Re: [PATCH v3 5/9] phy: freescale: pcie: initialize the imx8 pcie standalone phy driver

From: Tim Harvey
Date: Thu Oct 21 2021 - 12:00:32 EST

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On Tue, Oct 12, 2021 at 2:06 AM Richard Zhu <hongxing.zhu@xxxxxxx> wrote:
>
> Add the standalone i.MX8 PCIe PHY driver.
> Some reset bits should be manipulated between PHY configurations and
> status check(internal PLL is locked or not).
> So, do the PHY configuration in the phy_calibrate().
> And check the PHY is ready or not in the phy_init().
>
> Signed-off-by: Richard Zhu <hongxing.zhu@xxxxxxx>
> ---
> drivers/phy/freescale/Kconfig | 9 +
> drivers/phy/freescale/Makefile | 1 +
> drivers/phy/freescale/phy-fsl-imx8m-pcie.c | 218 +++++++++++++++++++++
> 3 files changed, 228 insertions(+)
> create mode 100644 drivers/phy/freescale/phy-fsl-imx8m-pcie.c
>
> diff --git a/drivers/phy/freescale/Kconfig b/drivers/phy/freescale/Kconfig
> index 320630ffe3cd..fb08e5242602 100644
> --- a/drivers/phy/freescale/Kconfig
> +++ b/drivers/phy/freescale/Kconfig
> @@ -14,3 +14,12 @@ config PHY_MIXEL_MIPI_DPHY
> help
> Enable this to add support for the Mixel DSI PHY as found
> on NXP's i.MX8 family of SOCs.
> +
> +config PHY_FSL_IMX8M_PCIE
> + tristate "Freescale i.MX8 PCIE PHY"
> + depends on OF && HAS_IOMEM
> + select GENERIC_PHY
> + default ARCH_MXC
> + help
> + Enable this to add support for the PCIE PHY as found on
> + i.MX8M family of SOCs.
> diff --git a/drivers/phy/freescale/Makefile b/drivers/phy/freescale/Makefile
> index 1d02e3869b45..55d07c742ab0 100644
> --- a/drivers/phy/freescale/Makefile
> +++ b/drivers/phy/freescale/Makefile
> @@ -1,3 +1,4 @@
> # SPDX-License-Identifier: GPL-2.0-only
> obj-$(CONFIG_PHY_FSL_IMX8MQ_USB) += phy-fsl-imx8mq-usb.o
> obj-$(CONFIG_PHY_MIXEL_MIPI_DPHY) += phy-fsl-imx8-mipi-dphy.o
> +obj-$(CONFIG_PHY_FSL_IMX8M_PCIE) += phy-fsl-imx8m-pcie.o
> diff --git a/drivers/phy/freescale/phy-fsl-imx8m-pcie.c b/drivers/phy/freescale/phy-fsl-imx8m-pcie.c
> new file mode 100644
> index 000000000000..317cf61bff37
> --- /dev/null
> +++ b/drivers/phy/freescale/phy-fsl-imx8m-pcie.c
> @@ -0,0 +1,218 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * Copyright 2021 NXP
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/io.h>
> +#include <linux/iopoll.h>
> +#include <linux/delay.h>
> +#include <linux/mfd/syscon.h>
> +#include <linux/mfd/syscon/imx7-iomuxc-gpr.h>
> +#include <linux/module.h>
> +#include <linux/phy/phy.h>
> +#include <linux/platform_device.h>
> +#include <linux/regmap.h>
> +#include <linux/reset.h>
> +#include <dt-bindings/phy/phy-imx8-pcie.h>
> +
> +#define IMX8MM_PCIE_PHY_CMN_REG061 0x184
> +#define ANA_PLL_CLK_OUT_TO_EXT_IO_EN BIT(0)
> +#define IMX8MM_PCIE_PHY_CMN_REG062 0x188
> +#define ANA_PLL_CLK_OUT_TO_EXT_IO_SEL BIT(3)
> +#define IMX8MM_PCIE_PHY_CMN_REG063 0x18C
> +#define AUX_PLL_REFCLK_SEL_SYS_PLL GENMASK(7, 6)
> +#define IMX8MM_PCIE_PHY_CMN_REG064 0x190
> +#define ANA_AUX_RX_TX_SEL_TX BIT(7)
> +#define ANA_AUX_RX_TERM_GND_EN BIT(3)
> +#define ANA_AUX_TX_TERM BIT(2)
> +#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 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)
> +#define IMX8MM_GPR_PCIE_REF_CLK_EXT FIELD_PREP(IMX8MM_GPR_PCIE_REF_CLK_SEL, 0x2)
> +#define IMX8MM_GPR_PCIE_AUX_EN BIT(19)
> +#define IMX8MM_GPR_PCIE_CMN_RST BIT(18)
> +#define IMX8MM_GPR_PCIE_POWER_OFF BIT(17)
> +#define IMX8MM_GPR_PCIE_SSC_EN BIT(16)
> +#define IMX8MM_GPR_PCIE_REF_USE_PAD BIT(9)
> +
> +struct imx8_pcie_phy {
> + u32 refclk_pad_mode;
> + void __iomem *base;
> + struct clk *clk;
> + struct phy *phy;
> + struct regmap *iomuxc_gpr;
> + struct reset_control *reset;
> +};
> +
> +static int imx8_pcie_phy_init(struct phy *phy)
> +{
> + int ret;
> + u32 val, pad_mode;
> + struct imx8_pcie_phy *imx8_phy = phy_get_drvdata(phy);
> +
> + reset_control_assert(imx8_phy->reset);
> +
> + regmap_update_bits(imx8_phy->iomuxc_gpr, IOMUXC_GPR14,
> + IMX8MM_GPR_PCIE_REF_USE_PAD,
> + imx8_phy->refclk_pad_mode == 1 ?

