[PATCH v5 1/2] platform/x86: wmi: Support reading/writing 16 bit EC values

[PATCH v5 1/2] platform/x86: wmi: Support reading/writing 16 bit EC values

[Armin Wolf]

The ACPI EC address space handler currently only supports
reading/writing 8 bit values. Some firmware implementations however
want to access for example 16 bit values, which is perfectly legal
according to the ACPI spec.

Add support for reading/writing such values.

Tested on a Dell Inspiron 3505 and a Asus Prime B650-Plus.

Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Armin Wolf <W_Armin@gmx.de>
---
Chnages since v4:
- spelling fix
- fix checkpatch warning

Changes since v3:
- change type of variable i to size_t

Changes since v2:
- fix address overflow check

Changes since v1:
- use BITS_PER_BYTE
- validate that number of bytes to read/write does not overflow the
  address
---
 drivers/platform/x86/wmi.c | 54 +++++++++++++++++++++++++++++---------
 1 file changed, 41 insertions(+), 13 deletions(-)

diff --git a/drivers/platform/x86/wmi.c b/drivers/platform/x86/wmi.c
index 1920e115da89..9602658711cf 100644
--- a/drivers/platform/x86/wmi.c
+++ b/drivers/platform/x86/wmi.c
@@ -1153,6 +1153,34 @@ static int parse_wdg(struct device *wmi_bus_dev, struct platform_device *pdev)
 	return 0;
 }

+static int ec_read_multiple(u8 address, u8 *buffer, size_t bytes)
+{
+	size_t i;
+	int ret;
+
+	for (i = 0; i < bytes; i++) {
+		ret = ec_read(address + i, &buffer[i]);
+		if (ret < 0)
+			return ret;
+	}
+
+	return 0;
+}
+
+static int ec_write_multiple(u8 address, u8 *buffer, size_t bytes)
+{
+	size_t i;
+	int ret;
+
+	for (i = 0; i < bytes; i++) {
+		ret = ec_write(address + i, buffer[i]);
+		if (ret < 0)
+			return ret;
+	}
+
+	return 0;
+}
+
 /*
  * WMI can have EmbeddedControl access regions. In which case, we just want to
  * hand these off to the EC driver.
@@ -1162,27 +1190,27 @@ acpi_wmi_ec_space_handler(u32 function, acpi_physical_address address,
 			  u32 bits, u64 *value,
 			  void *handler_context, void *region_context)
 {
-	int result = 0;
-	u8 temp = 0;
+	int bytes = bits / BITS_PER_BYTE;
+	int ret;

-	if ((address > 0xFF) || !value)
+	if (!value)
+		return AE_NULL_ENTRY;
+
+	if (!bytes || bytes > sizeof(*value))
 		return AE_BAD_PARAMETER;

-	if (function != ACPI_READ && function != ACPI_WRITE)
+	if (address > U8_MAX || address + bytes - 1 > U8_MAX)
 		return AE_BAD_PARAMETER;

-	if (bits != 8)
+	if (function != ACPI_READ && function != ACPI_WRITE)
 		return AE_BAD_PARAMETER;

-	if (function == ACPI_READ) {
-		result = ec_read(address, &temp);
-		*value = temp;
-	} else {
-		temp = 0xff & *value;
-		result = ec_write(address, temp);
-	}
+	if (function == ACPI_READ)
+		ret = ec_read_multiple(address, (u8 *)value, bytes);
+	else
+		ret = ec_write_multiple(address, (u8 *)value, bytes);

-	switch (result) {
+	switch (ret) {
 	case -EINVAL:
 		return AE_BAD_PARAMETER;
 	case -ENODEV:
--
2.39.2

[PATCH v5 2/2] platform/x86: wmi: Avoid returning AE_OK upon unknown error

[Armin Wolf]

If an error code other than EINVAL, ENODEV or ETIME is returned
by ec_read()/ec_write(), then AE_OK is wrongly returned.

Fix this by only returning AE_OK if the return code is 0, and
return AE_ERROR otherwise.

Tested on a Dell Inspiron 3505 and a Asus Prime B650-Plus.

Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Reviewed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Signed-off-by: Armin Wolf <W_Armin@gmx.de>
---
 drivers/platform/x86/wmi.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/platform/x86/wmi.c b/drivers/platform/x86/wmi.c
index 9602658711cf..060e4236f932 100644
--- a/drivers/platform/x86/wmi.c
+++ b/drivers/platform/x86/wmi.c
@@ -1217,8 +1217,10 @@ acpi_wmi_ec_space_handler(u32 function, acpi_physical_address address,
 		return AE_NOT_FOUND;
 	case -ETIME:
 		return AE_TIME;
-	default:
+	case 0:
 		return AE_OK;
+	default:
+		return AE_ERROR;
 	}
 }

--
2.39.2

Re: [PATCH v5 1/2] platform/x86: wmi: Support reading/writing 16 bit EC values

[Kuppuswamy Sathyanarayanan]

On 3/14/24 11:45 AM, Armin Wolf wrote:
> The ACPI EC address space handler currently only supports
> reading/writing 8 bit values. Some firmware implementations however
> want to access for example 16 bit values, which is perfectly legal
> according to the ACPI spec.
>
> Add support for reading/writing such values.
>
> Tested on a Dell Inspiron 3505 and a Asus Prime B650-Plus.
>
> Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
> Signed-off-by: Armin Wolf <W_Armin@gmx.de>
> ---

Reviewed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>

> Chnages since v4:
> - spelling fix
> - fix checkpatch warning
>
> Changes since v3:
> - change type of variable i to size_t
>
> Changes since v2:
> - fix address overflow check
>
> Changes since v1:
> - use BITS_PER_BYTE
> - validate that number of bytes to read/write does not overflow the
>   address
> ---
>  drivers/platform/x86/wmi.c | 54 +++++++++++++++++++++++++++++---------
>  1 file changed, 41 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/platform/x86/wmi.c b/drivers/platform/x86/wmi.c
> index 1920e115da89..9602658711cf 100644
> --- a/drivers/platform/x86/wmi.c
> +++ b/drivers/platform/x86/wmi.c
> @@ -1153,6 +1153,34 @@ static int parse_wdg(struct device *wmi_bus_dev, struct platform_device *pdev)
>  	return 0;
>  }
>
> +static int ec_read_multiple(u8 address, u8 *buffer, size_t bytes)
> +{
> +	size_t i;
> +	int ret;
> +
> +	for (i = 0; i < bytes; i++) {
> +		ret = ec_read(address + i, &buffer[i]);
> +		if (ret < 0)
> +			return ret;
> +	}
> +
> +	return 0;
> +}
> +
> +static int ec_write_multiple(u8 address, u8 *buffer, size_t bytes)
> +{
> +	size_t i;
> +	int ret;
> +
> +	for (i = 0; i < bytes; i++) {
> +		ret = ec_write(address + i, buffer[i]);
> +		if (ret < 0)
> +			return ret;
> +	}
> +
> +	return 0;
> +}
> +
>  /*
>   * WMI can have EmbeddedControl access regions. In which case, we just want to
>   * hand these off to the EC driver.
> @@ -1162,27 +1190,27 @@ acpi_wmi_ec_space_handler(u32 function, acpi_physical_address address,
>  			  u32 bits, u64 *value,
>  			  void *handler_context, void *region_context)
>  {
> -	int result = 0;
> -	u8 temp = 0;
> +	int bytes = bits / BITS_PER_BYTE;
> +	int ret;
>
> -	if ((address > 0xFF) || !value)
> +	if (!value)
> +		return AE_NULL_ENTRY;
> +
> +	if (!bytes || bytes > sizeof(*value))
>  		return AE_BAD_PARAMETER;
>
> -	if (function != ACPI_READ && function != ACPI_WRITE)
> +	if (address > U8_MAX || address + bytes - 1 > U8_MAX)
>  		return AE_BAD_PARAMETER;
>
> -	if (bits != 8)
> +	if (function != ACPI_READ && function != ACPI_WRITE)
>  		return AE_BAD_PARAMETER;
>
> -	if (function == ACPI_READ) {
> -		result = ec_read(address, &temp);
> -		*value = temp;
> -	} else {
> -		temp = 0xff & *value;
> -		result = ec_write(address, temp);
> -	}
> +	if (function == ACPI_READ)
> +		ret = ec_read_multiple(address, (u8 *)value, bytes);
> +	else
> +		ret = ec_write_multiple(address, (u8 *)value, bytes);
>
> -	switch (result) {
> +	switch (ret) {
>  	case -EINVAL:
>  		return AE_BAD_PARAMETER;
>  	case -ENODEV:
> --
> 2.39.2
>
-- 
Sathyanarayanan Kuppuswamy
Linux Kernel Developer

