PCI: dwc: Add Sophgo SG2044 PCIe controller driver in Root Complex mode

Add driver support for DesignWare based PCIe controller in SG2044 SoC. The
driver currently supports the Root Complex mode.

Signed-off-by: Inochi Amaoto <inochiama@gmail.com>
[mani: renamed the driver to 'pcie-sophgo.c' and Kconfig fix]
Signed-off-by: Manivannan Sadhasivam <mani@kernel.org>
[bhelgaas: whitespace]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Link: https://patch.msgid.link/20250504004420.202685-3-inochiama@gmail.com

drivers/pci/controller/dwc/Kconfig

@@ -402,6 +402,16 @@ config PCIE_UNIPHIER_EP
 	  Say Y here if you want PCIe endpoint controller support on
 	  UniPhier SoCs. This driver supports Pro5 SoC.
 
+config PCIE_SOPHGO_DW
+	bool "Sophgo DesignWare PCIe controller (host mode)"
+	depends on ARCH_SOPHGO || COMPILE_TEST
+	depends on PCI_MSI
+	depends on OF
+	select PCIE_DW_HOST
+	help
+	  Say Y here if you want PCIe host controller support on
+	  Sophgo SoCs.
+
 config PCIE_SPEAR13XX
 	bool "STMicroelectronics SPEAr PCIe controller"
 	depends on ARCH_SPEAR13XX || COMPILE_TEST

drivers/pci/controller/dwc/Makefile

@@ -20,6 +20,7 @@ obj-$(CONFIG_PCIE_QCOM_EP) += pcie-qcom-ep.o
 obj-$(CONFIG_PCIE_ARMADA_8K) += pcie-armada8k.o
 obj-$(CONFIG_PCIE_ARTPEC6) += pcie-artpec6.o
 obj-$(CONFIG_PCIE_ROCKCHIP_DW) += pcie-dw-rockchip.o
+obj-$(CONFIG_PCIE_SOPHGO_DW) += pcie-sophgo.o
 obj-$(CONFIG_PCIE_INTEL_GW) += pcie-intel-gw.o
 obj-$(CONFIG_PCIE_KEEMBAY) += pcie-keembay.o
 obj-$(CONFIG_PCIE_KIRIN) += pcie-kirin.o

