Re: [PATCH v4 1/2] mmc: dw_mmc: exynos: Support eMMC's HS400 mode

[Alim Akhtar <alim.akhtar@gmail.com>]

Hi Jaehoon

On Wed, Jan 21, 2015 at 4:32 AM, Jaehoon Chung <jh80.chung@samsung.com> wrote:
> Hi,
>
> This patch can be separated.
> When i tested on my board, it's not working fine.
> I think it depends on my timing, so i will check after change the timing.
>
> On 01/14/2015 07:30 PM, Alim Akhtar wrote:
>> From: Seungwon Jeon <tgih.jun@samsung.com>
>>
>> Implements HS400 mode support for exynos host driver.
>> This also include some updates as new mode is added.
>>
>> Signed-off-by: Seungwon Jeon <tgih.jun@samsung.com>
>> Signed-off-by: Alim Akhtar <alim.akhtar@samsung.com>
>> [Alim: addressed review comments]
>> ---
>>  .../devicetree/bindings/mmc/exynos-dw-mshc.txt     |    7 +
>>  drivers/mmc/host/dw_mmc-exynos.c                   |  187 ++++++++++++++++----
>>  drivers/mmc/host/dw_mmc-exynos.h                   |   19 +-
>>  drivers/mmc/host/dw_mmc.c                          |   16 +-
>>  drivers/mmc/host/dw_mmc.h                          |    2 +
>>  5 files changed, 196 insertions(+), 35 deletions(-)
>>
>> diff --git a/Documentation/devicetree/bindings/mmc/exynos-dw-mshc.txt b/Documentation/devicetree/bindings/mmc/exynos-dw-mshc.txt
>> index ee4fc05..dcab52c 100644
>> --- a/Documentation/devicetree/bindings/mmc/exynos-dw-mshc.txt
>> +++ b/Documentation/devicetree/bindings/mmc/exynos-dw-mshc.txt
>> @@ -36,6 +36,8 @@ Required Properties:
>>    in transmit mode and CIU clock phase shift value in receive mode for double
>>    data rate mode operation. Refer notes below for the order of the cells and the
>>    valid values.
>> +* samsung,dw-mshc-hs400-timing: Specifies the value of CIU TX and RX clock phase
>> +  shift value for hs400 mode operation.
>>
>>    Notes for the sdr-timing and ddr-timing values:
>>
>> @@ -50,6 +52,9 @@ Required Properties:
>>        - if CIU clock divider value is 0 (that is divide by 1), both tx and rx
>>          phase shift clocks should be 0.
>>
>> +* read-strobe-delay: RCLK (Data strobe) delay to control HS400 mode
>> +  (Latency value for delay line in Read path)
>> +
>>  Required properties for a slot (Deprecated - Recommend to use one slot per host):
>>
>>  * gpios: specifies a list of gpios used for command, clock and data bus. The
>> @@ -82,5 +87,7 @@ Example:
>>               samsung,dw-mshc-ciu-div = <3>;
>>               samsung,dw-mshc-sdr-timing = <2 3>;
>>               samsung,dw-mshc-ddr-timing = <1 2>;
>> +             samsung,dw-mshc-hs400-timing = <0 2>;
>> +             read-strobe-delay = <90>;
>
> read-strobe-delay is exynos specific, isn't?
> read-strobe-delay -> samsung.read-strobe-delay.
>
read-strobe are as per hs400 spec, ok I will change this to match the
naming with other properties.
