From: Doug Anderson <dianders@chromium.org>
To: lee.jones@linaro.org, swarren@nvidia.com, wsa@the-dreams.de
Cc: abrestic@chromium.org, dgreid@chromium.org, olof@lixom.net,
sjg@chromium.org, linux-samsung-soc@vger.kernel.org,
linux-tegra@vger.kernel.org,
Doug Anderson <dianders@chromium.org>,
sameo@linux.intel.com, linux-kernel@vger.kernel.org
Subject: [PATCH v2 3/7] mfd: cros_ec: spi: Make the cros_ec_spi timeout more reliable
Date: Tue, 22 Apr 2014 09:45:50 -0700 [thread overview]
Message-ID: <1398185154-19404-4-git-send-email-dianders@chromium.org> (raw)
In-Reply-To: <1398185154-19404-1-git-send-email-dianders@chromium.org>
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>
---
Changes in v2: None
drivers/mfd/cros_ec_spi.c | 15 ++++++++++++---
1 file changed, 12 insertions(+), 3 deletions(-)
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
--
1.9.1.423.g4596e3a
next prev parent reply other threads:[~2014-04-22 16:46 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-04-22 16:45 [PATCH v2 0/7] Add cros_ec changes for newer boards Doug Anderson
2014-04-22 16:45 ` [PATCH v2 1/7] mfd: cros_ec: spi: calculate delay between transfers correctly Doug Anderson
2014-04-23 12:33 ` Lee Jones
2014-04-22 16:45 ` [PATCH v2 2/7] mfd: cros_ec: spi: Add mutex to cros_ec_spi Doug Anderson
2014-04-23 12:34 ` Lee Jones
2014-04-22 16:45 ` Doug Anderson [this message]
2014-04-23 12:35 ` [PATCH v2 3/7] mfd: cros_ec: spi: Make the cros_ec_spi timeout more reliable Lee Jones
2014-04-22 16:45 ` [PATCH v2 4/7] mfd: cros_ec: spi: Increase cros_ec_spi deadline from 5ms to 100ms Doug Anderson
2014-04-23 12:36 ` Lee Jones
2014-04-22 16:45 ` [PATCH v2 5/7] mfd: cros_ec: Sync to the latest cros_ec_commands.h from EC sources Doug Anderson
2014-04-23 12:36 ` Lee Jones
2014-04-22 16:45 ` [PATCH v2 6/7] i2c: ChromeOS EC tunnel driver Doug Anderson
2014-04-23 12:37 ` Lee Jones
2014-04-29 12:33 ` Wolfram Sang
2014-04-22 16:45 ` [PATCH v2 7/7] ARM: tegra: Add the EC i2c tunnel to tegra124-venice2 Doug Anderson
2014-04-23 12:32 ` [PATCH v2 0/7] Add cros_ec changes for newer boards Lee Jones
2014-04-23 16:20 ` Stephen Warren
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