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authorDoug Anderson <dianders@chromium.org>2014-04-30 21:44:06 +0400
committerLee Jones <lee.jones@linaro.org>2014-06-03 11:11:47 +0400
commitc9a81d67ce4c9cd9b73f8ec6dba827882555d47e (patch)
tree743426964b110e65372e848ce4cad51e4183c5b1 /drivers/mfd
parent362196e5d0832ce3c4e1df376c02cff812a2391b (diff)
downloadlinux-c9a81d67ce4c9cd9b73f8ec6dba827882555d47e.tar.xz
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')
-rw-r--r--drivers/mfd/cros_ec_spi.c15
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