Commit 001dde94 authored by Shawn Nematbakhsh's avatar Shawn Nematbakhsh Committed by Lee Jones
Browse files

mfd: cros ec: spi: Fix "in progress" error signaling 



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-by: default avatarJon Hunter <jonathanh@nvidia.com>
Signed-off-by: default avatarShawn Nematbakhsh <shawnn@chromium.org>
Reviewed-by: default avatarBrian Norris <briannorris@chromium.org>
Tested-by: default avatarJon Hunter <jonathanh@nvidia.com>
Signed-off-by: default avatarLee Jones <lee.jones@linaro.org>
parent 85e9b13c

drivers/mfd/cros_ec_spi.c

+24 −28
Original line number Diff line number Diff line
@@ -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);
@@ -421,24 +422,21 @@ 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 {

	else

		dev_err(ec_dev->dev, "spi transfer failed: %d\n", ret);

	}



	final_ret = terminate_request(ec_dev);
@@ -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;
@@ -544,24 +543,21 @@ 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 {

	else

		dev_err(ec_dev->dev, "spi transfer failed: %d\n", ret);

	}



	final_ret = terminate_request(ec_dev);

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