Message-ID: <20251110173334.234303-4-vincent.guittot@linaro.org>
Date: Mon, 10 Nov 2025 18:33:33 +0100
From: Vincent Guittot <vincent.guittot@...aro.org>
To: chester62515@...il.com,
	mbrugger@...e.com,
	ghennadi.procopciuc@....nxp.com,
	s32@....com,
	bhelgaas@...gle.com,
	jingoohan1@...il.com,
	lpieralisi@...nel.org,
	kwilczynski@...nel.org,
	mani@...nel.org,
	robh@...nel.org,
	krzk+dt@...nel.org,
	conor+dt@...nel.org,
	Ionut.Vicovan@....com,
	larisa.grigore@....com,
	ciprianmarian.costea@....com,
	bogdan.hamciuc@....com,
	Frank.li@....com,
	linux-arm-kernel@...ts.infradead.org,
	linux-pci@...r.kernel.org,
	devicetree@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	imx@...ts.linux.dev
Cc: cassel@...nel.org
Subject: [PATCH 3/4 v4] PCI: s32g: Add initial PCIe support (RC)

Add initial support of the PCIe controller for S32G Soc family. Only
host mode is supported.

Co-developed-by: Ionut Vicovan <Ionut.Vicovan@....com>
Signed-off-by: Ionut Vicovan <Ionut.Vicovan@....com>
Co-developed-by: Ciprian Marian Costea <ciprianmarian.costea@....com>
Signed-off-by: Ciprian Marian Costea <ciprianmarian.costea@....com>
Co-developed-by: Ghennadi Procopciuc <Ghennadi.Procopciuc@....com>
Signed-off-by: Ghennadi Procopciuc <Ghennadi.Procopciuc@....com>
Co-developed-by: Larisa Grigore <larisa.grigore@....com>
Signed-off-by: Larisa Grigore <larisa.grigore@....com>
Signed-off-by: Vincent Guittot <vincent.guittot@...aro.org>
---
 drivers/pci/controller/dwc/Kconfig            |  10 +
 drivers/pci/controller/dwc/Makefile           |   1 +
 .../pci/controller/dwc/pcie-nxp-s32g-regs.h   |  27 ++
 drivers/pci/controller/dwc/pcie-nxp-s32g.c    | 435 ++++++++++++++++++
 4 files changed, 473 insertions(+)
 create mode 100644 drivers/pci/controller/dwc/pcie-nxp-s32g-regs.h
 create mode 100644 drivers/pci/controller/dwc/pcie-nxp-s32g.c

diff --git a/drivers/pci/controller/dwc/Kconfig b/drivers/pci/controller/dwc/Kconfig
index 349d4657393c..e276956c3fca 100644
--- a/drivers/pci/controller/dwc/Kconfig
+++ b/drivers/pci/controller/dwc/Kconfig
@@ -256,6 +256,16 @@ config PCIE_TEGRA194_EP
 	  in order to enable device-specific features PCIE_TEGRA194_EP must be
 	  selected. This uses the DesignWare core.
 
+config PCIE_NXP_S32G
+	tristate "NXP S32G PCIe controller (host mode)"
+	depends on ARCH_S32 || COMPILE_TEST
+	select PCIE_DW_HOST
+	help
+	  Enable support for the PCIe controller in NXP S32G based boards to
+	  work in Host mode. The controller is based on DesignWare IP and
+	  can work either as RC or EP. In order to enable host-specific
+	  features PCIE_NXP_S32G must be selected.
+
 config PCIE_DW_PLAT
 	bool
 
diff --git a/drivers/pci/controller/dwc/Makefile b/drivers/pci/controller/dwc/Makefile
index 7ae28f3b0fb3..3301bbbad78c 100644
--- a/drivers/pci/controller/dwc/Makefile
+++ b/drivers/pci/controller/dwc/Makefile
@@ -10,6 +10,7 @@ obj-$(CONFIG_PCI_DRA7XX) += pci-dra7xx.o
 obj-$(CONFIG_PCI_EXYNOS) += pci-exynos.o
 obj-$(CONFIG_PCIE_FU740) += pcie-fu740.o
 obj-$(CONFIG_PCI_IMX6) += pci-imx6.o
+obj-$(CONFIG_PCIE_NXP_S32G) += pcie-nxp-s32g.o
 obj-$(CONFIG_PCIE_SPEAR13XX) += pcie-spear13xx.o
 obj-$(CONFIG_PCI_KEYSTONE) += pci-keystone.o
 obj-$(CONFIG_PCI_LAYERSCAPE) += pci-layerscape.o
diff --git a/drivers/pci/controller/dwc/pcie-nxp-s32g-regs.h b/drivers/pci/controller/dwc/pcie-nxp-s32g-regs.h
new file mode 100644
index 000000000000..c264446a8f21
--- /dev/null
+++ b/drivers/pci/controller/dwc/pcie-nxp-s32g-regs.h
@@ -0,0 +1,27 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * Copyright 2015-2016 Freescale Semiconductor, Inc.
