Message-ID: <fb0f14cf952623557c8d71866b1d0eb38ffc4d11.camel@mediatek.com>
Date:   Tue, 22 Mar 2022 16:08:56 +0800
From:   Chunfeng Yun <chunfeng.yun@...iatek.com>
To:     Jianjun Wang <jianjun.wang@...iatek.com>,
        Kishon Vijay Abraham I <kishon@...com>,
        Vinod Koul <vkoul@...nel.org>,
        Rob Herring <robh+dt@...nel.org>,
        Matthias Brugger <matthias.bgg@...il.com>,
        "Chen-Yu Tsai" <wenst@...omium.org>,
        AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@...labora.com>,
        Krzysztof Kozlowski <krzk@...nel.org>
CC:     Wei-Shun Chang <weishunc@...gle.com>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-mediatek@...ts.infradead.org>,
        <linux-phy@...ts.infradead.org>, <devicetree@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>, <rex-bc.chen@...iatek.com>,
        <randy.wu@...iatek.com>, <jieyy.yang@...iatek.com>,
        <chuanjia.liu@...iatek.com>, <qizhong.cheng@...iatek.com>,
        <jian.yang@...iatek.com>
Subject: Re: [PATCH v3 2/2] phy: mediatek: Add PCIe PHY driver

On Tue, 2022-03-22 at 10:47 +0800, Jianjun Wang wrote:
> Add PCIe GEN3 PHY driver support on MediaTek chipsets.
> 
> Signed-off-by: Jianjun Wang <jianjun.wang@...iatek.com>
> ---
>  drivers/phy/mediatek/Kconfig        |  11 ++
>  drivers/phy/mediatek/Makefile       |   1 +
>  drivers/phy/mediatek/phy-mtk-pcie.c | 271
> ++++++++++++++++++++++++++++
>  3 files changed, 283 insertions(+)
>  create mode 100644 drivers/phy/mediatek/phy-mtk-pcie.c
> 
> diff --git a/drivers/phy/mediatek/Kconfig
> b/drivers/phy/mediatek/Kconfig
> index 55f8e6c048ab..387ed1b3f2cc 100644
> --- a/drivers/phy/mediatek/Kconfig
> +++ b/drivers/phy/mediatek/Kconfig
> @@ -55,3 +55,14 @@ config PHY_MTK_MIPI_DSI
>  	select GENERIC_PHY
>  	help
>  	  Support MIPI DSI for Mediatek SoCs.
> +
> +config PHY_MTK_PCIE
> +	tristate "MediaTek PCIe-PHY Driver"
> +	depends on ARCH_MEDIATEK || COMPILE_TEST
> +	depends on OF
> +	select GENERIC_PHY
> +	help
> +	  Say 'Y' here to add support for MediaTek PCIe PHY driver.
> +	  This driver create the basic PHY instance and provides
> initialize
> +	  callback for PCIe GEN3 port, it supports software efuse
> +	  initialization.
> diff --git a/drivers/phy/mediatek/Makefile
> b/drivers/phy/mediatek/Makefile
> index ace660fbed3a..788c13147f63 100644
> --- a/drivers/phy/mediatek/Makefile
> +++ b/drivers/phy/mediatek/Makefile
> @@ -6,6 +6,7 @@
>  obj-$(CONFIG_PHY_MTK_TPHY)		+= phy-mtk-tphy.o
>  obj-$(CONFIG_PHY_MTK_UFS)		+= phy-mtk-ufs.o
>  obj-$(CONFIG_PHY_MTK_XSPHY)		+= phy-mtk-xsphy.o
> +obj-$(CONFIG_PHY_MTK_PCIE)		+= phy-mtk-pcie.o
>  
>  phy-mtk-hdmi-drv-y			:= phy-mtk-hdmi.o
>  phy-mtk-hdmi-drv-y			+= phy-mtk-hdmi-mt2701.o
> diff --git a/drivers/phy/mediatek/phy-mtk-pcie.c
> b/drivers/phy/mediatek/phy-mtk-pcie.c
> new file mode 100644
> index 000000000000..2f19c253238f
> --- /dev/null
> +++ b/drivers/phy/mediatek/phy-mtk-pcie.c
> @@ -0,0 +1,271 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (c) 2022 MediaTek Inc.
> + * Author: Jianjun Wang <jianjun.wang@...iatek.com>
> + */
> +
> +#include <linux/bits.h>
> +#include <linux/compiler_types.h>
> +#include <linux/module.h>
> +#include <linux/nvmem-consumer.h>
> +#include <linux/of_device.h>
> +#include <linux/phy/phy.h>
> +#include <linux/platform_device.h>
> +#include <linux/slab.h>
> +
> +#include "phy-mtk-io.h"
> +
> +#define PEXTP_ANA_GLB_00_REG		0x9000
> +#define PEXTP_ANA_LN0_TRX_REG		0xa000
> +#define PEXTP_ANA_TX_OFFSET		0x04
> +#define PEXTP_ANA_RX_OFFSET		0x3c
> +#define PEXTP_ANA_LANE_OFFSET		0x100
> +
> +/* PEXTP_GLB_00_REG[28:24] Internal Resistor Selection of TX Bias
> Current */
> +#define EFUSE_GLB_INTR_SEL		GENMASK(28, 24)
> +#define EFUSE_GLB_INTR_VAL(x)		((0x1f & (x)) << 24)
> +
> +/* PEXTP_ANA_LN_RX_REG[3:0] RX impedance selection */
> +#define EFUSE_LN_RX_SEL			GENMASK(3, 0)
