diff mbox series

[v1,1/2] ACPI: utils: Add api to read _SUB from ACPI

Message ID 20220622130730.1573747-2-sbinding@opensource.cirrus.com (mailing list archive)
State Changes Requested, archived
Headers show
Series Read _SUB from ACPI to be able to identify firmware | expand

Commit Message

Stefan Binding June 22, 2022, 1:07 p.m. UTC 
Add a wrapper function to read the _SUB string from ACPI.

Signed-off-by: Stefan Binding <sbinding@opensource.cirrus.com>
---
 drivers/acpi/utils.c | 26 ++++++++++++++++++++++++++
 include/linux/acpi.h |  8 ++++++++
 2 files changed, 34 insertions(+)

Comments

Rafael J. Wysocki June 22, 2022, 1:19 p.m. UTC | #1 
On Wed, Jun 22, 2022 at 3:08 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 | 26 ++++++++++++++++++++++++++
>  include/linux/acpi.h |  8 ++++++++
>  2 files changed, 34 insertions(+)
>
> diff --git a/drivers/acpi/utils.c b/drivers/acpi/utils.c
> index 3a9773a09e19..5d1bdb79e372 100644
> --- a/drivers/acpi/utils.c
> +++ b/drivers/acpi/utils.c
> @@ -291,6 +291,32 @@ int acpi_get_local_address(acpi_handle handle, u32 *addr)
>  }
>  EXPORT_SYMBOL(acpi_get_local_address);
>
> +int acpi_get_sub(acpi_handle handle, char *sub, size_t size)

I'd call it acpi_get_subsystem_id().

> +{
> +       struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
> +       union acpi_object *obj;
> +       acpi_status status;
> +       int ret;
> +
> +       status = acpi_evaluate_object(handle, METHOD_NAME__SUB, NULL, &buffer);
> +       if (!ACPI_SUCCESS(status)) {

Typically, ACPI_FAILURE() is used in checks like this.

> +               acpi_handle_debug(handle, "Reading ACPI _SUB failed: %#x\n", status);

It would be enough to say "_SUB evaluation failed".

> +               return -ENOENT;

Why not use -ENODATA here?

> +       }
> +
> +       obj = buffer.pointer;
> +       if (obj->type == ACPI_TYPE_STRING) {
> +               ret = strscpy(sub, obj->string.pointer, size);

It may be simpler to allocate the memory here so that callers don't
have to worry about it.

Also, this is expected to be a proper device ID, not just a string, so
maybe some validation checks could be made here?

> +       } else {
> +               acpi_handle_warn(handle, "Warning ACPI _SUB did not return a string\n");
> +               ret = -EINVAL;
> +       }
> +       acpi_os_free(buffer.pointer);
> +
> +       return ret;
> +}
> +EXPORT_SYMBOL_GPL(acpi_get_sub);
> +
>  acpi_status
>  acpi_evaluate_reference(acpi_handle handle,
>                         acpi_string pathname,
> diff --git a/include/linux/acpi.h b/include/linux/acpi.h
> index 4f82a5bc6d98..9bf18adf5920 100644
> --- a/include/linux/acpi.h
> +++ b/include/linux/acpi.h
> @@ -21,6 +21,8 @@
>  #endif
>  #include <acpi/acpi.h>
>
> +#define ACPI_MAX_SUB_BUF_SIZE  9
> +
>  #ifdef CONFIG_ACPI
>
>  #include <linux/list.h>
> @@ -762,6 +764,7 @@ static inline u64 acpi_arch_get_root_pointer(void)
>  #endif
>
>  int acpi_get_local_address(acpi_handle handle, u32 *addr);
> +int acpi_get_sub(acpi_handle handle, char *sub, size_t size);
>
>  #else  /* !CONFIG_ACPI */
>
> @@ -1023,6 +1026,11 @@ static inline int acpi_get_local_address(acpi_handle handle, u32 *addr)
>         return -ENODEV;
>  }
>
> +static int acpi_get_sub(acpi_handle handle, char *sub, size_t size)
> +{
> +       return -ENODEV;
> +}
> +
>  static inline int acpi_register_wakeup_handler(int wake_irq,
>         bool (*wakeup)(void *context), void *context)
>  {
> --
kernel test robot June 22, 2022, 9 p.m. UTC | #2 
Hi Stefan,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on rafael-pm/linux-next]
[also build test ERROR on broonie-sound/for-next linus/master v5.19-rc3 next-20220622]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/intel-lab-lkp/linux/commits/Stefan-Binding/Read-_SUB-from-ACPI-to-be-able-to-identify-firmware/20220622-211004
base:   https://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm.git linux-next
config: powerpc-buildonly-randconfig-r002-20220622 (https://download.01.org/0day-ci/archive/20220623/202206230433.0LyjOI85-lkp@intel.com/config)
compiler: clang version 15.0.0 (https://github.com/llvm/llvm-project 8b8d126598ce7bd5243da7f94f69fa1104288bee)
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # install powerpc cross compiling tool for clang build
        # apt-get install binutils-powerpc-linux-gnu
        # https://github.com/intel-lab-lkp/linux/commit/97b928a895ce3105296f0036393bb9ee04f11ae4
        git remote add linux-review https://github.com/intel-lab-lkp/linux
        git fetch --no-tags linux-review Stefan-Binding/Read-_SUB-from-ACPI-to-be-able-to-identify-firmware/20220622-211004
        git checkout 97b928a895ce3105296f0036393bb9ee04f11ae4
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=powerpc SHELL=/bin/bash arch/powerpc/

