From: Ulf Hansson <ulf.hansson@xxxxxxxxxx> This is something like the 5th time this patch is posted, so let's try to fix this now, once and for all. For the ux500v2 variant of the PL18x block, odd block sizes are supported. This is necessary to support some SDIO transfers such as single bytes. This also affects the QCOM MMCI variant. This will work fine for PIO using IRQs: SDIO packets are accepted down to single bytes and the transfers go through just fine. This patch has proven necessary for enabling SDIO for WLAN on PostmarketOS-based Ux500 platforms. This patch is based on Ulf Hansson's patch http://www.spinics.net/lists/linux-mmc/msg12160.html Ulf noted on an earlier iteration in: https://marc.info/?l=linux-mmc&m=140845189316370&w=2 "There are some prerequisites of the data buffers to supports any block size, at least for ux500. (...) The conclusion from the above is that we need to adopt mmci_pio_write() to handle corner cases." This points back to a discussion in 2012. The main point was made by Russell in this message: https://marc.info/?l=linux-arm-kernel&m=135351237018301&w=2 IIUC this pertains to this code (now gone from the patch): if (data->sg->offset & 3) { dev_err(...); return -EINVAL; } This hit Stephan as he noticed that DMA (DMA40) would not work with the MMCI driver, so this patch combined with disabling DMA would do the trick. That way we don't toss unaligned accesses at the DMA engine as SDIO apparently tends to do. (This is not a problem when writing ordinary block device blocks as these are always 512 bytes aligned on a 4-byte boundary.) As Ulf notes, odd SG offsets like this should be handled by the driver even if we run it in DMA mode. I conclude it must be the duty of the DMA driver to say NO to SG offsets it cannot handle, or otherwise bitstuff things around to avoid the situation. So as a first step make sure errors are propagated upward from the DMA engine, and assume the DMA engine will say no to things with weird SG offsets that it cannot handle, and then the driver will fall back to using PIO. It might be that some DMA engines (such as the Ux500 DMA40) do not properly say no to sglists with uneven offsets, or ignore the offset altogether resulting in unpredictable behavior. That is in that case a bug in the DMA driver and needs to be fixed there. I got the impression that the Qualcomm DMA actually can handle these odd alignments without problems. (Make a drive-by fix for datactrl_blocksz, misspelled.) Cc: Ludovic Barre <ludovic.barre@xxxxxx> Cc: Brian Masney <masneyb@xxxxxxxxxxxxx> Cc: Stephan Gerhold <stephan@xxxxxxxxxxx> Cc: Niklas Cassel <niklas.cassel@xxxxxxxxxx> Cc: Russell King <rmk+kernel@xxxxxxxxxxxxxxx> Signed-off-by: Ulf Hansson <ulf.hansson@xxxxxxxxxx> Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@xxxxxxxxxx> Signed-off-by: Linus Walleij <linus.walleij@xxxxxxxxxx> --- Ludovic: are you using your MMCI derivative for SDIO? Can you check if the flag for odd lengths should be set on the late ST derivatives as well? --- drivers/mmc/host/mmci.c | 19 +++++++++++++++---- drivers/mmc/host/mmci.h | 6 +++++- 2 files changed, 20 insertions(+), 5 deletions(-) diff --git a/drivers/mmc/host/mmci.c b/drivers/mmc/host/mmci.c index c37e70dbe250..459969f410b2 100644 --- a/drivers/mmc/host/mmci.c +++ b/drivers/mmc/host/mmci.c @@ -168,6 +168,7 @@ static struct variant_data variant_ux500 = { .cmdreg_srsp = MCI_CPSM_RESPONSE, .datalength_bits = 24, .datactrl_blocksz = 11, + .datactrl_odd_blocksz = true, .datactrl_mask_sdio = MCI_DPSM_ST_SDIOEN, .st_sdio = true, .st_clkdiv = true, @@ -201,6 +202,7 @@ static struct variant_data variant_ux500v2 = { .datactrl_mask_ddrmode = MCI_DPSM_ST_DDRMODE, .datalength_bits = 24, .datactrl_blocksz = 11, + .datactrl_odd_blocksz = true, .datactrl_mask_sdio = MCI_DPSM_ST_SDIOEN, .st_sdio = true, .st_clkdiv = true, @@ -279,6 +281,7 @@ static struct variant_data variant_qcom = { .data_cmd_enable = MCI_CPSM_QCOM_DATCMD, .datalength_bits = 24, .datactrl_blocksz = 11, + .datactrl_odd_blocksz = true, .pwrreg_powerup = MCI_PWR_UP, .f_max = 208000000, .explicit_mclk_control = true, @@ -447,10 +450,11 @@ void mmci_dma_setup(struct mmci_host *host) static int mmci_validate_data(struct mmci_host *host, struct mmc_data *data) { + struct variant_data *variant = host->variant; + if (!data) return 0; - - if (!is_power_of_2(data->blksz)) { + if (!is_power_of_2(data->blksz) && !variant->datactrl_odd_blocksz) { dev_err(mmc_dev(host->mmc), "unsupported block size (%d bytes)\n", data->blksz); return -EINVAL; @@ -515,7 +519,9 @@ int mmci_dma_start(struct mmci_host *host, unsigned int datactrl) "Submit MMCI DMA job, sglen %d blksz %04x blks %04x flags %08x\n", data->sg_len, data->blksz, data->blocks, data->flags); - host->ops->dma_start(host, &datactrl); + ret = host->ops->dma_start(host, &datactrl); + if (ret) + return ret; /* Trigger the DMA transfer */ mmci_write_datactrlreg(host, datactrl); @@ -872,9 +878,14 @@ int mmci_dmae_prep_data(struct mmci_host *host, int mmci_dmae_start(struct mmci_host *host, unsigned int *datactrl) { struct mmci_dmae_priv *dmae = host->dma_priv; + int ret; host->dma_in_progress = true; - dmaengine_submit(dmae->desc_current); + ret = dma_submit_error(dmaengine_submit(dmae->desc_current)); + if (ret < 0) { + host->dma_in_progress = false; + return ret; + } dma_async_issue_pending(dmae->cur); *datactrl |= MCI_DPSM_DMAENABLE; diff --git a/drivers/mmc/host/mmci.h b/drivers/mmc/host/mmci.h index 833236ecb31e..4c4aa0a258fa 100644 --- a/drivers/mmc/host/mmci.h +++ b/drivers/mmc/host/mmci.h @@ -278,7 +278,10 @@ struct mmci_host; * @stm32_clkdiv: true if using a STM32-specific clock divider algorithm * @datactrl_mask_ddrmode: ddr mode mask in datactrl register. * @datactrl_mask_sdio: SDIO enable mask in datactrl register - * @datactrl_blksz: block size in power of two + * @datactrl_blocksz: block size in power of two + * @datactrl_odd_blocksz: true if block any sizes are supported, such as one + * single character, as is necessary when using some SDIO + * devices. * @datactrl_first: true if data must be setup before send command * @datacnt_useless: true if you could not use datacnt register to read * remaining data @@ -323,6 +326,7 @@ struct variant_data { unsigned int datactrl_mask_ddrmode; unsigned int datactrl_mask_sdio; unsigned int datactrl_blocksz; + u8 datactrl_odd_blocksz; u8 datactrl_first:1; u8 datacnt_useless:1; u8 st_sdio:1; -- 2.21.0
