Re: [PATCH V2] mmc: sdhci-acpi: Add 64-bit DMA support

[Arnd Bergmann <arnd@arndb.de>]

On Tuesday 28 October 2014 10:37:20 Adrian Hunter wrote:
>  static int sdhci_acpi_enable_dma(struct sdhci_host *host)
>  {
> -       return 0;
> +       struct sdhci_acpi_host *c = sdhci_priv(host);
> +       struct device *dev = &c->pdev->dev;
> +       int err = -1;
> +
> +       if (c->dma_setup)
> +               return 0;
> +
> +       if (host->flags & SDHCI_USE_64_BIT_DMA) {
> +               if (host->quirks2 & SDHCI_QUIRK2_BROKEN_64_BIT_DMA) {
> +                       host->flags &= ~SDHCI_USE_64_BIT_DMA;
> +               } else {
> +                       err = dma_set_mask_and_coherent(dev, DMA_BIT_MASK(64));
> +                       if (err)
> +                               dev_warn(dev, "Failed to set 64-bit DMA mask\n");
> +               }
> +       }
> +
> +       if (err)
> +               err = dma_set_mask_and_coherent(dev, DMA_BIT_MASK(32));
> +
> +       c->dma_setup = !err;
> +
> +       return err;
>  }
> 

I don't think it's worth a dev_warn() message (maybe dev_info), there is nothing
wrong in this case, but you probably have to clear the SDHCI_USE_64_BIT_DMA to
ensure that the driver won't try to to use the 64-bit DMA if the mask is not set.

	Arnd