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mfd: cros_ec: spi: Add mutex to cros_ec_spi
The main transfer function for cros_ec_spi can be called by more than one client at a time. Make sure that those clients don't stomp on each other by locking the bus for the duration of the transfer function. Signed-off-by: Doug Anderson <dianders@chromium.org> Reviewed-by: Simon Glass <sjg@chromium.org> Tested-by: Andrew Bresticker <abrestic@chromium.org> Tested-by: Stephen Warren <swarren@nvidia.com> Signed-off-by: Lee Jones <lee.jones@linaro.org>
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1fe368665b
commit
362196e5d0
1 changed files with 21 additions and 5 deletions
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@ -65,11 +65,13 @@
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* if no record
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* @end_of_msg_delay: used to set the delay_usecs on the spi_transfer that
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* is sent when we want to turn off CS at the end of a transaction.
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* @lock: mutex to ensure only one user of cros_ec_command_spi_xfer at a time
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*/
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struct cros_ec_spi {
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struct spi_device *spi;
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s64 last_transfer_ns;
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unsigned int end_of_msg_delay;
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struct mutex lock;
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};
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static void debug_packet(struct device *dev, const char *name, u8 *ptr,
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@ -208,6 +210,13 @@ static int cros_ec_command_spi_xfer(struct cros_ec_device *ec_dev,
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int ret = 0, final_ret;
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struct timespec ts;
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/*
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* We have the shared ec_dev buffer plus we do lots of separate spi_sync
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* calls, so we need to make sure only one person is using this at a
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* time.
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*/
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mutex_lock(&ec_spi->lock);
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len = cros_ec_prepare_tx(ec_dev, ec_msg);
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dev_dbg(ec_dev->dev, "prepared, len=%d\n", len);
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@ -260,7 +269,7 @@ static int cros_ec_command_spi_xfer(struct cros_ec_device *ec_dev,
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ret = final_ret;
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if (ret < 0) {
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dev_err(ec_dev->dev, "spi transfer failed: %d\n", ret);
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return ret;
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goto exit;
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}
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/* check response error code */
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@ -269,14 +278,16 @@ static int cros_ec_command_spi_xfer(struct cros_ec_device *ec_dev,
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dev_warn(ec_dev->dev, "command 0x%02x returned an error %d\n",
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ec_msg->cmd, ptr[0]);
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debug_packet(ec_dev->dev, "in_err", ptr, len);
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return -EINVAL;
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ret = -EINVAL;
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goto exit;
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}
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len = ptr[1];
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sum = ptr[0] + ptr[1];
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if (len > ec_msg->in_len) {
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dev_err(ec_dev->dev, "packet too long (%d bytes, expected %d)",
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len, ec_msg->in_len);
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return -ENOSPC;
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ret = -ENOSPC;
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goto exit;
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}
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/* copy response packet payload and compute checksum */
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@ -293,10 +304,14 @@ static int cros_ec_command_spi_xfer(struct cros_ec_device *ec_dev,
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dev_err(ec_dev->dev,
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"bad packet checksum, expected %02x, got %02x\n",
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sum, ptr[len + 2]);
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return -EBADMSG;
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ret = -EBADMSG;
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goto exit;
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}
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return 0;
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ret = 0;
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exit:
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mutex_unlock(&ec_spi->lock);
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return ret;
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}
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static void cros_ec_spi_dt_probe(struct cros_ec_spi *ec_spi, struct device *dev)
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@ -327,6 +342,7 @@ static int cros_ec_spi_probe(struct spi_device *spi)
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if (ec_spi == NULL)
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return -ENOMEM;
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ec_spi->spi = spi;
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mutex_init(&ec_spi->lock);
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ec_dev = devm_kzalloc(dev, sizeof(*ec_dev), GFP_KERNEL);
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if (!ec_dev)
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return -ENOMEM;
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