> +#define EFUSE_LN_RX_VAL(x)		(0xf & (x))
> +
> +/* PEXTP_ANA_LN_TX_REG[5:2] TX PMOS impedance selection */
> +#define EFUSE_LN_TX_PMOS_SEL		GENMASK(5, 2)
> +#define EFUSE_LN_TX_PMOS_VAL(x)		((0xf & (x)) << 2)
> +
> +/* PEXTP_ANA_LN_TX_REG[11:8] TX NMOS impedance selection */
> +#define EFUSE_LN_TX_NMOS_SEL		GENMASK(11, 8)
> +#define EFUSE_LN_TX_NMOS_VAL(x)		((0xf & (x)) << 8)
> +
> +/**
> + * struct mtk_pcie_lane_efuse - eFuse data for each lane
> + * @tx_pmos: TX PMOS impedance selection data
> + * @tx_nmos: TX NMOS impedance selection data
> + * @rx_data: RX impedance selection data
> + * @lane_efuse_supported: software eFuse data is supported for this
> lane
> + */
> +struct mtk_pcie_lane_efuse {
> +	u32 tx_pmos;
> +	u32 tx_nmos;
> +	u32 rx_data;
> +	bool lane_efuse_supported;
> +};
> +
> +/**
> + * struct mtk_pcie_phy_data - phy data for each SoC
> + * @num_lanes: supported lane numbers
> + * @sw_efuse_supported: support software to load eFuse data
> + */
> +struct mtk_pcie_phy_data {
> +	int num_lanes;
> +	bool sw_efuse_supported;
> +};
> +
> +/**
> + * struct mtk_pcie_phy - PCIe phy driver main structure
> + * @dev: pointer to device
> + * @phy: pointer to generic phy
> + * @sif_base: IO mapped register base address of system interface
> + * @data: pointer to SoC dependent data
> + * @sw_efuse_en: software eFuse enable status
> + * @efuse_glb_intr: internal resistor selection of TX bias current
> data
> + * @efuse: pointer to eFues data for each lane
> + */
> +struct mtk_pcie_phy {
> +	struct device *dev;
> +	struct phy *phy;
> +	void __iomem *sif_base;
> +	const struct mtk_pcie_phy_data *data;
> +
> +	bool sw_efuse_en;
> +	u32 efuse_glb_intr;
> +	struct mtk_pcie_lane_efuse *efuse;
> +};
> +
> +static void mtk_pcie_efuse_set_lane(struct mtk_pcie_phy *pcie_phy,
> +				    unsigned int lane)
> +{
> +	struct mtk_pcie_lane_efuse *data = &pcie_phy->efuse[lane];
> +	void __iomem *addr;
> +
> +	if (!data->lane_efuse_supported)
> +		return;
> +
> +	addr = pcie_phy->sif_base + PEXTP_ANA_LN0_TRX_REG +
> +	       lane * PEXTP_ANA_LANE_OFFSET;
> +
> +	mtk_phy_update_bits(addr + PEXTP_ANA_TX_OFFSET,
> EFUSE_LN_TX_PMOS_SEL,
> +			    EFUSE_LN_TX_PMOS_VAL(data->tx_pmos));
> +
> +	mtk_phy_update_bits(addr + PEXTP_ANA_TX_OFFSET,
> EFUSE_LN_TX_NMOS_SEL,
> +			    EFUSE_LN_TX_NMOS_VAL(data->tx_nmos));
> +
> +	mtk_phy_update_bits(addr + PEXTP_ANA_RX_OFFSET,
> EFUSE_LN_RX_SEL,
> +			    EFUSE_LN_RX_VAL(data->rx_data));
> +}
> +
> +/**
> + * mtk_pcie_phy_init() - Initialize the phy
> + * @phy: the phy to be initialized
> + *
> + * Initialize the phy by setting the efuse data.
> + * The hardware settings will be reset during suspend, it should be
> + * reinitialized when the consumer calls phy_init() again on resume.
> + */
> +static int mtk_pcie_phy_init(struct phy *phy)
> +{
> +	struct mtk_pcie_phy *pcie_phy = phy_get_drvdata(phy);
> +	int i;
> +
> +	if (!pcie_phy->sw_efuse_en)
> +		return 0;
> +
> +	/* Set global data */
> +	mtk_phy_update_bits(pcie_phy->sif_base + PEXTP_ANA_GLB_00_REG,
> +			    EFUSE_GLB_INTR_SEL,
> +			    EFUSE_GLB_INTR_VAL(pcie_phy-
> >efuse_glb_intr));
> +
> +	for (i = 0; i < pcie_phy->data->num_lanes; i++)
> +		mtk_pcie_efuse_set_lane(pcie_phy, i);
> +
> +	return 0;
> +}
> +
> +static const struct phy_ops mtk_pcie_phy_ops = {
> +	.init	= mtk_pcie_phy_init,
> +	.owner	= THIS_MODULE,
> +};
> +
> +static int mtk_pcie_efuse_read_for_lane(struct mtk_pcie_phy
> *pcie_phy,
> +					unsigned int lane)
> +{
> +	struct mtk_pcie_lane_efuse *efuse = &pcie_phy->efuse[lane];
> +	struct device *dev = pcie_phy->dev;
> +	char efuse_id[15];
> +	int ret;
> +
> +	snprintf(efuse_id, sizeof(efuse_id), "tx_ln%d_pmos", lane);
> +	ret = nvmem_cell_read_variable_le_u32(dev, efuse_id, &efuse-
> >tx_pmos);
> +	if (ret)
> +		dev_err_probe(dev, ret, "Failed to read %s\n",
> efuse_id);
skip this error?

