Re: [PATCH 1/7] mfd: cros-ec: Fix host command buffer size

Lee Jones
2017-04-04T08:39:49Z

On Fri, 24 Mar 2017, Enric Balletbo i Serra wrote:

> From: Vic Yang <victoryang@google.com>
>
> For SPI, we can get up to 32 additional bytes for response preamble.
> The current overhead (2 bytes) may cause problems when we try to receive
> a big response. Update it to 32 bytes.
>
> Without this fix we could see a kernel BUG when we receive a big response
> from the Chrome EC when is connected via SPI.
>
> Signed-off-by: Vic Yang <victoryang@google.com>
> Tested-by: Enric Balletbo i Serra <enric.balletbo.collabora.com>
> ---
>
> This patch is a FIX, and I think that would be interesting see it merged
> in this release cycle. This should go through the MFD tree and can be picked
> independently of the other patches. Lee Jones I think this is for you.
>
> include/linux/mfd/cros_ec.h | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)

Applied to -fixes.

> diff --git a/include/linux/mfd/cros_ec.h b/include/linux/mfd/cros_ec.h
> index b3e812f..3b16c90 100644
> --- a/include/linux/mfd/cros_ec.h
> +++ b/include/linux/mfd/cros_ec.h
> @@ -35,10 +35,11 @@
> * Max bus-specific overhead incurred by request/responses.
> * I2C requires 1 additional byte for requests.
> * I2C requires 2 additional bytes for responses.
> + * SPI requires up to 32 additional bytes for responses.
> * */
> #define EC_PROTO_VERSION_UNKNOWN 0
> #define EC_MAX_REQUEST_OVERHEAD 1
> -#define EC_MAX_RESPONSE_OVERHEAD 2
> +#define EC_MAX_RESPONSE_OVERHEAD 32
>
> /*
> * Command interface between EC and AP, for LPC, I2C and SPI interfaces.

--
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog