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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: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Shawn Nematbakhsh <shawnn@chromium.org>
Reviewed-by: Brian Norris <briannorris@chromium.org>
Tested-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
This commit is contained in:
Shawn Nematbakhsh 2017-09-27 14:35:27 -07:00 committed by Lee Jones
parent 85e9b13cbb
commit 001dde9400
1 changed files with 24 additions and 28 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

52
drivers/mfd/cros_ec_spi.c
View File

@ -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);