linux-kernel - Re: [PATCH v2] mmc: rtsx: add 74 Clocks in power on flow

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Date:   Wed, 2 Mar 2022 12:34:12 +0100
From:   Ulf Hansson <ulf.hansson@...aro.org>
To:     Ricky WU <ricky_wu@...ltek.com>
Cc:     "tommyhebb@...il.com" <tommyhebb@...il.com>,
        "kai.heng.feng@...onical.com" <kai.heng.feng@...onical.com>,
        "gregkh@...uxfoundation.org" <gregkh@...uxfoundation.org>,
        "linux-mmc@...r.kernel.org" <linux-mmc@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2] mmc: rtsx: add 74 Clocks in power on flow

On Wed, 2 Mar 2022 at 10:43, Ricky WU <ricky_wu@...ltek.com> wrote:
>
> SD spec definition:
> "Host provides at least 74 Clocks before issuing first command"
> After 1ms for the voltage stable then start issuing the Clock signals
>
> if POWER STATE is
> MMC_POWER_OFF to MMC_POWER_UP to issue Clock signal to card
> MMC_POWER_UP to MMC_POWER_ON to stop issuing signal to card
>
> Signed-off-by: Ricky Wu <ricky_wu@...ltek.com>

Applied for next, thanks!

Greg, I verified that this shouldn't conflict with the changes you
have picked up already for the rtsx mmc driver.

Kind regards
Uffe

> ---
> v2:
> modify commit message
> move mdelay(5) to host->power_delay_ms
> replace host->power_state with host->prev_power_state
> ---
>  drivers/mmc/host/rtsx_pci_sdmmc.c | 29 +++++++++++++++++++----------
>  1 file changed, 19 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/mmc/host/rtsx_pci_sdmmc.c b/drivers/mmc/host/rtsx_pci_sdmmc.c
> index 2a3f14afe9f8..d26803d3f4ca 100644
> --- a/drivers/mmc/host/rtsx_pci_sdmmc.c
> +++ b/drivers/mmc/host/rtsx_pci_sdmmc.c
> @@ -38,10 +38,7 @@ struct realtek_pci_sdmmc {
>         bool                    double_clk;
>         bool                    eject;
>         bool                    initial_mode;
> -       int                     power_state;
> -#define SDMMC_POWER_ON         1
> -#define SDMMC_POWER_OFF                0
> -
> +       int                     prev_power_state;
>         int                     sg_count;
>         s32                     cookie;
>         int                     cookie_sg_count;
> @@ -909,7 +906,7 @@ static int sd_set_bus_width(struct realtek_pci_sdmmc *host,
>         return err;
>  }
>
> -static int sd_power_on(struct realtek_pci_sdmmc *host)
> +static int sd_power_on(struct realtek_pci_sdmmc *host, unsigned char power_mode)
>  {
>         struct rtsx_pcr *pcr = host->pcr;
>         struct mmc_host *mmc = host->mmc;
> @@ -917,9 +914,14 @@ static int sd_power_on(struct realtek_pci_sdmmc *host)
>         u32 val;
>         u8 test_mode;
>
> -       if (host->power_state == SDMMC_POWER_ON)
> +       if (host->prev_power_state == MMC_POWER_ON)
>                 return 0;
>
> +       if (host->prev_power_state == MMC_POWER_UP) {
> +               rtsx_pci_write_register(pcr, SD_BUS_STAT, SD_CLK_TOGGLE_EN, 0);
> +               goto finish;
> +       }
> +
>         msleep(100);
>
>         rtsx_pci_init_cmd(pcr);
> @@ -940,10 +942,15 @@ static int sd_power_on(struct realtek_pci_sdmmc *host)
>         if (err < 0)
>                 return err;
>
> +       mdelay(1);
> +
>         err = rtsx_pci_write_register(pcr, CARD_OE, SD_OUTPUT_EN, SD_OUTPUT_EN);
>         if (err < 0)
>                 return err;
>
> +       /* send at least 74 clocks */
> +       rtsx_pci_write_register(pcr, SD_BUS_STAT, SD_CLK_TOGGLE_EN, SD_CLK_TOGGLE_EN);
> +
>         if (PCI_PID(pcr) == PID_5261) {
>                 /*
>                  * If test mode is set switch to SD Express mandatorily,
> @@ -968,7 +975,8 @@ static int sd_power_on(struct realtek_pci_sdmmc *host)
>                 }
>         }
>
> -       host->power_state = SDMMC_POWER_ON;
> +finish:
> +       host->prev_power_state = power_mode;
>         return 0;
>  }
>
> @@ -977,7 +985,7 @@ static int sd_power_off(struct realtek_pci_sdmmc *host)
>         struct rtsx_pcr *pcr = host->pcr;
>         int err;
>
> -       host->power_state = SDMMC_POWER_OFF;
> +       host->prev_power_state = MMC_POWER_OFF;
>
>         rtsx_pci_init_cmd(pcr);
>
> @@ -1003,7 +1011,7 @@ static int sd_set_power_mode(struct realtek_pci_sdmmc *host,
>         if (power_mode == MMC_POWER_OFF)
>                 err = sd_power_off(host);
>         else
> -               err = sd_power_on(host);
> +               err = sd_power_on(host, power_mode);
>
>         return err;
>  }
> @@ -1506,10 +1514,11 @@ static int rtsx_pci_sdmmc_drv_probe(struct platform_device *pdev)
>
>         host = mmc_priv(mmc);
>         host->pcr = pcr;
> +       mmc->ios.power_delay_ms = 5;
>         host->mmc = mmc;
>         host->pdev = pdev;
>         host->cookie = -1;
> -       host->power_state = SDMMC_POWER_OFF;
> +       host->prev_power_state = MMC_POWER_OFF;
>         INIT_WORK(&host->work, sd_request);
>         platform_set_drvdata(pdev, host);
>         pcr->slots[RTSX_SD_CARD].p_dev = pdev;
> --
> 2.25.1