Re: [PATCH v3 2/3] mmc: dw_mmc-rockchip: Add v2 tuning support

Re: [PATCH v3 2/3] mmc: dw_mmc-rockchip: Add v2 tuning support

[Shawn Lin]

Hi Detlev

在 2024/8/15 6:34, Detlev Casanova 写道:
> From: Shawn Lin <shawn.lin@rock-chips.com>
> 
> v2 tuning will inherit pre-stage loader's phase settings for the first
> time, and do re-tune if necessary.
> Re-tune will still try the rough degrees, for instance, 90, 180, 270,
> 360 but continue to do the fine tuning if sample window isn't good
> enough.
> 
> Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>
> Signed-off-by: Detlev Casanova <detlev.casanova@collabora.com>
> ---
>   drivers/mmc/host/dw_mmc-rockchip.c | 49 ++++++++++++++++++++++++++++++
>   1 file changed, 49 insertions(+)
> 
> diff --git a/drivers/mmc/host/dw_mmc-rockchip.c b/drivers/mmc/host/dw_mmc-rockchip.c
> index b07190ba4b7ac..367633f4e8892 100644
> --- a/drivers/mmc/host/dw_mmc-rockchip.c
> +++ b/drivers/mmc/host/dw_mmc-rockchip.c
> @@ -24,6 +24,8 @@ struct dw_mci_rockchip_priv_data {
>   	struct clk		*sample_clk;
>   	int			default_sample_phase;
>   	int			num_phases;
> +	bool			use_v2_tuning;
> +	int			last_degree;
>   };
>   
>   static void dw_mci_rk3288_set_ios(struct dw_mci *host, struct mmc_ios *ios)
> @@ -134,6 +136,42 @@ static void dw_mci_rk3288_set_ios(struct dw_mci *host, struct mmc_ios *ios)
>   #define TUNING_ITERATION_TO_PHASE(i, num_phases) \
>   		(DIV_ROUND_UP((i) * 360, num_phases))
>   
> +static int dw_mci_v2_execute_tuning(struct dw_mci_slot *slot, u32 opcode)
> +{
> +	struct dw_mci *host = slot->host;
> +	struct dw_mci_rockchip_priv_data *priv = host->priv;
> +	struct mmc_host *mmc = slot->mmc;
> +	u32 degrees[4] = {90, 180, 270, 360};
> +	int i;
> +	static bool inherit = true;
> +
> +	if (inherit) {
> +		inherit = false;
> +		i = clk_get_phase(priv->sample_clk) / 90 - 1;
> +		goto done;
> +	}
> +
> +	/* v2 only support 4 degrees in theory */
> +	for (i = 0; i < ARRAY_SIZE(degrees); i++) {
> +		if (degrees[i] == priv->last_degree)
> +			continue;
> +
> +		clk_set_phase(priv->sample_clk, degrees[i]);
> +		if (!mmc_send_tuning(mmc, opcode, NULL))
> +			break;
> +	}
> +
> +	if (i == ARRAY_SIZE(degrees)) {
> +		dev_warn(host->dev, "All phases bad!");
> +		return -EIO;
> +	}
> +
> +done:
> +	dev_info(host->dev, "Successfully tuned phase to %d\n", degrees[i]);
> +	priv->last_degree = degrees[i];
> +	return 0;
> +}
> +
>   static int dw_mci_rk3288_execute_tuning(struct dw_mci_slot *slot, u32 opcode)
>   {
>   	struct dw_mci *host = slot->host;
> @@ -157,6 +195,13 @@ static int dw_mci_rk3288_execute_tuning(struct dw_mci_slot *slot, u32 opcode)
>   		return -EIO;
>   	}
>   
> +	if (priv->use_v2_tuning) {
> +		ret = dw_mci_v2_execute_tuning(slot, opcode);
> +		if (!ret)
> +			return 0;
> +		/* Otherwise we continue using fine tuning */
> +	}
> +
>   	ranges = kmalloc_array(priv->num_phases / 2 + 1,
>   			       sizeof(*ranges), GFP_KERNEL);
>   	if (!ranges)
> @@ -277,6 +322,10 @@ static int dw_mci_rk3288_parse_dt(struct dw_mci *host)
>   					&priv->default_sample_phase))
>   		priv->default_sample_phase = 0;
>   
> +	priv->use_v2_tuning =
> +		of_device_is_compatible(host->dev->of_node,
> +					"rockchip,rk3576-dw-mshc");
> +

v2 is a kind of software decision instead of hardware dependency.
So in theory, any SoC can claim to use it via DT.

>   	priv->drv_clk = devm_clk_get(host->dev, "ciu-drive");
>   	if (IS_ERR(priv->drv_clk))
>   		dev_dbg(host->dev, "ciu-drive not available\n");

Re: [PATCH v3 3/3] mmc: dw_mmc-rockchip: Add internal phase support

[Shawn Lin]

Hi Detlev

在 2024/8/15 6:34, Detlev Casanova 写道:
> From: Shawn Lin <shawn.lin@rock-chips.com>
> 
> Some Rockchip devices put the phase settings into the dw_mmc controller.
> 
> The feature is implemented in devices where the USRID register contains
> 0x20230002.
> 

Thanks for helping upstream it. USRID is 0x20230001 actually, so commit
msg should be amended. Otherwise,

