RE: [PATCH v2 2/2] mmc: sdhci-of-arasan: Add support for eMMC5.1 on Xilinx Versal Net platform

[Potthuri, Sai Krishna]

Hi Adrian Hunter,

> -----Original Message-----
> From: Adrian Hunter <adrian.hunter@xxxxxxxxx>
> Sent: Thursday, March 30, 2023 1:45 PM
> To: Potthuri, Sai Krishna <sai.krishna.potthuri@xxxxxxx>; Ulf Hansson
> <ulf.hansson@xxxxxxxxxx>; Rob Herring <robh+dt@xxxxxxxxxx>; Krzysztof
> Kozlowski <krzysztof.kozlowski+dt@xxxxxxxxxx>; Michal Simek
> <michal.simek@xxxxxxxxxx>
> Cc: linux-mmc@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx;
> devicetree@xxxxxxxxxxxxxxx; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; git (AMD-
> Xilinx) <git@xxxxxxx>; saikrishna12468@xxxxxxxxx; Agarwal, Swati
> <swati.agarwal@xxxxxxx>
> Subject: Re: [PATCH v2 2/2] mmc: sdhci-of-arasan: Add support for eMMC5.1 on
> Xilinx Versal Net platform
> 
> On 30/03/23 09:52, Sai Krishna Potthuri wrote:
> > From: Swati Agarwal <swati.agarwal@xxxxxxx>
> >
> > Add support for eMMC5.1 on Xilinx Versal Net platform
> > - Add new compatible string(xlnx,versal-net-emmc).
> > - Add support for PHY which is part of Host Controller register space.
> > - Add DLL and Delay Chain mode support and corresponding tap delays
> > for all eMMC modes.
> > - Add Strobe select tap for HS400 mode.
> >
> > Signed-off-by: Swati Agarwal <swati.agarwal@xxxxxxx>
> > Co-developed-by: Sai Krishna Potthuri <sai.krishna.potthuri@xxxxxxx>
> > Signed-off-by: Sai Krishna Potthuri <sai.krishna.potthuri@xxxxxxx>
> > ---
> >  drivers/mmc/host/sdhci-of-arasan.c | 237
> > ++++++++++++++++++++++++++++-
> >  1 file changed, 236 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/mmc/host/sdhci-of-arasan.c
> > b/drivers/mmc/host/sdhci-of-arasan.c
> > index deb67daf179f..d9a29c346745 100644
> > --- a/drivers/mmc/host/sdhci-of-arasan.c
> > +++ b/drivers/mmc/host/sdhci-of-arasan.c
> > @@ -41,11 +41,41 @@
> >  #define VENDOR_ENHANCED_STROBE		BIT(0)
> >
> >  #define PHY_CLK_TOO_SLOW_HZ		400000
> > +#define MIN_PHY_CLK_HZ			50000000
> >
> >  #define SDHCI_ITAPDLY_CHGWIN		0x200
> >  #define SDHCI_ITAPDLY_ENABLE		0x100
> >  #define SDHCI_OTAPDLY_ENABLE		0x40
> >
> > +#define PHY_CTRL_REG1			0x270
> > +#define PHY_CTRL_ITAPDLY_ENA_MASK	BIT(0)
> > +#define PHY_CTRL_ITAPDLY_SEL_MASK	GENMASK(5, 1)
> > +#define PHY_CTRL_ITAPDLY_SEL_SHIFT	1
> > +#define PHY_CTRL_ITAP_CHG_WIN_MASK	BIT(6)
> > +#define PHY_CTRL_OTAPDLY_ENA_MASK	BIT(8)
> > +#define PHY_CTRL_OTAPDLY_SEL_MASK	GENMASK(15, 12)
> > +#define PHY_CTRL_OTAPDLY_SEL_SHIFT	12
> > +#define PHY_CTRL_STRB_SEL_MASK		GENMASK(23, 16)
> > +#define PHY_CTRL_STRB_SEL_SHIFT		16
> > +#define PHY_CTRL_TEST_CTRL_MASK		GENMASK(31, 24)
> > +
> > +#define PHY_CTRL_REG2			0x274
> > +#define PHY_CTRL_EN_DLL_MASK		BIT(0)
> > +#define PHY_CTRL_DLL_RDY_MASK		BIT(1)
> > +#define PHY_CTRL_FREQ_SEL_MASK		GENMASK(6, 4)
