diff options
Diffstat (limited to 'drivers/mmc/host/sdhci.c')
| -rw-r--r-- | drivers/mmc/host/sdhci.c | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c index 112584aa0772..fbf7a91bed35 100644 --- a/drivers/mmc/host/sdhci.c +++ b/drivers/mmc/host/sdhci.c @@ -4727,6 +4727,21 @@ int sdhci_setup_host(struct sdhci_host *host) if (host->quirks & SDHCI_QUIRK_BROKEN_ADMA_ZEROLEN_DESC) { host->max_adma = 65532; /* 32-bit alignment */ mmc->max_seg_size = 65535; + /* + * sdhci_adma_table_pre() expects to define 1 DMA + * descriptor per segment, so the maximum segment size + * is set accordingly. SDHCI allows up to 64KiB per DMA + * descriptor (16-bit field), but some controllers do + * not support "zero means 65536" reducing the maximum + * for them to 65535. That is a problem if PAGE_SIZE is + * 64KiB because the block layer does not support + * max_seg_size < PAGE_SIZE, however + * sdhci_adma_table_pre() has a workaround to handle + * that case, and split the descriptor. Refer also + * comment in sdhci_adma_table_pre(). + */ + if (mmc->max_seg_size < PAGE_SIZE) + mmc->max_seg_size = PAGE_SIZE; } else { mmc->max_seg_size = 65536; } |