diff options
| author | Doug Anderson <dianders@chromium.org> | 2014-04-30 19:44:06 +0200 |
|---|---|---|
| committer | Lee Jones <lee.jones@linaro.org> | 2014-06-03 09:11:47 +0200 |
| commit | c9a81d67ce4c9cd9b73f8ec6dba827882555d47e (patch) | |
| tree | 743426964b110e65372e848ce4cad51e4183c5b1 /drivers/mfd/cros_ec_spi.c | |
| parent | mfd: cros_ec: spi: Add mutex to cros_ec_spi (diff) | |
| download | linux-c9a81d67ce4c9cd9b73f8ec6dba827882555d47e.tar.xz linux-c9a81d67ce4c9cd9b73f8ec6dba827882555d47e.zip | |
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 <dianders@chromium.org>
Reviewed-by: Simon Glass <sjg@chromium.org>
Tested-by: Andrew Bresticker <abrestic@chromium.org>
Tested-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Diffstat (limited to 'drivers/mfd/cros_ec_spi.c')
| -rw-r--r-- | drivers/mfd/cros_ec_spi.c | 15 |
1 files changed, 12 insertions, 3 deletions
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 |