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mmc: sdhci: Set DMA mask when adding host
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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@nvidia.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
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Alexandre Courbot authored and Ulf Hansson committed Mar 18, 2016
1 parent 83c742c commit 7b91369
Showing 1 changed file with 41 additions and 7 deletions.
48 changes: 41 additions & 7 deletions drivers/mmc/host/sdhci.c
Original file line number Diff line number Diff line change
Expand Up @@ -2804,6 +2804,36 @@ 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));
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;
Expand Down Expand Up @@ -2879,13 +2909,17 @@ 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;
}
}

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