drivers/pci/controller/dwc/pcie-sophgo.c

@@ -0,0 +1,257 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Sophgo DesignWare based PCIe host controller driver
+ */
+
+#include <linux/bits.h>
+#include <linux/clk.h>
+#include <linux/irqchip/chained_irq.h>
+#include <linux/irqdomain.h>
+#include <linux/module.h>
+#include <linux/property.h>
+#include <linux/platform_device.h>
+
+#include "pcie-designware.h"
+
+#define to_sophgo_pcie(x)		dev_get_drvdata((x)->dev)
+
+#define PCIE_INT_SIGNAL			0xc48
+#define PCIE_INT_EN			0xca0
+
+#define PCIE_INT_SIGNAL_INTX		GENMASK(8, 5)
+
+#define PCIE_INT_EN_INTX		GENMASK(4, 1)
+#define PCIE_INT_EN_INT_MSI		BIT(5)
+
+struct sophgo_pcie {
+	struct dw_pcie		pci;
+	void __iomem		*app_base;
+	struct clk_bulk_data	*clks;
+	unsigned int		clk_cnt;
+	struct irq_domain	*irq_domain;
+};
+
+static int sophgo_pcie_readl_app(struct sophgo_pcie *sophgo, u32 reg)
+{
+	return readl_relaxed(sophgo->app_base + reg);
+}
+
+static void sophgo_pcie_writel_app(struct sophgo_pcie *sophgo, u32 val, u32 reg)
+{
+	writel_relaxed(val, sophgo->app_base + reg);
+}
+
+static void sophgo_pcie_intx_handler(struct irq_desc *desc)
+{
+	struct dw_pcie_rp *pp = irq_desc_get_handler_data(desc);
+	struct irq_chip *chip = irq_desc_get_chip(desc);
+	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
+	struct sophgo_pcie *sophgo = to_sophgo_pcie(pci);
+	unsigned long hwirq, reg;
+
+	chained_irq_enter(chip, desc);
+
+	reg = sophgo_pcie_readl_app(sophgo, PCIE_INT_SIGNAL);
+	reg = FIELD_GET(PCIE_INT_SIGNAL_INTX, reg);
+
+	for_each_set_bit(hwirq, &reg, PCI_NUM_INTX)
+		generic_handle_domain_irq(sophgo->irq_domain, hwirq);
+
+	chained_irq_exit(chip, desc);
+}
+
+static void sophgo_intx_irq_mask(struct irq_data *d)
+{
+	struct dw_pcie_rp *pp = irq_data_get_irq_chip_data(d);
+	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
+	struct sophgo_pcie *sophgo = to_sophgo_pcie(pci);
+	unsigned long flags;
+	u32 val;
+
+	raw_spin_lock_irqsave(&pp->lock, flags);
+
+	val = sophgo_pcie_readl_app(sophgo, PCIE_INT_EN);
+	val &= ~FIELD_PREP(PCIE_INT_EN_INTX, BIT(d->hwirq));
+	sophgo_pcie_writel_app(sophgo, val, PCIE_INT_EN);
+
+	raw_spin_unlock_irqrestore(&pp->lock, flags);
+};
+
+static void sophgo_intx_irq_unmask(struct irq_data *d)
+{
+	struct dw_pcie_rp *pp = irq_data_get_irq_chip_data(d);
+	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
+	struct sophgo_pcie *sophgo = to_sophgo_pcie(pci);
+	unsigned long flags;
+	u32 val;
+
+	raw_spin_lock_irqsave(&pp->lock, flags);
+
+	val = sophgo_pcie_readl_app(sophgo, PCIE_INT_EN);
+	val |= FIELD_PREP(PCIE_INT_EN_INTX, BIT(d->hwirq));
+	sophgo_pcie_writel_app(sophgo, val, PCIE_INT_EN);
+
+	raw_spin_unlock_irqrestore(&pp->lock, flags);
+};
+
+static struct irq_chip sophgo_intx_irq_chip = {
+	.name			= "INTx",
+	.irq_mask		= sophgo_intx_irq_mask,
+	.irq_unmask		= sophgo_intx_irq_unmask,
+};
+
+static int sophgo_pcie_intx_map(struct irq_domain *domain, unsigned int irq,
+				irq_hw_number_t hwirq)
+{
+	irq_set_chip_and_handler(irq, &sophgo_intx_irq_chip, handle_level_irq);
+	irq_set_chip_data(irq, domain->host_data);
+
+	return 0;
+}
+
+static const struct irq_domain_ops intx_domain_ops = {
+	.map = sophgo_pcie_intx_map,
+};
+
+static int sophgo_pcie_init_irq_domain(struct dw_pcie_rp *pp)
+{
+	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
+	struct sophgo_pcie *sophgo = to_sophgo_pcie(pci);
+	struct device *dev = sophgo->pci.dev;
+	struct fwnode_handle *intc;
+	int irq;
+
+	intc = device_get_named_child_node(dev, "interrupt-controller");
+	if (!intc) {
+		dev_err(dev, "missing child interrupt-controller node\n");
+		return -ENODEV;
+	}
+
+	irq = fwnode_irq_get(intc, 0);
+	if (irq < 0) {
+		dev_err(dev, "failed to get INTx irq number\n");
+		fwnode_handle_put(intc);
+		return irq;
+	}
+
+	sophgo->irq_domain = irq_domain_create_linear(intc, PCI_NUM_INTX,
+						      &intx_domain_ops, pp);
+	fwnode_handle_put(intc);
+	if (!sophgo->irq_domain) {
+		dev_err(dev, "failed to get a INTx irq domain\n");
+		return -EINVAL;
+	}
+
+	return irq;
+}
+
+static void sophgo_pcie_msi_enable(struct dw_pcie_rp *pp)
+{
+	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
+	struct sophgo_pcie *sophgo = to_sophgo_pcie(pci);
+	unsigned long flags;
+	u32 val;
+
+	raw_spin_lock_irqsave(&pp->lock, flags);
+
+	val = sophgo_pcie_readl_app(sophgo, PCIE_INT_EN);
+	val |= PCIE_INT_EN_INT_MSI;
+	sophgo_pcie_writel_app(sophgo, val, PCIE_INT_EN);
+
+	raw_spin_unlock_irqrestore(&pp->lock, flags);
+}
+
+static int sophgo_pcie_host_init(struct dw_pcie_rp *pp)
+{
+	int irq;
+
+	irq = sophgo_pcie_init_irq_domain(pp);
+	if (irq < 0)
+		return irq;
+
+	irq_set_chained_handler_and_data(irq, sophgo_pcie_intx_handler, pp);
+
+	sophgo_pcie_msi_enable(pp);
+
+	return 0;
+}
+
+static const struct dw_pcie_host_ops sophgo_pcie_host_ops = {
+	.init = sophgo_pcie_host_init,
+};
+
+static int sophgo_pcie_clk_init(struct sophgo_pcie *sophgo)
+{
+	struct device *dev = sophgo->pci.dev;
+	int ret;
+
+	ret = devm_clk_bulk_get_all_enabled(dev, &sophgo->clks);
+	if (ret < 0)
+		return dev_err_probe(dev, ret, "failed to get clocks\n");
+
+	sophgo->clk_cnt = ret;
+
+	return 0;
+}
+
+static int sophgo_pcie_resource_get(struct platform_device *pdev,
+				    struct sophgo_pcie *sophgo)
+{
+	sophgo->app_base = devm_platform_ioremap_resource_byname(pdev, "app");
+	if (IS_ERR(sophgo->app_base))
+		return dev_err_probe(&pdev->dev, PTR_ERR(sophgo->app_base),
+				     "failed to map app registers\n");
+
+	return 0;
+}
+
+static int sophgo_pcie_configure_rc(struct sophgo_pcie *sophgo)
+{
+	struct dw_pcie_rp *pp;
+
+	pp = &sophgo->pci.pp;
+	pp->ops = &sophgo_pcie_host_ops;
+
+	return dw_pcie_host_init(pp);
+}
+
+static int sophgo_pcie_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct sophgo_pcie *sophgo;
+	int ret;
+
+	sophgo = devm_kzalloc(dev, sizeof(*sophgo), GFP_KERNEL);
+	if (!sophgo)
+		return -ENOMEM;
+
+	platform_set_drvdata(pdev, sophgo);
+
+	sophgo->pci.dev = dev;
+
+	ret = sophgo_pcie_resource_get(pdev, sophgo);
+	if (ret)
+		return ret;
+
+	ret = sophgo_pcie_clk_init(sophgo);
+	if (ret)
+		return ret;
+
+	return sophgo_pcie_configure_rc(sophgo);
+}
+
+static const struct of_device_id sophgo_pcie_of_match[] = {
+	{ .compatible = "sophgo,sg2044-pcie" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, sophgo_pcie_of_match);
+
+static struct platform_driver sophgo_pcie_driver = {
+	.driver = {
+		.name = "sophgo-pcie",
+		.of_match_table = sophgo_pcie_of_match,
+		.suppress_bind_attrs = true,
+	},
+	.probe = sophgo_pcie_probe,
+};
+builtin_platform_driver(sophgo_pcie_driver);