PCI: rockchip-dwc: Add Rockchip RK356X host controller driver

Add a driver for the DesignWare-based PCIe controller found on
RK356X. The existing pcie-rockchip-host driver is only used for
the Rockchip-designed IP found on RK3399.

Link: https://lore.kernel.org/r/20210625065511.1096935-1-xxm@rock-chips.com
Tested-by: Peter Geis <pgwipeout@gmail.com>
Signed-off-by: Simon Xue <xxm@rock-chips.com>
Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>
Reviewed-by: Rob Herring <robh@kernel.org>

drivers/pci/controller/dwc/Kconfig

@@ -214,6 +214,17 @@ config PCIE_ARTPEC6_EP
 	  Enables support for the PCIe controller in the ARTPEC-6 SoC to work in
 	  endpoint mode. This uses the DesignWare core.
 
+config PCIE_ROCKCHIP_DW_HOST
+	bool "Rockchip DesignWare PCIe controller"
+	select PCIE_DW
+	select PCIE_DW_HOST
+	depends on PCI_MSI_IRQ_DOMAIN
+	depends on ARCH_ROCKCHIP || COMPILE_TEST
+	depends on OF
+	help
+	  Enables support for the DesignWare PCIe controller in the
+	  Rockchip SoC except RK3399.
+
 config PCIE_INTEL_GW
 	bool "Intel Gateway PCIe host controller support"
 	depends on OF && (X86 || COMPILE_TEST)

drivers/pci/controller/dwc/Makefile

@@ -14,6 +14,7 @@ obj-$(CONFIG_PCI_LAYERSCAPE_EP) += pci-layerscape-ep.o
 obj-$(CONFIG_PCIE_QCOM) += pcie-qcom.o
 obj-$(CONFIG_PCIE_ARMADA_8K) += pcie-armada8k.o
 obj-$(CONFIG_PCIE_ARTPEC6) += pcie-artpec6.o
+obj-$(CONFIG_PCIE_ROCKCHIP_DW_HOST) += pcie-dw-rockchip.o
 obj-$(CONFIG_PCIE_INTEL_GW) += pcie-intel-gw.o
 obj-$(CONFIG_PCIE_KIRIN) += pcie-kirin.o
 obj-$(CONFIG_PCIE_HISI_STB) += pcie-histb.o

