| Message ID | 20210426175559.3110575-2-narmstrong@baylibre.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [1/2] mmc: meson-gx: make replace WARN_ONCE with dev_warn_once about scatterlist offset alignment | expand |
On Mon, 26 Apr 2021 at 19:56, Neil Armstrong <narmstrong@baylibre.com> wrote: > > The brcmfmac driver can generate a scatterlist from a skb with each packets > not aligned to the block size. This is not supported by the Amlogic Descriptor > dma engine where each descriptor must match a multiple of the block size. > > The sg list is valid, since the sum of the sg buffers is a multiple of the > block size, but we must discard those when in SD_IO_RW_EXTENDED mode since > SDIO block mode can be used under the hood even with data->blocks == 1. > > Those transfers are very rare, thus can be replaced by a bounce buffer > without real performance loss. > > Fixes: 7412dee9f1fd ("mmc: meson-gx: replace WARN_ONCE with dev_warn_once about scatterlist size alignment in block mode") > Reported-by: Christian Hewitt <christianshewitt@gmail.com> > Signed-off-by: Neil Armstrong <narmstrong@baylibre.com> Applied for fixes and by adding a stable tag, thanks! Kind regards Uffe > --- > drivers/mmc/host/meson-gx-mmc.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/drivers/mmc/host/meson-gx-mmc.c b/drivers/mmc/host/meson-gx-mmc.c > index 1c61f0f24c09..016a6106151a 100644 > --- a/drivers/mmc/host/meson-gx-mmc.c > +++ b/drivers/mmc/host/meson-gx-mmc.c > @@ -236,7 +236,8 @@ static void meson_mmc_get_transfer_mode(struct mmc_host *mmc, > if (host->dram_access_quirk) > return; > > - if (data->blocks > 1) { > + /* SD_IO_RW_EXTENDED (CMD53) can also use block mode under the hood */ > + if (data->blocks > 1 || mrq->cmd->opcode == SD_IO_RW_EXTENDED) { > /* > * In block mode DMA descriptor format, "length" field indicates > * number of blocks and there is no way to pass DMA size that > -- > 2.25.1 >
diff --git a/drivers/mmc/host/meson-gx-mmc.c b/drivers/mmc/host/meson-gx-mmc.c index 1c61f0f24c09..016a6106151a 100644 --- a/drivers/mmc/host/meson-gx-mmc.c +++ b/drivers/mmc/host/meson-gx-mmc.c @@ -236,7 +236,8 @@ static void meson_mmc_get_transfer_mode(struct mmc_host *mmc, if (host->dram_access_quirk) return; - if (data->blocks > 1) { + /* SD_IO_RW_EXTENDED (CMD53) can also use block mode under the hood */ + if (data->blocks > 1 || mrq->cmd->opcode == SD_IO_RW_EXTENDED) { /* * In block mode DMA descriptor format, "length" field indicates * number of blocks and there is no way to pass DMA size that
The brcmfmac driver can generate a scatterlist from a skb with each packets not aligned to the block size. This is not supported by the Amlogic Descriptor dma engine where each descriptor must match a multiple of the block size. The sg list is valid, since the sum of the sg buffers is a multiple of the block size, but we must discard those when in SD_IO_RW_EXTENDED mode since SDIO block mode can be used under the hood even with data->blocks == 1. Those transfers are very rare, thus can be replaced by a bounce buffer without real performance loss. Fixes: 7412dee9f1fd ("mmc: meson-gx: replace WARN_ONCE with dev_warn_once about scatterlist size alignment in block mode") Reported-by: Christian Hewitt <christianshewitt@gmail.com> Signed-off-by: Neil Armstrong <narmstrong@baylibre.com> --- drivers/mmc/host/meson-gx-mmc.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)