> > +#define PHY_CTRL_FREQ_SEL_SHIFT		4
> > +#define PHY_CTRL_SEL_DLY_TX_MASK	BIT(16)
> > +#define PHY_CTRL_SEL_DLY_RX_MASK	BIT(17)
> > +#define FREQSEL_200M_170M		0x0
> > +#define FREQSEL_170M_140M	        0x1
> > +#define FREQSEL_140M_110M	        0x2
> > +#define FREQSEL_110M_80M	        0x3
> > +#define FREQSEL_80M_50M			0x4
> > +#define FREQSEL_275M_250M		0x5
> > +#define FREQSEL_250M_225M		0x6
> > +#define FREQSEL_225M_200M		0x7
> > +#define PHY_DLL_TIMEOUT_MS		100
> > +
> >  /* Default settings for ZynqMP Clock Phases */
> >  #define ZYNQMP_ICLK_PHASE {0, 63, 63, 0, 63,  0,   0, 183, 54,  0, 0}
> >  #define ZYNQMP_OCLK_PHASE {0, 72, 60, 0, 60, 72, 135, 48, 72, 135, 0}
> > @@ -53,6 +83,11 @@  #define VERSAL_ICLK_PHASE {0, 132, 132, 0, 132, 0,
> > 0, 162, 90, 0, 0}  #define VERSAL_OCLK_PHASE {0,  60, 48, 0, 48, 72,
> > 90, 36, 60, 90, 0}
> >
> > +#define VERSAL_NET_EMMC_ICLK_PHASE {0, 0, 0, 0, 0, 0, 0, 0, 39, 0, 0}
> > +#define VERSAL_NET_EMMC_OCLK_PHASE {0, 113, 0, 0, 0, 0, 0, 0, 113,
> > +79, 45}
> > +
> > +#define VERSAL_NET_PHY_CTRL_STRB90_STRB180_VAL		0X77
> > +
> >  /*
> >   * On some SoCs the syscon area has a feature where the upper 16-bits of
> >   * each 32-bit register act as a write mask for the lower 16-bits.
> > This allows @@ -135,6 +170,7 @@ struct sdhci_arasan_clk_data {
> >   * @clk_ahb:		Pointer to the AHB clock
> >   * @phy:		Pointer to the generic phy
> >   * @is_phy_on:		True if the PHY is on; false if not.
> > + * @internal_phy_reg:	True if the PHY is within the Host controller.
> >   * @has_cqe:		True if controller has command queuing engine.
> >   * @clk_data:		Struct for the Arasan Controller Clock Data.
> >   * @clk_ops:		Struct for the Arasan Controller Clock Operations.
> > @@ -147,6 +183,7 @@ struct sdhci_arasan_data {
> >  	struct clk	*clk_ahb;
> >  	struct phy	*phy;
> >  	bool		is_phy_on;
> > +	bool		internal_phy_reg;
> >
> >  	bool		has_cqe;
> >  	struct sdhci_arasan_clk_data clk_data; @@ -207,6 +244,61 @@ static
> > const struct sdhci_arasan_soc_ctl_map intel_keembay_soc_ctl_map = {
> >  	.hiword_update = false,
> >  };
> >
> > +static void sdhci_arasan_phy_set_delaychain(struct sdhci_host *host,
> > +bool enable) {
> > +	u32 reg;
> > +
> > +	reg = readl(host->ioaddr + PHY_CTRL_REG2);
> > +	if (enable)
> > +		reg |= (PHY_CTRL_SEL_DLY_TX_MASK |
> PHY_CTRL_SEL_DLY_RX_MASK);
> > +	else
> > +		reg &= ~(PHY_CTRL_SEL_DLY_TX_MASK |
> PHY_CTRL_SEL_DLY_RX_MASK);
> > +
> > +	writel(reg, host->ioaddr + PHY_CTRL_REG2); }
> > +
> > +static int sdhci_arasan_phy_set_dll(struct sdhci_host *host, bool
> > +enable) {
> > +	u32 reg;
> > +
> > +	reg = readl(host->ioaddr + PHY_CTRL_REG2);
> > +	if (enable)
> > +		reg |= PHY_CTRL_EN_DLL_MASK;
> > +	else
> > +		reg &= ~PHY_CTRL_EN_DLL_MASK;
> > +
> > +	writel(reg, host->ioaddr + PHY_CTRL_REG2);
> > +
> > +	if (!enable)
> > +		return 0;
> > +
