RE: [PATCH v2 3/7] phy: freescale: imx8m-pcie: Add iMX8MP PCIe PHY support

From: Hongxing Zhu
Date: Wed Mar 09 2022 - 01:05:29 EST

> -----Original Message-----
> From: Lucas Stach <l.stach@xxxxxxxxxxxxxx>
> Sent: 2022年3月8日 18:05
> To: Hongxing Zhu <hongxing.zhu@xxxxxxx>; p.zabel@xxxxxxxxxxxxxx;
> bhelgaas@xxxxxxxxxx; lorenzo.pieralisi@xxxxxxx; robh@xxxxxxxxxx;
> shawnguo@xxxxxxxxxx; vkoul@xxxxxxxxxx; alexander.stein@xxxxxxxxxxxxxxx
> Cc: linux-phy@xxxxxxxxxxxxxxxxxxx; devicetree@xxxxxxxxxxxxxxx;
> linux-pci@xxxxxxxxxxxxxxx; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx;
> linux-kernel@xxxxxxxxxxxxxxx; kernel@xxxxxxxxxxxxxx; dl-linux-imx
> <linux-imx@xxxxxxx>
> Subject: Re: [PATCH v2 3/7] phy: freescale: imx8m-pcie: Add iMX8MP PCIe PHY
> support
>
> Hi Richard,
>
> Am Montag, dem 07.03.2022 um 17:07 +0800 schrieb Richard Zhu:
> > Add the i.MX8MP PCIe PHY support
> >
> > Signed-off-by: Richard Zhu <hongxing.zhu@xxxxxxx>
> > ---
> > drivers/phy/freescale/phy-fsl-imx8m-pcie.c | 205
> > ++++++++++++++++-----
> > 1 file changed, 163 insertions(+), 42 deletions(-)
> >
> > diff --git a/drivers/phy/freescale/phy-fsl-imx8m-pcie.c
> > b/drivers/phy/freescale/phy-fsl-imx8m-pcie.c
> > index 04b1aafb29f4..3d01da4323a6 100644
> > --- a/drivers/phy/freescale/phy-fsl-imx8m-pcie.c
> > +++ b/drivers/phy/freescale/phy-fsl-imx8m-pcie.c
> > @@ -11,6 +11,8 @@
> > #include <linux/mfd/syscon.h>
> > #include <linux/mfd/syscon/imx7-iomuxc-gpr.h>
> > #include <linux/module.h>
> > +#include <linux/of_address.h>
> > +#include <linux/of_device.h>
> > #include <linux/phy/phy.h>
> > #include <linux/platform_device.h>
> > #include <linux/regmap.h>
> > @@ -30,12 +32,10 @@
> > #define IMX8MM_PCIE_PHY_CMN_REG065 0x194
> > #define ANA_AUX_RX_TERM (BIT(7) | BIT(4))
> > #define ANA_AUX_TX_LVL GENMASK(3, 0)
> > -#define IMX8MM_PCIE_PHY_CMN_REG75 0x1D4
> > -#define PCIE_PHY_CMN_REG75_PLL_DONE 0x3
> > +#define IMX8MM_PCIE_PHY_CMN_REG075 0x1D4
> > +#define ANA_PLL_DONE 0x3
> > #define PCIE_PHY_TRSV_REG5 0x414
> > -#define PCIE_PHY_TRSV_REG5_GEN1_DEEMP 0x2D
> > #define PCIE_PHY_TRSV_REG6 0x418
> > -#define PCIE_PHY_TRSV_REG6_GEN2_DEEMP 0xF
> >
> > #define IMX8MM_GPR_PCIE_REF_CLK_SEL GENMASK(25, 24)
> > #define IMX8MM_GPR_PCIE_REF_CLK_PLL
> FIELD_PREP(IMX8MM_GPR_PCIE_REF_CLK_SEL, 0x3)
> > @@ -46,16 +46,43 @@
> > #define IMX8MM_GPR_PCIE_SSC_EN BIT(16)
> > #define IMX8MM_GPR_PCIE_AUX_EN_OVERRIDE BIT(9)
> >
> > +#define IMX8MP_GPR_REG0 0x0
> > +#define IMX8MP_GPR_CLK_MOD_EN BIT(0)
> > +#define IMX8MP_GPR_PHY_APB_RST BIT(4)
> > +#define IMX8MP_GPR_PHY_INIT_RST BIT(5)
> > +#define IMX8MP_GPR_REG1 0x4
> > +#define IMX8MP_GPR_PM_EN_CORE_CLK BIT(0)
> > +#define IMX8MP_GPR_PLL_LOCK BIT(13)
> > +#define IMX8MP_GPR_REG2 0x8
> > +#define IMX8MP_GPR_P_PLL_MASK GENMASK(5, 0)