+ * Copyright 2016-2023, 2025 NXP
+ */
+
+#ifndef PCIE_S32G_REGS_H
+#define PCIE_S32G_REGS_H
+
+/* PCIe controller Sub-System */
+
+/* PCIe controller 0 General Control 1 */
+#define PCIE_S32G_PE0_GEN_CTRL_1		0x50
+#define DEVICE_TYPE_MASK			GENMASK(3, 0)
+#define SRIS_MODE				BIT(8)
+
+/* PCIe controller 0 General Control 3 */
+#define PCIE_S32G_PE0_GEN_CTRL_3		0x58
+#define LTSSM_EN				BIT(0)
+
+/* PCIe Controller 0 Link Debug 2 */
+#define PCIE_S32G_PE0_LINK_DBG_2		0xB4
+#define SMLH_LTSSM_STATE_MASK			GENMASK(5, 0)
+#define SMLH_LINK_UP				BIT(6)
+#define RDLH_LINK_UP				BIT(7)
+
+#endif  /* PCI_S32G_REGS_H */
diff --git a/drivers/pci/controller/dwc/pcie-nxp-s32g.c b/drivers/pci/controller/dwc/pcie-nxp-s32g.c
new file mode 100644
index 000000000000..18bf0fe6f416
--- /dev/null
+++ b/drivers/pci/controller/dwc/pcie-nxp-s32g.c
@@ -0,0 +1,435 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * PCIe host controller driver for NXP S32G SoCs
+ *
+ * Copyright 2019-2025 NXP
+ */
+
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/memblock.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/of_address.h>
+#include <linux/pci.h>
+#include <linux/phy/phy.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+#include <linux/sizes.h>
+#include <linux/types.h>
+
+#include "pcie-designware.h"
+#include "pcie-nxp-s32g-regs.h"
+
+struct s32g_pcie_port {
+	struct list_head list;
+	struct phy *phy;
+};
+
+struct s32g_pcie {
+	struct dw_pcie	pci;
+	void __iomem *ctrl_base;
+	struct list_head ports;
+};
+
+#define to_s32g_from_dw_pcie(x) \
+	container_of(x, struct s32g_pcie, pci)
+
+static void s32g_pcie_writel_ctrl(struct s32g_pcie *s32g_pp, u32 reg, u32 val)
+{
+	writel(val, s32g_pp->ctrl_base + reg);
+}
+
+static u32 s32g_pcie_readl_ctrl(struct s32g_pcie *s32g_pp, u32 reg)
+{
+	return readl(s32g_pp->ctrl_base + reg);
+}
+
+static void s32g_pcie_enable_ltssm(struct s32g_pcie *s32g_pp)
+{
+	u32 reg;
+
+	reg = s32g_pcie_readl_ctrl(s32g_pp, PCIE_S32G_PE0_GEN_CTRL_3);
+	reg |= LTSSM_EN;
+	s32g_pcie_writel_ctrl(s32g_pp, PCIE_S32G_PE0_GEN_CTRL_3, reg);
+}
+
+static void s32g_pcie_disable_ltssm(struct s32g_pcie *s32g_pp)
+{
+	u32 reg;
+
+	reg = s32g_pcie_readl_ctrl(s32g_pp, PCIE_S32G_PE0_GEN_CTRL_3);
+	reg &= ~LTSSM_EN;
+	s32g_pcie_writel_ctrl(s32g_pp, PCIE_S32G_PE0_GEN_CTRL_3, reg);
+}
+
+static bool is_s32g_pcie_ltssm_enabled(struct s32g_pcie *s32g_pp)
+{
+	return (s32g_pcie_readl_ctrl(s32g_pp, PCIE_S32G_PE0_GEN_CTRL_3) & LTSSM_EN);
+}
+
+static enum dw_pcie_ltssm s32g_pcie_get_ltssm(struct dw_pcie *pci)
+{
+	struct s32g_pcie *s32g_pp = to_s32g_from_dw_pcie(pci);
+	u32 reg = s32g_pcie_readl_ctrl(s32g_pp, PCIE_S32G_PE0_LINK_DBG_2);
+
+	return (enum dw_pcie_ltssm)FIELD_GET(SMLH_LTSSM_STATE_MASK, reg);
+}
+
+#define PCIE_LINKUP	(SMLH_LINK_UP | RDLH_LINK_UP)
+
+static bool s32g_has_data_phy_link(struct s32g_pcie *s32g_pp)
