| Message ID | 1398879850-9111-3-git-send-email-dianders@chromium.org (mailing list archive) |
|---|---|
| State | Not Applicable, archived |
| Headers | show |
On Wed, 30 Apr 2014, Doug Anderson wrote: > 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> > Acked-by: Lee Jones <lee.jones@linaro.org> > Reviewed-by: Simon Glass <sjg@chromium.org> > Tested-by: Andrew Bresticker <abrestic@chromium.org> > Tested-by: Stephen Warren <swarren@nvidia.com> > --- > Changes in v3: None > Changes in v2: None > > drivers/mfd/cros_ec_spi.c | 26 +++++++++++++++++++++----- > 1 file changed, 21 insertions(+), 5 deletions(-) Applied, thanks. > diff --git a/drivers/mfd/cros_ec_spi.c b/drivers/mfd/cros_ec_spi.c > index c185eb6..a2a605d 100644 > --- a/drivers/mfd/cros_ec_spi.c > +++ b/drivers/mfd/cros_ec_spi.c > @@ -65,11 +65,13 @@ > * if no record > * @end_of_msg_delay: used to set the delay_usecs on the spi_transfer that > * is sent when we want to turn off CS at the end of a transaction. > + * @lock: mutex to ensure only one user of cros_ec_command_spi_xfer at a time > */ > struct cros_ec_spi { > struct spi_device *spi; > s64 last_transfer_ns; > unsigned int end_of_msg_delay; > + struct mutex lock; > }; > > static void debug_packet(struct device *dev, const char *name, u8 *ptr, > @@ -208,6 +210,13 @@ static int cros_ec_command_spi_xfer(struct cros_ec_device *ec_dev, > int ret = 0, final_ret; > struct timespec ts; > > + /* > + * We have the shared ec_dev buffer plus we do lots of separate spi_sync > + * calls, so we need to make sure only one person is using this at a > + * time. > + */ > + mutex_lock(&ec_spi->lock); > + > len = cros_ec_prepare_tx(ec_dev, ec_msg); > dev_dbg(ec_dev->dev, "prepared, len=%d\n", len); > > @@ -260,7 +269,7 @@ static int cros_ec_command_spi_xfer(struct cros_ec_device *ec_dev, > ret = final_ret; > if (ret < 0) { > dev_err(ec_dev->dev, "spi transfer failed: %d\n", ret); > - return ret; > + goto exit; > } > > /* check response error code */ > @@ -269,14 +278,16 @@ static int cros_ec_command_spi_xfer(struct cros_ec_device *ec_dev, > dev_warn(ec_dev->dev, "command 0x%02x returned an error %d\n", > ec_msg->cmd, ptr[0]); > debug_packet(ec_dev->dev, "in_err", ptr, len); > - return -EINVAL; > + ret = -EINVAL; > + goto exit; > } > len = ptr[1]; > sum = ptr[0] + ptr[1]; > if (len > ec_msg->in_len) { > dev_err(ec_dev->dev, "packet too long (%d bytes, expected %d)", > len, ec_msg->in_len); > - return -ENOSPC; > + ret = -ENOSPC; > + goto exit; > } > > /* copy response packet payload and compute checksum */ > @@ -293,10 +304,14 @@ static int cros_ec_command_spi_xfer(struct cros_ec_device *ec_dev, > dev_err(ec_dev->dev, > "bad packet checksum, expected %02x, got %02x\n", > sum, ptr[len + 2]); > - return -EBADMSG; > + ret = -EBADMSG; > + goto exit; > } > > - return 0; > + ret = 0; > +exit: > + mutex_unlock(&ec_spi->lock); > + return ret; > } > > static void cros_ec_spi_dt_probe(struct cros_ec_spi *ec_spi, struct device *dev) > @@ -327,6 +342,7 @@ static int cros_ec_spi_probe(struct spi_device *spi) > if (ec_spi == NULL) > return -ENOMEM; > ec_spi->spi = spi; > + mutex_init(&ec_spi->lock); > ec_dev = devm_kzalloc(dev, sizeof(*ec_dev), GFP_KERNEL); > if (!ec_dev) > return -ENOMEM;
diff --git a/drivers/mfd/cros_ec_spi.c b/drivers/mfd/cros_ec_spi.c index c185eb6..a2a605d 100644 --- a/drivers/mfd/cros_ec_spi.c +++ b/drivers/mfd/cros_ec_spi.c @@ -65,11 +65,13 @@ * if no record * @end_of_msg_delay: used to set the delay_usecs on the spi_transfer that * is sent when we want to turn off CS at the end of a transaction. + * @lock: mutex to ensure only one user of cros_ec_command_spi_xfer at a time */ struct cros_ec_spi { struct spi_device *spi; s64 last_transfer_ns; unsigned int end_of_msg_delay; + struct mutex lock; }; static void debug_packet(struct device *dev, const char *name, u8 *ptr, @@ -208,6 +210,13 @@ static int cros_ec_command_spi_xfer(struct cros_ec_device *ec_dev, int ret = 0, final_ret; struct timespec ts; + /* + * We have the shared ec_dev buffer plus we do lots of separate spi_sync + * calls, so we need to make sure only one person is using this at a + * time. + */ + mutex_lock(&ec_spi->lock); + len = cros_ec_prepare_tx(ec_dev, ec_msg); dev_dbg(ec_dev->dev, "prepared, len=%d\n", len); @@ -260,7 +269,7 @@ static int cros_ec_command_spi_xfer(struct cros_ec_device *ec_dev, ret = final_ret; if (ret < 0) { dev_err(ec_dev->dev, "spi transfer failed: %d\n", ret); - return ret; + goto exit; } /* check response error code */ @@ -269,14 +278,16 @@ static int cros_ec_command_spi_xfer(struct cros_ec_device *ec_dev, dev_warn(ec_dev->dev, "command 0x%02x returned an error %d\n", ec_msg->cmd, ptr[0]); debug_packet(ec_dev->dev, "in_err", ptr, len); - return -EINVAL; + ret = -EINVAL; + goto exit; } len = ptr[1]; sum = ptr[0] + ptr[1]; if (len > ec_msg->in_len) { dev_err(ec_dev->dev, "packet too long (%d bytes, expected %d)", len, ec_msg->in_len); - return -ENOSPC; + ret = -ENOSPC; + goto exit; } /* copy response packet payload and compute checksum */ @@ -293,10 +304,14 @@ static int cros_ec_command_spi_xfer(struct cros_ec_device *ec_dev, dev_err(ec_dev->dev, "bad packet checksum, expected %02x, got %02x\n", sum, ptr[len + 2]); - return -EBADMSG; + ret = -EBADMSG; + goto exit; } - return 0; + ret = 0; +exit: + mutex_unlock(&ec_spi->lock); + return ret; } static void cros_ec_spi_dt_probe(struct cros_ec_spi *ec_spi, struct device *dev) @@ -327,6 +342,7 @@ static int cros_ec_spi_probe(struct spi_device *spi) if (ec_spi == NULL) return -ENOMEM; ec_spi->spi = spi; + mutex_init(&ec_spi->lock); ec_dev = devm_kzalloc(dev, sizeof(*ec_dev), GFP_KERNEL); if (!ec_dev) return -ENOMEM;