drivers/pci/controller/dwc/pcie-dw-rockchip.c

@@ -0,0 +1,279 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * PCIe host controller driver for Rockchip SoCs.
+ *
+ * Copyright (C) 2021 Rockchip Electronics Co., Ltd.
+ *		http://www.rock-chips.com
+ *
+ * Author: Simon Xue <xxm@rock-chips.com>
+ */
+
+#include <linux/clk.h>
+#include <linux/gpio/consumer.h>
+#include <linux/mfd/syscon.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/phy/phy.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/reset.h>
+
+#include "pcie-designware.h"
+
+/*
+ * The upper 16 bits of PCIE_CLIENT_CONFIG are a write
+ * mask for the lower 16 bits.
+ */
+#define HIWORD_UPDATE(mask, val) (((mask) << 16) | (val))
+#define HIWORD_UPDATE_BIT(val)	HIWORD_UPDATE(val, val)
+
+#define to_rockchip_pcie(x) dev_get_drvdata((x)->dev)
+
+#define PCIE_CLIENT_RC_MODE		HIWORD_UPDATE_BIT(0x40)
+#define PCIE_CLIENT_ENABLE_LTSSM	HIWORD_UPDATE_BIT(0xc)
+#define PCIE_SMLH_LINKUP		BIT(16)
+#define PCIE_RDLH_LINKUP		BIT(17)
+#define PCIE_LINKUP			(PCIE_SMLH_LINKUP | PCIE_RDLH_LINKUP)
+#define PCIE_L0S_ENTRY			0x11
+#define PCIE_CLIENT_GENERAL_CONTROL	0x0
+#define PCIE_CLIENT_GENERAL_DEBUG	0x104
+#define PCIE_CLIENT_HOT_RESET_CTRL      0x180
+#define PCIE_CLIENT_LTSSM_STATUS	0x300
+#define PCIE_LTSSM_ENABLE_ENHANCE       BIT(4)
+#define PCIE_LTSSM_STATUS_MASK		GENMASK(5, 0)
+
+struct rockchip_pcie {
+	struct dw_pcie			pci;
+	void __iomem			*apb_base;
+	struct phy			*phy;
+	struct clk_bulk_data		*clks;
+	unsigned int			clk_cnt;
+	struct reset_control		*rst;
+	struct gpio_desc		*rst_gpio;
+	struct regulator                *vpcie3v3;
+};
+
+static int rockchip_pcie_readl_apb(struct rockchip_pcie *rockchip,
+					     u32 reg)
+{
+	return readl_relaxed(rockchip->apb_base + reg);
+}
+
+static void rockchip_pcie_writel_apb(struct rockchip_pcie *rockchip,
+						u32 val, u32 reg)
+{
+	writel_relaxed(val, rockchip->apb_base + reg);
+}
+
+static void rockchip_pcie_enable_ltssm(struct rockchip_pcie *rockchip)
+{
+	rockchip_pcie_writel_apb(rockchip, PCIE_CLIENT_ENABLE_LTSSM,
+				 PCIE_CLIENT_GENERAL_CONTROL);
+}
+
+static int rockchip_pcie_link_up(struct dw_pcie *pci)
+{
+	struct rockchip_pcie *rockchip = to_rockchip_pcie(pci);
+	u32 val = rockchip_pcie_readl_apb(rockchip, PCIE_CLIENT_LTSSM_STATUS);
+
+	if ((val & PCIE_LINKUP) == PCIE_LINKUP &&
+	    (val & PCIE_LTSSM_STATUS_MASK) == PCIE_L0S_ENTRY)
+		return 1;
+
+	return 0;
+}
+
+static int rockchip_pcie_start_link(struct dw_pcie *pci)
+{
+	struct rockchip_pcie *rockchip = to_rockchip_pcie(pci);
+
+	/* Reset device */
+	gpiod_set_value_cansleep(rockchip->rst_gpio, 0);
+
+	rockchip_pcie_enable_ltssm(rockchip);
+
+	/*
+	 * PCIe requires the refclk to be stable for 100µs prior to releasing
+	 * PERST. See table 2-4 in section 2.6.2 AC Specifications of the PCI
+	 * Express Card Electromechanical Specification, 1.1. However, we don't
+	 * know if the refclk is coming from RC's PHY or external OSC. If it's
+	 * from RC, so enabling LTSSM is the just right place to release #PERST.
+	 * We need more extra time as before, rather than setting just
+	 * 100us as we don't know how long should the device need to reset.
+	 */
+	msleep(100);
+	gpiod_set_value_cansleep(rockchip->rst_gpio, 1);
+
+	return 0;
+}
+
+static int rockchip_pcie_host_init(struct pcie_port *pp)
+{
+	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
+	struct rockchip_pcie *rockchip = to_rockchip_pcie(pci);
+	u32 val = HIWORD_UPDATE_BIT(PCIE_LTSSM_ENABLE_ENHANCE);
+
+	/* LTSSM enable control mode */
+	rockchip_pcie_writel_apb(rockchip, val, PCIE_CLIENT_HOT_RESET_CTRL);
+
+	rockchip_pcie_writel_apb(rockchip, PCIE_CLIENT_RC_MODE,
+				 PCIE_CLIENT_GENERAL_CONTROL);
+
+	return 0;
+}
+
+static const struct dw_pcie_host_ops rockchip_pcie_host_ops = {