> > +	return readl_relaxed_poll_timeout(host->ioaddr + PHY_CTRL_REG2, reg,
> > +					  (reg & PHY_CTRL_DLL_RDY_MASK),
> 10,
> > +					  1000 * PHY_DLL_TIMEOUT_MS);
> > +}
> > +
> > +static void sdhci_arasan_phy_dll_set_freq(struct sdhci_host *host,
> > +int clock) {
> > +	u32 reg, freq_sel, freq;
> > +
> > +	freq = DIV_ROUND_CLOSEST(clock, 1000000);
> > +	if (freq <= 200 && freq > 170)
> > +		freq_sel = FREQSEL_200M_170M;
> > +	else if (freq <= 170 && freq > 140)
> > +		freq_sel = FREQSEL_170M_140M;
> > +	else if (freq <= 140 && freq > 110)
> > +		freq_sel = FREQSEL_140M_110M;
> > +	else if (freq <= 110 && freq > 80)
> > +		freq_sel = FREQSEL_110M_80M;
> > +	else
> > +		freq_sel = FREQSEL_80M_50M;
> > +
> > +	reg = readl(host->ioaddr + PHY_CTRL_REG2);
> > +	reg &= ~PHY_CTRL_FREQ_SEL_MASK;
> > +	reg |= (freq_sel << PHY_CTRL_FREQ_SEL_SHIFT);
> > +	writel(reg, host->ioaddr + PHY_CTRL_REG2); }
> > +
> >  /**
> >   * sdhci_arasan_syscon_write - Write to a field in soc_ctl registers
> >   *
> > @@ -321,11 +413,24 @@ static void sdhci_arasan_set_clock(struct sdhci_host
> *host, unsigned int clock)
> >  	}
> >
> >  	/* Set the Input and Output Clock Phase Delays */
> > -	if (clk_data->set_clk_delays)
> > +	if (clk_data->set_clk_delays && clock > PHY_CLK_TOO_SLOW_HZ)
> 
> This change looks like it would affect other devices than "xlnx,versal-net-emmc",
> in which case it should be a separate patch?
Agree, this change is added to avoid calling the delay settings for 400KHz clock
as we don’t have any delays defined for it.
Will create a separate patch for this change in next version.

Regards
Sai Krishna
> 
> >  		clk_data->set_clk_delays(host);
> >
> > +	if (sdhci_arasan->internal_phy_reg && clock >= MIN_PHY_CLK_HZ) {
> > +		sdhci_writew(host, 0, SDHCI_CLOCK_CONTROL);
> > +		sdhci_arasan_phy_set_dll(host, 0);
> > +		sdhci_arasan_phy_set_delaychain(host, 0);
> > +		sdhci_arasan_phy_dll_set_freq(host, clock);
> > +	} else if (sdhci_arasan->internal_phy_reg) {
> > +		sdhci_writew(host, 0, SDHCI_CLOCK_CONTROL);
> > +		sdhci_arasan_phy_set_delaychain(host, 1);
> > +	}
> > +
> >  	sdhci_set_clock(host, clock);
> >
> > +	if (sdhci_arasan->internal_phy_reg && clock >= MIN_PHY_CLK_HZ)
> > +		sdhci_arasan_phy_set_dll(host, 1);
> > +
> >  	if (sdhci_arasan->quirks & SDHCI_ARASAN_QUIRK_CLOCK_UNSTABLE)
> >  		/*
> >  		 * Some controllers immediately report
> SDHCI_CLOCK_INT_STABLE @@
> > -897,6 +1002,101 @@ static const struct clk_ops versal_sampleclk_ops = {
> >  	.set_phase = sdhci_versal_sampleclk_set_phase,  };
> >
> > +static int sdhci_versal_net_emmc_sdcardclk_set_phase(struct clk_hw
> > +*hw, int degrees) {
> > +	struct sdhci_arasan_clk_data *clk_data =
> > +		container_of(hw, struct sdhci_arasan_clk_data, sdcardclk_hw);
> > +	struct sdhci_arasan_data *sdhci_arasan =
> > +		container_of(clk_data, struct sdhci_arasan_data, clk_data);
