On Fri 18 Dec 2020 at 10:08, Heiner Kallweit <hkallweit1@xxxxxxxxx> wrote:
> Am 18.12.2020 um 08:53 schrieb Dmitry Lebed:
>> Enable SGDMA support for SD_IO_RW_EXTENDED and add proper check
>> for scatterlist size alignment in block mode.
>>
>> According to documentation, in SDIO block mode meson-gx DMA could
>> only handle buffers with sizes that are multiples of SDIO block size.
>>
>> Some SDIO drivers like brcmfmac use scatterlist API, but do not enforce
>> proper scatterlist buffer size alignemnt, this looks like a root cause
>> of non-working CMD53.
>>
> It's been too long ago that I worked on this to provide real feedback.
> Just one comment: Your commit description sounds like there's a problem
> in drivers like brcmfmac. Wouldn't it be better then to first fix these
> drivers?
While this may be true, I think the proposed change is better than the
device/command specific work around we had so far.
>
>> Some minor style fixes.
>>
>> Signed-off-by: Dmitry Lebed <lebed.dmitry@xxxxxxxxx>
Thx.
Reviewed-by: Jerome Brunet <jbrunet@xxxxxxxxxxxx>
>> ---
>> drivers/mmc/host/meson-gx-mmc.c | 37 ++++++++++++++++++++-------------
>> 1 file changed, 22 insertions(+), 15 deletions(-)
>>
>> diff --git a/drivers/mmc/host/meson-gx-mmc.c b/drivers/mmc/host/meson-gx-mmc.c
>> index 13f6a2c0ed04..eb6c02bc4a02 100644
>> --- a/drivers/mmc/host/meson-gx-mmc.c
>> +++ b/drivers/mmc/host/meson-gx-mmc.c
>> @@ -227,7 +227,6 @@ static void meson_mmc_get_transfer_mode(struct mmc_host *mmc,
>> struct mmc_data *data = mrq->data;
>> struct scatterlist *sg;
>> int i;
>> - bool use_desc_chain_mode = true;
>>
>> /*
>> * When Controller DMA cannot directly access DDR memory, disable
>> @@ -237,25 +236,33 @@ static void meson_mmc_get_transfer_mode(struct mmc_host *mmc,
>> if (host->dram_access_quirk)
>> return;
>>
>> - /*
>> - * Broken SDIO with AP6255-based WiFi on Khadas VIM Pro has been
>> - * reported. For some strange reason this occurs in descriptor
>> - * chain mode only. So let's fall back to bounce buffer mode
>> - * for command SD_IO_RW_EXTENDED.
>> - */
>> - if (mrq->cmd->opcode == SD_IO_RW_EXTENDED)
>> - return;
>> + if (data->blocks > 1) {
>> + /*
>> + * In block mode DMA descriptor format, "length" field indicates
>> + * number of blocks and there is no way to pass DMA size that
>> + * is not multiple of SDIO block size, making it impossible to
>> + * tie more than one memory buffer with single SDIO block.
>> + * Block mode sg buffer size should be aligned with SDIO block
>> + * size, otherwise chain mode could not be used.
>> + */
>> + for_each_sg(data->sg, sg, data->sg_len, i) {
>> + if (sg->length % data->blksz) {
>> + WARN_ONCE(1, "unaligned sg len %u blksize %u\n",
>> + sg->length, data->blksz);
>> + return;
>> + }
>> + }
>> + }
>>
>> - for_each_sg(data->sg, sg, data->sg_len, i)
>> + for_each_sg(data->sg, sg, data->sg_len, i) {
>> /* check for 8 byte alignment */
>> - if (sg->offset & 7) {
>> + if (sg->offset % 8) {
>> WARN_ONCE(1, "unaligned scatterlist buffer\n");
>> - use_desc_chain_mode = false;
>> - break;
>> + return;
>> }
>> + }
>>
>> - if (use_desc_chain_mode)
>> - data->host_cookie |= SD_EMMC_DESC_CHAIN_MODE;
>> + data->host_cookie |= SD_EMMC_DESC_CHAIN_MODE;
>> }
>>
>> static inline bool meson_mmc_desc_chain_mode(const struct mmc_data *data)
>>
>
>
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