On 07/03/16 04:07, Alexandre Courbot wrote: > Set the DMA mask in sdhci_add_host() after we determined the > capabilities of the device. 64-bit devices in particular are given the > proper mask that ensures bounce buffers are not used. > > Also disable DMA if no proper DMA mask can be set, as the DMA-API > documentation specifies. > > Signed-off-by: Alexandre Courbot <acourbot@xxxxxxxxxx> > --- > drivers/mmc/host/sdhci.c | 48 +++++++++++++++++++++++++++++++++++++++++------- > 1 file changed, 41 insertions(+), 7 deletions(-) > > diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c > index fd9139947fa3..920e1c996280 100644 > --- a/drivers/mmc/host/sdhci.c > +++ b/drivers/mmc/host/sdhci.c > @@ -2857,6 +2857,36 @@ struct sdhci_host *sdhci_alloc_host(struct device *dev, > > EXPORT_SYMBOL_GPL(sdhci_alloc_host); > > +static int sdhci_set_dma_mask(struct sdhci_host *host) > +{ > + struct mmc_host *mmc = host->mmc; > + struct device *dev = mmc_dev(mmc); > + int ret = -EINVAL; > + > + if (host->quirks2 & SDHCI_QUIRK2_BROKEN_64_BIT_DMA) > + host->flags &= ~SDHCI_USE_64_BIT_DMA; > + > + /* Try 64-bit mask if hardware is capable of it */ > + if (host->flags & SDHCI_USE_64_BIT_DMA) { > + ret = dma_set_mask_and_coherent(dev, DMA_BIT_MASK(64)); > + if (ret) { > + pr_warn("%s: Failed to set 64-bit DMA mask.\n", > + mmc_hostname(mmc)); > + host->flags &= ~SDHCI_USE_64_BIT_DMA; > + } > + } > + > + /* 32-bit mask as default & fallback */ > + if (ret) { > + ret = dma_set_mask_and_coherent(dev, DMA_BIT_MASK(32)); What happens if device enumeration (e.g. of_dma_configure) has already set a more restrictive DMA mask? > + if (ret) > + pr_warn("%s: Failed to set 32-bit DMA mask.\n", > + mmc_hostname(mmc)); > + } > + > + return ret; > +} > + > int sdhci_add_host(struct sdhci_host *host) > { > struct mmc_host *mmc; > @@ -2932,13 +2962,17 @@ int sdhci_add_host(struct sdhci_host *host) > host->flags |= SDHCI_USE_64_BIT_DMA; > > if (host->flags & (SDHCI_USE_SDMA | SDHCI_USE_ADMA)) { > - if (host->ops->enable_dma) { > - if (host->ops->enable_dma(host)) { > - pr_warn("%s: No suitable DMA available - falling back to PIO\n", > - mmc_hostname(mmc)); > - host->flags &= > - ~(SDHCI_USE_SDMA | SDHCI_USE_ADMA); > - } > + ret = sdhci_set_dma_mask(host); > + > + if (!ret && host->ops->enable_dma) > + ret = host->ops->enable_dma(host); > + > + if (ret) { > + pr_warn("%s: No suitable DMA available - falling back to PIO\n", > + mmc_hostname(mmc)); > + host->flags &= ~(SDHCI_USE_SDMA | SDHCI_USE_ADMA); > + > + ret = 0; > } > } > > -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html