e95336094..447898685e09 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) {