Acked-by: Shawn Lin <shawn.lin@rock-chips.com>

> Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>
> Signed-off-by: Detlev Casanova <detlev.casanova@collabora.com>
> ---
>   drivers/mmc/host/dw_mmc-rockchip.c | 184 ++++++++++++++++++++++++++---
>   1 file changed, 170 insertions(+), 14 deletions(-)
> 
> diff --git a/drivers/mmc/host/dw_mmc-rockchip.c b/drivers/mmc/host/dw_mmc-rockchip.c
> index 367633f4e8892..03e25a8b8a305 100644
> --- a/drivers/mmc/host/dw_mmc-rockchip.c
> +++ b/drivers/mmc/host/dw_mmc-rockchip.c
> @@ -16,6 +16,17 @@
>   #include "dw_mmc-pltfm.h"
>   
>   #define RK3288_CLKGEN_DIV	2
> +#define USRID_INTER_PHASE	0x20230001
> +#define SDMMC_TIMING_CON0	0x130
> +#define SDMMC_TIMING_CON1	0x134
> +#define ROCKCHIP_MMC_DELAY_SEL BIT(10)
> +#define ROCKCHIP_MMC_DEGREE_MASK 0x3
> +#define ROCKCHIP_MMC_DELAYNUM_OFFSET 2
> +#define ROCKCHIP_MMC_DELAYNUM_MASK (0xff << ROCKCHIP_MMC_DELAYNUM_OFFSET)
> +#define PSECS_PER_SEC 1000000000000LL
> +#define ROCKCHIP_MMC_DELAY_ELEMENT_PSEC 60
> +#define HIWORD_UPDATE(val, mask, shift) \
> +		((val) << (shift) | (mask) << ((shift) + 16))
>   
>   static const unsigned int freqs[] = { 100000, 200000, 300000, 400000 };
>   
> @@ -25,9 +36,121 @@ struct dw_mci_rockchip_priv_data {
>   	int			default_sample_phase;
>   	int			num_phases;
>   	bool			use_v2_tuning;
> +	int			usrid;
>   	int			last_degree;
>   };
>   
> +/*
> + * Each fine delay is between 44ps-77ps. Assume each fine delay is 60ps to
> + * simplify calculations. So 45degs could be anywhere between 33deg and 57.8deg.
> + */
> +static int rockchip_mmc_get_phase(struct dw_mci *host, bool sample)
> +{
> +	unsigned long rate = clk_get_rate(host->ciu_clk);
> +	u32 raw_value;
> +	u16 degrees;
> +	u32 delay_num = 0;
> +
> +	/* Constant signal, no measurable phase shift */
> +	if (!rate)
> +		return 0;
> +
> +	if (sample)
> +		raw_value = mci_readl(host, TIMING_CON1) >> 1;
> +	else
> +		raw_value = mci_readl(host, TIMING_CON0) >> 1;
> +
> +	degrees = (raw_value & ROCKCHIP_MMC_DEGREE_MASK) * 90;
> +
> +	if (raw_value & ROCKCHIP_MMC_DELAY_SEL) {
> +		/* degrees/delaynum * 1000000 */
> +		unsigned long factor = (ROCKCHIP_MMC_DELAY_ELEMENT_PSEC / 10) *
> +					36 * (rate / 10000);
> +
> +		delay_num = (raw_value & ROCKCHIP_MMC_DELAYNUM_MASK);
> +		delay_num >>= ROCKCHIP_MMC_DELAYNUM_OFFSET;
> +		degrees += DIV_ROUND_CLOSEST(delay_num * factor, 1000000);
> +	}
> +
> +	return degrees % 360;
> +}
> +
> +static int rockchip_mmc_set_phase(struct dw_mci *host, bool sample, int degrees)
> +{
> +	unsigned long rate = clk_get_rate(host->ciu_clk);
> +	u8 nineties, remainder;
> +	u8 delay_num;
> +	u32 raw_value;
> +	u32 delay;
> +
> +	/*
> +	 * The below calculation is based on the output clock from
> +	 * MMC host to the card, which expects the phase clock inherits
> +	 * the clock rate from its parent, namely the output clock
> +	 * provider of MMC host. However, things may go wrong if
> +	 * (1) It is orphan.
> +	 * (2) It is assigned to the wrong parent.
> +	 *
> +	 * This check help debug the case (1), which seems to be the
> +	 * most likely problem we often face and which makes it difficult
> +	 * for people to debug unstable mmc tuning results.
> +	 */
> +	if (!rate) {
> +		dev_err(host->dev, "%s: invalid clk rate\n", __func__);
> +		return -EINVAL;
> +	}
> +
> +	nineties = degrees / 90;
> +	remainder = (degrees % 90);
> +
> +	/*
> +	 * Due to the inexact nature of the "fine" delay, we might
> +	 * actually go non-monotonic.  We don't go _too_ monotonic
> +	 * though, so we should be OK.  Here are options of how we may
> +	 * work:
> +	 *
> +	 * Ideally we end up with:
> +	 *   1.0, 2.0, ..., 69.0, 70.0, ...,  89.0, 90.0
> +	 *
> +	 * On one extreme (if delay is actually 44ps):
> +	 *   .73, 1.5, ..., 50.6, 51.3, ...,  65.3, 90.0
> +	 * The other (if delay is actually 77ps):
> +	 *   1.3, 2.6, ..., 88.6. 89.8, ..., 114.0, 90
> +	 *
> +	 * It's possible we might make a delay that is up to 25
> +	 * degrees off from what we think we're making.  That's OK
> +	 * though because we should be REALLY far from any bad range.
> +	 */
> +
> +	/*
> +	 * Convert to delay; do a little extra work to make sure we
> +	 * don't overflow 32-bit / 64-bit numbers.
> +	 */
> +	delay = 10000000; /* PSECS_PER_SEC / 10000 / 10 */
> +	delay *= remainder;
> +	delay = DIV_ROUND_CLOSEST(delay,
> +			(rate / 1000) * 36 *
> +				(ROCKCHIP_MMC_DELAY_ELEMENT_PSEC / 10));
> +
> +	delay_num = (u8) min_t(u32, delay, 255);
> +
> +	raw_value = delay_num ? ROCKCHIP_MMC_DELAY_SEL : 0;
> +	raw_value |= delay_num << ROCKCHIP_MMC_DELAYNUM_OFFSET;
> +	raw_value |= nineties;
> +
> +	if (sample)
> +		mci_writel(host, TIMING_CON1, HIWORD_UPDATE(raw_value, 0x07ff, 1));
> +	else
> +		mci_writel(host, TIMING_CON0, HIWORD_UPDATE(raw_value, 0x07ff, 1));
> +
> +	dev_dbg(host->dev, "set %s_phase(%d) delay_nums=%u actual_degrees=%d\n",
> +		sample ? "sample" : "drv", degrees, delay_num,
> +		rockchip_mmc_get_phase(host, sample)
> +	);
> +
> +	return 0;
> +}
> +
>   static void dw_mci_rk3288_set_ios(struct dw_mci *host, struct mmc_ios *ios)
>   {
>   	struct dw_mci_rockchip_priv_data *priv = host->priv;
> @@ -65,8 +188,12 @@ static void dw_mci_rk3288_set_ios(struct dw_mci *host, struct mmc_ios *ios)
>   	}
>   
>   	/* Make sure we use phases which we can enumerate with */
> -	if (!IS_ERR(priv->sample_clk) && ios->timing <= MMC_TIMING_SD_HS)
> -		clk_set_phase(priv->sample_clk, priv->default_sample_phase);
> +	if (!IS_ERR(priv->sample_clk) && ios->timing <= MMC_TIMING_SD_HS) {
> +		if (priv->usrid == USRID_INTER_PHASE)
> +			rockchip_mmc_set_phase(host, true, priv->default_sample_phase);
> +		else
> +			clk_set_phase(priv->sample_clk, priv->default_sample_phase);
> +	}
>   
>   	/*
>   	 * Set the drive phase offset based on speed mode to achieve hold times.
> @@ -129,7 +256,10 @@ static void dw_mci_rk3288_set_ios(struct dw_mci *host, struct mmc_ios *ios)
>   			break;
>   		}
>   
> -		clk_set_phase(priv->drv_clk, phase);
> +		if (priv->usrid == USRID_INTER_PHASE)
> +			rockchip_mmc_set_phase(host, false, phase);
> +		else
> +			clk_set_phase(priv->drv_clk, phase);
>   	}
>   }
>   
> @@ -141,13 +271,16 @@ static int dw_mci_v2_execute_tuning(struct dw_mci_slot *slot, u32 opcode)
>   	struct dw_mci *host = slot->host;
>   	struct dw_mci_rockchip_priv_data *priv = host->priv;
>   	struct mmc_host *mmc = slot->mmc;
> -	u32 degrees[4] = {90, 180, 270, 360};
> +	u32 degree, degrees[4] = {90, 180, 270, 360};
>   	int i;
>   	static bool inherit = true;
>   
>   	if (inherit) {
>   		inherit = false;
> -		i = clk_get_phase(priv->sample_clk) / 90 - 1;
> +		if (priv->usrid == USRID_INTER_PHASE)
> +			i = rockchip_mmc_get_phase(host, true) / 90;
> +		else
> +			i = clk_get_phase(priv->sample_clk) / 90 - 1;
>   		goto done;
>   	}
>   
> @@ -156,7 +289,11 @@ static int dw_mci_v2_execute_tuning(struct dw_mci_slot *slot, u32 opcode)
>   		if (degrees[i] == priv->last_degree)
>   			continue;
>   
> -		clk_set_phase(priv->sample_clk, degrees[i]);
> +		degree = (degrees[i] + priv->last_degree + 90) % 360;
> +		if (priv->usrid == USRID_INTER_PHASE)
> +			rockchip_mmc_set_phase(host, true, degree);
> +		else
> +			clk_set_phase(priv->sample_clk, degree);
>   		if (!mmc_send_tuning(mmc, opcode, NULL))
>   			break;
>   	}
> @@ -189,6 +326,7 @@ static int dw_mci_rk3288_execute_tuning(struct dw_mci_slot *slot, u32 opcode)
>   	int longest_range_len = -1;
>   	int longest_range = -1;
>   	int middle_phase;
> +	int phase;
>   
>   	if (IS_ERR(priv->sample_clk)) {
>   		dev_err(host->dev, "Tuning clock (sample_clk) not defined.\n");
> @@ -209,8 +347,15 @@ static int dw_mci_rk3288_execute_tuning(struct dw_mci_slot *slot, u32 opcode)
>   
>   	/* Try each phase and extract good ranges */
>   	for (i = 0; i < priv->num_phases; ) {
> -		clk_set_phase(priv->sample_clk,
> -			      TUNING_ITERATION_TO_PHASE(i, priv->num_phases));
> +		/* Cannot guarantee any phases larger than 270 would work well */
> +		if (TUNING_ITERATION_TO_PHASE(i, priv->num_phases) > 270)
> +			break;
> +		if (priv->usrid == USRID_INTER_PHASE)
> +			rockchip_mmc_set_phase(host, true,
> +				TUNING_ITERATION_TO_PHASE(i, priv->num_phases));
> +		else
> +			clk_set_phase(priv->sample_clk,
> +				TUNING_ITERATION_TO_PHASE(i, priv->num_phases));
>   
>   		v = !mmc_send_tuning(mmc, opcode, NULL);
>   
> @@ -256,7 +401,10 @@ static int dw_mci_rk3288_execute_tuning(struct dw_mci_slot *slot, u32 opcode)
>   	}
>   
>   	if (ranges[0].start == 0 && ranges[0].end == priv->num_phases - 1) {
> -		clk_set_phase(priv->sample_clk, priv->default_sample_phase);
> +		if (priv->usrid == USRID_INTER_PHASE)
> +			rockchip_mmc_set_phase(host, true, priv->default_sample_phase);
> +		else
> +			clk_set_phase(priv->sample_clk, priv->default_sample_phase);
>   		dev_info(host->dev, "All phases work, using default phase %d.",
>   			 priv->default_sample_phase);
>   		goto free;
> @@ -293,12 +441,13 @@ static int dw_mci_rk3288_execute_tuning(struct dw_mci_slot *slot, u32 opcode)
>   
>   	middle_phase = ranges[longest_range].start + longest_range_len / 2;
>   	middle_phase %= priv->num_phases;
> -	dev_info(host->dev, "Successfully tuned phase to %d\n",
> -		 TUNING_ITERATION_TO_PHASE(middle_phase, priv->num_phases));
> +	phase = TUNING_ITERATION_TO_PHASE(middle_phase, priv->num_phases);
> +	dev_info(host->dev, "Successfully tuned phase to %d\n", phase);
>   
> -	clk_set_phase(priv->sample_clk,
> -		      TUNING_ITERATION_TO_PHASE(middle_phase,
> -						priv->num_phases));
> +	if (priv->usrid == USRID_INTER_PHASE)
> +		rockchip_mmc_set_phase(host, true, phase);
> +	else
> +		clk_set_phase(priv->sample_clk, phase);
>   
>   free:
>   	kfree(ranges);
> @@ -342,6 +491,7 @@ static int dw_mci_rk3288_parse_dt(struct dw_mci *host)
>   static int dw_mci_rockchip_init(struct dw_mci *host)
>   {
>   	int ret, i;
> +	struct dw_mci_rockchip_priv_data *priv = host->priv;
>   
>   	/* It is slot 8 on Rockchip SoCs */
>   	host->sdio_id0 = 8;
> @@ -365,6 +515,12 @@ static int dw_mci_rockchip_init(struct dw_mci *host)
>   			dev_warn(host->dev, "no valid minimum freq: %d\n", ret);
>   	}
>   
> +	priv->usrid = mci_readl(host, USRID);
> +	if (priv->usrid == USRID_INTER_PHASE) {
> +		priv->sample_clk = NULL;
> +		priv->drv_clk = NULL;
> +	}
> +
>   	return 0;
>   }
>   

