Re: [PATCH V2] mmc: renesas_sdhi_core: on R-Car 2+, make use of CBSY bit

[Ulf Hansson <ulf.hansson@linaro.org>]

On 28 June 2017 at 17:21, Wolfram Sang <wsa+renesas@sang-engineering.com> wrote:
> Most registers need to wait until the command is completed, not
> necessarily until the bus is free. At least, R-Car 2+ SoCs can signal
> that via the CBSY bit, so let's use it there instead of SCLKDIVEN to
> save a little bit of delay.
>
> Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>


Thanks, applied for next!

Kind regards
Uffe

> ---
>
> Tested on H2 and M3-W.
>
> Change since V1:
>
> Rebased on top of mmc/next with Simon's Gen3 DMA patches.
>
>  drivers/mmc/host/renesas_sdhi_core.c | 17 ++++++++++++-----
>  1 file changed, 12 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/mmc/host/renesas_sdhi_core.c b/drivers/mmc/host/renesas_sdhi_core.c
> index 569bcdd5e6537a..be806d3e9afeec 100644
> --- a/drivers/mmc/host/renesas_sdhi_core.c
> +++ b/drivers/mmc/host/renesas_sdhi_core.c
> @@ -398,12 +398,14 @@ static void renesas_sdhi_hw_reset(struct tmio_mmc_host *host)
>                        sd_scc_read32(host, priv, SH_MOBILE_SDHI_SCC_RVSCNTL));
>  }
>
> -static int renesas_sdhi_wait_idle(struct tmio_mmc_host *host)
> +static int renesas_sdhi_wait_idle(struct tmio_mmc_host *host, u32 bit)
>  {
>         int timeout = 1000;
> +       /* CBSY is set when busy, SCLKDIVEN is cleared when busy */
> +       u32 wait_state = (bit == TMIO_STAT_CMD_BUSY ? TMIO_STAT_CMD_BUSY : 0);
>
> -       while (--timeout && !(sd_ctrl_read16_and_16_as_32(host, CTL_STATUS)
> -                             & TMIO_STAT_SCLKDIVEN))
> +       while (--timeout && (sd_ctrl_read16_and_16_as_32(host, CTL_STATUS)
> +                             & bit) == wait_state)
>                 udelay(1);
>
>         if (!timeout) {
> @@ -416,17 +418,22 @@ static int renesas_sdhi_wait_idle(struct tmio_mmc_host *host)
>
>  static int renesas_sdhi_write16_hook(struct tmio_mmc_host *host, int addr)
>  {
> +       u32 bit = TMIO_STAT_SCLKDIVEN;
> +
>         switch (addr) {
>         case CTL_SD_CMD:
>         case CTL_STOP_INTERNAL_ACTION:
>         case CTL_XFER_BLK_COUNT:
> -       case CTL_SD_CARD_CLK_CTL:
>         case CTL_SD_XFER_LEN:
>         case CTL_SD_MEM_CARD_OPT:
>         case CTL_TRANSACTION_CTL:
>         case CTL_DMA_ENABLE:
>         case EXT_ACC:
> -               return renesas_sdhi_wait_idle(host);
> +               if (host->pdata->flags & TMIO_MMC_MIN_RCAR2)
> +                       bit = TMIO_STAT_CMD_BUSY;
> +               /* fallthrough */
> +       case CTL_SD_CARD_CLK_CTL:
> +               return renesas_sdhi_wait_idle(host, bit);
>         }
>
>         return 0;
> --
> 2.11.0
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-mmc" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html