| From 1a198794451449113fa86994ed491d6986802c23 Mon Sep 17 00:00:00 2001 |
| From: Eugen Hristev <eugen.hristev@microchip.com> |
| Date: Wed, 23 Sep 2020 15:17:48 +0300 |
| Subject: iio: adc: at91-sama5d2_adc: fix DMA conversion crash |
| |
| From: Eugen Hristev <eugen.hristev@microchip.com> |
| |
| commit 1a198794451449113fa86994ed491d6986802c23 upstream. |
| |
| After the move of the postenable code to preenable, the DMA start was |
| done before the DMA init, which is not correct. |
| The DMA is initialized in set_watermark. Because of this, we need to call |
| the DMA start functions in set_watermark, after the DMA init, instead of |
| preenable hook, when the DMA is not properly setup yet. |
| |
| Fixes: f3c034f61775 ("iio: at91-sama5d2_adc: adjust iio_triggered_buffer_{predisable,postenable} positions") |
| Signed-off-by: Eugen Hristev <eugen.hristev@microchip.com> |
| Link: https://lore.kernel.org/r/20200923121748.49384-1-eugen.hristev@microchip.com |
| Cc: <Stable@vger.kernel.org> |
| Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| drivers/iio/adc/at91-sama5d2_adc.c | 16 ++++++++++++---- |
| 1 file changed, 12 insertions(+), 4 deletions(-) |
| |
| --- a/drivers/iio/adc/at91-sama5d2_adc.c |
| +++ b/drivers/iio/adc/at91-sama5d2_adc.c |
| @@ -884,7 +884,7 @@ static bool at91_adc_current_chan_is_tou |
| AT91_SAMA5D2_MAX_CHAN_IDX + 1); |
| } |
| |
| -static int at91_adc_buffer_preenable(struct iio_dev *indio_dev) |
| +static int at91_adc_buffer_prepare(struct iio_dev *indio_dev) |
| { |
| int ret; |
| u8 bit; |
| @@ -901,7 +901,7 @@ static int at91_adc_buffer_preenable(str |
| /* we continue with the triggered buffer */ |
| ret = at91_adc_dma_start(indio_dev); |
| if (ret) { |
| - dev_err(&indio_dev->dev, "buffer postenable failed\n"); |
| + dev_err(&indio_dev->dev, "buffer prepare failed\n"); |
| return ret; |
| } |
| |
| @@ -989,7 +989,6 @@ static int at91_adc_buffer_postdisable(s |
| } |
| |
| static const struct iio_buffer_setup_ops at91_buffer_setup_ops = { |
| - .preenable = &at91_adc_buffer_preenable, |
| .postdisable = &at91_adc_buffer_postdisable, |
| }; |
| |
| @@ -1563,6 +1562,7 @@ static void at91_adc_dma_disable(struct |
| static int at91_adc_set_watermark(struct iio_dev *indio_dev, unsigned int val) |
| { |
| struct at91_adc_state *st = iio_priv(indio_dev); |
| + int ret; |
| |
| if (val > AT91_HWFIFO_MAX_SIZE) |
| return -EINVAL; |
| @@ -1586,7 +1586,15 @@ static int at91_adc_set_watermark(struct |
| else if (val > 1) |
| at91_adc_dma_init(to_platform_device(&indio_dev->dev)); |
| |
| - return 0; |
| + /* |
| + * We can start the DMA only after setting the watermark and |
| + * having the DMA initialization completed |
| + */ |
| + ret = at91_adc_buffer_prepare(indio_dev); |
| + if (ret) |
| + at91_adc_dma_disable(to_platform_device(&indio_dev->dev)); |
| + |
| + return ret; |
| } |
| |
| static int at91_adc_update_scan_mode(struct iio_dev *indio_dev, |