PCI: mediatek-gen3: Add Airoha EN7581 support

Introduce support for Airoha EN7581 PCIe controller to mediatek-gen3
PCIe controller driver.

Link: https://lore.kernel.org/linux-pci/aca00bd672ee576ad96d279414fc0835ff31f637.1720022580.git.lorenzo@kernel.org
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>
Tested-by: Zhengping Zhang <zhengping.zhang@airoha.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Acked-by: Jianjun Wang <jianjun.wang@mediatek.com>

drivers/pci/controller/Kconfig

@@ -196,7 +196,7 @@ config PCIE_MEDIATEK
 
 config PCIE_MEDIATEK_GEN3
 	tristate "MediaTek Gen3 PCIe controller"
-	depends on ARCH_MEDIATEK || COMPILE_TEST
+	depends on ARCH_AIROHA || ARCH_MEDIATEK || COMPILE_TEST
 	depends on PCI_MSI
 	help
 	  Adds support for PCIe Gen3 MAC controller for MediaTek SoCs.

drivers/pci/controller/pcie-mediatek-gen3.c

@@ -6,7 +6,9 @@
  * Author: Jianjun Wang <jianjun.wang@mediatek.com>
  */
 
+#include <linux/bitfield.h>
 #include <linux/clk.h>
+#include <linux/clk-provider.h>
 #include <linux/delay.h>
 #include <linux/iopoll.h>
 #include <linux/irq.h>
@@ -15,6 +17,8 @@
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/msi.h>
+#include <linux/of_device.h>
+#include <linux/of_pci.h>
 #include <linux/pci.h>
 #include <linux/phy/phy.h>
 #include <linux/platform_device.h>
@@ -29,6 +33,12 @@
 #define PCI_CLASS(class)		(class << 8)
 #define PCIE_RC_MODE			BIT(0)
 
+#define PCIE_EQ_PRESET_01_REG		0x100
+#define PCIE_VAL_LN0_DOWNSTREAM		GENMASK(6, 0)
+#define PCIE_VAL_LN0_UPSTREAM		GENMASK(14, 8)
+#define PCIE_VAL_LN1_DOWNSTREAM		GENMASK(22, 16)
+#define PCIE_VAL_LN1_UPSTREAM		GENMASK(30, 24)
+
 #define PCIE_CFGNUM_REG			0x140
 #define PCIE_CFG_DEVFN(devfn)		((devfn) & GENMASK(7, 0))
 #define PCIE_CFG_BUS(bus)		(((bus) << 8) & GENMASK(15, 8))
@@ -68,6 +78,14 @@
 #define PCIE_MSI_SET_ENABLE_REG		0x190
 #define PCIE_MSI_SET_ENABLE		GENMASK(PCIE_MSI_SET_NUM - 1, 0)
 
+#define PCIE_PIPE4_PIE8_REG		0x338
+#define PCIE_K_FINETUNE_MAX		GENMASK(5, 0)
+#define PCIE_K_FINETUNE_ERR		GENMASK(7, 6)
+#define PCIE_K_PRESET_TO_USE		GENMASK(18, 8)
+#define PCIE_K_PHYPARAM_QUERY		BIT(19)
+#define PCIE_K_QUERY_TIMEOUT		BIT(20)
+#define PCIE_K_PRESET_TO_USE_16G	GENMASK(31, 21)
+
 #define PCIE_MSI_SET_BASE_REG		0xc00
 #define PCIE_MSI_SET_OFFSET		0x10
 #define PCIE_MSI_SET_STATUS_OFFSET	0x04
@@ -100,7 +118,10 @@
 #define PCIE_ATR_TLP_TYPE_MEM		PCIE_ATR_TLP_TYPE(0)
 #define PCIE_ATR_TLP_TYPE_IO		PCIE_ATR_TLP_TYPE(2)
 
-#define MAX_NUM_PHY_RESETS		1
+#define MAX_NUM_PHY_RESETS		3
+
+/* Time in ms needed to complete PCIe reset on EN7581 SoC */
+#define PCIE_EN7581_RESET_TIME_MS	100
 
 struct mtk_gen3_pcie;
 
@@ -847,6 +868,85 @@ static int mtk_pcie_parse_port(struct mtk_gen3_pcie *pcie)
 	return 0;
 }
 