If you fix the issue, kindly add following tag where applicable
Reported-by: kernel test robot <lkp@intel.com>

All errors (new ones prefixed by >>):

   In file included from arch/powerpc/kernel/traps.c:32:
   In file included from include/linux/backlight.h:13:
   In file included from include/linux/fb.h:7:
   In file included from include/uapi/linux/fb.h:6:
   In file included from include/linux/i2c.h:13:
>> include/linux/acpi.h:1029:12: error: unused function 'acpi_get_sub' [-Werror,-Wunused-function]
   static int acpi_get_sub(acpi_handle handle, char *sub, size_t size)
              ^
   1 error generated.


vim +/acpi_get_sub +1029 include/linux/acpi.h

  1028	
> 1029	static int acpi_get_sub(acpi_handle handle, char *sub, size_t size)
  1030	{
  1031		return -ENODEV;
  1032	}
  1033
kernel test robot June 22, 2022, 9:10 p.m. UTC | #3 
Hi Stefan,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on rafael-pm/linux-next]
[also build test ERROR on broonie-sound/for-next linus/master v5.19-rc3 next-20220622]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/intel-lab-lkp/linux/commits/Stefan-Binding/Read-_SUB-from-ACPI-to-be-able-to-identify-firmware/20220622-211004
base:   https://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm.git linux-next
config: powerpc-pasemi_defconfig (https://download.01.org/0day-ci/archive/20220623/202206230402.9xK6YlsY-lkp@intel.com/config)
compiler: powerpc-linux-gcc (GCC) 11.3.0
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://github.com/intel-lab-lkp/linux/commit/97b928a895ce3105296f0036393bb9ee04f11ae4
        git remote add linux-review https://github.com/intel-lab-lkp/linux
        git fetch --no-tags linux-review Stefan-Binding/Read-_SUB-from-ACPI-to-be-able-to-identify-firmware/20220622-211004
        git checkout 97b928a895ce3105296f0036393bb9ee04f11ae4
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.3.0 make.cross W=1 O=build_dir ARCH=powerpc SHELL=/bin/bash

If you fix the issue, kindly add following tag where applicable
Reported-by: kernel test robot <lkp@intel.com>

All errors (new ones prefixed by >>):

   In file included from include/linux/i2c.h:13,
                    from include/uapi/linux/fb.h:6,
                    from include/linux/fb.h:7,
                    from include/linux/backlight.h:13,
                    from arch/powerpc/kernel/traps.c:32:
>> include/linux/acpi.h:1029:12: error: 'acpi_get_sub' defined but not used [-Werror=unused-function]
    1029 | static int acpi_get_sub(acpi_handle handle, char *sub, size_t size)
         |            ^~~~~~~~~~~~
   cc1: all warnings being treated as errors


vim +/acpi_get_sub +1029 include/linux/acpi.h

  1028	
> 1029	static int acpi_get_sub(acpi_handle handle, char *sub, size_t size)
  1030	{
  1031		return -ENODEV;
  1032	}
  1033
diff mbox series

Patch

diff --git a/drivers/acpi/utils.c b/drivers/acpi/utils.c
index 3a9773a09e19..5d1bdb79e372 100644
--- a/drivers/acpi/utils.c
+++ b/drivers/acpi/utils.c
@@ -291,6 +291,32 @@  int acpi_get_local_address(acpi_handle handle, u32 *addr)
 }
 EXPORT_SYMBOL(acpi_get_local_address);
 
+int acpi_get_sub(acpi_handle handle, char *sub, size_t size)
+{
+	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
+	union acpi_object *obj;
+	acpi_status status;
+	int ret;
+
+	status = acpi_evaluate_object(handle, METHOD_NAME__SUB, NULL, &buffer);
+	if (!ACPI_SUCCESS(status)) {
+		acpi_handle_debug(handle, "Reading ACPI _SUB failed: %#x\n", status);
+		return -ENOENT;
+	}
+
+	obj = buffer.pointer;
+	if (obj->type == ACPI_TYPE_STRING) {
+		ret = strscpy(sub, obj->string.pointer, size);
+	} else {
+		acpi_handle_warn(handle, "Warning ACPI _SUB did not return a string\n");
+		ret = -EINVAL;
+	}
+	acpi_os_free(buffer.pointer);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(acpi_get_sub);
+
 acpi_status
 acpi_evaluate_reference(acpi_handle handle,
 			acpi_string pathname,
diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index 4f82a5bc6d98..9bf18adf5920 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -21,6 +21,8 @@ 
 #endif
 #include <acpi/acpi.h>
 
+#define ACPI_MAX_SUB_BUF_SIZE	9
+
 #ifdef	CONFIG_ACPI
 
 #include <linux/list.h>
@@ -762,6 +764,7 @@  static inline u64 acpi_arch_get_root_pointer(void)
 #endif
 
 int acpi_get_local_address(acpi_handle handle, u32 *addr);
+int acpi_get_sub(acpi_handle handle, char *sub, size_t size);
 
 #else	/* !CONFIG_ACPI */
 
@@ -1023,6 +1026,11 @@  static inline int acpi_get_local_address(acpi_handle handle, u32 *addr)
 	return -ENODEV;
 }
 
+static int acpi_get_sub(acpi_handle handle, char *sub, size_t size)
+{
+	return -ENODEV;
+}
+
 static inline int acpi_register_wakeup_handler(int wake_irq,
 	bool (*wakeup)(void *context), void *context)
 {