+{
+	u32 reg = s32g_pcie_readl_ctrl(s32g_pp, PCIE_S32G_PE0_LINK_DBG_2);
+
+	if ((reg & PCIE_LINKUP) == PCIE_LINKUP) {
+		switch (FIELD_GET(SMLH_LTSSM_STATE_MASK, reg)) {
+		case DW_PCIE_LTSSM_L0:
+		case DW_PCIE_LTSSM_L0S:
+		case DW_PCIE_LTSSM_L1_IDLE:
+			return true;
+		default:
+			return false;
+		}
+	}
+
+	return false;
+}
+
+static bool s32g_pcie_link_up(struct dw_pcie *pci)
+{
+	struct s32g_pcie *s32g_pp = to_s32g_from_dw_pcie(pci);
+
+	if (!is_s32g_pcie_ltssm_enabled(s32g_pp))
+		return false;
+
+	return s32g_has_data_phy_link(s32g_pp);
+}
+
+static int s32g_pcie_start_link(struct dw_pcie *pci)
+{
+	struct s32g_pcie *s32g_pp = to_s32g_from_dw_pcie(pci);
+
+	s32g_pcie_enable_ltssm(s32g_pp);
+
+	return 0;
+}
+
+static void s32g_pcie_stop_link(struct dw_pcie *pci)
+{
+	struct s32g_pcie *s32g_pp = to_s32g_from_dw_pcie(pci);
+
+	s32g_pcie_disable_ltssm(s32g_pp);
+}
+
+static struct dw_pcie_ops s32g_pcie_ops = {
+	.get_ltssm = s32g_pcie_get_ltssm,
+	.link_up = s32g_pcie_link_up,
+	.start_link = s32g_pcie_start_link,
+	.stop_link = s32g_pcie_stop_link,
+};
+
+/* Configure the AMBA AXI Coherency Extensions (ACE) interface */
+static void s32g_pcie_reset_mstr_ace(struct dw_pcie *pci, u64 ddr_base_addr)
+{
+	u32 ddr_base_low = lower_32_bits(ddr_base_addr);
+	u32 ddr_base_high = upper_32_bits(ddr_base_addr);
+
+	dw_pcie_dbi_ro_wr_en(pci);
+	dw_pcie_writel_dbi(pci, COHERENCY_CONTROL_3_OFF, 0x0);
+
+	/*
+	 * Ncore is a cache-coherent interconnect module that enables the
+	 * integration of heterogeneous coherent and non-coherent agents in
+	 * the chip. Ncore Transactions to peripheral should be non-coherent
+	 * or it might drop them.
+	 *
+	 * One example where this is needed are PCIe MSIs, which use NoSnoop=0
+	 * and might end up routed to Ncore.
+	 * Define the start of DDR as seen by Linux as the boundary between
+	 * "memory" and "peripherals", with peripherals being below.
+	 */
+	dw_pcie_writel_dbi(pci, COHERENCY_CONTROL_1_OFF,
+			   (ddr_base_low & CFG_MEMTYPE_BOUNDARY_LOW_ADDR_MASK));
+	dw_pcie_writel_dbi(pci, COHERENCY_CONTROL_2_OFF, ddr_base_high);
+	dw_pcie_dbi_ro_wr_dis(pci);
+}
+
+static int s32g_init_pcie_controller(struct dw_pcie_rp *pp)
+{
+	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
+	struct s32g_pcie *s32g_pp = to_s32g_from_dw_pcie(pci);
+	u32 val;
+
+	/* Set RP mode */
+	val = s32g_pcie_readl_ctrl(s32g_pp, PCIE_S32G_PE0_GEN_CTRL_1);
+	val &= ~DEVICE_TYPE_MASK;
+	val |= FIELD_PREP(DEVICE_TYPE_MASK, PCI_EXP_TYPE_ROOT_PORT);
+
+	/* Use default CRNS */
+	val &= ~SRIS_MODE;
+
+	s32g_pcie_writel_ctrl(s32g_pp, PCIE_S32G_PE0_GEN_CTRL_1, val);
+
+	/*
+	 * Make sure we use the coherency defaults (just in case the settings
+	 * have been changed from their reset values)
+	 */
+	s32g_pcie_reset_mstr_ace(pci, memblock_start_of_DRAM());
