[2/4] PCI: add driver for Faraday Technology Host Bridge

diff --git a/drivers/pci/host/Kconfig b/drivers/pci/host/Kconfig
index 898d2c48239c..ab5536101ffb 100644
--- a/drivers/pci/host/Kconfig
+++ b/drivers/pci/host/Kconfig
@@ -60,6 +60,11 @@  config PCI_EXYNOS
 	select PCIEPORTBUS
 	select PCIE_DW
 
+config PCI_FARADAY
+	bool "Faraday Technology PCI controller"
+	depends on OF
+	default ARCH_GEMINI
+
 config PCI_IMX6
 	bool "Freescale i.MX6 PCIe controller"
 	depends on SOC_IMX6Q
diff --git a/drivers/pci/host/Makefile b/drivers/pci/host/Makefile
index bfe3179ae74c..71bd839127a4 100644
--- a/drivers/pci/host/Makefile
+++ b/drivers/pci/host/Makefile
@@ -2,6 +2,7 @@  obj-$(CONFIG_PCIE_DW) += pcie-designware.o
 obj-$(CONFIG_PCIE_DW_PLAT) += pcie-designware-plat.o
 obj-$(CONFIG_PCI_DRA7XX) += pci-dra7xx.o
 obj-$(CONFIG_PCI_EXYNOS) += pci-exynos.o
+obj-$(CONFIG_PCI_FARADAY) += pci-faraday.o
 obj-$(CONFIG_PCI_IMX6) += pci-imx6.o
 obj-$(CONFIG_PCI_HYPERV) += pci-hyperv.o
 obj-$(CONFIG_PCI_MVEBU) += pci-mvebu.o
diff --git a/drivers/pci/host/pci-faraday.c b/drivers/pci/host/pci-faraday.c
new file mode 100644
index 000000000000..29e893381c89
--- /dev/null
+++ b/drivers/pci/host/pci-faraday.c
@@ -0,0 +1,399 @@ 
+/*
+ * Support for Faraday Technologt PCI Controller
+ *
+ * Copyright (C) 2017 Linus Walleij <linus.walleij@linaro.org>
+ *
+ * Based on the out-of-tree OpenWRT patch for Cortina Gemini:
+ * Copyright (C) 2009 Janos Laube <janos.dev@gmail.com>
+ * Copyright (C) 2009 Paulius Zaleckas <paulius.zaleckas@teltonika.lt>
+ * Based on SL2312 PCI controller code
+ * Storlink (C) 2003
+ */
+
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/of_address.h>
+#include <linux/of_device.h>
+#include <linux/of_irq.h>
+#include <linux/of_pci.h>
+#include <linux/pci.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/irqdomain.h>
+#include <linux/irqchip/chained_irq.h>
+#include <linux/bitops.h>
+#include <linux/irq.h>
+
+#define FARADAY_PCI_IOSIZE_1M		0x0000
+
+#define FARADAY_PCI_PMC			0x40
+#define FARADAY_PCI_PMCSR		0x44
+#define FARADAY_PCI_CTRL1		0x48
+#define FARADAY_PCI_CTRL2		0x4C
+#define FARADAY_PCI_MEM1_BASE_SIZE	0x50
+#define FARADAY_PCI_MEM2_BASE_SIZE	0x54
+#define FARADAY_PCI_MEM3_BASE_SIZE	0x58
+
+#define PCI_CTRL2_INTSTS_SHIFT		28
+#define PCI_CTRL2_INTMASK_SHIFT		22
+
+#define FARADAY_PCI_DMA_MASK		0xFFF00000
+#define FARADAY_PCI_DMA_MEM1_BASE	0x00000000
+#define FARADAY_PCI_DMA_MEM2_BASE	0x00000000
+#define FARADAY_PCI_DMA_MEM3_BASE	0x00000000
+#define FARADAY_PCI_DMA_MEM1_SIZE	7
+#define FARADAY_PCI_DMA_MEM2_SIZE	6
+#define FARADAY_PCI_DMA_MEM3_SIZE	6
+
+#define PCI_CONF_ENABLE		BIT(31)
+#define PCI_CONF_WHERE(r)	((r) & 0xFC)
+#define PCI_CONF_BUS(b)		(((b) & 0xFF) << 16)
+#define PCI_CONF_DEVICE(d)	(((d) & 0x1F) << 11)
+#define PCI_CONF_FUNCTION(f)	(((f) & 0x07) << 8)
+
+/*
+ * Special configuration registers directly in the first few words
+ * in he I/O space.
