Re: [PATCH 4/5] mmc: mmci: stm32: define get_dctrl_cfg

[Ludovic BARRE]

On 3/6/19 2:31 PM, Ulf Hansson wrote:
> On Mon, 4 Mar 2019 at 11:17, Ludovic Barre <ludovic.Barre@xxxxxx> wrote:
> > From: Ludovic Barre <ludovic.barre@xxxxxx>
> >
> > This patch defines get_dctrl_cfg callback for sdmmc variant.
> > sdmmc variant has specific stm32 transfer modes.
> > sdmmc data transfer mode selection could be:
> > -Block data transfer ending on block count.
> > -SDIO multibyte data transfer.
> > -MMC Stream data transfer (not used).
> > -Block data transfer ending with STOP_TRANSMISSION command.
> >
> > Signed-off-by: Ludovic Barre <ludovic.barre@xxxxxx>
> > ---
> >   drivers/mmc/host/mmci.h             |  5 +++++
> >   drivers/mmc/host/mmci_stm32_sdmmc.c | 21 +++++++++++++++++++++
> >   2 files changed, 26 insertions(+)
> >
> > diff --git a/drivers/mmc/host/mmci.h b/drivers/mmc/host/mmci.h
> > index 6f28f71..eb5d99af 100644
> > --- a/drivers/mmc/host/mmci.h
> > +++ b/drivers/mmc/host/mmci.h
> > @@ -131,6 +131,11 @@
> >   /* Control register extensions in the Qualcomm versions */
> >   #define MCI_DPSM_QCOM_DATA_PEND        BIT(17)
> >   #define MCI_DPSM_QCOM_RX_DATA_PEND BIT(20)
> > +/* Control register extensions in STM32 versions */
> > +#define MCI_DPSM_STM32_MODE_BLOCK      (0 << 2)
> > +#define MCI_DPSM_STM32_MODE_SDIO       (1 << 2)
> > +#define MCI_DPSM_STM32_MODE_STREAM     (2 << 2)
> > +#define MCI_DPSM_STM32_MODE_BLOCK_STOP (3 << 2)
> >
> >   #define MMCIDATACNT            0x030
> >   #define MMCISTATUS             0x034
> > diff --git a/drivers/mmc/host/mmci_stm32_sdmmc.c b/drivers/mmc/host/mmci_stm32_sdmmc.c
> > index cfbfc6f..e7bf744 100644
> > --- a/drivers/mmc/host/mmci_stm32_sdmmc.c
> > +++ b/drivers/mmc/host/mmci_stm32_sdmmc.c
> > @@ -265,10 +265,31 @@ static void mmci_sdmmc_set_pwrreg(struct mmci_host *host, unsigned int pwr)
> >          }
> >   }
> >
> > +u32 sdmmc_get_dctrl_cfg(struct mmci_host *host)
> > +{
> > +       struct variant_data *variant = host->variant;
> > +       int blksz_bits;
> > +       u32 datactrl;
> > +
> > +       blksz_bits = ffs(host->data->blksz) - 1;
> > +       datactrl = variant->datactrl_dpsm_enable | blksz_bits << 4;
> > +
> > +       if (host->mmc->card && mmc_card_sdio(host->mmc->card) &&
> > +           host->data->blocks == 1)
>
> These settings are not limited to deal with the block size bits.
>
> Don't get me wrong, it seems reasonable to include them, but the
> generic code in mmci_start_data() also have code to cope with SDIO. I
> think we should start by splitting that up into a couple of
> helper/library functions, and make the legacy variant to use them.
> This should probably be done as a preparation to your series, so you
> can build on top of that.

I think you wish helper functions for each group of datactrl feature,
like for dpsm direction|sdio|ios timming. Each variant call theses 
helpers to define its own datactrl value. it's possible, no problem.

In mmci_start_data will remain the part on clk_reg for sdio card
	if (host->mmc->card && mmc_card_sdio(host->mmc->card)) {
		u32 clk;

		/*
		 * The ST Micro variant for SDIO small write transfers
		 * needs to have clock H/W flow control disabled,
		 * otherwise the transfer will not start. The threshold
		 * depends on the rate of MCLK.
		 */
		if (variant->st_sdio && data->flags & MMC_DATA_WRITE &&
		    (host->size < 8 ||
		     (host->size <= 8 && host->mclk > 50000000)))
			clk = host->clk_reg & ~variant->clkreg_enable;
		else
			clk = host->clk_reg | variant->clkreg_enable;

		mmci_write_clkreg(host, clk);
	}

it's OK ?

> Does it make sense? If not, please tell and I can try to provide some
> patch to show you what I mean.
>
>
> > +               datactrl |= MCI_DPSM_STM32_MODE_SDIO;
> > +       else if (host->data->stop && !host->mrq->sbc)
> > +               datactrl |= MCI_DPSM_STM32_MODE_BLOCK_STOP;
> > +       else
> > +               datactrl |= MCI_DPSM_STM32_MODE_BLOCK;
> > +
> > +       return datactrl;
> > +}
> > +
> >   static struct mmci_host_ops sdmmc_variant_ops = {
> >          .validate_data = sdmmc_idma_validate_data,
> >          .prep_data = sdmmc_idma_prep_data,
> >          .unprep_data = sdmmc_idma_unprep_data,
> > +       .get_datactrl_cfg = sdmmc_get_dctrl_cfg,
> >          .dma_setup = sdmmc_idma_setup,
> >          .dma_start = sdmmc_idma_start,
> >          .dma_finalize = sdmmc_idma_finalize,
> > --
> > 2.7.4
>
> Kind regards
> Uffe