Hi Richard,

use the enumerated type for the comparison above for clarity:
imx8_phy->refclk_pad_mode == IMX8_PCIE_REFCLK_PAD_INPUT

Also, this is the configuration that makes my imx8mm-venice boards
which do not use CLKREQ# hang while waiting for PHY. I am setting in
my dt:
&pcie_phy {
fsl,refclk-pad-mode = <IMX8_PCIE_REFCLK_PAD_INPUT>;
clocks = <&clk IMX8MM_CLK_DUMMY>;
status = "okay";
};

The NXP kernel woudl always set this bit to 0 which makes my board work.

The IMX8MMRM documentation appears incorrect here:
IOMUXC_GPR_GPR14 bit 9: GPR_PCIE1_ PHY_I_AUX_ EN_OVERRIDE_ EN:
{GPR_PCIE1_PHY_I_AUX_EN_OVERRIDE_EN, GPR_PCIE1_PHY_FUNC_I_AUX_EN}
2'b00 External Reference Clock I/O (for PLL) Disable
2'b01 External Reference Clock I/O (for PLL) Enable
2'b10 External Reference Clock I/O (for PLL) Disable
2'b11 External Reference Clock I/O (for PLL) output is controlled by CLKREQ#

How is it they define this as a single bit then give descriptions for
2 bits? Something is wrong here.

> + IMX8MM_GPR_PCIE_REF_USE_PAD : 0);
> + regmap_update_bits(imx8_phy->iomuxc_gpr, IOMUXC_GPR14,
> + IMX8MM_GPR_PCIE_AUX_EN,
> + IMX8MM_GPR_PCIE_AUX_EN);
> + regmap_update_bits(imx8_phy->iomuxc_gpr, IOMUXC_GPR14,
> + IMX8MM_GPR_PCIE_POWER_OFF, 0);
> + regmap_update_bits(imx8_phy->iomuxc_gpr, IOMUXC_GPR14,
> + IMX8MM_GPR_PCIE_SSC_EN, 0);
> +
> + regmap_update_bits(imx8_phy->iomuxc_gpr, IOMUXC_GPR14,
> + IMX8MM_GPR_PCIE_REF_CLK_SEL,
> + imx8_phy->refclk_pad_mode == 1 ?

