On 6/10/20 6:42 PM, Krzysztof Kozlowski wrote:
>
> Driver allocates DMA memory with dma_alloc_coherent() but frees it with
> dma_unmap_single().
>
> This causes DMA warning during system shutdown (with DMA debugging) on
> Toradex Colibri VF50 module:
>
> WARNING: CPU: 0 PID: 1 at ../kernel/dma/debug.c:1036 check_unmap+0x3fc/0xb04
> DMA-API: fsl-edma 40098000.dma-controller: device driver frees DMA memory with wrong function
> [device address=0x0000000087040000] [size=8 bytes] [mapped as coherent] [unmapped as single]
> Hardware name: Freescale Vybrid VF5xx/VF6xx (Device Tree)
> (unwind_backtrace) from [<8010bb34>] (show_stack+0x10/0x14)
> (show_stack) from [<8011ced8>] (__warn+0xf0/0x108)
> (__warn) from [<8011cf64>] (warn_slowpath_fmt+0x74/0xb8)
> (warn_slowpath_fmt) from [<8017d170>] (check_unmap+0x3fc/0xb04)
> (check_unmap) from [<8017d900>] (debug_dma_unmap_page+0x88/0x90)
> (debug_dma_unmap_page) from [<80601d68>] (dspi_release_dma+0x88/0x110)
> (dspi_release_dma) from [<80601e4c>] (dspi_shutdown+0x5c/0x80)
> (dspi_shutdown) from [<805845f8>] (device_shutdown+0x17c/0x220)
> (device_shutdown) from [<80143ef8>] (kernel_restart+0xc/0x50)
> (kernel_restart) from [<801441cc>] (__do_sys_reboot+0x18c/0x210)
> (__do_sys_reboot) from [<80100060>] (ret_fast_syscall+0x0/0x28)
> DMA-API: Mapped at:
> dma_alloc_attrs+0xa4/0x130
> dspi_probe+0x568/0x7b4
> platform_drv_probe+0x6c/0xa4
> really_probe+0x208/0x348
> driver_probe_device+0x5c/0xb4
>
> Fixes: 90ba37033cb9 ("spi: spi-fsl-dspi: Add DMA support for Vybrid")
> Cc: <stable@xxxxxxxxxxxxxxx>
> Signed-off-by: Krzysztof Kozlowski <krzk@xxxxxxxxxx>
> ---
Sounds reasonable. I always wondered why err_slave_config and
err_rx_dma_buf call something different than dspi_release_dma, but I
didn't see any problem so I didn't investigate it further.
Acked-by: Vladimir Oltean <vladimir.oltean@xxxxxxx>
> drivers/spi/spi-fsl-dspi.c | 8 ++++----
> 1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/spi/spi-fsl-dspi.c b/drivers/spi/spi-fsl-dspi.c
> index a35faced0456..58190c94561f 100644
> --- a/drivers/spi/spi-fsl-dspi.c
> +++ b/drivers/spi/spi-fsl-dspi.c
> @@ -588,14 +588,14 @@ static void dspi_release_dma(struct fsl_dspi *dspi)
> return;
>
> if (dma->chan_tx) {
> - dma_unmap_single(dma->chan_tx->device->dev, dma->tx_dma_phys,
> - dma_bufsize, DMA_TO_DEVICE);
> + dma_free_coherent(dma->chan_tx->device->dev, dma_bufsize,
> + dma->tx_dma_buf, dma->tx_dma_phys);
> dma_release_channel(dma->chan_tx);
> }
>
> if (dma->chan_rx) {
> - dma_unmap_single(dma->chan_rx->device->dev, dma->rx_dma_phys,
> - dma_bufsize, DMA_FROM_DEVICE);
> + dma_free_coherent(dma->chan_rx->device->dev, dma_bufsize,
> + dma->rx_dma_buf, dma->rx_dma_phys);
> dma_release_channel(dma->chan_rx);
> }
> }
> --
> 2.7.4
>
>
Thanks!
-Vladimir