> +
> +	snprintf(efuse_id, sizeof(efuse_id), "tx_ln%d_nmos", lane);
> +	ret = nvmem_cell_read_variable_le_u32(dev, efuse_id, &efuse-
> >tx_nmos);
> +	if (ret)
> +		dev_err_probe(dev, ret, "Failed to read %s\n",
> efuse_id);
> +
> +	snprintf(efuse_id, sizeof(efuse_id), "rx_ln%d", lane);
> +	ret = nvmem_cell_read_variable_le_u32(dev, efuse_id, &efuse-
> >rx_data);
> +	if (ret)
> +		dev_err_probe(dev, ret, "Failed to read %s\n",
> efuse_id);
> +
> +	if (!(efuse->tx_pmos || efuse->tx_nmos || efuse->rx_data))
> +		dev_err_probe(dev, -EINVAL,
> +			      "No eFuse data found for lane%d, but dts
> enable it\n",
> +			      lane);
> +
> +	efuse->lane_efuse_supported = true;

Seems efuse->lane_efuse_supported is always true?
but is false if all these three efuse values are zero, right?

> +
> +	return 0;
> +}
> +
> +static int mtk_pcie_read_efuse(struct mtk_pcie_phy *pcie_phy)
> +{
> +	struct device *dev = pcie_phy->dev;
> +	bool nvmem_enabled;
> +	int ret, i;
> +
> +	nvmem_enabled = device_property_read_bool(dev, "nvmem-cells");
> +	if (!nvmem_enabled)
> +		return -ENODEV;
> +
> +	ret = nvmem_cell_read_variable_le_u32(dev, "glb_intr",
> +					      &pcie_phy-
> >efuse_glb_intr);
> +	if (ret)
> +		dev_err_probe(dev, ret, "Failed to read glb_intr\n");
also here, skip the error?

