On 15/11/19 1:07 PM, haibo.chen@xxxxxxx wrote:
> From: Haibo Chen <haibo.chen@xxxxxxx>
>
> The default max segment size of IOMMU is 64KB, which exceed the ADMA
> limitation if ADMA only support max to 65535, 64KB - 1Byte. IOMMU will
> optimize the segments it received, merge the little segment into one
> big segment. If we use the default IOMMU config, then ADMA will get
> some segments which it's size is 64KB. Then ADMA error will shows up.
>
> Signed-off-by: Haibo Chen <haibo.chen@xxxxxxx>
> ---
> drivers/mmc/host/sdhci.c | 16 ++++++++++++++--
> 1 file changed, 14 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
> index 1436cc9c5f82..3a8093de26c7 100644
> --- a/drivers/mmc/host/sdhci.c
> +++ b/drivers/mmc/host/sdhci.c
> @@ -3743,6 +3743,7 @@ static inline bool sdhci_can_64bit_dma(struct sdhci_host *host)
> int sdhci_setup_host(struct sdhci_host *host)
> {
> struct mmc_host *mmc;
> + struct device *dev;
> u32 max_current_caps;
> unsigned int ocr_avail;
> unsigned int override_timeout_clk;
> @@ -3754,6 +3755,7 @@ int sdhci_setup_host(struct sdhci_host *host)
> return -EINVAL;
>
> mmc = host->mmc;
> + dev = mmc_dev(mmc);
>
> /*
> * If there are external regulators, get them. Note this must be done
> @@ -4224,10 +4226,20 @@ int sdhci_setup_host(struct sdhci_host *host)
> * be larger than 64 KiB though.
> */
> if (host->flags & SDHCI_USE_ADMA) {
> - if (host->quirks & SDHCI_QUIRK_BROKEN_ADMA_ZEROLEN_DESC)
> + if (host->quirks & SDHCI_QUIRK_BROKEN_ADMA_ZEROLEN_DESC) {
> mmc->max_seg_size = 65535;
> - else
> +
> + /*
> + * send the ADMA limitation to IOMMU. In default,
> + * the max segment size of IOMMU is 64KB, this exceed
> + * the ADMA max segment limitation, which is 65535.
> + */
> + dev->dma_parms = devm_kzalloc(dev,
> + sizeof(*dev->dma_parms), GFP_KERNEL);
> + dma_set_max_seg_size(dev, SZ_64K - 1);
Doesn't mmc_setup_queue() already do this?
> + } else {
> mmc->max_seg_size = 65536;
> + }
> } else {
> mmc->max_seg_size = mmc->max_req_size;
> }
>