Re: [PATCH v3 2/3] mmc: dw_mmc-rockchip: Add v2 tuning support

[Heiko Stübner]

Am Donnerstag, 15. August 2024, 02:55:37 CEST schrieb Shawn Lin:
> Hi Detlev
> 
> 在 2024/8/15 6:34, Detlev Casanova 写道:
> > From: Shawn Lin <shawn.lin@rock-chips.com>
> > 
> > v2 tuning will inherit pre-stage loader's phase settings for the first
> > time, and do re-tune if necessary.
> > Re-tune will still try the rough degrees, for instance, 90, 180, 270,
> > 360 but continue to do the fine tuning if sample window isn't good
> > enough.
> > 
> > Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>
> > Signed-off-by: Detlev Casanova <detlev.casanova@collabora.com>

> > @@ -277,6 +322,10 @@ static int dw_mci_rk3288_parse_dt(struct dw_mci *host)
> >   					&priv->default_sample_phase))
> >   		priv->default_sample_phase = 0;
> >   
> > +	priv->use_v2_tuning =
> > +		of_device_is_compatible(host->dev->of_node,
> > +					"rockchip,rk3576-dw-mshc");
> > +
> 
> v2 is a kind of software decision instead of hardware dependency.
> So in theory, any SoC can claim to use it via DT.

which actually makes it unsuitable for dt.

Devicetree describes hardware-properties and should _not_ be used for
software configuration.

From the comment above, I assume the rk3576 does not need that feature
and can just work with the regular tuning?

So there are two routes for the immediate future:
(1) rk3576 _needs_ that feature, then going with the compatible is fine

(2) rk3576 does not need absolutely need that feature, then I'd expect
the basic rk3576 to first come without, as I'd expect a lot more explanation
on why it is actually needed, and which cases it does improve.
The commit message does not really explain that much about why this
is a great/needed feature and which areas it does improve.