> +
> +	pcie_phy->sw_efuse_en = true;
> +
> +	pcie_phy->efuse = devm_kzalloc(dev, pcie_phy->data->num_lanes *
> +				       sizeof(*pcie_phy->efuse),
> GFP_KERNEL);
> +	if (!pcie_phy->efuse)
> +		return -ENOMEM;
> +
> +	for (i = 0; i < pcie_phy->data->num_lanes; i++) {
> +		ret = mtk_pcie_efuse_read_for_lane(pcie_phy, i);
> +		if (ret)
> +			return ret;
> +	}
> +
> +	return 0;
> +}
> +
> +static int mtk_pcie_phy_probe(struct platform_device *pdev)
> +{
> +	struct device *dev = &pdev->dev;
> +	struct phy_provider *provider;
> +	struct mtk_pcie_phy *pcie_phy;
> +	int ret;
> +
> +	pcie_phy = devm_kzalloc(dev, sizeof(*pcie_phy), GFP_KERNEL);
> +	if (!pcie_phy)
> +		return -ENOMEM;
> +
> +	pcie_phy->sif_base =
> devm_platform_ioremap_resource_byname(pdev, "sif");
> +	if (IS_ERR(pcie_phy->sif_base))
> +		return dev_err_probe(dev, PTR_ERR(pcie_phy->sif_base),
> +				     "Failed to map phy-sif base\n");
> +
> +	pcie_phy->phy = devm_phy_create(dev, dev->of_node,
> &mtk_pcie_phy_ops);
> +	if (IS_ERR(pcie_phy->phy))
> +		return dev_err_probe(dev, PTR_ERR(pcie_phy->phy),
> +				     "Failed to create PCIe phy\n");
> +
> +	pcie_phy->dev = dev;
> +	pcie_phy->data = of_device_get_match_data(dev);
> +	if (!pcie_phy->data)
> +		return dev_err_probe(dev, -EINVAL, "Failed to get phy
> data\n");
> +
> +	if (pcie_phy->data->sw_efuse_supported) {
> +		/*
> +		 * Failed to read the efuse data is not a fatal
> problem,
> +		 * ignore the failure and keep going.
> +		 */
> +		ret = mtk_pcie_read_efuse(pcie_phy);
> +		if (ret == -EPROBE_DEFER)
> +			return ret;
> +	}
> +
> +	phy_set_drvdata(pcie_phy->phy, pcie_phy);
> +
> +	provider = devm_of_phy_provider_register(dev,
> of_phy_simple_xlate);
> +	if (IS_ERR(provider))
> +		return dev_err_probe(dev, PTR_ERR(provider),
> +				     "PCIe phy probe failed\n");
> +
> +	return 0;
> +}
> +
> +static const struct mtk_pcie_phy_data mt8195_data = {
> +	.num_lanes = 2,
> +	.sw_efuse_supported = true,
> +};
> +
> +static const struct of_device_id mtk_pcie_phy_of_match[] = {
> +	{ .compatible = "mediatek,mt8195-pcie-phy", .data =
> &mt8195_data },
> +	{ },
> +};
> +MODULE_DEVICE_TABLE(of, mtk_pcie_phy_of_match);
Do we need add a generic compatible which sw_efuse_supported is set
false? if no need, then pcie driver should handle the case without phy
due to we may use hw auto efuse and do not this driver anymore.


> +
> +static struct platform_driver mtk_pcie_phy_driver = {
> +	.probe	= mtk_pcie_phy_probe,
> +	.driver	= {
> +		.name = "mtk-pcie-phy",
> +		.of_match_table = mtk_pcie_phy_of_match,
> +	},
> +};
> +module_platform_driver(mtk_pcie_phy_driver);
> +
> +MODULE_DESCRIPTION("MediaTek PCIe PHY driver");
> +MODULE_AUTHOR("Jianjun Wang <jianjun.wang@...iatek.com>");
> +MODULE_LICENSE("GPL v2");

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