Merge tag 'mfd-fixes-4.17' of git://git.kernel.org/pub/scm/linux/kernel/git/lee/mfd
Pull MFD fix from Lee Jones:
"A single cros_ec_spi fix correcting the handling for long-running
commands"
* tag 'mfd-fixes-4.17' of git://git.kernel.org/pub/scm/linux/kernel/git/lee/mfd:
mfd: cros_ec: Retry commands when EC is known to be busy
diff --git a/drivers/mfd/cros_ec_spi.c b/drivers/mfd/cros_ec_spi.c
index 1b52b85..2060d14 100644
--- a/drivers/mfd/cros_ec_spi.c
+++ b/drivers/mfd/cros_ec_spi.c
@@ -419,10 +419,25 @@ static int cros_ec_pkt_xfer_spi(struct cros_ec_device *ec_dev,
/* Verify that EC can process command */
for (i = 0; i < len; i++) {
rx_byte = rx_buf[i];
+ /*
+ * Seeing the PAST_END, RX_BAD_DATA, or NOT_READY
+ * markers are all signs that the EC didn't fully
+ * receive our command. e.g., if the EC is flashing
+ * itself, it can't respond to any commands and instead
+ * clocks out EC_SPI_PAST_END from its SPI hardware
+ * buffer. Similar occurrences can happen if the AP is
+ * too slow to clock out data after asserting CS -- the
+ * EC will abort and fill its buffer with
+ * EC_SPI_RX_BAD_DATA.
+ *
+ * In all cases, these errors should be safe to retry.
+ * Report -EAGAIN and let the caller decide what to do
+ * about that.
+ */
if (rx_byte == EC_SPI_PAST_END ||
rx_byte == EC_SPI_RX_BAD_DATA ||
rx_byte == EC_SPI_NOT_READY) {
- ret = -EREMOTEIO;
+ ret = -EAGAIN;
break;
}
}
@@ -431,7 +446,7 @@ static int cros_ec_pkt_xfer_spi(struct cros_ec_device *ec_dev,
if (!ret)
ret = cros_ec_spi_receive_packet(ec_dev,
ec_msg->insize + sizeof(*response));
- else
+ else if (ret != -EAGAIN)
dev_err(ec_dev->dev, "spi transfer failed: %d\n", ret);
final_ret = terminate_request(ec_dev);
@@ -537,10 +552,11 @@ static int cros_ec_cmd_xfer_spi(struct cros_ec_device *ec_dev,
/* Verify that EC can process command */
for (i = 0; i < len; i++) {
rx_byte = rx_buf[i];
+ /* See comments in cros_ec_pkt_xfer_spi() */
if (rx_byte == EC_SPI_PAST_END ||
rx_byte == EC_SPI_RX_BAD_DATA ||
rx_byte == EC_SPI_NOT_READY) {
- ret = -EREMOTEIO;
+ ret = -EAGAIN;
break;
}
}
@@ -549,7 +565,7 @@ static int cros_ec_cmd_xfer_spi(struct cros_ec_device *ec_dev,
if (!ret)
ret = cros_ec_spi_receive_response(ec_dev,
ec_msg->insize + EC_MSG_TX_PROTO_BYTES);
- else
+ else if (ret != -EAGAIN)
dev_err(ec_dev->dev, "spi transfer failed: %d\n", ret);
final_ret = terminate_request(ec_dev);
diff --git a/drivers/platform/chrome/cros_ec_proto.c b/drivers/platform/chrome/cros_ec_proto.c
index e7bbdf9..8350ca2 100644
--- a/drivers/platform/chrome/cros_ec_proto.c
+++ b/drivers/platform/chrome/cros_ec_proto.c
@@ -91,6 +91,8 @@ static int send_command(struct cros_ec_device *ec_dev,
usleep_range(10000, 11000);
ret = (*xfer_fxn)(ec_dev, status_msg);
+ if (ret == -EAGAIN)
+ continue;
if (ret < 0)
break;