Re: [PATCH RFC 3/4] mmc: host: renesas_sdhi_sys_dmac: add DMACR setting

[Ulrich Hecht <uli@fpond.eu>]

> On November 22, 2019 at 7:13 AM Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com> wrote:
> 
> 
> This patch adds DMACR setting which needs to use the 32 bytes
> transfer mode of SYS-DMAC.
> 
> Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
> ---
>  drivers/mmc/host/renesas_sdhi_core.c | 35 +++++++++++++++++++++++++++++++++++
>  1 file changed, 35 insertions(+)
> 
> diff --git a/drivers/mmc/host/renesas_sdhi_core.c b/drivers/mmc/host/renesas_sdhi_core.c
> index 234551a..d9a69f6 100644
> --- a/drivers/mmc/host/renesas_sdhi_core.c
> +++ b/drivers/mmc/host/renesas_sdhi_core.c
> @@ -20,6 +20,7 @@
>  
>  #include <linux/kernel.h>
>  #include <linux/clk.h>
> +#include <linux/dmaengine.h>
>  #include <linux/slab.h>
>  #include <linux/module.h>
>  #include <linux/of_device.h>
> @@ -46,6 +47,12 @@
>  #define SDHI_VER_GEN3_SD	0xcc10
>  #define SDHI_VER_GEN3_SDMMC	0xcd10
>  
> +#define DMACR_SDR104		0x192
> +#define DMACR_SDR104_32BYTE	0x0004
> +#define DMACR_SDR50		0xe4
> +#define DMACR_SDR50_32BYTE	0x000a
> +#define DMACR_2_OR_4BYTE	0x0000
> +

Could you give me a pointer to where these magic numbers are documented? In my (rather old) SDHI docs the register addresses don't match.

>  struct renesas_sdhi_quirks {
>  	bool hs400_disabled;
>  	bool hs400_4taps;
> @@ -604,6 +611,32 @@ static int renesas_sdhi_multi_io_quirk(struct mmc_card *card,
>  	return blk_size;
>  }
>  
> +static void renesas_sdhi_set_dmacr(struct tmio_mmc_host *host)
> +{
> +	struct renesas_sdhi *priv = host_to_priv(host);
> +	u16 val = DMACR_2_OR_4BYTE;
> +	u16 reg;
> +	enum dma_slave_buswidth width = priv->dma_priv.dma_buswidth;
> +
> +	switch (sd_ctrl_read16(host, CTL_VERSION)) {
> +	case SDHI_VER_GEN2_SDR50:
> +		if (width == DMA_SLAVE_BUSWIDTH_32_BYTES)
> +			val = DMACR_SDR50_32BYTE;
> +		reg = DMACR_SDR50;
> +		break;
> +	case SDHI_VER_GEN2_SDR104:
> +		if (width == DMA_SLAVE_BUSWIDTH_32_BYTES)
> +			val = DMACR_SDR104_32BYTE;
> +		reg = DMACR_SDR104;
> +		break;
> +	default:
> +		/* nothing to do */
> +		return;
> +	}
> +
> +	sd_ctrl_write16(host, reg, val);
> +}
> +
>  static void renesas_sdhi_enable_dma(struct tmio_mmc_host *host, bool enable)
>  {
>  	/* Iff regs are 8 byte apart, sdbuf is 64 bit. Otherwise always 32. */
> @@ -611,6 +644,8 @@ static void renesas_sdhi_enable_dma(struct tmio_mmc_host *host, bool enable)
>  
>  	sd_ctrl_write16(host, CTL_DMA_ENABLE, enable ? DMA_ENABLE_DMASDRW : 0);
>  	renesas_sdhi_sdbuf_width(host, enable ? width : 16);
> +
> +	renesas_sdhi_set_dmacr(host);
>  }
>  
>  static const struct renesas_sdhi_quirks sdhi_quirks_4tap_nohs400 = {
> -- 
> 2.7.4
>

Assuming that the register addresses are correct,
Reviewed-by: Ulrich Hecht <uli+renesas@fpond.eu>

CU
Uli