+
+	dw_pcie_dbi_ro_wr_en(pci);
+
+	val = dw_pcie_readl_dbi(pci, PCIE_PORT_FORCE);
+	val |= PORT_FORCE_DO_DESKEW_FOR_SRIS;
+	dw_pcie_writel_dbi(pci, PCIE_PORT_FORCE, val);
+
+	val = dw_pcie_readl_dbi(pci, GEN3_RELATED_OFF);
+	val |= GEN3_RELATED_OFF_EQ_PHASE_2_3;
+	dw_pcie_writel_dbi(pci, GEN3_RELATED_OFF, val);
+
+	dw_pcie_dbi_ro_wr_dis(pci);
+
+	return 0;
+}
+
+static const struct dw_pcie_host_ops s32g_pcie_host_ops = {
+	.init = s32g_init_pcie_controller,
+};
+
+static int s32g_init_pcie_phy(struct s32g_pcie *s32g_pp)
+{
+	struct dw_pcie *pci = &s32g_pp->pci;
+	struct device *dev = pci->dev;
+	struct s32g_pcie_port *port, *tmp;
+	int ret;
+
+	list_for_each_entry(port, &s32g_pp->ports, list) {
+		ret = phy_init(port->phy);
+		if (ret) {
+			dev_err(dev, "Failed to init serdes PHY\n");
+			goto err_phy_revert;
+		}
+
+		ret = phy_set_mode_ext(port->phy, PHY_MODE_PCIE, 0);
+		if (ret) {
+			dev_err(dev, "Failed to set mode on serdes PHY\n");
+			goto err_phy_exit;
+		}
+
+		ret = phy_power_on(port->phy);
+		if (ret) {
+			dev_err(dev, "Failed to power on serdes PHY\n");
+			goto err_phy_exit;
+		}
+	}
+
+	return 0;
+
+err_phy_exit:
+	phy_exit(port->phy);
+
+err_phy_revert:
+	list_for_each_entry_continue_reverse(port, &s32g_pp->ports, list) {
+		phy_power_off(port->phy);
+		phy_exit(port->phy);
+	}
+
+	list_for_each_entry_safe(port, tmp, &s32g_pp->ports, list)
+		list_del(&port->list);
+
+	return ret;
+}
+
+static void s32g_deinit_pcie_phy(struct s32g_pcie *s32g_pp)
+{
+	struct s32g_pcie_port *port, *tmp;
+
+	list_for_each_entry_safe(port, tmp, &s32g_pp->ports, list) {
+		phy_power_off(port->phy);
+		phy_exit(port->phy);
+		list_del(&port->list);
+	}
+}
+
+static int s32g_pcie_init(struct device *dev, struct s32g_pcie *s32g_pp)
+{
+	int ret;
+
+	s32g_pcie_disable_ltssm(s32g_pp);
+
+	ret = s32g_init_pcie_phy(s32g_pp);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+static void s32g_pcie_deinit(struct s32g_pcie *s32g_pp)
+{
+	s32g_pcie_disable_ltssm(s32g_pp);
+
+	s32g_deinit_pcie_phy(s32g_pp);
+}
+
+static int s32g_pcie_parse_port(struct s32g_pcie *s32g_pp, struct device_node *node)
+{
+	struct device *dev = s32g_pp->pci.dev;
+	struct s32g_pcie_port *port;
+	int num_lanes;
+
+	port = devm_kzalloc(dev, sizeof(*port), GFP_KERNEL);
+	if (!port)
+		return -ENOMEM;
+
+	port->phy = devm_of_phy_get(dev, node, NULL);
+	if (IS_ERR(port->phy))
+		return dev_err_probe(dev, PTR_ERR(port->phy),
+				"Failed to get serdes PHY\n");
+
+	INIT_LIST_HEAD(&port->list);
+	list_add_tail(&port->list, &s32g_pp->ports);
+
+	/*
+	 * The DWC core initialization code cannot parse yet the num-lanes
+	 * attribute in the Root Port node. The S32G only supports one Root
+	 * Port for now so its driver can parse the node and set the num_lanes
+	 * field of struct dwc_pcie before calling dw_pcie_host_init().