Re: [PATCH v5 1/2] platform/x86: wmi: Support reading/writing 16 bit EC values

[Hans de Goede]

Hi,

On 3/14/24 7:45 PM, Armin Wolf wrote:
> The ACPI EC address space handler currently only supports
> reading/writing 8 bit values. Some firmware implementations however
> want to access for example 16 bit values, which is perfectly legal
> according to the ACPI spec.
> 
> Add support for reading/writing such values.
> 
> Tested on a Dell Inspiron 3505 and a Asus Prime B650-Plus.
> 
> Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
> Signed-off-by: Armin Wolf <W_Armin@gmx.de>

Thank you for your patch-series, I've applied the series to my
review-hans branch:
https://git.kernel.org/pub/scm/linux/kernel/git/pdx86/platform-drivers-x86.git/log/?h=review-hans

Note it will show up in my review-hans branch once I've pushed my
local branch there, which might take a while.

Once I've run some tests on this branch the patches there will be
added to the platform-drivers-x86/for-next branch and eventually
will be included in the pdx86 pull-request to Linus for the next
merge-window.

Regards,

Hans




> ---
> Chnages since v4:
> - spelling fix
> - fix checkpatch warning
> 
> Changes since v3:
> - change type of variable i to size_t
> 
> Changes since v2:
> - fix address overflow check
> 
> Changes since v1:
> - use BITS_PER_BYTE
> - validate that number of bytes to read/write does not overflow the
>   address
> ---
>  drivers/platform/x86/wmi.c | 54 +++++++++++++++++++++++++++++---------
>  1 file changed, 41 insertions(+), 13 deletions(-)
> 
> diff --git a/drivers/platform/x86/wmi.c b/drivers/platform/x86/wmi.c
> index 1920e115da89..9602658711cf 100644
> --- a/drivers/platform/x86/wmi.c
> +++ b/drivers/platform/x86/wmi.c
> @@ -1153,6 +1153,34 @@ static int parse_wdg(struct device *wmi_bus_dev, struct platform_device *pdev)
>  	return 0;
>  }
> 
> +static int ec_read_multiple(u8 address, u8 *buffer, size_t bytes)
> +{
> +	size_t i;
> +	int ret;
> +
> +	for (i = 0; i < bytes; i++) {
> +		ret = ec_read(address + i, &buffer[i]);
> +		if (ret < 0)
> +			return ret;
> +	}
> +
> +	return 0;
> +}
> +
> +static int ec_write_multiple(u8 address, u8 *buffer, size_t bytes)
> +{
> +	size_t i;
> +	int ret;
> +
> +	for (i = 0; i < bytes; i++) {
> +		ret = ec_write(address + i, buffer[i]);
> +		if (ret < 0)
> +			return ret;
> +	}
> +
> +	return 0;
> +}
> +
>  /*
>   * WMI can have EmbeddedControl access regions. In which case, we just want to
>   * hand these off to the EC driver.
> @@ -1162,27 +1190,27 @@ acpi_wmi_ec_space_handler(u32 function, acpi_physical_address address,
>  			  u32 bits, u64 *value,
>  			  void *handler_context, void *region_context)
>  {
> -	int result = 0;
> -	u8 temp = 0;
> +	int bytes = bits / BITS_PER_BYTE;
> +	int ret;
> 
> -	if ((address > 0xFF) || !value)
> +	if (!value)
> +		return AE_NULL_ENTRY;
> +
> +	if (!bytes || bytes > sizeof(*value))
>  		return AE_BAD_PARAMETER;
> 
> -	if (function != ACPI_READ && function != ACPI_WRITE)
> +	if (address > U8_MAX || address + bytes - 1 > U8_MAX)
>  		return AE_BAD_PARAMETER;
> 
> -	if (bits != 8)
> +	if (function != ACPI_READ && function != ACPI_WRITE)
>  		return AE_BAD_PARAMETER;
> 
> -	if (function == ACPI_READ) {
> -		result = ec_read(address, &temp);
> -		*value = temp;
> -	} else {
> -		temp = 0xff & *value;
> -		result = ec_write(address, temp);
> -	}
> +	if (function == ACPI_READ)
> +		ret = ec_read_multiple(address, (u8 *)value, bytes);
> +	else
> +		ret = ec_write_multiple(address, (u8 *)value, bytes);
> 
> -	switch (result) {
> +	switch (ret) {
>  	case -EINVAL:
>  		return AE_BAD_PARAMETER;
>  	case -ENODEV:
> --
> 2.39.2
>