> > +#define IMX8MP_GPR_M_PLL_MASK GENMASK(15, 6)
> > +#define IMX8MP_GPR_S_PLL_MASK GENMASK(18, 16)
> > +#define IMX8MP_GPR_P_PLL (0xc << 0)
> > +#define IMX8MP_GPR_M_PLL (0x320 << 6)
> > +#define IMX8MP_GPR_S_PLL (0x4 << 16)
> > +#define IMX8MP_GPR_REG3 0xc
> > +#define IMX8MP_GPR_PLL_CKE BIT(17)
> > +#define IMX8MP_GPR_PLL_RST BIT(31)
> > +
> > +enum imx8_pcie_phy_type {
> > + IMX8MM,
> > + IMX8MP,
> > +};
> > +
> > struct imx8_pcie_phy {
> > void __iomem *base;
> > + struct device *dev;
> > struct clk *clk;
> > struct phy *phy;
> > + struct regmap *hsio_blk_ctrl;
> > struct regmap *iomuxc_gpr;
> > struct reset_control *reset;
> > + struct reset_control *perst;
> > u32 refclk_pad_mode;
> > u32 tx_deemph_gen1;
> > u32 tx_deemph_gen2;
> > bool clkreq_unused;
> > + enum imx8_pcie_phy_type variant;
> > };
> >
> > static int imx8_pcie_phy_init(struct phy *phy) @@ -67,6 +94,87 @@
> > static int imx8_pcie_phy_init(struct phy *phy)
> > reset_control_assert(imx8_phy->reset);
> >
> > pad_mode = imx8_phy->refclk_pad_mode;
> > + switch (imx8_phy->variant) {
> > + case IMX8MM:
> > + /* Tune PHY de-emphasis setting to pass PCIe compliance. */
> > + if (imx8_phy->tx_deemph_gen1)
> > + writel(imx8_phy->tx_deemph_gen1,
> > + imx8_phy->base + PCIE_PHY_TRSV_REG5);
> > + if (imx8_phy->tx_deemph_gen2)
> > + writel(imx8_phy->tx_deemph_gen2,
> > + imx8_phy->base + PCIE_PHY_TRSV_REG6);
> > + break;
> > + case IMX8MP:
> > + reset_control_assert(imx8_phy->perst);
> > + /* Set P=12,M=800,S=4 and must set ICP=2'b01. */
> > + regmap_update_bits(imx8_phy->hsio_blk_ctrl, IMX8MP_GPR_REG2,
> > + IMX8MP_GPR_P_PLL_MASK |
> > + IMX8MP_GPR_M_PLL_MASK |
> > + IMX8MP_GPR_S_PLL_MASK,
> > + IMX8MP_GPR_P_PLL |
> > + IMX8MP_GPR_M_PLL |
> > + IMX8MP_GPR_S_PLL);
> > + /* wait greater than 1/F_FREF =1/2MHZ=0.5us */
> > + udelay(1);
> > +
> > + regmap_update_bits(imx8_phy->hsio_blk_ctrl, IMX8MP_GPR_REG3,
> > + IMX8MP_GPR_PLL_RST,
> > + IMX8MP_GPR_PLL_RST);
> > + udelay(10);
> > +
> > + /* Set 1 to pll_cke of GPR_REG3 */
> > + regmap_update_bits(imx8_phy->hsio_blk_ctrl, IMX8MP_GPR_REG3,
> > + IMX8MP_GPR_PLL_CKE,
> > + IMX8MP_GPR_PLL_CKE);
> > +
> > + /* Lock time should be greater than 300cycle=300*0.5us=150us */
> > + ret = regmap_read_poll_timeout(imx8_phy->hsio_blk_ctrl,
> > + IMX8MP_GPR_REG1, val,
> > + val & IMX8MP_GPR_PLL_LOCK,
> > + 10, 1000);
> > + if (ret) {
> > + dev_err(imx8_phy->dev, "PCIe PLL lock timeout\n");
> > + return ret;
> > + }
>
> As far as I understand the reference manual, this PLL is not exclusive to the
> PCIe core, but can be used as a alternate reference clock for the USB PHYs. I
> think we should not poke the PLL registers from the PCIe PHY driver, but
> should make this PLL a real clock provided by the HSIO blk-ctrl.