>>               bus-width = <8>;
>>       };
>> diff --git a/drivers/mmc/host/dw_mmc-exynos.c b/drivers/mmc/host/dw_mmc-exynos.c
>> index 12a5eaa..172a2a8 100644
>> --- a/drivers/mmc/host/dw_mmc-exynos.c
>> +++ b/drivers/mmc/host/dw_mmc-exynos.c
>> @@ -40,7 +40,12 @@ struct dw_mci_exynos_priv_data {
>>       u8                              ciu_div;
>>       u32                             sdr_timing;
>>       u32                             ddr_timing;
>> +     u32                             hs400_timing;
>> +     u32                             tuned_sample;
>>       u32                             cur_speed;
>> +     u32                             dqs_delay;
>> +     u32                             saved_dqs_en;
>> +     u32                             saved_strobe_ctrl;
>>  };
>>
>>  static struct dw_mci_exynos_compatible {
>> @@ -71,6 +76,21 @@ static struct dw_mci_exynos_compatible {
>>       },
>>  };
>>
>> +static inline u8 dw_mci_exynos_get_ciu_div(struct dw_mci *host)
>> +{
>> +     struct dw_mci_exynos_priv_data *priv = host->priv;
>> +
>> +     if (priv->ctrl_type == DW_MCI_TYPE_EXYNOS4412)
>> +             return EXYNOS4412_FIXED_CIU_CLK_DIV;
>> +     else if (priv->ctrl_type == DW_MCI_TYPE_EXYNOS4210)
>> +             return EXYNOS4210_FIXED_CIU_CLK_DIV;
>> +     else if (priv->ctrl_type == DW_MCI_TYPE_EXYNOS7 ||
>> +                     priv->ctrl_type == DW_MCI_TYPE_EXYNOS7_SMU)
>> +             return SDMMC_CLKSEL_GET_DIV(mci_readl(host, CLKSEL64)) + 1;
>> +     else
>> +             return SDMMC_CLKSEL_GET_DIV(mci_readl(host, CLKSEL)) + 1;
>> +}
>> +
>>  static int dw_mci_exynos_priv_init(struct dw_mci *host)
>>  {
>>       struct dw_mci_exynos_priv_data *priv = host->priv;
>> @@ -85,6 +105,16 @@ static int dw_mci_exynos_priv_init(struct dw_mci *host)
>>                          SDMMC_MPSCTRL_NON_SECURE_WRITE_BIT);
>>       }
>>
>> +     if (priv->ctrl_type >= DW_MCI_TYPE_EXYNOS5420) {
>> +             priv->saved_strobe_ctrl = mci_readl(host, HS400_DLINE_CTRL);
>> +             priv->saved_dqs_en = mci_readl(host, HS400_DQS_EN);
>> +             priv->saved_dqs_en |= AXI_NON_BLOCKING_WR;
>> +             mci_writel(host, HS400_DQS_EN, priv->saved_dqs_en);
>> +             if (!priv->dqs_delay)
>> +                     priv->dqs_delay =
>> +                             DQS_CTRL_GET_RD_DELAY(priv->saved_strobe_ctrl);
>> +     }
>> +
>>       return 0;
>>  }
>>
>> @@ -92,11 +122,31 @@ static int dw_mci_exynos_setup_clock(struct dw_mci *host)
>>  {
>>       struct dw_mci_exynos_priv_data *priv = host->priv;
>>
>> -     host->bus_hz /= (priv->ciu_div + 1);
>> +     host->bus_hz /= priv->ciu_div;
>
> Don't need to consider the case that priv->ciu_div set to 0?
>
Ah ok, I know at least one board sets ciu_div as zero, let me remove
this change. thanks
>>
>>       return 0;
>>  }
>>
>> +static void dw_mci_exynos_set_clksel_timing(struct dw_mci *host, u32 timing)
>> +{
>> +     struct dw_mci_exynos_priv_data *priv = host->priv;
>> +     u32 clksel;
>> +
>> +     if (priv->ctrl_type == DW_MCI_TYPE_EXYNOS7 ||
>> +             priv->ctrl_type == DW_MCI_TYPE_EXYNOS7_SMU)
>> +             clksel = mci_readl(host, CLKSEL64);
>> +     else
>> +             clksel = mci_readl(host, CLKSEL);
>> +
>> +     clksel = (clksel & ~SDMMC_CLKSEL_TIMING_MASK) | timing;
>> +
>> +     if (priv->ctrl_type == DW_MCI_TYPE_EXYNOS7 ||
>> +             priv->ctrl_type == DW_MCI_TYPE_EXYNOS7_SMU)
>> +             mci_writel(host, CLKSEL64, clksel);
>> +     else
>> +             mci_writel(host, CLKSEL, clksel);
>> +}
>> +
>>  #ifdef CONFIG_PM_SLEEP
>>  static int dw_mci_exynos_suspend(struct device *dev)
>>  {
>> @@ -172,30 +222,38 @@ static void dw_mci_exynos_prepare_command(struct dw_mci *host, u32 *cmdr)
>>       }
>>  }
>>
>> -static void dw_mci_exynos_set_ios(struct dw_mci *host, struct mmc_ios *ios)
>> +static void dw_mci_exynos_config_hs400(struct dw_mci *host, u32 timing)
>>  {
>>       struct dw_mci_exynos_priv_data *priv = host->priv;
>> -     unsigned int wanted = ios->clock;
>> -     unsigned long actual;
>> -     u8 div = priv->ciu_div + 1;
>> +     u32 dqs, strobe;
>>
>> -     if (ios->timing == MMC_TIMING_MMC_DDR52) {
>> -             if (priv->ctrl_type == DW_MCI_TYPE_EXYNOS7 ||
>> -                     priv->ctrl_type == DW_MCI_TYPE_EXYNOS7_SMU)
>> -                     mci_writel(host, CLKSEL64, priv->ddr_timing);
>> -             else
>> -                     mci_writel(host, CLKSEL, priv->ddr_timing);
>> -             /* Should be double rate for DDR mode */
>> -             if (ios->bus_width == MMC_BUS_WIDTH_8)
>> -                     wanted <<= 1;
>> +     /*
>> +      * Not suppported to configure register
>
> Typo..supported
>
ok will correct.