Heiko

Re: [PATCH v3 1/3] dt-bindings: mmc: Add support for rk3576 dw-mshc

[Heiko Stübner]

Am Donnerstag, 15. August 2024, 00:34:00 CEST schrieb Detlev Casanova:
> Add the compatible string for rockchip,rk3576-dw-mshc and add support
> for the rockchip,v2-tuning flag, a new feature of this core.
> 
> Signed-off-by: Detlev Casanova <detlev.casanova@collabora.com>
> ---
>  Documentation/devicetree/bindings/mmc/rockchip-dw-mshc.yaml | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/Documentation/devicetree/bindings/mmc/rockchip-dw-mshc.yaml b/Documentation/devicetree/bindings/mmc/rockchip-dw-mshc.yaml
> index 211cd0b0bc5f3..0543cdb51c657 100644
> --- a/Documentation/devicetree/bindings/mmc/rockchip-dw-mshc.yaml
> +++ b/Documentation/devicetree/bindings/mmc/rockchip-dw-mshc.yaml
> @@ -39,6 +39,7 @@ properties:
>                - rockchip,rk3368-dw-mshc
>                - rockchip,rk3399-dw-mshc
>                - rockchip,rk3568-dw-mshc
> +              - rockchip,rk3576-dw-mshc
>                - rockchip,rk3588-dw-mshc
>                - rockchip,rv1108-dw-mshc
>                - rockchip,rv1126-dw-mshc

this would mark the rk3576-dw-mshc as being the "same" as the
core rk3288 variant. rk3288 was the first controller introducing the
clock tuning for higher speeds. with the clocks being part of the CRU.

As we can see in later patches, this rk3576 though changes that
setup with moving the tunable clock configurations into the controller
itself.

So please don't claim to be compatible to the 3288, but instead start
a new block for this new set of controllers:


  compatible:
    oneOf:
      # for Rockchip RK2928 and before RK3288
      - const: rockchip,rk2928-dw-mshc
      # for Rockchip RK3288
      - const: rockchip,rk3288-dw-mshc
      - items:
          - enum:
              - rockchip,px30-dw-mshc
              - rockchip,rk1808-dw-mshc
              - rockchip,rk3036-dw-mshc
              - rockchip,rk3128-dw-mshc
              - rockchip,rk3228-dw-mshc
              - rockchip,rk3308-dw-mshc
              - rockchip,rk3328-dw-mshc
              - rockchip,rk3368-dw-mshc
              - rockchip,rk3399-dw-mshc
              - rockchip,rk3568-dw-mshc
              - rockchip,rk3588-dw-mshc
              - rockchip,rv1108-dw-mshc
              - rockchip,rv1126-dw-mshc
          - const: rockchip,rk3288-dw-mshc
+      # for Rockchip RK3576 with phase tuning inside the controller
+      - const: rockchip,rk3576-dw-mshc

That way you can simplify the dt-parsing code too.


Heiko

Re: [PATCH v3 3/3] mmc: dw_mmc-rockchip: Add internal phase support

[Heiko Stübner]

Am Donnerstag, 15. August 2024, 00:34:02 CEST schrieb Detlev Casanova:
> From: Shawn Lin <shawn.lin@rock-chips.com>
> 
> Some Rockchip devices put the phase settings into the dw_mmc controller.
> 
> The feature is implemented in devices where the USRID register contains
> 0x20230002.
> 
> Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>
> Signed-off-by: Detlev Casanova <detlev.casanova@collabora.com>
> ---
>  drivers/mmc/host/dw_mmc-rockchip.c | 184 ++++++++++++++++++++++++++---
>  1 file changed, 170 insertions(+), 14 deletions(-)
> 
> diff --git a/drivers/mmc/host/dw_mmc-rockchip.c b/drivers/mmc/host/dw_mmc-rockchip.c
> index 367633f4e8892..03e25a8b8a305 100644
> --- a/drivers/mmc/host/dw_mmc-rockchip.c
> +++ b/drivers/mmc/host/dw_mmc-rockchip.c
> @@ -16,6 +16,17 @@
>  #include "dw_mmc-pltfm.h"
>  
>  #define RK3288_CLKGEN_DIV	2
> +#define USRID_INTER_PHASE	0x20230001
> +#define SDMMC_TIMING_CON0	0x130
> +#define SDMMC_TIMING_CON1	0x134
> +#define ROCKCHIP_MMC_DELAY_SEL BIT(10)
> +#define ROCKCHIP_MMC_DEGREE_MASK 0x3
> +#define ROCKCHIP_MMC_DELAYNUM_OFFSET 2

the delaynum offset in the register is 3, please don't encode how you
use constants below into the values. So the constants should reflect the
register setup


> +#define ROCKCHIP_MMC_DELAYNUM_MASK (0xff << ROCKCHIP_MMC_DELAYNUM_OFFSET)

please use one firm of mask values ROCKCHIP_MMC_DEGREE_MASK is used
for values _after_ they are shifted, while your DELAYNUM_MASK is vor values
_before_ they are shifted. Please decide on one form for both.


> +#define PSECS_PER_SEC 1000000000000LL

this is the second definition of this value, after clk/rockchip/clk-mmc-phase.c [0] .
The kernel already has a PSEC_PER_SEC definition in vdso/time64.h [1] and
thus linux/time64.h, so please re-use that - the innosilicon-dsi-phy
already does it too [2].

[0] https://elixir.bootlin.com/linux/v6.10.5/source/drivers/clk/rockchip/clk-mmc-phase.c#L37
[1] https://elixir.bootlin.com/linux/v6.10.5/source/include/vdso/time64.h#L11
[2] https://elixir.bootlin.com/linux/v6.11-rc3/source/drivers/phy/rockchip/phy-rockchip-inno-dsidphy.c#L415


> +#define ROCKCHIP_MMC_DELAY_ELEMENT_PSEC 60
> +#define HIWORD_UPDATE(val, mask, shift) \
> +		((val) << (shift) | (mask) << ((shift) + 16))
>  
>  static const unsigned int freqs[] = { 100000, 200000, 300000, 400000 };
>  
> @@ -25,9 +36,121 @@ struct dw_mci_rockchip_priv_data {
>  	int			default_sample_phase;
>  	int			num_phases;
>  	bool			use_v2_tuning;
> +	int			usrid;
>  	int			last_degree;
>  };
>  
> +/*
> + * Each fine delay is between 44ps-77ps. Assume each fine delay is 60ps to
> + * simplify calculations. So 45degs could be anywhere between 33deg and 57.8deg.
> + */
> +static int rockchip_mmc_get_phase(struct dw_mci *host, bool sample)
> +{
> +	unsigned long rate = clk_get_rate(host->ciu_clk);
> +	u32 raw_value;
> +	u16 degrees;
> +	u32 delay_num = 0;
> +
> +	/* Constant signal, no measurable phase shift */
> +	if (!rate)
> +		return 0;
> +
> +	if (sample)
> +		raw_value = mci_readl(host, TIMING_CON1) >> 1;
> +	else
> +		raw_value = mci_readl(host, TIMING_CON0) >> 1;

please define some sort of 
	#define ROCKCHIP_MMC_DEGREE_OFFSET	1 
above and use that constant instead of hard-coding the 1 shift