>
> It's probably a good prove of concept for other clocks that need to be provided
> by the blk-ctrls, as the audio blk-ctrl has much more of this secondary clock
> controller functionality.
>
> Do you want to give it a shot at integrating this into the blk-ctrl driver, or
> should I take a look?
>
Hi Lucas:
Thanks for your comments.
Yes, refer to the reference manual, most bits of the hsio-blk registers are
defined for this PLL clock. But there are still two PCIe PHY reset bits,
BIT(4) and BIT(5) of GPR_REG0.
Can all this bits and manipulations be encapsulated into one clock provided
by blk-ctrls?

It's my pleasure that if you can take a look at it, and let blk-ctrls provide
one clock for PCIe or USB modules.

Best Regards
Richard Zhu
> Regards,
> Lucas
>
> > +
> > + /* pcie_clock_module_en */
> > + regmap_update_bits(imx8_phy->hsio_blk_ctrl, IMX8MP_GPR_REG0,
> > + IMX8MP_GPR_CLK_MOD_EN,
> > + IMX8MP_GPR_CLK_MOD_EN);
> > + udelay(10);
> > +
> > + reset_control_deassert(imx8_phy->reset);
> > + reset_control_deassert(imx8_phy->perst);
> > +
> > + /* release pcie_phy_apb_reset and pcie_phy_init_resetn */
> > + regmap_update_bits(imx8_phy->hsio_blk_ctrl, IMX8MP_GPR_REG0,
> > + IMX8MP_GPR_PHY_APB_RST |
> > + IMX8MP_GPR_PHY_INIT_RST,
> > + IMX8MP_GPR_PHY_APB_RST |
> > + IMX8MP_GPR_PHY_INIT_RST);
> > + break;
> > + }
> > +
> > + if (pad_mode == IMX8_PCIE_REFCLK_PAD_INPUT) {
> > + /* Configure the pad as input */
> > + val = readl(imx8_phy->base + IMX8MM_PCIE_PHY_CMN_REG061);
> > + writel(val & ~ANA_PLL_CLK_OUT_TO_EXT_IO_EN,
> > + imx8_phy->base + IMX8MM_PCIE_PHY_CMN_REG061);
> > + } else if (pad_mode == IMX8_PCIE_REFCLK_PAD_OUTPUT) {
> > + /* Configure the PHY to output the refclock via pad */
> > + writel(ANA_PLL_CLK_OUT_TO_EXT_IO_EN,
> > + imx8_phy->base + IMX8MM_PCIE_PHY_CMN_REG061);
> > + writel(ANA_PLL_CLK_OUT_TO_EXT_IO_SEL,
> > + imx8_phy->base + IMX8MM_PCIE_PHY_CMN_REG062);
> > + writel(AUX_PLL_REFCLK_SEL_SYS_PLL,
> > + imx8_phy->base + IMX8MM_PCIE_PHY_CMN_REG063);
> > + val = ANA_AUX_RX_TX_SEL_TX | ANA_AUX_TX_TERM;
> > + writel(val | ANA_AUX_RX_TERM_GND_EN,
> > + imx8_phy->base + IMX8MM_PCIE_PHY_CMN_REG064);
> > + writel(ANA_AUX_RX_TERM | ANA_AUX_TX_LVL,
> > + imx8_phy->base + IMX8MM_PCIE_PHY_CMN_REG065);
> > + }
> > +
> > /* Set AUX_EN_OVERRIDE 1'b0, when the CLKREQ# isn't hooked */
> > regmap_update_bits(imx8_phy->iomuxc_gpr, IOMUXC_GPR14,
