From: Andrew Bresticker <abrestic@xxxxxxxxxxxx>
When an EC command returns EC_RES_IN_PROGRESS, we need to query
the state of the EC until it indicates that it is no longer busy.
Do this in cros_ec_cmd_xfer() under the EC's mutex so that other
commands (e.g. keyboard, I2C passtru) aren't issued to the EC while
it is working on the in-progress command.
The 10 milliseconds delay and the number of retries are the values
that were used by the flashrom tool when retrying commands.
Signed-off-by: Andrew Bresticker <abrestic@xxxxxxxxxxxx>
Reviewed-by: Simon Glass <sjg@xxxxxxxxxxxx>
Signed-off-by: Javier Martinez Canillas <javier.martinez@xxxxxxxxxxxxxxx>
---
Changes since v3:
- Fix us time and use raw values instead of a define. Suggested by Lee Jones.
Changes since v2:
- Explain in the commit message from where the delay and retry values come from.
Commented by Andrew Bresticker.
- Move the needed definitions inside the if block. Suggested by Lee Jones.
- Only check if result is EC_RES_IN_PROGRESS instead of checking also if ret is
-EAGAIN since the former implies the later. Suggested by Lee Jones.
- Use usleep_range() instead of msleep() since doesn't handle values between 1~20.
Suggested by Lee Jones.
Changes since v1:
- The *xfer() calls don't modify the passed cros_ec_command so there is
no need to populate it inside the for loop. Suggested by Lee Jones.
drivers/mfd/cros_ec.c | 33 +++++++++++++++++++++++++++++++++
1 file changed, 33 insertions(+)
diff --git a/drivers/mfd/cros_ec.c b/drivers/mfd/cros_ec.c
index c53804a..fc0c81e 100644
--- a/drivers/mfd/cros_ec.c
+++ b/drivers/mfd/cros_ec.c
@@ -23,6 +23,9 @@
#include <linux/mfd/core.h>
#include <linux/mfd/cros_ec.h>
#include <linux/mfd/cros_ec_commands.h>
+#include <linux/delay.h>
+
+#define EC_COMMAND_RETRIES 50
int cros_ec_prepare_tx(struct cros_ec_device *ec_dev,
struct cros_ec_command *msg)
@@ -69,6 +72,36 @@ int cros_ec_cmd_xfer(struct cros_ec_device *ec_dev,
mutex_lock(&ec_dev->lock);
ret = ec_dev->cmd_xfer(ec_dev, msg);
+ if (msg->result == EC_RES_IN_PROGRESS) {
+ int i;
+ struct cros_ec_command status_msg;
+ struct ec_response_get_comms_status status;
+
+ status_msg.version = 0;
+ status_msg.command = EC_CMD_GET_COMMS_STATUS;
+ status_msg.outdata = NULL;
+ status_msg.outsize = 0;
+ status_msg.indata = (uint8_t *)&status;
+ status_msg.insize = sizeof(status);
+
+ /*
+ * Query the EC's status until it's no longer busy or
+ * we encounter an error.
+ */
+ for (i = 0; i < EC_COMMAND_RETRIES; i++) {
+ usleep_range(10000, 11000);
+
+ ret = ec_dev->cmd_xfer(ec_dev, &status_msg);
+ if (ret < 0)
+ break;
+
+ msg->result = status_msg.result;
+ if (status_msg.result != EC_RES_SUCCESS)
+ break;
+ if (!(status.flags & EC_COMMS_STATUS_PROCESSING))
+ break;
+ }
+ }
mutex_unlock(&ec_dev->lock);
return ret;
--
2.1.0
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