For host commands that take a long time to process, cros ec can return early by signaling a EC_RES_IN_PROGRESS result. The host must then poll status with EC_CMD_GET_COMMS_STATUS until completion of the command.
None of the above applies when data link errors are encountered. When errors such as EC_SPI_PAST_END are encountered during command transmission, it usually means the command was not received by the EC. Treating such errors as if they were 'EC_RES_IN_PROGRESS' results is almost always the wrong decision, and can result in host commands silently being lost. Reported-and-tested-by: Jon Hunter <[email protected]> Signed-off-by: Shawn Nematbakhsh <[email protected]> --- drivers/mfd/cros_ec_spi.c | 52 ++++++++++++++++++++++------------------------- 1 file changed, 24 insertions(+), 28 deletions(-) diff --git a/drivers/mfd/cros_ec_spi.c b/drivers/mfd/cros_ec_spi.c index c9714072e224..d019b5b00b67 100644 --- a/drivers/mfd/cros_ec_spi.c +++ b/drivers/mfd/cros_ec_spi.c @@ -377,6 +377,7 @@ static int cros_ec_pkt_xfer_spi(struct cros_ec_device *ec_dev, u8 *ptr; u8 *rx_buf; u8 sum; + u8 rx_byte; int ret = 0, final_ret; len = cros_ec_prepare_tx(ec_dev, ec_msg); @@ -421,25 +422,22 @@ static int cros_ec_pkt_xfer_spi(struct cros_ec_device *ec_dev, if (!ret) { /* Verify that EC can process command */ for (i = 0; i < len; i++) { - switch (rx_buf[i]) { - case EC_SPI_PAST_END: - case EC_SPI_RX_BAD_DATA: - case EC_SPI_NOT_READY: - ret = -EAGAIN; - ec_msg->result = EC_RES_IN_PROGRESS; - default: + rx_byte = rx_buf[i]; + if (rx_byte == EC_SPI_PAST_END || + rx_byte == EC_SPI_RX_BAD_DATA || + rx_byte == EC_SPI_NOT_READY) { + ret = -EREMOTEIO; break; } - if (ret) - break; } - if (!ret) - ret = cros_ec_spi_receive_packet(ec_dev, - ec_msg->insize + sizeof(*response)); - } else { - dev_err(ec_dev->dev, "spi transfer failed: %d\n", ret); } + if (!ret) + ret = cros_ec_spi_receive_packet(ec_dev, + ec_msg->insize + sizeof(*response)); + else + dev_err(ec_dev->dev, "spi transfer failed: %d\n", ret); + final_ret = terminate_request(ec_dev); spi_bus_unlock(ec_spi->spi->master); @@ -508,6 +506,7 @@ static int cros_ec_cmd_xfer_spi(struct cros_ec_device *ec_dev, int i, len; u8 *ptr; u8 *rx_buf; + u8 rx_byte; int sum; int ret = 0, final_ret; @@ -544,25 +543,22 @@ static int cros_ec_cmd_xfer_spi(struct cros_ec_device *ec_dev, if (!ret) { /* Verify that EC can process command */ for (i = 0; i < len; i++) { - switch (rx_buf[i]) { - case EC_SPI_PAST_END: - case EC_SPI_RX_BAD_DATA: - case EC_SPI_NOT_READY: - ret = -EAGAIN; - ec_msg->result = EC_RES_IN_PROGRESS; - default: + rx_byte = rx_buf[i]; + if (rx_byte == EC_SPI_PAST_END || + rx_byte == EC_SPI_RX_BAD_DATA || + rx_byte == EC_SPI_NOT_READY) { + ret = -EREMOTEIO; break; } - if (ret) - break; } - if (!ret) - ret = cros_ec_spi_receive_response(ec_dev, - ec_msg->insize + EC_MSG_TX_PROTO_BYTES); - } else { - dev_err(ec_dev->dev, "spi transfer failed: %d\n", ret); } + if (!ret) + ret = cros_ec_spi_receive_response(ec_dev, + ec_msg->insize + EC_MSG_TX_PROTO_BYTES); + else + dev_err(ec_dev->dev, "spi transfer failed: %d\n", ret); + final_ret = terminate_request(ec_dev); spi_bus_unlock(ec_spi->spi->master); -- 2.12.2
