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Re: [PATCH v2] mmc: omap: Initialize dma_slave_config to avoid random data in it's fields

From Ulf Hansson <ulf.hansson@linaro.org>
Newsgroups linux.kernel
Subject Re: [PATCH v2] mmc: omap: Initialize dma_slave_config to avoid random data in it's fields
Date 2016-09-14 14:10 +0200
Message-ID <shhaN-GA-19@gated-at.bofh.it> (permalink)
References <shgy5-dA-1@gated-at.bofh.it>
Organization linux.* mail to news gateway

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On 14 September 2016 at 13:21, Peter Ujfalusi <peter.ujfalusi@ti.com> wrote:
> It is wrong to use uninitialized dma_slave_config and configure only
> certain fields as the DMAengine driver might look at non initialized
> (random data) fields and tries to interpret it.
>
> Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>

Thanks, applied for fixes!

Kind regards
Uffe

> ---
> Hi,
>
> Changes since v1:
> - do the field initialization in one step
>
> would it be possible to send this patch for 4.8? I have omap-dma DMAengine
> driver changes pending, but they break the MMC/SD because of the uninitialized
> fields in dma_slave_config.
>
> Thanks,
> Peter
>
>  drivers/mmc/host/omap.c | 18 ++++++++++--------
>  1 file changed, 10 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/mmc/host/omap.c b/drivers/mmc/host/omap.c
> index f23d65eb070d..be3c49fa7382 100644
> --- a/drivers/mmc/host/omap.c
> +++ b/drivers/mmc/host/omap.c
> @@ -1016,14 +1016,16 @@ mmc_omap_prepare_data(struct mmc_omap_host *host, struct mmc_request *req)
>
>                 /* Only reconfigure if we have a different burst size */
>                 if (*bp != burst) {
> -                       struct dma_slave_config cfg;
> -
> -                       cfg.src_addr = host->phys_base + OMAP_MMC_REG(host, DATA);
> -                       cfg.dst_addr = host->phys_base + OMAP_MMC_REG(host, DATA);
> -                       cfg.src_addr_width = DMA_SLAVE_BUSWIDTH_2_BYTES;
> -                       cfg.dst_addr_width = DMA_SLAVE_BUSWIDTH_2_BYTES;
> -                       cfg.src_maxburst = burst;
> -                       cfg.dst_maxburst = burst;
> +                       struct dma_slave_config cfg = {
> +                               .src_addr = host->phys_base +
> +                                           OMAP_MMC_REG(host, DATA),
> +                               .dst_addr = host->phys_base +
> +                                           OMAP_MMC_REG(host, DATA),
> +                               .src_addr_width = DMA_SLAVE_BUSWIDTH_2_BYTES,
> +                               .dst_addr_width = DMA_SLAVE_BUSWIDTH_2_BYTES,
> +                               .src_maxburst = burst,
> +                               .dst_maxburst = burst,
> +                       };
>
>                         if (dmaengine_slave_config(c, &cfg))
>                                 goto use_pio;
> --
> 2.10.0
>

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Thread

[PATCH v2] mmc: omap: Initialize dma_slave_config to avoid random data in it's fields Peter Ujfalusi <peter.ujfalusi@ti.com> - 2016-09-14 13:30 +0200
  Re: [PATCH v2] mmc: omap: Initialize dma_slave_config to avoid random  data in it's fields Ulf Hansson <ulf.hansson@linaro.org> - 2016-09-14 14:10 +0200
  Re: [PATCH v2] mmc: omap: Initialize dma_slave_config to avoid random  data in it's fields Ulf Hansson <ulf.hansson@linaro.org> - 2016-09-14 14:10 +0200

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