> +
> +	degrees = (raw_value & ROCKCHIP_MMC_DEGREE_MASK) * 90;
> +
> +	if (raw_value & ROCKCHIP_MMC_DELAY_SEL) {
> +		/* degrees/delaynum * 1000000 */
> +		unsigned long factor = (ROCKCHIP_MMC_DELAY_ELEMENT_PSEC / 10) *
> +					36 * (rate / 10000);
> +
> +		delay_num = (raw_value & ROCKCHIP_MMC_DELAYNUM_MASK);
> +		delay_num >>= ROCKCHIP_MMC_DELAYNUM_OFFSET;
> +		degrees += DIV_ROUND_CLOSEST(delay_num * factor, 1000000);
> +	}
> +
> +	return degrees % 360;
> +}
> +
> +static int rockchip_mmc_set_phase(struct dw_mci *host, bool sample, int degrees)
> +{
> +	unsigned long rate = clk_get_rate(host->ciu_clk);
> +	u8 nineties, remainder;
> +	u8 delay_num;
> +	u32 raw_value;
> +	u32 delay;
> +
> +	/*
> +	 * The below calculation is based on the output clock from
> +	 * MMC host to the card, which expects the phase clock inherits
> +	 * the clock rate from its parent, namely the output clock
> +	 * provider of MMC host. However, things may go wrong if
> +	 * (1) It is orphan.
> +	 * (2) It is assigned to the wrong parent.
> +	 *
> +	 * This check help debug the case (1), which seems to be the
> +	 * most likely problem we often face and which makes it difficult
> +	 * for people to debug unstable mmc tuning results.
> +	 */
> +	if (!rate) {
> +		dev_err(host->dev, "%s: invalid clk rate\n", __func__);
> +		return -EINVAL;
> +	}
> +
> +	nineties = degrees / 90;
> +	remainder = (degrees % 90);
> +
> +	/*
> +	 * Due to the inexact nature of the "fine" delay, we might
> +	 * actually go non-monotonic.  We don't go _too_ monotonic
> +	 * though, so we should be OK.  Here are options of how we may
> +	 * work:
> +	 *
> +	 * Ideally we end up with:
> +	 *   1.0, 2.0, ..., 69.0, 70.0, ...,  89.0, 90.0
> +	 *
> +	 * On one extreme (if delay is actually 44ps):
> +	 *   .73, 1.5, ..., 50.6, 51.3, ...,  65.3, 90.0
> +	 * The other (if delay is actually 77ps):
> +	 *   1.3, 2.6, ..., 88.6. 89.8, ..., 114.0, 90
> +	 *
> +	 * It's possible we might make a delay that is up to 25
> +	 * degrees off from what we think we're making.  That's OK
> +	 * though because we should be REALLY far from any bad range.
> +	 */
> +
> +	/*
> +	 * Convert to delay; do a little extra work to make sure we
> +	 * don't overflow 32-bit / 64-bit numbers.
> +	 */
> +	delay = 10000000; /* PSECS_PER_SEC / 10000 / 10 */
> +	delay *= remainder;
> +	delay = DIV_ROUND_CLOSEST(delay,
> +			(rate / 1000) * 36 *
> +				(ROCKCHIP_MMC_DELAY_ELEMENT_PSEC / 10));
> +
> +	delay_num = (u8) min_t(u32, delay, 255);
> +
> +	raw_value = delay_num ? ROCKCHIP_MMC_DELAY_SEL : 0;
> +	raw_value |= delay_num << ROCKCHIP_MMC_DELAYNUM_OFFSET;
> +	raw_value |= nineties;
> +
> +	if (sample)
> +		mci_writel(host, TIMING_CON1, HIWORD_UPDATE(raw_value, 0x07ff, 1));
> +	else
> +		mci_writel(host, TIMING_CON0, HIWORD_UPDATE(raw_value, 0x07ff, 1));
> +
> +	dev_dbg(host->dev, "set %s_phase(%d) delay_nums=%u actual_degrees=%d\n",
> +		sample ? "sample" : "drv", degrees, delay_num,
> +		rockchip_mmc_get_phase(host, sample)
> +	);
> +
> +	return 0;
> +}
> +
>  static void dw_mci_rk3288_set_ios(struct dw_mci *host, struct mmc_ios *ios)
>  {
>  	struct dw_mci_rockchip_priv_data *priv = host->priv;
> @@ -65,8 +188,12 @@ static void dw_mci_rk3288_set_ios(struct dw_mci *host, struct mmc_ios *ios)
>  	}
>  
>  	/* Make sure we use phases which we can enumerate with */
> -	if (!IS_ERR(priv->sample_clk) && ios->timing <= MMC_TIMING_SD_HS)
> -		clk_set_phase(priv->sample_clk, priv->default_sample_phase);
> +	if (!IS_ERR(priv->sample_clk) && ios->timing <= MMC_TIMING_SD_HS) {
> +		if (priv->usrid == USRID_INTER_PHASE)
> +			rockchip_mmc_set_phase(host, true, priv->default_sample_phase);
> +		else
> +			clk_set_phase(priv->sample_clk, priv->default_sample_phase);
> +	}
>  
>  	/*
>  	 * Set the drive phase offset based on speed mode to achieve hold times.
> @@ -129,7 +256,10 @@ static void dw_mci_rk3288_set_ios(struct dw_mci *host, struct mmc_ios *ios)
>  			break;
>  		}
>  
> -		clk_set_phase(priv->drv_clk, phase);
> +		if (priv->usrid == USRID_INTER_PHASE)
> +			rockchip_mmc_set_phase(host, false, phase);
> +		else
> +			clk_set_phase(priv->drv_clk, phase);
>  	}
>  }
>  
> @@ -141,13 +271,16 @@ static int dw_mci_v2_execute_tuning(struct dw_mci_slot *slot, u32 opcode)
>  	struct dw_mci *host = slot->host;
>  	struct dw_mci_rockchip_priv_data *priv = host->priv;
>  	struct mmc_host *mmc = slot->mmc;
> -	u32 degrees[4] = {90, 180, 270, 360};
> +	u32 degree, degrees[4] = {90, 180, 270, 360};
>  	int i;
>  	static bool inherit = true;
>  
>  	if (inherit) {
>  		inherit = false;
> -		i = clk_get_phase(priv->sample_clk) / 90 - 1;
> +		if (priv->usrid == USRID_INTER_PHASE)
> +			i = rockchip_mmc_get_phase(host, true) / 90;
> +		else
> +			i = clk_get_phase(priv->sample_clk) / 90 - 1;
>  		goto done;
>  	}
>  
> @@ -156,7 +289,11 @@ static int dw_mci_v2_execute_tuning(struct dw_mci_slot *slot, u32 opcode)
>  		if (degrees[i] == priv->last_degree)
>  			continue;
>  
> -		clk_set_phase(priv->sample_clk, degrees[i]);
> +		degree = (degrees[i] + priv->last_degree + 90) % 360;
> +		if (priv->usrid == USRID_INTER_PHASE)
> +			rockchip_mmc_set_phase(host, true, degree);
> +		else
> +			clk_set_phase(priv->sample_clk, degree);
>  		if (!mmc_send_tuning(mmc, opcode, NULL))
>  			break;
>  	}
> @@ -189,6 +326,7 @@ static int dw_mci_rk3288_execute_tuning(struct dw_mci_slot *slot, u32 opcode)
>  	int longest_range_len = -1;
>  	int longest_range = -1;
>  	int middle_phase;
> +	int phase;
>  
>  	if (IS_ERR(priv->sample_clk)) {
>  		dev_err(host->dev, "Tuning clock (sample_clk) not defined.\n");
> @@ -209,8 +347,15 @@ static int dw_mci_rk3288_execute_tuning(struct dw_mci_slot *slot, u32 opcode)
>  
>  	/* Try each phase and extract good ranges */
>  	for (i = 0; i < priv->num_phases; ) {
> -		clk_set_phase(priv->sample_clk,
> -			      TUNING_ITERATION_TO_PHASE(i, priv->num_phases));
> +		/* Cannot guarantee any phases larger than 270 would work well */
> +		if (TUNING_ITERATION_TO_PHASE(i, priv->num_phases) > 270)
> +			break;

