On Wed, 30 Apr 2014, Doug Anderson wrote:
> The cros_ec_spi transfer had two problems with its timeout code:
>
> 1. It looked at the timeout even in the case that it found valid data.
> 2. If the cros_ec_spi code got switched out for a while, it's possible
> it could get a timeout after a single loop. Let's be paranoid and
> make sure we do one last transfer after the timeout expires.
>
> Signed-off-by: Doug Anderson <dianders@xxxxxxxxxxxx>
> Acked-by: Lee Jones <lee.jones@xxxxxxxxxx>
> Reviewed-by: Simon Glass <sjg@xxxxxxxxxxxx>
> Tested-by: Andrew Bresticker <abrestic@xxxxxxxxxxxx>
> Tested-by: Stephen Warren <swarren@xxxxxxxxxx>
> ---
> Changes in v3: None
> Changes in v2: None
>
> drivers/mfd/cros_ec_spi.c | 15 ++++++++++++---
> 1 file changed, 12 insertions(+), 3 deletions(-)
Applied, thanks.
> diff --git a/drivers/mfd/cros_ec_spi.c b/drivers/mfd/cros_ec_spi.c
> index a2a605d..4f863c3 100644
> --- a/drivers/mfd/cros_ec_spi.c
> +++ b/drivers/mfd/cros_ec_spi.c
> @@ -113,7 +113,9 @@ static int cros_ec_spi_receive_response(struct cros_ec_device *ec_dev,
>
> /* Receive data until we see the header byte */
> deadline = jiffies + msecs_to_jiffies(EC_MSG_DEADLINE_MS);
> - do {
> + while (true) {
> + unsigned long start_jiffies = jiffies;
> +
> memset(&trans, 0, sizeof(trans));
> trans.cs_change = 1;
> trans.rx_buf = ptr = ec_dev->din;
> @@ -134,12 +136,19 @@ static int cros_ec_spi_receive_response(struct cros_ec_device *ec_dev,
> break;
> }
> }
> + if (ptr != end)
> + break;
>
> - if (time_after(jiffies, deadline)) {
> + /*
> + * Use the time at the start of the loop as a timeout. This
> + * gives us one last shot at getting the transfer and is useful
> + * in case we got context switched out for a while.
> + */
> + if (time_after(start_jiffies, deadline)) {
> dev_warn(ec_dev->dev, "EC failed to respond in time\n");
> return -ETIMEDOUT;
> }
> - } while (ptr == end);
> + }
>
> /*
> * ptr now points to the header byte. Copy any valid data to the
--
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
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