+static int mtk_pcie_en7581_power_up(struct mtk_gen3_pcie *pcie)
+{
+	struct device *dev = pcie->dev;
+	int err;
+	u32 val;
+
+	/*
+	 * Wait for the time needed to complete the bulk assert in
+	 * mtk_pcie_setup for EN7581 SoC.
+	 */
+	mdelay(PCIE_EN7581_RESET_TIME_MS);
+
+	err = phy_init(pcie->phy);
+	if (err) {
+		dev_err(dev, "failed to initialize PHY\n");
+		return err;
+	}
+
+	err = phy_power_on(pcie->phy);
+	if (err) {
+		dev_err(dev, "failed to power on PHY\n");
+		goto err_phy_on;
+	}
+
+	err = reset_control_bulk_deassert(pcie->soc->phy_resets.num_resets, pcie->phy_resets);
+	if (err) {
+		dev_err(dev, "failed to deassert PHYs\n");
+		goto err_phy_deassert;
+	}
+
+	/*
+	 * Wait for the time needed to complete the bulk de-assert above.
+	 * This time is specific for EN7581 SoC.
+	 */
+	mdelay(PCIE_EN7581_RESET_TIME_MS);
+
+	pm_runtime_enable(dev);
+	pm_runtime_get_sync(dev);
+
+	err = clk_bulk_prepare(pcie->num_clks, pcie->clks);
+	if (err) {
+		dev_err(dev, "failed to prepare clock\n");
+		goto err_clk_prepare;
+	}
+
+	val = FIELD_PREP(PCIE_VAL_LN0_DOWNSTREAM, 0x47) |
+	      FIELD_PREP(PCIE_VAL_LN1_DOWNSTREAM, 0x47) |
+	      FIELD_PREP(PCIE_VAL_LN0_UPSTREAM, 0x41) |
+	      FIELD_PREP(PCIE_VAL_LN1_UPSTREAM, 0x41);
+	writel_relaxed(val, pcie->base + PCIE_EQ_PRESET_01_REG);
+
+	val = PCIE_K_PHYPARAM_QUERY | PCIE_K_QUERY_TIMEOUT |
+	      FIELD_PREP(PCIE_K_PRESET_TO_USE_16G, 0x80) |
+	      FIELD_PREP(PCIE_K_PRESET_TO_USE, 0x2) |
+	      FIELD_PREP(PCIE_K_FINETUNE_MAX, 0xf);
+	writel_relaxed(val, pcie->base + PCIE_PIPE4_PIE8_REG);
+
+	err = clk_bulk_enable(pcie->num_clks, pcie->clks);
+	if (err) {
+		dev_err(dev, "failed to prepare clock\n");
+		goto err_clk_enable;
+	}
+
+	return 0;
+
+err_clk_enable:
+	clk_bulk_unprepare(pcie->num_clks, pcie->clks);
+err_clk_prepare:
+	pm_runtime_put_sync(dev);
+	pm_runtime_disable(dev);
+	reset_control_bulk_assert(pcie->soc->phy_resets.num_resets, pcie->phy_resets);
+err_phy_deassert:
+	phy_power_off(pcie->phy);
+err_phy_on:
+	phy_exit(pcie->phy);
+
+	return err;
+}
+
 static int mtk_pcie_power_up(struct mtk_gen3_pcie *pcie)
 {
 	struct device *dev = pcie->dev;
@@ -1113,7 +1213,18 @@ static const struct mtk_gen3_pcie_pdata mtk_pcie_soc_mt8192 = {
 	},
 };
 
+static const struct mtk_gen3_pcie_pdata mtk_pcie_soc_en7581 = {
+	.power_up = mtk_pcie_en7581_power_up,
+	.phy_resets = {
+		.id[0] = "phy-lane0",
+		.id[1] = "phy-lane1",
+		.id[2] = "phy-lane2",
+		.num_resets = 3,
+	},
+};
+
 static const struct of_device_id mtk_pcie_of_match[] = {
+	{ .compatible = "airoha,en7581-pcie", .data = &mtk_pcie_soc_en7581 },
 	{ .compatible = "mediatek,mt8192-pcie", .data = &mtk_pcie_soc_mt8192 },
 	{},
 };