this changes behaviour for the existing user as well.
Not say that this is incorrect, but limiting phases to a working area should be a separate change.

> +		if (priv->usrid == USRID_INTER_PHASE)
> +			rockchip_mmc_set_phase(host, true,
> +				TUNING_ITERATION_TO_PHASE(i, priv->num_phases));
> +		else
> +			clk_set_phase(priv->sample_clk,
> +				TUNING_ITERATION_TO_PHASE(i, priv->num_phases));
>  
>  		v = !mmc_send_tuning(mmc, opcode, NULL);
>  
> @@ -256,7 +401,10 @@ static int dw_mci_rk3288_execute_tuning(struct dw_mci_slot *slot, u32 opcode)
>  	}
>  
>  	if (ranges[0].start == 0 && ranges[0].end == priv->num_phases - 1) {
> -		clk_set_phase(priv->sample_clk, priv->default_sample_phase);
> +		if (priv->usrid == USRID_INTER_PHASE)
> +			rockchip_mmc_set_phase(host, true, priv->default_sample_phase);
> +		else
> +			clk_set_phase(priv->sample_clk, priv->default_sample_phase);
>  		dev_info(host->dev, "All phases work, using default phase %d.",
>  			 priv->default_sample_phase);
>  		goto free;
> @@ -293,12 +441,13 @@ static int dw_mci_rk3288_execute_tuning(struct dw_mci_slot *slot, u32 opcode)
>  
>  	middle_phase = ranges[longest_range].start + longest_range_len / 2;
>  	middle_phase %= priv->num_phases;
> -	dev_info(host->dev, "Successfully tuned phase to %d\n",
> -		 TUNING_ITERATION_TO_PHASE(middle_phase, priv->num_phases));
> +	phase = TUNING_ITERATION_TO_PHASE(middle_phase, priv->num_phases);
> +	dev_info(host->dev, "Successfully tuned phase to %d\n", phase);
>  
> -	clk_set_phase(priv->sample_clk,
> -		      TUNING_ITERATION_TO_PHASE(middle_phase,
> -						priv->num_phases));
> +	if (priv->usrid == USRID_INTER_PHASE)
> +		rockchip_mmc_set_phase(host, true, phase);
> +	else
> +		clk_set_phase(priv->sample_clk, phase);

with the change in compatible (not claiming to be compatible with tk3288)
you can also just introduce a new dw_mci_drv_data for the rk3576 and
following can therefore create a separate tuning function to not need all
those ifs.

And also a shorter parse_dt function that does not tries to get non-existent
clocks.


>  
>  free:
>  	kfree(ranges);
> @@ -342,6 +491,7 @@ static int dw_mci_rk3288_parse_dt(struct dw_mci *host)
>  static int dw_mci_rockchip_init(struct dw_mci *host)
>  {
>  	int ret, i;
> +	struct dw_mci_rockchip_priv_data *priv = host->priv;
>  
>  	/* It is slot 8 on Rockchip SoCs */
>  	host->sdio_id0 = 8;
> @@ -365,6 +515,12 @@ static int dw_mci_rockchip_init(struct dw_mci *host)
>  			dev_warn(host->dev, "no valid minimum freq: %d\n", ret);
>  	}
>  
> +	priv->usrid = mci_readl(host, USRID);
> +	if (priv->usrid == USRID_INTER_PHASE) {
> +		priv->sample_clk = NULL;
> +		priv->drv_clk = NULL;
> +	}
> +

in any case, shouldn't the clocks be NULL anyway?


Heiko

Re: [PATCH v3 2/3] mmc: dw_mmc-rockchip: Add v2 tuning support

[Heiko Stübner]

Am Donnerstag, 15. August 2024, 15:23:40 CEST schrieb Detlev Casanova:
> On Wednesday, 14 August 2024 20:55:37 EDT Shawn Lin wrote:
> > Hi Detlev
> > 
> > 在 2024/8/15 6:34, Detlev Casanova 写道:
> > > From: Shawn Lin <shawn.lin@rock-chips.com>
> > > 
> > > v2 tuning will inherit pre-stage loader's phase settings for the first
> > > time, and do re-tune if necessary.
> > > Re-tune will still try the rough degrees, for instance, 90, 180, 270,
> > > 360 but continue to do the fine tuning if sample window isn't good
> > > enough.
> > > 
> > > Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>
> > > Signed-off-by: Detlev Casanova <detlev.casanova@collabora.com>
> > > ---
> > > 
> > >   drivers/mmc/host/dw_mmc-rockchip.c | 49 ++++++++++++++++++++++++++++++
> > >   1 file changed, 49 insertions(+)
> > > 
> > > diff --git a/drivers/mmc/host/dw_mmc-rockchip.c
> > > b/drivers/mmc/host/dw_mmc-rockchip.c index b07190ba4b7ac..367633f4e8892
> > > 100644
> > > --- a/drivers/mmc/host/dw_mmc-rockchip.c
> > > +++ b/drivers/mmc/host/dw_mmc-rockchip.c
> 
> [...]
> 
> > >   		
> > >   		priv->default_sample_phase = 0;
> > > 
> > > +	priv->use_v2_tuning =
> > > +		of_device_is_compatible(host->dev->of_node,
> > > +					"rockchip,rk3576-dw-
> mshc");
> > > +
> > 
> > v2 is a kind of software decision instead of hardware dependency.
> > So in theory, any SoC can claim to use it via DT.
> 
> Yes but from my tests, only rk3576 won't work without it. So it makes sense to 
> only use v2 for this SoC (and other future ones not supported yet)

Good know and thanks for testing that scenario.