imx8_phy->refclk_pad_mode == IMX8_PCIE_REFCLK_PAD_INPUT

Best regards,

Tim

> + IMX8MM_GPR_PCIE_REF_CLK_EXT :
> + IMX8MM_GPR_PCIE_REF_CLK_PLL);
> + usleep_range(100, 200);
> +
> + /* Do the PHY common block reset */
> + regmap_update_bits(imx8_phy->iomuxc_gpr, IOMUXC_GPR14,
> + IMX8MM_GPR_PCIE_CMN_RST,
> + IMX8MM_GPR_PCIE_CMN_RST);
> + usleep_range(200, 500);
> +
> +
> + pad_mode = imx8_phy->refclk_pad_mode;
> + 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);
> + }
> +
> + /* Tune PHY de-emphasis setting to pass PCIe compliance. */
> + writel(PCIE_PHY_TRSV_REG5_GEN1_DEEMP,
> + imx8_phy->base + PCIE_PHY_TRSV_REG5);
> + writel(PCIE_PHY_TRSV_REG6_GEN2_DEEMP,
> + 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);
> + return ret;
> +}
> +
> +static int imx8_pcie_phy_power_on(struct phy *phy)
> +{
> + struct imx8_pcie_phy *imx8_phy = phy_get_drvdata(phy);
> +
> + return clk_prepare_enable(imx8_phy->clk);
> +}
> +
> +static int imx8_pcie_phy_power_off(struct phy *phy)
> +{
> + struct imx8_pcie_phy *imx8_phy = phy_get_drvdata(phy);
> +
> + clk_disable_unprepare(imx8_phy->clk);
> +
> + return 0;
> +}
> +
> +static const struct phy_ops imx8_pcie_phy_ops = {
> + .init = imx8_pcie_phy_init,
> + .power_on = imx8_pcie_phy_power_on,
> + .power_off = imx8_pcie_phy_power_off,
> + .owner = THIS_MODULE,
> +};
> +
> +static int imx8_pcie_phy_probe(struct platform_device *pdev)
> +{
> + struct phy_provider *phy_provider;
> + struct device *dev = &pdev->dev;
> + struct device_node *np = dev->of_node;
> + struct imx8_pcie_phy *imx8_phy;
> + struct resource *res;
> +
> + imx8_phy = devm_kzalloc(dev, sizeof(*imx8_phy), GFP_KERNEL);
> + if (!imx8_phy)
> + return -ENOMEM;
> +
> + /* get PHY refclk pad mode */
> + of_property_read_u32(np, "fsl,refclk-pad-mode",
> + &imx8_phy->refclk_pad_mode);
> +
> + imx8_phy->clk = devm_clk_get(dev, "phy");
> + if (IS_ERR(imx8_phy->clk)) {
> + dev_err(dev, "failed to get imx pcie phy clock\n");
> + return PTR_ERR(imx8_phy->clk);
> + }
> +
> + /* Grab GPR config register range */
> + imx8_phy->iomuxc_gpr =
> + syscon_regmap_lookup_by_compatible("fsl,imx6q-iomuxc-gpr");
> + if (IS_ERR(imx8_phy->iomuxc_gpr)) {
> + dev_err(dev, "unable to find iomuxc registers\n");
> + return PTR_ERR(imx8_phy->iomuxc_gpr);
> + }
> +
> + imx8_phy->reset = devm_reset_control_get_exclusive(dev, "pciephy");
> + if (IS_ERR(imx8_phy->reset)) {
> + dev_err(dev, "Failed to get PCIEPHY reset control\n");
> + return PTR_ERR(imx8_phy->reset);
> + }
> +
> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + imx8_phy->base = devm_ioremap_resource(dev, res);
> + if (IS_ERR(imx8_phy->base))
> + return PTR_ERR(imx8_phy->base);
> +
> + imx8_phy->phy = devm_phy_create(dev, NULL, &imx8_pcie_phy_ops);
> + if (IS_ERR(imx8_phy->phy))
> + return PTR_ERR(imx8_phy->phy);
> +
> + phy_set_drvdata(imx8_phy->phy, imx8_phy);
> +
> + phy_provider = devm_of_phy_provider_register(dev, of_phy_simple_xlate);
> +
> + 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 = {
> + .name = "imx8-pcie-phy",
> + .of_match_table = imx8_pcie_phy_of_match,
> + }
> +};
> +module_platform_driver(imx8_pcie_phy_driver);
> +
> +MODULE_DESCRIPTION("FSL IMX8 PCIE PHY driver");
> +MODULE_LICENSE("GPL");
> --
> 2.25.1
>

Next message: Kees Cook: "Re: [PATCH 02/20] exit: Remove calls of do_exit after noreturn versions of die"
Previous message: Pali Rohár: "Re: [PATCH v3 02/25] PCI: Set error response in config access defines when ops->read() fails"
Next in thread: Richard Zhu: "RE: [PATCH v3 5/9] phy: freescale: pcie: initialize the imx8 pcie standalone phy driver"
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