+ */
+#define PCI_IOSIZE	0x00
+#define PCI_PROT	0x04
+#define PCI_CTRL	0x08
+#define PCI_SOFTRST	0x10
+#define PCI_CONFIG	0x28
+#define PCI_DATA	0x2C
+
+/**
+ * struct faraday_pci_variant - encodes IP block differences
+ * @cascaded_irq: this host has cascaded IRQs from an interrupt controller
+ *	embedded in the host bridge.
+ */
+struct faraday_pci_variant {
+	bool cascaded_irq;
+};
+
+struct faraday_pci {
+	struct device *dev;
+	void __iomem *base;
+	struct irq_domain *irqdomain;
+	struct pci_bus *bus;
+};
+
+static int faraday_pci_read_config(struct pci_bus *bus, unsigned int fn,
+				  int config, int size, u32 *value)
+{
+	struct faraday_pci *p = bus->sysdata;
+
+	writel(PCI_CONF_BUS(bus->number) |
+			PCI_CONF_DEVICE(PCI_SLOT(fn)) |
+			PCI_CONF_FUNCTION(PCI_FUNC(fn)) |
+			PCI_CONF_WHERE(config) |
+			PCI_CONF_ENABLE,
+			p->base + PCI_CONFIG);
+
+	*value = readl(p->base + PCI_DATA);
+
+	if (size == 1)
+		*value = (*value >> (8 * (config & 3))) & 0xFF;
+	else if (size == 2)
+		*value = (*value >> (8 * (config & 3))) & 0xFFFF;
+
+	dev_dbg(&bus->dev,
+		"[read]  slt: %.2d, fnc: %d, cnf: 0x%.2X, val (%d bytes): 0x%.8X\n",
+		PCI_SLOT(fn), PCI_FUNC(fn), config, size, *value);
+
+	return PCIBIOS_SUCCESSFUL;
+}
+
+static int faraday_pci_write_config(struct pci_bus *bus, unsigned int fn,
+				   int config, int size, u32 value)
+{
+	struct faraday_pci *p = bus->sysdata;
+	int ret = PCIBIOS_SUCCESSFUL;
+
+	dev_dbg(&bus->dev,
+		"[write] slt: %.2d, fnc: %d, cnf: 0x%.2X, val (%d bytes): 0x%.8X\n",
+		PCI_SLOT(fn), PCI_FUNC(fn), config, size, value);
+
+	writel(PCI_CONF_BUS(bus->number) |
+			PCI_CONF_DEVICE(PCI_SLOT(fn)) |
+			PCI_CONF_FUNCTION(PCI_FUNC(fn)) |
+			PCI_CONF_WHERE(config) |
+			PCI_CONF_ENABLE,
+			p->base + PCI_CONFIG);
+
+	switch (size) {
+	case 4:
+		writel(value, p->base + PCI_DATA);
+		break;
+	case 2:
+		writew(value, p->base + PCI_DATA + (config & 3));
+		break;
+	case 1:
+		writeb(value, p->base + PCI_DATA + (config & 3));
+		break;
+	default:
+		ret = PCIBIOS_BAD_REGISTER_NUMBER;
+	}
+
+	return ret;
+}
+
+static struct pci_ops faraday_pci_ops = {
+	.read	= faraday_pci_read_config,
+	.write	= faraday_pci_write_config,
+};
+
+static void faraday_pci_ack_irq(struct irq_data *d)
+{
+	struct faraday_pci *p = irq_data_get_irq_chip_data(d);
+	unsigned int reg;
+
+	faraday_pci_read_config(p->bus, 0, FARADAY_PCI_CTRL2, 4, &reg);
+	reg &= ~(0xF << PCI_CTRL2_INTSTS_SHIFT);
+	reg |= BIT(irqd_to_hwirq(d) + PCI_CTRL2_INTSTS_SHIFT);
+	faraday_pci_write_config(p->bus, 0, FARADAY_PCI_CTRL2, 4, reg);
+}
+
+static void faraday_pci_mask_irq(struct irq_data *d)
+{
+	struct faraday_pci *p = irq_data_get_irq_chip_data(d);
+	unsigned int reg;
+
+	faraday_pci_read_config(p->bus, 0, FARADAY_PCI_CTRL2, 4, &reg);
+	reg &= ~((0xF << PCI_CTRL2_INTSTS_SHIFT)
+		 | BIT(irqd_to_hwirq(d) + PCI_CTRL2_INTMASK_SHIFT));
+	faraday_pci_write_config(p->bus, 0, FARADAY_PCI_CTRL2, 4, reg);
+}
+
+static void faraday_pci_unmask_irq(struct irq_data *d)