> > IMX8MM_GPR_PCIE_AUX_EN_OVERRIDE, @@ -91,42
> +199,30 @@ static
> > int imx8_pcie_phy_init(struct phy *phy)
> > regmap_update_bits(imx8_phy->iomuxc_gpr, IOMUXC_GPR14,
> > IMX8MM_GPR_PCIE_CMN_RST,
> > IMX8MM_GPR_PCIE_CMN_RST);
> > - usleep_range(200, 500);
> >
> > - if (pad_mode == IMX8_PCIE_REFCLK_PAD_INPUT) {
> > - /* Configure the pad as input */
> > - val = readl(imx8_phy->base + IMX8MM_PCIE_PHY_CMN_REG061);
> > - writel(val & ~ANA_PLL_CLK_OUT_TO_EXT_IO_EN,
> > - imx8_phy->base + IMX8MM_PCIE_PHY_CMN_REG061);
> > - } else if (pad_mode == IMX8_PCIE_REFCLK_PAD_OUTPUT) {
> > - /* Configure the PHY to output the refclock via pad */
> > - writel(ANA_PLL_CLK_OUT_TO_EXT_IO_EN,
> > - imx8_phy->base + IMX8MM_PCIE_PHY_CMN_REG061);
> > - writel(ANA_PLL_CLK_OUT_TO_EXT_IO_SEL,
> > - imx8_phy->base + IMX8MM_PCIE_PHY_CMN_REG062);
> > - writel(AUX_PLL_REFCLK_SEL_SYS_PLL,
> > - imx8_phy->base + IMX8MM_PCIE_PHY_CMN_REG063);
> > - val = ANA_AUX_RX_TX_SEL_TX | ANA_AUX_TX_TERM;
> > - writel(val | ANA_AUX_RX_TERM_GND_EN,
> > - imx8_phy->base + IMX8MM_PCIE_PHY_CMN_REG064);
> > - writel(ANA_AUX_RX_TERM | ANA_AUX_TX_LVL,
> > - imx8_phy->base + IMX8MM_PCIE_PHY_CMN_REG065);
> > + switch (imx8_phy->variant) {
> > + case IMX8MM:
> > + reset_control_deassert(imx8_phy->reset);
> > + usleep_range(200, 500);
> > + break;
> > +
> > + case IMX8MP:
> > + /* wait for core_clk enabled */
> > + ret = regmap_read_poll_timeout(imx8_phy->hsio_blk_ctrl,
> > + IMX8MP_GPR_REG1, val,
> > + val & IMX8MP_GPR_PM_EN_CORE_CLK,
> > + 10, 20000);
> > + if (ret) {
> > + dev_err(imx8_phy->dev, "PCIe CORE CLK enable failed\n");
> > + return ret;
> > + }
> > +
> > + break;
> > }
> >
> > - /* Tune PHY de-emphasis setting to pass PCIe compliance. */
> > - if (imx8_phy->tx_deemph_gen1)
> > - writel(imx8_phy->tx_deemph_gen1,
> > - imx8_phy->base + PCIE_PHY_TRSV_REG5);
> > - if (imx8_phy->tx_deemph_gen2)
> > - writel(imx8_phy->tx_deemph_gen2,
> > - imx8_phy->base + PCIE_PHY_TRSV_REG6);
> > -
> > - reset_control_deassert(imx8_phy->reset);
> > -
> > /* Polling to check the phy is ready or not. */
> > - ret = readl_poll_timeout(imx8_phy->base +
> IMX8MM_PCIE_PHY_CMN_REG75,
> > - val, val == PCIE_PHY_CMN_REG75_PLL_DONE,
> > - 10, 20000);
> > + ret = readl_poll_timeout(imx8_phy->base +
> IMX8MM_PCIE_PHY_CMN_REG075,
> > + val, val == ANA_PLL_DONE, 10, 20000);
> > return ret;
> > }
> >
> > @@ -153,18 +249,33 @@ static const struct phy_ops imx8_pcie_phy_ops =