> > +	struct sdhci_host *host = sdhci_arasan->host;
> > +	u8 tap_delay, tap_max = 0;
> > +
> > +	switch (host->timing) {
> > +	case MMC_TIMING_MMC_HS:
> > +	case MMC_TIMING_MMC_DDR52:
> > +		tap_max = 16;
> > +		break;
> > +	case MMC_TIMING_MMC_HS200:
> > +	case MMC_TIMING_MMC_HS400:
> > +		 /* For 200MHz clock, 32 Taps are available */
> > +		tap_max = 32;
> > +		break;
> > +	default:
> > +		break;
> > +	}
> > +
> > +	tap_delay = (degrees * tap_max) / 360;
> > +
> > +	/* Set the Clock Phase */
> > +	if (tap_delay) {
> > +		u32 regval;
> > +
> > +		regval = sdhci_readl(host, PHY_CTRL_REG1);
> > +		regval |= PHY_CTRL_OTAPDLY_ENA_MASK;
> > +		sdhci_writel(host, regval, PHY_CTRL_REG1);
> > +		regval &= ~PHY_CTRL_OTAPDLY_SEL_MASK;
> > +		regval |= tap_delay << PHY_CTRL_OTAPDLY_SEL_SHIFT;
> > +		sdhci_writel(host, regval, PHY_CTRL_REG1);
> > +	}
> > +
> > +	return 0;
> > +}
> > +
> > +static const struct clk_ops versal_net_sdcardclk_ops = {
> > +	.recalc_rate = sdhci_arasan_sdcardclk_recalc_rate,
> > +	.set_phase = sdhci_versal_net_emmc_sdcardclk_set_phase,
> > +};
> > +
> > +static int sdhci_versal_net_emmc_sampleclk_set_phase(struct clk_hw
> > +*hw, int degrees) {
> > +	struct sdhci_arasan_clk_data *clk_data =
> > +		container_of(hw, struct sdhci_arasan_clk_data, sampleclk_hw);
> > +	struct sdhci_arasan_data *sdhci_arasan =
> > +		container_of(clk_data, struct sdhci_arasan_data, clk_data);
> > +	struct sdhci_host *host = sdhci_arasan->host;
> > +	u8 tap_delay, tap_max = 0;
> > +	u32 regval;
> > +
> > +	switch (host->timing) {
> > +	case MMC_TIMING_MMC_HS:
> > +	case MMC_TIMING_MMC_DDR52:
> > +		tap_max = 32;
> > +		break;
> > +	case MMC_TIMING_MMC_HS400:
> > +		/* Strobe select tap point for strb90 and strb180 */
> > +		regval = sdhci_readl(host, PHY_CTRL_REG1);
> > +		regval &= ~PHY_CTRL_STRB_SEL_MASK;
> > +		regval |= VERSAL_NET_PHY_CTRL_STRB90_STRB180_VAL <<
> PHY_CTRL_STRB_SEL_SHIFT;
> > +		sdhci_writel(host, regval, PHY_CTRL_REG1);
> > +		break;
> > +	default:
> > +		break;
> > +	}
> > +
> > +	tap_delay = (degrees * tap_max) / 360;
> > +
> > +	/* Set the Clock Phase */
> > +	if (tap_delay) {
> > +		regval = sdhci_readl(host, PHY_CTRL_REG1);
> > +		regval |= PHY_CTRL_ITAP_CHG_WIN_MASK;
> > +		sdhci_writel(host, regval, PHY_CTRL_REG1);
> > +		regval |= PHY_CTRL_ITAPDLY_ENA_MASK;
> > +		sdhci_writel(host, regval, PHY_CTRL_REG1);
> > +		regval &= ~PHY_CTRL_ITAPDLY_SEL_MASK;
> > +		regval |= tap_delay << PHY_CTRL_ITAPDLY_SEL_SHIFT;
> > +		sdhci_writel(host, regval, PHY_CTRL_REG1);
> > +		regval &= ~PHY_CTRL_ITAP_CHG_WIN_MASK;
> > +		sdhci_writel(host, regval, PHY_CTRL_REG1);
> > +	}
> > +
> > +	return 0;
> > +}
> > +
> > +static const struct clk_ops versal_net_sampleclk_ops = {
> > +	.recalc_rate = sdhci_arasan_sampleclk_recalc_rate,
> > +	.set_phase = sdhci_versal_net_emmc_sampleclk_set_phase,
> > +};
> > +
