| Message ID | 20220630150135.1799535-2-sbinding@opensource.cirrus.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | Read _SUB from ACPI to be able to identify firmware | expand |
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 >
On Thu, Jun 30, 2022 at 5:17 PM Stefan Binding <sbinding@opensource.cirrus.com> wrote: > > Add a wrapper function to read the _SUB string from ACPI. ... > + 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); > + } else { > + acpi_handle_err(handle, "ACPI _SUB Length %zu is Invalid\n", > + strlen(obj->string.pointer)); Three times to evaluate strlen()... Can we do better, please? > + sub = ERR_PTR(-EINVAL); > + } > + } else { > + acpi_handle_warn(handle, "Warning ACPI _SUB did not return a string\n"); > + sub = ERR_PTR(-EINVAL); > + }
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); + } else { + acpi_handle_err(handle, "ACPI _SUB Length %zu is Invalid\n", + strlen(obj->string.pointer)); + sub = ERR_PTR(-EINVAL); + } + } else { + acpi_handle_warn(handle, "Warning ACPI _SUB did not return a string\n"); + sub = ERR_PTR(-EINVAL); + } + + 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) {
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(+)