+{
+	struct faraday_pci *p = irq_data_get_irq_chip_data(d);
+	unsigned int reg;
+
+	faraday_pci_read_config(p->bus, 0, FARADAY_PCI_CTRL2, 4, &reg);
+	reg &= ~(0xF << PCI_CTRL2_INTSTS_SHIFT);
+	reg |= BIT(irqd_to_hwirq(d) + PCI_CTRL2_INTMASK_SHIFT);
+	faraday_pci_write_config(p->bus, 0, FARADAY_PCI_CTRL2, 4, reg);
+}
+
+static void faraday_pci_irq_handler(struct irq_desc *desc)
+{
+	struct faraday_pci *p = irq_desc_get_handler_data(desc);
+	struct irq_chip *irqchip = irq_desc_get_chip(desc);
+	unsigned int irq_stat, reg, i;
+
+	faraday_pci_read_config(p->bus, 0, FARADAY_PCI_CTRL2, 4, &reg);
+	irq_stat = reg >> PCI_CTRL2_INTSTS_SHIFT;
+
+	chained_irq_enter(irqchip, desc);
+
+	for (i = 0; i < 4; i++) {
+		if ((irq_stat & BIT(i)) == 0)
+			continue;
+		generic_handle_irq(irq_find_mapping(p->irqdomain, i));
+	}
+
+	chained_irq_exit(irqchip, desc);
+}
+
+static struct irq_chip faraday_pci_irq_chip = {
+	.name = "PCI",
+	.irq_ack = faraday_pci_ack_irq,
+	.irq_mask = faraday_pci_mask_irq,
+	.irq_unmask = faraday_pci_unmask_irq,
+};
+
+static int faraday_pci_irq_map(struct irq_domain *domain, unsigned int irq,
+			      irq_hw_number_t hwirq)
+{
+	irq_set_chip_and_handler(irq, &faraday_pci_irq_chip, handle_level_irq);
+	irq_set_chip_data(irq, domain->host_data);
+
+	return 0;
+}
+
+static const struct irq_domain_ops faraday_pci_irqdomain_ops = {
+	.map = faraday_pci_irq_map,
+};
+
+static int faraday_pci_setup_cascaded_irq(struct faraday_pci *p)
+{
+	struct device_node *intc = of_get_next_child(p->dev->of_node, NULL);
+	int irq;
+	int i;
+
+	if (!intc) {
+		dev_err(p->dev, "missing child interrupt-controller node\n");
+		return -EINVAL;
+	}
+
+	/* All PCI IRQs cascade off this one */
+	irq = of_irq_get(intc, 0);
+	if (!irq) {
+		dev_err(p->dev, "failed to get parent IRQ\n");
+		return -EINVAL;
+	}
+
+	p->irqdomain = irq_domain_add_linear(intc, 4,
+					     &faraday_pci_irqdomain_ops,
+					     p);
+	if (!p->irqdomain) {
+		dev_err(p->dev, "failed to create Gemini PCI IRQ domain\n");
+		return -EINVAL;
+	}
+
+	irq_set_chained_handler_and_data(irq, faraday_pci_irq_handler, p);
+
+	for (i = 0; i < 4; i++)
+		irq_create_mapping(p->irqdomain, i);
+
+	return 0;
+}
+
+static int faraday_pci_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	const struct faraday_pci_variant *variant =
+		of_device_get_match_data(dev);
+	struct resource *regs;
+	resource_size_t io_base;
+	struct resource_entry *win;
+	struct faraday_pci *p;
+	struct resource *mem;
+	struct resource *io;
+	struct pci_bus *bus;
+	int ret;
+	u32 val;
+	LIST_HEAD(res);
+
+	p = devm_kzalloc(dev, sizeof(*p), GFP_KERNEL);
+	if (!p)
+		return -ENOMEM;
+
+	p->dev = dev;
+
+	regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	p->base = devm_ioremap_resource(dev, regs);
+	if (IS_ERR(p->base))
+		return PTR_ERR(p->base);
+
+	ret = of_pci_get_host_bridge_resources(dev->of_node, 0, 0xff,
+					       &res, &io_base);
+	if (ret)
+		return ret;
+