>> +      * related to HS400
>> +      */
>> +     if (priv->ctrl_type < DW_MCI_TYPE_EXYNOS5420)
>> +             return;
>> +
>> +     dqs = priv->saved_dqs_en;
>> +     strobe = priv->saved_strobe_ctrl;
>
> priv->saved_dqs_en is set at init-time.
> And you read the RDDQS_EN and HS400_DLINE_CTRL register at that time.
> Doesn't it need to consider the changed value at those register?
>
> priv->saved_xxx is reset value?
>
Default values are read in init and adjusted below, for now only these
bits are touched other bits of these register are kept as their reset
values.
>> +
>> +     if (timing == MMC_TIMING_MMC_HS400) {
>> +             dqs |= DATA_STROBE_EN;
>> +             strobe = DQS_CTRL_RD_DELAY(strobe, priv->dqs_delay);
>>       } else {
>> -             if (priv->ctrl_type == DW_MCI_TYPE_EXYNOS7 ||
>> -                     priv->ctrl_type == DW_MCI_TYPE_EXYNOS7_SMU)
>> -                     mci_writel(host, CLKSEL64, priv->sdr_timing);
>> -             else
>> -                     mci_writel(host, CLKSEL, priv->sdr_timing);
>> +             dqs &= ~DATA_STROBE_EN;
>>       }
>>
>> +     mci_writel(host, HS400_DQS_EN, dqs);
>> +     mci_writel(host, HS400_DLINE_CTRL, strobe);
>> +}
>> +
>> +static void dw_mci_exynos_adjust_clock(struct dw_mci *host, unsigned int wanted)
>> +{
>> +     struct dw_mci_exynos_priv_data *priv = host->priv;
>> +     unsigned long actual;
>> +     u8 div;
>> +     int ret;
>>       /*
>>        * Don't care if wanted clock is zero or
>>        * ciu clock is unavailable
>> @@ -207,17 +265,52 @@ static void dw_mci_exynos_set_ios(struct dw_mci *host, struct mmc_ios *ios)
>>       if (wanted < EXYNOS_CCLKIN_MIN)
>>               wanted = EXYNOS_CCLKIN_MIN;
>>
>> -     if (wanted != priv->cur_speed) {
>> -             int ret = clk_set_rate(host->ciu_clk, wanted * div);
>> -             if (ret)
>> -                     dev_warn(host->dev,
>> -                             "failed to set clk-rate %u error: %d\n",
>> -                              wanted * div, ret);
>> -             actual = clk_get_rate(host->ciu_clk);
>> -             host->bus_hz = actual / div;
>> -             priv->cur_speed = wanted;
>> -             host->current_speed = 0;
>> +     if (wanted == priv->cur_speed)
>> +             return;
>> +
>> +     div = dw_mci_exynos_get_ciu_div(host);
>> +     ret = clk_set_rate(host->ciu_clk, wanted * div);
>> +     if (ret)
>> +             dev_warn(host->dev,
>> +                     "failed to set clk-rate %u error: %d\n",
>> +                     wanted * div, ret);
>> +     actual = clk_get_rate(host->ciu_clk);
>> +     host->bus_hz = actual / div;
>> +     priv->cur_speed = wanted;
>> +     host->current_speed = 0;
>> +}
>> +
>> +static void dw_mci_exynos_set_ios(struct dw_mci *host, struct mmc_ios *ios)
>> +{
>> +     struct dw_mci_exynos_priv_data *priv = host->priv;
>> +     unsigned int wanted = ios->clock;
>> +     u32 timing = ios->timing, clksel;
>> +
>> +     switch (timing) {
>> +     case MMC_TIMING_MMC_HS400:
>> +             /* Update tuned sample timing */
>> +             clksel = SDMMC_CLKSEL_UP_SAMPLE(
>> +                             priv->hs400_timing, priv->tuned_sample);
>> +             wanted <<= 1;
>> +             break;
>> +     case MMC_TIMING_MMC_DDR52:
>> +             clksel = priv->ddr_timing;
>> +             /* Should be double rate for DDR mode */
>> +             if (ios->bus_width == MMC_BUS_WIDTH_8)
>> +                     wanted <<= 1;
>> +             break;
>> +     default:
>> +             clksel = priv->sdr_timing;
>>       }
>> +
>> +     /* Set clock timing for the requested speed mode*/
>> +     dw_mci_exynos_set_clksel_timing(host, clksel);
>> +
>> +     /* Configure setting for HS400 */
>> +     dw_mci_exynos_config_hs400(host, timing);
>> +
>> +     /* Configure clock rate */
>> +     dw_mci_exynos_adjust_clock(host, wanted);
>>  }
>>
>>  static int dw_mci_exynos_parse_dt(struct dw_mci *host)
>> @@ -260,6 +353,16 @@ static int dw_mci_exynos_parse_dt(struct dw_mci *host)
>>               return ret;
>>
>>       priv->ddr_timing = SDMMC_CLKSEL_TIMING(timing[0], timing[1], div);
>> +
>> +     ret = of_property_read_u32_array(np,
>> +                     "samsung,dw-mshc-hs400-timing", timing, 2);
>> +     if (!ret && of_property_read_u32(np,
>> +                             "read-strobe-delay", &priv->dqs_delay))
>> +             dev_info(host->dev,
>> +                     "read-strobe-delay is not found, assuming usage of default value\n");
>
> Need the message?
>
Just in case the default values does not work, then user will know
this is something they need to change as per their boards.
>> +
>> +     priv->hs400_timing = SDMMC_CLKSEL_TIMING(timing[0], timing[1],
>> +                                             HS400_FIXED_CIU_CLK_DIV);
>
> Why useed the HS400_FIXED_CIU_CLK_DIV? always set to 1?
>
I thought about this, but I didn't find a case where it is anytime set
to more then div by 2 to support HS400 clock input value requirement.
So instead of getting this via DT, I kept fixed value,
Let me know your opinion on this, in case you wants me to change this.
> Best Regards,
> Jaehoon Chung
>
>>       host->priv = priv;
>>       return 0;
>>  }
>> @@ -285,7 +388,7 @@ static inline void dw_mci_exynos_set_clksmpl(struct dw_mci *host, u8 sample)
>>               clksel = mci_readl(host, CLKSEL64);
>>       else
>>               clksel = mci_readl(host, CLKSEL);
>> -     clksel = (clksel & ~0x7) | SDMMC_CLKSEL_CCLK_SAMPLE(sample);
>> +     clksel = SDMMC_CLKSEL_UP_SAMPLE(clksel, sample);
>>       if (priv->ctrl_type == DW_MCI_TYPE_EXYNOS7 ||
>>               priv->ctrl_type == DW_MCI_TYPE_EXYNOS7_SMU)
>>               mci_writel(host, CLKSEL64, clksel);
>> @@ -304,13 +407,16 @@ static inline u8 dw_mci_exynos_move_next_clksmpl(struct dw_mci *host)
>>               clksel = mci_readl(host, CLKSEL64);
>>       else
>>               clksel = mci_readl(host, CLKSEL);
>> +
>>       sample = (clksel + 1) & 0x7;
>> -     clksel = (clksel & ~0x7) | sample;
>> +     clksel = SDMMC_CLKSEL_UP_SAMPLE(clksel, sample);
>> +
>>       if (priv->ctrl_type == DW_MCI_TYPE_EXYNOS7 ||
>>               priv->ctrl_type == DW_MCI_TYPE_EXYNOS7_SMU)
>>               mci_writel(host, CLKSEL64, clksel);
>>       else