If you go with my suggestion from patch3 and separate the rk3576
from the original rk3288 type, you can even just assume this v2-tuning
for all those types (rk3576 only so far)


> > >   	priv->drv_clk = devm_clk_get(host->dev, "ciu-drive");
> > >   	if (IS_ERR(priv->drv_clk))
> > >   	
> > >   		dev_dbg(host->dev, "ciu-drive not available\n");
> 
> 
> Detlev.
> 
> 
> 

Re: [PATCH v3 2/3] mmc: dw_mmc-rockchip: Add v2 tuning support

[Shawn Lin]

Hi Heiko,

在 2024/8/15 21:17, Heiko Stübner 写道:
> Am Donnerstag, 15. August 2024, 02:55:37 CEST schrieb Shawn Lin:
>> Hi Detlev
>>
>> 在 2024/8/15 6:34, Detlev Casanova 写道:
>>> From: Shawn Lin <shawn.lin@rock-chips.com>
>>>
>>> v2 tuning will inherit pre-stage loader's phase settings for the first
>>> time, and do re-tune if necessary.
>>> Re-tune will still try the rough degrees, for instance, 90, 180, 270,
>>> 360 but continue to do the fine tuning if sample window isn't good
>>> enough.
>>>
>>> Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>
>>> Signed-off-by: Detlev Casanova <detlev.casanova@collabora.com>
> 
>>> @@ -277,6 +322,10 @@ static int dw_mci_rk3288_parse_dt(struct dw_mci *host)
>>>    					&priv->default_sample_phase))
>>>    		priv->default_sample_phase = 0;
>>>    
>>> +	priv->use_v2_tuning =
>>> +		of_device_is_compatible(host->dev->of_node,
>>> +					"rockchip,rk3576-dw-mshc");
>>> +
>>
>> v2 is a kind of software decision instead of hardware dependency.
>> So in theory, any SoC can claim to use it via DT.
> 
> which actually makes it unsuitable for dt. >

Understood.

> Devicetree describes hardware-properties and should _not_ be used for
> software configuration.
> 
>  From the comment above, I assume the rk3576 does not need that feature
> and can just work with the regular tuning?

Yep, your are right.

> 
> So there are two routes for the immediate future:
> (1) rk3576 _needs_ that feature, then going with the compatible is fine
> 
> (2) rk3576 does not need absolutely need that feature, then I'd expect
> the basic rk3576 to first come without, as I'd expect a lot more explanation
> on why it is actually needed, and which cases it does improve.
> The commit message does not really explain that much about why this
> is a great/needed feature and which areas it does improve.
> 

Vote for the 2nd. rk3576 just need
[PATCH v3 3/3] mmc: dw_mmc-rockchip: Add internal phase support


> 
> Heiko
> 
> 

Re: [PATCH v3 2/3] mmc: dw_mmc-rockchip: Add v2 tuning support

[Shawn Lin]

在 2024/8/15 21:23, Detlev Casanova 写道:
> On Wednesday, 14 August 2024 20:55:37 EDT Shawn Lin wrote:
>> Hi Detlev
>>
>> 在 2024/8/15 6:34, Detlev Casanova 写道:
>>> From: Shawn Lin <shawn.lin@rock-chips.com>
>>>
>>> v2 tuning will inherit pre-stage loader's phase settings for the first
>>> time, and do re-tune if necessary.
>>> Re-tune will still try the rough degrees, for instance, 90, 180, 270,
>>> 360 but continue to do the fine tuning if sample window isn't good
>>> enough.
>>>
>>> Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>
>>> Signed-off-by: Detlev Casanova <detlev.casanova@collabora.com>
>>> ---
>>>
>>>    drivers/mmc/host/dw_mmc-rockchip.c | 49 ++++++++++++++++++++++++++++++
>>>    1 file changed, 49 insertions(+)
>>>
>>> diff --git a/drivers/mmc/host/dw_mmc-rockchip.c
>>> b/drivers/mmc/host/dw_mmc-rockchip.c index b07190ba4b7ac..367633f4e8892
>>> 100644
>>> --- a/drivers/mmc/host/dw_mmc-rockchip.c
>>> +++ b/drivers/mmc/host/dw_mmc-rockchip.c
> 
> [...]
> 
>>>    		
>>>    		priv->default_sample_phase = 0;
>>>
>>> +	priv->use_v2_tuning =
>>> +		of_device_is_compatible(host->dev->of_node,
>>> +					"rockchip,rk3576-dw-
> mshc");
>>> +
>>
>> v2 is a kind of software decision instead of hardware dependency.
>> So in theory, any SoC can claim to use it via DT.
> 
> Yes but from my tests, only rk3576 won't work without it. So it makes sense to
> only use v2 for this SoC (and other future ones not supported yet)
> 

However from both of the IC design POV and the test from my side,
we just need internal phase support patch, and rk3576 could
work.

>>
>>>    	priv->drv_clk = devm_clk_get(host->dev, "ciu-drive");
>>>    	if (IS_ERR(priv->drv_clk))
>>>    	
>>>    		dev_dbg(host->dev, "ciu-drive not available\n");
> 
> 
> Detlev.
> 
> 

Re: [PATCH v3 1/3] dt-bindings: mmc: Add support for rk3576 dw-mshc

[Krzysztof Kozlowski]

On 15/08/2024 15:49, Heiko Stübner wrote:
> Am Donnerstag, 15. August 2024, 00:34:00 CEST schrieb Detlev Casanova:
>> Add the compatible string for rockchip,rk3576-dw-mshc and add support
>> for the rockchip,v2-tuning flag, a new feature of this core.
>>
>> Signed-off-by: Detlev Casanova <detlev.casanova@collabora.com>
>> ---
>>  Documentation/devicetree/bindings/mmc/rockchip-dw-mshc.yaml | 1 +
>>  1 file changed, 1 insertion(+)
>>
>> diff --git a/Documentation/devicetree/bindings/mmc/rockchip-dw-mshc.yaml b/Documentation/devicetree/bindings/mmc/rockchip-dw-mshc.yaml
>> index 211cd0b0bc5f3..0543cdb51c657 100644
>> --- a/Documentation/devicetree/bindings/mmc/rockchip-dw-mshc.yaml
>> +++ b/Documentation/devicetree/bindings/mmc/rockchip-dw-mshc.yaml
>> @@ -39,6 +39,7 @@ properties:
>>                - rockchip,rk3368-dw-mshc
>>                - rockchip,rk3399-dw-mshc
>>                - rockchip,rk3568-dw-mshc
>> +              - rockchip,rk3576-dw-mshc
>>                - rockchip,rk3588-dw-mshc
>>                - rockchip,rv1108-dw-mshc
>>                - rockchip,rv1126-dw-mshc
> 
> this would mark the rk3576-dw-mshc as being the "same" as the

Not the same, but compatible.

> core rk3288 variant. rk3288 was the first controller introducing the
> clock tuning for higher speeds. with the clocks being part of the CRU.
> 
> As we can see in later patches, this rk3576 though changes that
> setup with moving the tunable clock configurations into the controller
> itself.
> 
> So please don't claim to be compatible to the 3288, but instead start
> a new block for this new set of controllers:

The question is can new device work with old compatible (without new
features)?