> >  static void arasan_zynqmp_dll_reset(struct sdhci_host *host, u32
> > deviceid)  {
> >  	u16 clk;
> > @@ -1107,7 +1307,17 @@ static void arasan_dt_parse_clk_phases(struct
> device *dev,
> >  			clk_data->clk_phase_out[i] = versal_oclk_phase[i];
> >  		}
> >  	}
> > +	if (of_device_is_compatible(dev->of_node, "xlnx,versal-net-emmc")) {
> > +		u32 versal_net_iclk_phase[MMC_TIMING_MMC_HS400 + 1] =
> > +			VERSAL_NET_EMMC_ICLK_PHASE;
> > +		u32 versal_net_oclk_phase[MMC_TIMING_MMC_HS400 + 1] =
> > +			VERSAL_NET_EMMC_OCLK_PHASE;
> >
> > +		for (i = 0; i <= MMC_TIMING_MMC_HS400; i++) {
> > +			clk_data->clk_phase_in[i] = versal_net_iclk_phase[i];
> > +			clk_data->clk_phase_out[i] = versal_net_oclk_phase[i];
> > +		}
> > +	}
> >  	arasan_dt_read_clk_phase(dev, clk_data, MMC_TIMING_LEGACY,
> >  				 "clk-phase-legacy");
> >  	arasan_dt_read_clk_phase(dev, clk_data, MMC_TIMING_MMC_HS, @@
> > -1225,6 +1435,14 @@ static const struct sdhci_pltfm_data
> sdhci_arasan_zynqmp_pdata = {
> >  			SDHCI_QUIRK2_STOP_WITH_TC,
> >  };
> >
> > +static const struct sdhci_pltfm_data sdhci_arasan_versal_net_pdata = {
> > +	.ops = &sdhci_arasan_ops,
> > +	.quirks2 = SDHCI_QUIRK2_PRESET_VALUE_BROKEN |
> > +			SDHCI_QUIRK2_CLOCK_DIV_ZERO_BROKEN |
> > +			SDHCI_QUIRK2_STOP_WITH_TC |
> > +			SDHCI_QUIRK2_CAPS_BIT63_FOR_HS400,
> > +};
> > +
> >  static const struct sdhci_arasan_clk_ops zynqmp_clk_ops = {
> >  	.sdcardclk_ops = &zynqmp_sdcardclk_ops,
> >  	.sampleclk_ops = &zynqmp_sampleclk_ops, @@ -1245,6 +1463,16 @@
> > static struct sdhci_arasan_of_data sdhci_arasan_versal_data = {
> >  	.clk_ops = &versal_clk_ops,
> >  };
> >
> > +static const struct sdhci_arasan_clk_ops versal_net_clk_ops = {
> > +	.sdcardclk_ops = &versal_net_sdcardclk_ops,
> > +	.sampleclk_ops = &versal_net_sampleclk_ops, };
> > +
> > +static struct sdhci_arasan_of_data sdhci_arasan_versal_net_data = {
> > +	.pdata = &sdhci_arasan_versal_net_pdata,
> > +	.clk_ops = &versal_net_clk_ops,
> > +};
> > +
> >  static struct sdhci_arasan_of_data intel_keembay_emmc_data = {
> >  	.soc_ctl_map = &intel_keembay_soc_ctl_map,
> >  	.pdata = &sdhci_keembay_emmc_pdata,
> > @@ -1314,6 +1542,10 @@ static const struct of_device_id
> sdhci_arasan_of_match[] = {
> >  		.compatible = "xlnx,versal-8.9a",
> >  		.data = &sdhci_arasan_versal_data,
> >  	},
> > +	{
> > +		.compatible = "xlnx,versal-net-emmc",
> > +		.data = &sdhci_arasan_versal_net_data,
> > +	},
> >  	{ /* sentinel */ }
> >  };
> >  MODULE_DEVICE_TABLE(of, sdhci_arasan_of_match); @@ -1788,6 +2020,9
> @@
> > static int sdhci_arasan_probe(struct platform_device *pdev)
> >  			host->mmc->caps2 |= MMC_CAP2_CQE_DCMD;
> >  	}
> >
> > +	if (of_device_is_compatible(np, "xlnx,versal-net-emmc"))
> > +		sdhci_arasan->internal_phy_reg = true;
> > +
> >  	ret = sdhci_arasan_add_host(sdhci_arasan);
> >  	if (ret)
> >  		goto err_add_host;