>>               mci_writel(host, CLKSEL, clksel);
>> +
>>       return sample;
>>  }
>>
>> @@ -343,6 +449,7 @@ out:
>>  static int dw_mci_exynos_execute_tuning(struct dw_mci_slot *slot)
>>  {
>>       struct dw_mci *host = slot->host;
>> +     struct dw_mci_exynos_priv_data *priv = host->priv;
>>       struct mmc_host *mmc = slot->mmc;
>>       u8 start_smpl, smpl, candiates = 0;
>>       s8 found = -1;
>> @@ -360,14 +467,27 @@ static int dw_mci_exynos_execute_tuning(struct dw_mci_slot *slot)
>>       } while (start_smpl != smpl);
>>
>>       found = dw_mci_exynos_get_best_clksmpl(candiates);
>> -     if (found >= 0)
>> +     if (found >= 0) {
>>               dw_mci_exynos_set_clksmpl(host, found);
>> -     else
>> +             priv->tuned_sample = found;
>> +     } else {
>>               ret = -EIO;
>> +     }
>>
>>       return ret;
>>  }
>>
>> +int dw_mci_exynos_prepare_hs400_tuning(struct dw_mci *host,
>> +                                     struct mmc_ios *ios)
>> +{
>> +     struct dw_mci_exynos_priv_data *priv = host->priv;
>> +
>> +     dw_mci_exynos_set_clksel_timing(host, priv->hs400_timing);
>> +     dw_mci_exynos_adjust_clock(host, (ios->clock) << 1);
>> +
>> +     return 0;
>> +}
>> +
>>  /* Common capabilities of Exynos4/Exynos5 SoC */
>>  static unsigned long exynos_dwmmc_caps[4] = {
>>       MMC_CAP_1_8V_DDR | MMC_CAP_8_BIT_DATA | MMC_CAP_CMD23,
>> @@ -384,6 +504,7 @@ static const struct dw_mci_drv_data exynos_drv_data = {
>>       .set_ios                = dw_mci_exynos_set_ios,
>>       .parse_dt               = dw_mci_exynos_parse_dt,
>>       .execute_tuning         = dw_mci_exynos_execute_tuning,
>> +     .prepare_hs400_tuning   = dw_mci_exynos_prepare_hs400_tuning,
>>  };
>>
>>  static const struct of_device_id dw_mci_exynos_match[] = {
>> diff --git a/drivers/mmc/host/dw_mmc-exynos.h b/drivers/mmc/host/dw_mmc-exynos.h
>> index 7872ce5..595c934 100644
>> --- a/drivers/mmc/host/dw_mmc-exynos.h
>> +++ b/drivers/mmc/host/dw_mmc-exynos.h
>> @@ -12,20 +12,36 @@
>>  #ifndef _DW_MMC_EXYNOS_H_
>>  #define _DW_MMC_EXYNOS_H_
>>
>> -/* Extended Register's Offset */
>>  #define SDMMC_CLKSEL                 0x09C
>>  #define SDMMC_CLKSEL64                       0x0A8
>>
>> +/* Extended Register's Offset */
>> +#define SDMMC_HS400_DQS_EN           0x180
>> +#define SDMMC_HS400_ASYNC_FIFO_CTRL  0x184
>> +#define SDMMC_HS400_DLINE_CTRL               0x188
>> +
>>  /* CLKSEL register defines */
>>  #define SDMMC_CLKSEL_CCLK_SAMPLE(x)  (((x) & 7) << 0)
>>  #define SDMMC_CLKSEL_CCLK_DRIVE(x)   (((x) & 7) << 16)
>>  #define SDMMC_CLKSEL_CCLK_DIVIDER(x) (((x) & 7) << 24)
>>  #define SDMMC_CLKSEL_GET_DRV_WD3(x)  (((x) >> 16) & 0x7)
>> +#define SDMMC_CLKSEL_GET_DIV(x)              (((x) >> 24) & 0x7)
>> +#define SDMMC_CLKSEL_UP_SAMPLE(x, y) (((x) & ~SDMMC_CLKSEL_CCLK_SAMPLE(7)) |\
>> +                                      SDMMC_CLKSEL_CCLK_SAMPLE(y))
>>  #define SDMMC_CLKSEL_TIMING(x, y, z) (SDMMC_CLKSEL_CCLK_SAMPLE(x) |  \
>>                                        SDMMC_CLKSEL_CCLK_DRIVE(y) |   \
>>                                        SDMMC_CLKSEL_CCLK_DIVIDER(z))
>> +#define SDMMC_CLKSEL_TIMING_MASK     SDMMC_CLKSEL_TIMING(0x7, 0x7, 0x7)
