On Mon, 15 Nov 2021 at 09:24, Adrian Hunter <adrian.hunter@xxxxxxxxx> wrote:
>
> The block layer forces a minimum segment size of PAGE_SIZE, so a segment
> can be too big for the ADMA table, if PAGE_SIZE >= 64KiB. Fix by writing
> multiple descriptors, noting that the ADMA table is sized for 4KiB chunks
> anyway, so it will be big enough.
>
> Reported-and-tested-by: Bough Chen <haibo.chen@xxxxxxx>
> Signed-off-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Applied for next, thanks!
Should we perhaps tag this for stable and/or queue it as a fix for v5.16?
Kind regards
Uffe
> ---
> drivers/mmc/host/sdhci.c | 21 ++++++++++++++++++---
> drivers/mmc/host/sdhci.h | 4 +++-
> 2 files changed, 21 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
> index 269c86569402..07c6da1f2f0f 100644
> --- a/drivers/mmc/host/sdhci.c
> +++ b/drivers/mmc/host/sdhci.c
> @@ -771,7 +771,19 @@ static void sdhci_adma_table_pre(struct sdhci_host *host,
> len -= offset;
> }
>
> - BUG_ON(len > 65536);
> + /*
> + * The block layer forces a minimum segment size of PAGE_SIZE,
> + * so 'len' can be too big here if PAGE_SIZE >= 64KiB. Write
> + * multiple descriptors, noting that the ADMA table is sized
> + * for 4KiB chunks anyway, so it will be big enough.
> + */
> + while (len > host->max_adma) {
> + int n = 32 * 1024; /* 32KiB*/
> +
> + __sdhci_adma_write_desc(host, &desc, addr, n, ADMA2_TRAN_VALID);
> + addr += n;
> + len -= n;
> + }
>
> /* tran, valid */
> if (len)
> @@ -3968,6 +3980,7 @@ struct sdhci_host *sdhci_alloc_host(struct device *dev,
> * descriptor for each segment, plus 1 for a nop end descriptor.
> */
> host->adma_table_cnt = SDHCI_MAX_SEGS * 2 + 1;
> + host->max_adma = 65536;
>
> host->max_timeout_count = 0xE;
>
> @@ -4633,10 +4646,12 @@ 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) {
> + host->max_adma = 65532; /* 32-bit alignment */
> mmc->max_seg_size = 65535;
> - else
> + } else {
> mmc->max_seg_size = 65536;
> + }
> } else {
> mmc->max_seg_size = mmc->max_req_size;
> }
> diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h
> index bb883553d3b4..d7929d725730 100644
> --- a/drivers/mmc/host/sdhci.h
> +++ b/drivers/mmc/host/sdhci.h
> @@ -340,7 +340,8 @@ struct sdhci_adma2_64_desc {
>
> /*
> * Maximum segments assuming a 512KiB maximum requisition size and a minimum
> - * 4KiB page size.
> + * 4KiB page size. Note this also allows enough for multiple descriptors in
> + * case of PAGE_SIZE >= 64KiB.
> */
> #define SDHCI_MAX_SEGS 128
>
> @@ -543,6 +544,7 @@ struct sdhci_host {
> unsigned int blocks; /* remaining PIO blocks */
>
> int sg_count; /* Mapped sg entries */
> + int max_adma; /* Max. length in ADMA descriptor */
>
> void *adma_table; /* ADMA descriptor table */
> void *align_buffer; /* Bounce buffer */
> --
> 2.25.1
>
