From: Doug Anderson Date: Wed, 30 Apr 2014 17:44:06 +0000 (-0700) Subject: mfd: cros_ec: spi: Make the cros_ec_spi timeout more reliable X-Git-Tag: firefly_0821_release~176^2~3820^2~6^2~12 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=c9a81d67ce4c9cd9b73f8ec6dba827882555d47e;p=firefly-linux-kernel-4.4.55.git mfd: cros_ec: spi: Make the cros_ec_spi timeout more reliable 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 Reviewed-by: Simon Glass Tested-by: Andrew Bresticker Tested-by: Stephen Warren Signed-off-by: Lee Jones --- diff --git a/drivers/mfd/cros_ec_spi.c b/drivers/mfd/cros_ec_spi.c index a2a605de79a7..4f863c346547 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