>>  #define SDMMC_CLKSEL_WAKEUP_INT              BIT(11)
>>
>> +/* RCLK_EN register defines */
>> +#define DATA_STROBE_EN                       BIT(0)
>> +#define AXI_NON_BLOCKING_WR  BIT(7)
>> +
>> +/* DLINE_CTRL register defines */
>> +#define DQS_CTRL_RD_DELAY(x, y)              (((x) & ~0x3FF) | ((y) & 0x3FF))
>> +#define DQS_CTRL_GET_RD_DELAY(x)     ((x) & 0x3FF)
>> +
>>  /* Protector Register */
>>  #define SDMMC_EMMCP_BASE     0x1000
>>  #define SDMMC_MPSECURITY     (SDMMC_EMMCP_BASE + 0x0010)
>> @@ -49,6 +65,7 @@
>>  /* Fixed clock divider */
>>  #define EXYNOS4210_FIXED_CIU_CLK_DIV 2
>>  #define EXYNOS4412_FIXED_CIU_CLK_DIV 4
>> +#define HS400_FIXED_CIU_CLK_DIV              1
>>
>>  /* Minimal required clock frequency for cclkin, unit: HZ */
>>  #define EXYNOS_CCLKIN_MIN    50000000
>> diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
>> index 2e8abc8..43a3a5b 100644
>> --- a/drivers/mmc/host/dw_mmc.c
>> +++ b/drivers/mmc/host/dw_mmc.c
>> @@ -1084,7 +1084,8 @@ static void dw_mci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
>>       regs = mci_readl(slot->host, UHS_REG);
>>
>>       /* DDR mode set */
>> -     if (ios->timing == MMC_TIMING_MMC_DDR52)
>> +     if (ios->timing == MMC_TIMING_MMC_DDR52 ||
>> +         ios->timing == MMC_TIMING_MMC_HS400)
>>               regs |= ((0x1 << slot->id) << 16);
>>       else
>>               regs &= ~((0x1 << slot->id) << 16);
>> @@ -1321,6 +1322,18 @@ static int dw_mci_execute_tuning(struct mmc_host *mmc, u32 opcode)
>>       return err;
>>  }
>>
>> +int dw_mci_prepare_hs400_tuning(struct mmc_host *mmc, struct mmc_ios *ios)
>> +{
>> +     struct dw_mci_slot *slot = mmc_priv(mmc);
>> +     struct dw_mci *host = slot->host;
>> +     const struct dw_mci_drv_data *drv_data = host->drv_data;
>> +
>> +     if (drv_data && drv_data->prepare_hs400_tuning)
>> +             return drv_data->prepare_hs400_tuning(host, ios);
>> +
>> +     return 0;
>> +}
>> +
>>  static const struct mmc_host_ops dw_mci_ops = {
>>       .request                = dw_mci_request,
>>       .pre_req                = dw_mci_pre_req,
>> @@ -1333,6 +1346,7 @@ static const struct mmc_host_ops dw_mci_ops = {
>>       .card_busy              = dw_mci_card_busy,
>>       .start_signal_voltage_switch = dw_mci_switch_voltage,
>>       .init_card              = dw_mci_init_card,
>> +     .prepare_hs400_tuning   = dw_mci_prepare_hs400_tuning,
>>  };
>>
>>  static void dw_mci_request_end(struct dw_mci *host, struct mmc_request *mrq)
>> diff --git a/drivers/mmc/host/dw_mmc.h b/drivers/mmc/host/dw_mmc.h
>> index 18c4afe..d239867 100644
>> --- a/drivers/mmc/host/dw_mmc.h
>> +++ b/drivers/mmc/host/dw_mmc.h
>> @@ -271,5 +271,7 @@ struct dw_mci_drv_data {
>>       void            (*set_ios)(struct dw_mci *host, struct mmc_ios *ios);
>>       int             (*parse_dt)(struct dw_mci *host);
>>       int             (*execute_tuning)(struct dw_mci_slot *slot);
>> +     int             (*prepare_hs400_tuning)(struct dw_mci *host,
>> +                                             struct mmc_ios *ios);
>>  };
>>  #endif /* _DW_MMC_H_ */
>>
>



-- 
Regards,
Alim