phy: mediatek: Add PCIe PHY driver

Add PCIe GEN3 PHY driver support on MediaTek chipsets.

Signed-off-by: Jianjun Wang <jianjun.wang@mediatek.com>
Reviewed-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
Reviewed-by: AngeloGioachino Del Regno <angelogioacchino.delregno@collabora.com>
Link: https://lore.kernel.org/r/20220617070246.20142-3-jianjun.wang@mediatek.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

3 files changed, 279 insertions, 0 deletions

diff --git a/drivers/phy/mediatek/Kconfig b/drivers/phy/mediatek/Kconfig
index 55f8e6c048ab..dfb18b490d07 100644
--- a/drivers/phy/mediatek/Kconfig
+++ b/drivers/phy/mediatek/Kconfig
@@ -2,6 +2,17 @@
 #
 # Phy drivers for Mediatek devices
 #
+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.
+
 config PHY_MTK_TPHY
 	tristate "MediaTek T-PHY Driver"
 	depends on ARCH_MEDIATEK || COMPILE_TEST
diff --git a/drivers/phy/mediatek/Makefile b/drivers/phy/mediatek/Makefile
index ace660fbed3a..445b23728a61 100644
--- a/drivers/phy/mediatek/Makefile
+++ b/drivers/phy/mediatek/Makefile
@@ -3,6 +3,7 @@
 # Makefile for the phy drivers.
 #
 
+obj-$(CONFIG_PHY_MTK_PCIE)		+= phy-mtk-pcie.o
 obj-$(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
diff --git a/drivers/phy/mediatek/phy-mtk-pcie.c b/drivers/phy/mediatek/phy-mtk-pcie.c
new file mode 100644
index 000000000000..7f29d43442bf
--- /dev/null
+++ b/drivers/phy/mediatek/phy-mtk-pcie.c
@@ -0,0 +1,267 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2022 MediaTek Inc.
+ * Author: Jianjun Wang <jianjun.wang@mediatek.com>
+ */
+
+#include <linux/bitfield.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
+/* Internal Resistor Selection of TX Bias Current */
+#define EFUSE_GLB_INTR_SEL		GENMASK(28, 24)
+
+#define PEXTP_ANA_LN0_TRX_REG		0xa000
+
+#define PEXTP_ANA_TX_REG		0x04
+/* TX PMOS impedance selection */
+#define EFUSE_LN_TX_PMOS_SEL		GENMASK(5, 2)
+/* TX NMOS impedance selection */
+#define EFUSE_LN_TX_NMOS_SEL		GENMASK(11, 8)
+
+#define PEXTP_ANA_RX_REG		0x3c
+/* RX impedance selection */
+#define EFUSE_LN_RX_SEL			GENMASK(3, 0)
+
+#define PEXTP_ANA_LANE_OFFSET		0x100
+
+/**
+ * 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 eFuse 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_REG, EFUSE_LN_TX_PMOS_SEL,
+			    FIELD_PREP(EFUSE_LN_TX_PMOS_SEL, data->tx_pmos));
+
+	mtk_phy_update_bits(addr + PEXTP_ANA_TX_REG, EFUSE_LN_TX_NMOS_SEL,
+			    FIELD_PREP(EFUSE_LN_TX_NMOS_SEL, data->tx_nmos));
+
+	mtk_phy_update_bits(addr + PEXTP_ANA_RX_REG, EFUSE_LN_RX_SEL,
+			    FIELD_PREP(EFUSE_LN_RX_SEL, 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,
+			    FIELD_PREP(EFUSE_GLB_INTR_SEL, 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[16];
+	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)
+		return dev_err_probe(dev, ret, "Failed to read %s\n", efuse_id);
+
+	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)
+		return 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)
+		return dev_err_probe(dev, ret, "Failed to read %s\n", efuse_id);
+
+	if (!(efuse->tx_pmos || efuse->tx_nmos || efuse->rx_data))
+		return dev_err_probe(dev, -EINVAL,
+				     "No eFuse data found for lane%d, but dts enable it\n",
+				     lane);
+
+	efuse->lane_efuse_supported = true;
+
+	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 data is optional */
+	nvmem_enabled = device_property_present(dev, "nvmem-cells");
+	if (!nvmem_enabled)
+		return 0;
+
+	ret = nvmem_cell_read_variable_le_u32(dev, "glb_intr",
+					      &pcie_phy->efuse_glb_intr);
+	if (ret)
+		return dev_err_probe(dev, ret, "Failed to read glb_intr\n");
+
+	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 || ret == -ENOMEM)
+			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);
+
+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@mediatek.com>");
+MODULE_LICENSE("GPL");