> -----Original Message----- > From: Adrian Hunter [mailto:adrian.hunter@xxxxxxxxx] > Sent: 2021年10月27日 13:50 > To: Bough Chen <haibo.chen@xxxxxxx>; ulf.hansson@xxxxxxxxxx > Cc: linux-mmc@xxxxxxxxxxxxxxx; dl-linux-imx <linux-imx@xxxxxxx> > Subject: Re: [PATCH] mmc: sdhci: disable ADMA when PAGE SIZE is 64K > > On 27/10/2021 05:47, haibo.chen@xxxxxxx wrote: > > From: Haibo Chen <haibo.chen@xxxxxxx> > > > > For ADMA with quirks SDHCI_QUIRK_BROKEN_ADMA_ZEROLEN_DESC, it > limit > > the max segment size as 64K-1. Currently, linux kernel support > > 4K/16K/64K PAGE_SIZE. If choose 64K PAGE_SIZE, sdhci in ADMA mode with > > the upper quirks will meet issue. > > > > Though mmc driver give block layer the max segment size through > > blk_queue_max_segment_size(), but in this function, it will compare > > the argument with PAGE_SIZE, and will choose PAGE_SIZE if the argument > > is smaller than PAGE_SIZE. When PAGE_SIZE is 64K, finally the mmc > > request queue will get 64K as the max segment size. Once the sg data > > length=64K, ADMA will meet issue. For this case, need to disable ADMA > > mode. > > Sorry, I didn't look closely enough at this. > > For the 64K PAGE_SIZE case, did you try blk_queue_virt_boundary() with a 32K > mask instead of blk_queue_max_segment_size() ? > e.g. a hack for testing purposes like this: I test on my board, this do not work, I still can see sg data_length = 65536. Best Regards Haibo Chen > > diff --git a/drivers/mmc/core/queue.c b/drivers/mmc/core/queue.c index > b15c034b42fb..4c3a9d999500 100644 > --- a/drivers/mmc/core/queue.c > +++ b/drivers/mmc/core/queue.c > @@ -376,8 +376,7 @@ static void mmc_setup_queue(struct mmc_queue *mq, > struct mmc_card *card) > * both blk_queue_max_segment_size(). > */ > if (!host->can_dma_map_merge) > - blk_queue_max_segment_size(mq->queue, > - round_down(host->max_seg_size, block_size)); > + blk_queue_virt_boundary(mq->queue, 0x7fff); > > dma_set_max_seg_size(mmc_dev(host), > queue_max_segment_size(mq->queue)); > > > > > > > > Signed-off-by: Haibo Chen <haibo.chen@xxxxxxx> > > --- > > drivers/mmc/host/sdhci.c | 6 ++++++ > > 1 file changed, 6 insertions(+) > > > > diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c index > > dbe87995596c..47e0c0156b94 100644 > > --- a/drivers/mmc/host/sdhci.c > > +++ b/drivers/mmc/host/sdhci.c > > @@ -4187,6 +4187,12 @@ int sdhci_setup_host(struct sdhci_host *host) > > host->flags &= ~SDHCI_USE_ADMA; > > } > > > > + if ((host->quirks & SDHCI_QUIRK_BROKEN_ADMA_ZEROLEN_DESC) && > > + PAGE_SIZE >= 65536 && (host->flags & SDHCI_USE_ADMA)) { > > + DBG("Disabling ADMA as it don't support >= 64K PAGE_SIZE\n"); > > + host->flags &= ~SDHCI_USE_ADMA; > > + } > > + > > if (sdhci_can_64bit_dma(host)) > > host->flags |= SDHCI_USE_64_BIT_DMA; > > > >
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