+	.host_init = rockchip_pcie_host_init,
+};
+
+static int rockchip_pcie_clk_init(struct rockchip_pcie *rockchip)
+{
+	struct device *dev = rockchip->pci.dev;
+	int ret;
+
+	ret = devm_clk_bulk_get_all(dev, &rockchip->clks);
+	if (ret < 0)
+		return ret;
+
+	rockchip->clk_cnt = ret;
+
+	return clk_bulk_prepare_enable(rockchip->clk_cnt, rockchip->clks);
+}
+
+static int rockchip_pcie_resource_get(struct platform_device *pdev,
+				      struct rockchip_pcie *rockchip)
+{
+	rockchip->apb_base = devm_platform_ioremap_resource_byname(pdev, "apb");
+	if (IS_ERR(rockchip->apb_base))
+		return PTR_ERR(rockchip->apb_base);
+
+	rockchip->rst_gpio = devm_gpiod_get_optional(&pdev->dev, "reset",
+						     GPIOD_OUT_HIGH);
+	if (IS_ERR(rockchip->rst_gpio))
+		return PTR_ERR(rockchip->rst_gpio);
+
+	return 0;
+}
+
+static int rockchip_pcie_phy_init(struct rockchip_pcie *rockchip)
+{
+	struct device *dev = rockchip->pci.dev;
+	int ret;
+
+	rockchip->phy = devm_phy_get(dev, "pcie-phy");
+	if (IS_ERR(rockchip->phy))
+		return dev_err_probe(dev, PTR_ERR(rockchip->phy),
+				     "missing PHY\n");
+
+	ret = phy_init(rockchip->phy);
+	if (ret < 0)
+		return ret;
+
+	ret = phy_power_on(rockchip->phy);
+	if (ret)
+		phy_exit(rockchip->phy);
+
+	return ret;
+}
+
+static void rockchip_pcie_phy_deinit(struct rockchip_pcie *rockchip)
+{
+	phy_exit(rockchip->phy);
+	phy_power_off(rockchip->phy);
+}
+
+static int rockchip_pcie_reset_control_release(struct rockchip_pcie *rockchip)
+{
+	struct device *dev = rockchip->pci.dev;
+
+	rockchip->rst = devm_reset_control_array_get_exclusive(dev);
+	if (IS_ERR(rockchip->rst))
+		return dev_err_probe(dev, PTR_ERR(rockchip->rst),
+				     "failed to get reset lines\n");
+
+	return reset_control_deassert(rockchip->rst);
+}
+
+static const struct dw_pcie_ops dw_pcie_ops = {
+	.link_up = rockchip_pcie_link_up,
+	.start_link = rockchip_pcie_start_link,
+};
+
+static int rockchip_pcie_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct rockchip_pcie *rockchip;
+	struct pcie_port *pp;
+	int ret;
+
+	rockchip = devm_kzalloc(dev, sizeof(*rockchip), GFP_KERNEL);
+	if (!rockchip)
+		return -ENOMEM;
+
+	platform_set_drvdata(pdev, rockchip);
+
+	rockchip->pci.dev = dev;
+	rockchip->pci.ops = &dw_pcie_ops;
+
+	pp = &rockchip->pci.pp;
+	pp->ops = &rockchip_pcie_host_ops;
+
+	ret = rockchip_pcie_resource_get(pdev, rockchip);
+	if (ret)
+		return ret;
+
+	/* DON'T MOVE ME: must be enable before PHY init */
+	rockchip->vpcie3v3 = devm_regulator_get_optional(dev, "vpcie3v3");
+	if (IS_ERR(rockchip->vpcie3v3)) {
+		if (PTR_ERR(rockchip->vpcie3v3) != -ENODEV)
+			return dev_err_probe(dev, PTR_ERR(rockchip->vpcie3v3),
+					"failed to get vpcie3v3 regulator\n");
+		rockchip->vpcie3v3 = NULL;
+	} else {
+		ret = regulator_enable(rockchip->vpcie3v3);
+		if (ret) {
+			dev_err(dev, "failed to enable vpcie3v3 regulator\n");
+			return ret;
+		}
+	}
+
+	ret = rockchip_pcie_phy_init(rockchip);
+	if (ret)
+		goto disable_regulator;
+
+	ret = rockchip_pcie_reset_control_release(rockchip);
+	if (ret)
+		goto deinit_phy;
+
+	ret = rockchip_pcie_clk_init(rockchip);
+	if (ret)
+		goto deinit_phy;
+
+	ret = dw_pcie_host_init(pp);
+	if (!ret)
+		return 0;
+
+	clk_bulk_disable_unprepare(rockchip->clk_cnt, rockchip->clks);
+deinit_phy:
+	rockchip_pcie_phy_deinit(rockchip);
+disable_regulator:
+	if (rockchip->vpcie3v3)
+		regulator_disable(rockchip->vpcie3v3);
+
+	return ret;
+}
+
+static const struct of_device_id rockchip_pcie_of_match[] = {
+	{ .compatible = "rockchip,rk3568-pcie", },
+	{},
+};
+
+static struct platform_driver rockchip_pcie_driver = {
+	.driver = {
+		.name	= "rockchip-dw-pcie",
+		.of_match_table = rockchip_pcie_of_match,
+		.suppress_bind_attrs = true,
+	},
+	.probe = rockchip_pcie_probe,
+};
+builtin_platform_driver(rockchip_pcie_driver);