+	 */
+	if (!of_property_read_u32(node, "num-lanes", &num_lanes))
+		s32g_pp->pci.num_lanes = num_lanes;
+
+	return 0;
+}
+
+static int s32g_pcie_parse_ports(struct device *dev, struct s32g_pcie *s32g_pp)
+{
+	struct s32g_pcie_port *port, *tmp;
+	int ret = -ENOENT;
+
+	for_each_available_child_of_node_scoped(dev->of_node, of_port) {
+		if (!of_node_is_type(of_port, "pci"))
+			continue;
+		ret = s32g_pcie_parse_port(s32g_pp, of_port);
+		if (ret)
+			goto err_port;
+	}
+
+err_port:
+	list_for_each_entry_safe(port, tmp, &s32g_pp->ports, list)
+		list_del(&port->list);
+
+	return ret;
+}
+
+static int s32g_pcie_get_resources(struct platform_device *pdev,
+				   struct s32g_pcie *s32g_pp)
+{
+	struct dw_pcie *pci = &s32g_pp->pci;
+	struct device *dev = &pdev->dev;
+	int ret;
+
+	pci->dev = dev;
+	pci->ops = &s32g_pcie_ops;
+
+	s32g_pp->ctrl_base = devm_platform_ioremap_resource_byname(pdev, "ctrl");
+	if (IS_ERR(s32g_pp->ctrl_base))
+		return PTR_ERR(s32g_pp->ctrl_base);
+
+	INIT_LIST_HEAD(&s32g_pp->ports);
+
+	ret = s32g_pcie_parse_ports(dev, s32g_pp);
+	if (ret)
+		return dev_err_probe(dev, ret,
+				"Failed to parse Root Port: %d\n", ret);
+
+	platform_set_drvdata(pdev, s32g_pp);
+
+	return 0;
+}
+
+static int s32g_pcie_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct s32g_pcie *s32g_pp;
+	struct dw_pcie_rp *pp;
+	int ret;
+
+	s32g_pp = devm_kzalloc(dev, sizeof(*s32g_pp), GFP_KERNEL);
+	if (!s32g_pp)
+		return -ENOMEM;
+
+	ret = s32g_pcie_get_resources(pdev, s32g_pp);
+	if (ret)
+		return ret;
+
+	pm_runtime_no_callbacks(dev);
+	devm_pm_runtime_enable(dev);
+	ret = pm_runtime_get_sync(dev);
+	if (ret < 0)
+		goto err_pm_runtime_put;
+
+	ret = s32g_pcie_init(dev, s32g_pp);
+	if (ret)
+		goto err_pm_runtime_put;
+
+	pp = &s32g_pp->pci.pp;
+	pp->ops = &s32g_pcie_host_ops;
+	pp->use_atu_msg = true;
+
+	ret = dw_pcie_host_init(pp);
+	if (ret)
+		goto err_pcie_deinit;
+
+	return 0;
+
+err_pcie_deinit:
+	s32g_pcie_deinit(s32g_pp);
+err_pm_runtime_put:
+	pm_runtime_put(dev);
+
+	return ret;
+}
+
+static int s32g_pcie_suspend_noirq(struct device *dev)
+{
+	struct s32g_pcie *s32g_pp = dev_get_drvdata(dev);
+	struct dw_pcie *pci = &s32g_pp->pci;
+
+	return dw_pcie_suspend_noirq(pci);
+}
+
+static int s32g_pcie_resume_noirq(struct device *dev)
+{
+	struct s32g_pcie *s32g_pp = dev_get_drvdata(dev);
+	struct dw_pcie *pci = &s32g_pp->pci;
+
+	return dw_pcie_resume_noirq(pci);
+}
+
+static const struct dev_pm_ops s32g_pcie_pm_ops = {
+	NOIRQ_SYSTEM_SLEEP_PM_OPS(s32g_pcie_suspend_noirq,
+				  s32g_pcie_resume_noirq)
+};
+
+static const struct of_device_id s32g_pcie_of_match[] = {
+	{ .compatible = "nxp,s32g2-pcie" },
+	{ /* sentinel */ },
+};
+MODULE_DEVICE_TABLE(of, s32g_pcie_of_match);
+
+static struct platform_driver s32g_pcie_driver = {
+	.driver = {
+		.name	= "s32g-pcie",
+		.of_match_table = s32g_pcie_of_match,
+		.suppress_bind_attrs = true,
+		.pm = pm_sleep_ptr(&s32g_pcie_pm_ops),
+		.probe_type = PROBE_PREFER_ASYNCHRONOUS,
+	},
+	.probe = s32g_pcie_probe,
+};
+
+module_platform_driver(s32g_pcie_driver);
+
+MODULE_AUTHOR("Ionut Vicovan <Ionut.Vicovan@....com>");
+MODULE_DESCRIPTION("NXP S32G PCIe Host controller driver");
+MODULE_LICENSE("GPL");
-- 
2.43.0

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