> {
> > .owner = THIS_MODULE,
> > };
> >
> > +static const struct of_device_id imx8_pcie_phy_of_match[] = {
> > + {.compatible = "fsl,imx8mm-pcie-phy", .data = (void *)IMX8MM},
> > + {.compatible = "fsl,imx8mp-pcie-phy", .data = (void *)IMX8MP},
> > + { },
> > +};
> > +MODULE_DEVICE_TABLE(of, imx8_pcie_phy_of_match);
> > +
> > static int imx8_pcie_phy_probe(struct platform_device *pdev) {
> > struct phy_provider *phy_provider;
> > struct device *dev = &pdev->dev;
> > + const struct of_device_id *of_id;
> > struct device_node *np = dev->of_node;
> > struct imx8_pcie_phy *imx8_phy;
> > struct resource *res;
> >
> > + of_id = of_match_device(imx8_pcie_phy_of_match, dev);
> > + if (!of_id)
> > + return -EINVAL;
> > +
> > imx8_phy = devm_kzalloc(dev, sizeof(*imx8_phy), GFP_KERNEL);
> > if (!imx8_phy)
> > return -ENOMEM;
> >
> > + imx8_phy->dev = dev;
> > + imx8_phy->variant = (enum imx8_pcie_phy_type)of_id->data;
> > +
> > /* get PHY refclk pad mode */
> > of_property_read_u32(np, "fsl,refclk-pad-mode",
> > &imx8_phy->refclk_pad_mode);
> > @@ -201,6 +312,22 @@ static int imx8_pcie_phy_probe(struct
> platform_device *pdev)
> > dev_err(dev, "Failed to get PCIEPHY reset control\n");
> > return PTR_ERR(imx8_phy->reset);
> > }
> > + if (imx8_phy->variant == IMX8MP) {
> > + /* Grab HSIO MIX config register range */
> > + imx8_phy->hsio_blk_ctrl =
> > +
> syscon_regmap_lookup_by_compatible("fsl,imx8mp-hsio-blk-ctrl");
> > + if (IS_ERR(imx8_phy->hsio_blk_ctrl)) {
> > + dev_err(dev, "unable to find hsio mix registers\n");
> > + return PTR_ERR(imx8_phy->hsio_blk_ctrl);
> > + }
> > +
> > + imx8_phy->perst =
> > + devm_reset_control_get_exclusive(dev, "perst");
> > + if (IS_ERR(imx8_phy->perst)) {
> > + dev_err(dev, "Failed to get PCIEPHY perst control\n");
> > + return PTR_ERR(imx8_phy->perst);
> > + }
> > + }
> >
> > res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> > imx8_phy->base = devm_ioremap_resource(dev, res); @@ -218,12 +345,6
> > @@ static int imx8_pcie_phy_probe(struct platform_device *pdev)
> > return PTR_ERR_OR_ZERO(phy_provider); }
> >
> > -static const struct of_device_id imx8_pcie_phy_of_match[] = {
> > - {.compatible = "fsl,imx8mm-pcie-phy",},
> > - { },
> > -};
> > -MODULE_DEVICE_TABLE(of, imx8_pcie_phy_of_match);
> > -
> > static struct platform_driver imx8_pcie_phy_driver = {
> > .probe = imx8_pcie_phy_probe,
> > .driver = {
>