Best regards,
Krzysztof

Re: [PATCH v3 1/3] dt-bindings: mmc: Add support for rk3576 dw-mshc

[Heiko Stübner]

Am Freitag, 16. August 2024, 08:52:04 CEST schrieb Krzysztof Kozlowski:
> On 15/08/2024 15:49, Heiko Stübner wrote:
> > Am Donnerstag, 15. August 2024, 00:34:00 CEST schrieb Detlev Casanova:
> >> Add the compatible string for rockchip,rk3576-dw-mshc and add support
> >> for the rockchip,v2-tuning flag, a new feature of this core.
> >>
> >> Signed-off-by: Detlev Casanova <detlev.casanova@collabora.com>
> >> ---
> >>  Documentation/devicetree/bindings/mmc/rockchip-dw-mshc.yaml | 1 +
> >>  1 file changed, 1 insertion(+)
> >>
> >> diff --git a/Documentation/devicetree/bindings/mmc/rockchip-dw-mshc.yaml b/Documentation/devicetree/bindings/mmc/rockchip-dw-mshc.yaml
> >> index 211cd0b0bc5f3..0543cdb51c657 100644
> >> --- a/Documentation/devicetree/bindings/mmc/rockchip-dw-mshc.yaml
> >> +++ b/Documentation/devicetree/bindings/mmc/rockchip-dw-mshc.yaml
> >> @@ -39,6 +39,7 @@ properties:
> >>                - rockchip,rk3368-dw-mshc
> >>                - rockchip,rk3399-dw-mshc
> >>                - rockchip,rk3568-dw-mshc
> >> +              - rockchip,rk3576-dw-mshc
> >>                - rockchip,rk3588-dw-mshc
> >>                - rockchip,rv1108-dw-mshc
> >>                - rockchip,rv1126-dw-mshc
> > 
> > this would mark the rk3576-dw-mshc as being the "same" as the
> 
> Not the same, but compatible.
> 
> > core rk3288 variant. rk3288 was the first controller introducing the
> > clock tuning for higher speeds. with the clocks being part of the CRU.
> > 
> > As we can see in later patches, this rk3576 though changes that
> > setup with moving the tunable clock configurations into the controller
> > itself.
> > 
> > So please don't claim to be compatible to the 3288, but instead start
> > a new block for this new set of controllers:
> 
> The question is can new device work with old compatible (without new
> features)?

the rk3288 and following have their clock phase tuning for hs-modes in
the main soc's clock controller. Hence you have the "ciu-drive" and
"ciu-sample" clocks [0].

On the rk3576 (and probably following) those clock phase settings moved
inside the mmc controller itself. So there are no external phase clocks
anymore.

So right now we have two types in the binding, the rk2928 type [1],
used on the old rk3066 and rk3188 socs, that did not support mmc hs-modes
and the rk3288-type which introduced phase tuning via clocks from the
main clock controller.

The rk3576 now switches to having phase tuning in the mmc controller
itself. So throwing that on unmodified code for the rk3288 will get you
degraded functionality, because the tuning won't work because there are
no "ciu-drive" and "ciu-sample" anymore .


And with that separate compatible we could also "tighten" the binding
a bit to make those additional clocks more explicit for the rk3288 type.


Heiko


[0] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/arch/arm64/boot/dts/rockchip/rk3399.dtsi#n410
[1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/devicetree/bindings/mmc/rockchip-dw-mshc.yaml#n27

Re: [PATCH v3 1/3] dt-bindings: mmc: Add support for rk3576 dw-mshc

[Krzysztof Kozlowski]

On 16/08/2024 09:45, Heiko Stübner wrote:
> Am Freitag, 16. August 2024, 08:52:04 CEST schrieb Krzysztof Kozlowski:
>> On 15/08/2024 15:49, Heiko Stübner wrote:
>>> Am Donnerstag, 15. August 2024, 00:34:00 CEST schrieb Detlev Casanova:
>>>> Add the compatible string for rockchip,rk3576-dw-mshc and add support
>>>> for the rockchip,v2-tuning flag, a new feature of this core.
>>>>
>>>> Signed-off-by: Detlev Casanova <detlev.casanova@collabora.com>
>>>> ---
>>>>  Documentation/devicetree/bindings/mmc/rockchip-dw-mshc.yaml | 1 +
>>>>  1 file changed, 1 insertion(+)
>>>>
>>>> diff --git a/Documentation/devicetree/bindings/mmc/rockchip-dw-mshc.yaml b/Documentation/devicetree/bindings/mmc/rockchip-dw-mshc.yaml
>>>> index 211cd0b0bc5f3..0543cdb51c657 100644
>>>> --- a/Documentation/devicetree/bindings/mmc/rockchip-dw-mshc.yaml
>>>> +++ b/Documentation/devicetree/bindings/mmc/rockchip-dw-mshc.yaml
>>>> @@ -39,6 +39,7 @@ properties:
>>>>                - rockchip,rk3368-dw-mshc
>>>>                - rockchip,rk3399-dw-mshc
>>>>                - rockchip,rk3568-dw-mshc
>>>> +              - rockchip,rk3576-dw-mshc
>>>>                - rockchip,rk3588-dw-mshc
>>>>                - rockchip,rv1108-dw-mshc
>>>>                - rockchip,rv1126-dw-mshc
>>>
>>> this would mark the rk3576-dw-mshc as being the "same" as the
>>
>> Not the same, but compatible.
>>
>>> core rk3288 variant. rk3288 was the first controller introducing the
>>> clock tuning for higher speeds. with the clocks being part of the CRU.
>>>
>>> As we can see in later patches, this rk3576 though changes that
>>> setup with moving the tunable clock configurations into the controller
>>> itself.
>>>
>>> So please don't claim to be compatible to the 3288, but instead start
>>> a new block for this new set of controllers:
>>
>> The question is can new device work with old compatible (without new
>> features)?
> 
> the rk3288 and following have their clock phase tuning for hs-modes in
> the main soc's clock controller. Hence you have the "ciu-drive" and
> "ciu-sample" clocks [0].
> 
> On the rk3576 (and probably following) those clock phase settings moved
> inside the mmc controller itself. So there are no external phase clocks
> anymore.
> 
> So right now we have two types in the binding, the rk2928 type [1],
> used on the old rk3066 and rk3188 socs, that did not support mmc hs-modes
> and the rk3288-type which introduced phase tuning via clocks from the
> main clock controller.
> 
> The rk3576 now switches to having phase tuning in the mmc controller
> itself. So throwing that on unmodified code for the rk3288 will get you
> degraded functionality, because the tuning won't work because there are
> no "ciu-drive" and "ciu-sample" anymore .

One could still argue that rest of programming model is the same, thus
"degraded" mode counts as compatibility, but I do not insist on that.

> 
> 
> And with that separate compatible we could also "tighten" the binding
> a bit to make those additional clocks more explicit for the rk3288 type.
This you can, and actually should, do with existing binding. Maybe just
a bit more tricky/complicated code.

Anyway, fine with both compatibility-approaches.

Best regards,
Krzysztof