+	ret = devm_request_pci_bus_resources(dev, &res);
+	if (ret)
+		return ret;
+
+	/* Get the I/O and memory ranges from DT */
+	resource_list_for_each_entry(win, &res) {
+		switch (resource_type(win->res)) {
+		case IORESOURCE_IO:
+			io = win->res;
+			io->name = "Gemini PCI I/O";
+			if (resource_size(io) == SZ_1M) {
+				/* setup I/O space to 1MB size */
+				writel(FARADAY_PCI_IOSIZE_1M,
+				       p->base + PCI_IOSIZE);
+			} else {
+				dev_err(dev,
+					"illegal IO mem size, must be 1 MiB\n");
+			}
+			ret = pci_remap_iospace(io, io_base);
+			if (ret) {
+				dev_warn(dev, "error %d: failed to map resource %pR\n",
+					 ret, io);
+				continue;
+			}
+			break;
+		case IORESOURCE_MEM:
+			mem = win->res;
+			mem->name = "Gemini PCI MEM";
+			break;
+		case IORESOURCE_BUS:
+			break;
+		default:
+			break;
+		}
+	}
+
+	/* Setup hostbridge */
+	val = readl(p->base + PCI_CTRL);
+	val |= PCI_COMMAND_IO;
+	val |= PCI_COMMAND_MEMORY;
+	val |= PCI_COMMAND_MASTER;
+	writel(val, p->base + PCI_CTRL);
+
+	bus = pci_scan_root_bus(&pdev->dev, 0, &faraday_pci_ops, p, &res);
+	if (!bus)
+		return -ENOMEM;
+	p->bus = bus;
+
+	dev_info(dev, "clear all IRQs\n");
+
+	/* Mask and clear all interrupts */
+	faraday_pci_write_config(bus, 0, FARADAY_PCI_CTRL2 + 2, 2, 0xF000);
+
+	if (variant->cascaded_irq) {
+		ret = faraday_pci_setup_cascaded_irq(p);
+		if (ret) {
+			dev_err(dev, "failed to setup cascaded IRQ\n");
+			return ret;
+		}
+	}
+
+	dev_info(dev, "setting up PCI DMA\n");
+	val = (FARADAY_PCI_DMA_MEM1_BASE & FARADAY_PCI_DMA_MASK)
+		| (FARADAY_PCI_DMA_MEM1_SIZE << 16);
+	faraday_pci_write_config(bus, 0, FARADAY_PCI_MEM1_BASE_SIZE, 4, val);
+	val = (FARADAY_PCI_DMA_MEM2_BASE & FARADAY_PCI_DMA_MASK)
+		| (FARADAY_PCI_DMA_MEM2_SIZE << 16);
+	faraday_pci_write_config(bus, 0, FARADAY_PCI_MEM2_BASE_SIZE, 4, val);
+	val = (FARADAY_PCI_DMA_MEM3_BASE & FARADAY_PCI_DMA_MASK)
+		| (FARADAY_PCI_DMA_MEM3_SIZE << 16);
+	faraday_pci_write_config(bus, 0, FARADAY_PCI_MEM3_BASE_SIZE, 4, val);
+
+	pci_fixup_irqs(pci_common_swizzle, of_irq_parse_and_map_pci);
+	pci_bus_assign_resources(bus);
+	pci_assign_unassigned_bus_resources(bus);
+	pci_bus_add_devices(bus);
+	pci_free_resource_list(&res);
+
+	return 0;
+}
+
+/*
+ * We encode bridge variants here, we have at least two so it doesn't
+ * hurt to have infrastructure to encompass future variants as well.
+ */
+const struct faraday_pci_variant faraday_regular = {
+	.cascaded_irq = true,
+};
+
+const struct faraday_pci_variant faraday_dual = {
+	.cascaded_irq = false,
+};
+
+static const struct of_device_id faraday_pci_of_match[] = {
+	{
+		.compatible = "faraday,pci",
+		.data = &faraday_regular,
+	},
+	{
+		.compatible = "faraday,pci-dual",
+		.data = &faraday_dual,
+	},
+	{},
+};
+
+static struct platform_driver faraday_pci_driver = {
+	.driver = {
+		.name = "gemini-pci",
+		.of_match_table = of_match_ptr(faraday_pci_of_match),
+	},
+	.probe  = faraday_pci_probe,
+};
+builtin_platform_driver(faraday_pci_driver);