Re: [PATCH] mmc: mmci: stm32: fix DMA API overlapping mappings warning

[Ulf Hansson]

On Wed, 7 Feb 2024 at 15:40, Christophe Kerello
<christophe.kerello@xxxxxxxxxxx> wrote:
>
> Turning on CONFIG_DMA_API_DEBUG_SG results in the following warning:
>
> DMA-API: mmci-pl18x 48220000.mmc: cacheline tracking EEXIST,
> overlapping mappings aren't supported
> WARNING: CPU: 1 PID: 51 at kernel/dma/debug.c:568
> add_dma_entry+0x234/0x2f4
> Modules linked in:
> CPU: 1 PID: 51 Comm: kworker/1:2 Not tainted 6.1.28 #1
> Hardware name: STMicroelectronics STM32MP257F-EV1 Evaluation Board (DT)
> Workqueue: events_freezable mmc_rescan
> Call trace:
> add_dma_entry+0x234/0x2f4
> debug_dma_map_sg+0x198/0x350
> __dma_map_sg_attrs+0xa0/0x110
> dma_map_sg_attrs+0x10/0x2c
> sdmmc_idma_prep_data+0x80/0xc0
> mmci_prep_data+0x38/0x84
> mmci_start_data+0x108/0x2dc
> mmci_request+0xe4/0x190
> __mmc_start_request+0x68/0x140
> mmc_start_request+0x94/0xc0
> mmc_wait_for_req+0x70/0x100
> mmc_send_tuning+0x108/0x1ac
> sdmmc_execute_tuning+0x14c/0x210
> mmc_execute_tuning+0x48/0xec
> mmc_sd_init_uhs_card.part.0+0x208/0x464
> mmc_sd_init_card+0x318/0x89c
> mmc_attach_sd+0xe4/0x180
> mmc_rescan+0x244/0x320
>
> DMA API debug brings to light leaking dma-mappings as dma_map_sg and
> dma_unmap_sg are not correctly balanced.
>
> If an error occurs in mmci_cmd_irq function, only mmci_dma_error
> function is called and as this API is not managed on stm32 variant,
> dma_unmap_sg is never called in this error path.
>
> Signed-off-by: Christophe Kerello <christophe.kerello@xxxxxxxxxxx>

Applied for fixes and by adding a fixes- and stable-tag, thanks!

Kind regards
Uffe


> ---
>  drivers/mmc/host/mmci_stm32_sdmmc.c | 24 ++++++++++++++++++++++++
>  1 file changed, 24 insertions(+)
>
> diff --git a/drivers/mmc/host/mmci_stm32_sdmmc.c b/drivers/mmc/host/mmci_stm32_sdmmc.c
> index 35067e1e6cd8..f5da7f9baa52 100644
> --- a/drivers/mmc/host/mmci_stm32_sdmmc.c
> +++ b/drivers/mmc/host/mmci_stm32_sdmmc.c
> @@ -225,6 +225,8 @@ static int sdmmc_idma_start(struct mmci_host *host, unsigned int *datactrl)
>         struct scatterlist *sg;
>         int i;
>
> +       host->dma_in_progress = true;
> +
>         if (!host->variant->dma_lli || data->sg_len == 1 ||
>             idma->use_bounce_buffer) {
>                 u32 dma_addr;
> @@ -263,9 +265,30 @@ static int sdmmc_idma_start(struct mmci_host *host, unsigned int *datactrl)
>         return 0;
>  }
>
> +static void sdmmc_idma_error(struct mmci_host *host)
> +{
> +       struct mmc_data *data = host->data;
> +       struct sdmmc_idma *idma = host->dma_priv;
> +
> +       if (!dma_inprogress(host))
> +               return;
> +
> +       writel_relaxed(0, host->base + MMCI_STM32_IDMACTRLR);
> +       host->dma_in_progress = false;
> +       data->host_cookie = 0;
> +
> +       if (!idma->use_bounce_buffer)
> +               dma_unmap_sg(mmc_dev(host->mmc), data->sg, data->sg_len,
> +                            mmc_get_dma_dir(data));
> +}
> +
>  static void sdmmc_idma_finalize(struct mmci_host *host, struct mmc_data *data)
>  {
> +       if (!dma_inprogress(host))
> +               return;
> +
>         writel_relaxed(0, host->base + MMCI_STM32_IDMACTRLR);
> +       host->dma_in_progress = false;
>
>         if (!data->host_cookie)
>                 sdmmc_idma_unprep_data(host, data, 0);
> @@ -676,6 +699,7 @@ static struct mmci_host_ops sdmmc_variant_ops = {
>         .dma_setup = sdmmc_idma_setup,
>         .dma_start = sdmmc_idma_start,
>         .dma_finalize = sdmmc_idma_finalize,
> +       .dma_error = sdmmc_idma_error,
>         .set_clkreg = mmci_sdmmc_set_clkreg,
>         .set_pwrreg = mmci_sdmmc_set_pwrreg,
>         .busy_complete = sdmmc_busy_complete,
> --
> 2.25.1
>