PCI: faraday: Add Faraday Technology FTPCI100 PCI Host Bridge driver

Add a host bridge driver for the Faraday Technology FPPCI100 host bridge,
used for Cortina Systems Gemini SoC (SL3516) PCI Host Bridge.

This code is inspired by the out-of-tree OpenWRT patch and then extensively
rewritten for device tree and using the modern helpers to cut down and
modernize the code to all new PCI frameworks.  A driver exists in U-Boot as
well.

Tested on the ITian Square One SQ201 NAS with the following result in the
boot log (trimmed to relevant parts):

  OF: PCI: host bridge /soc/pci@50000000 ranges:
  OF: PCI:    IO 0x50000000..0x500fffff -> 0x00000000
  OF: PCI:   MEM 0x58000000..0x5fffffff -> 0x58000000
  ftpci100 50000000.pci: PCI host bridge to bus 0000:00
  pci_bus 0000:00: root bus resource [bus 00-ff]
  pci_bus 0000:00: root bus resource [io  0x0000-0xfffff]
  pci_bus 0000:00: root bus resource [mem 0x58000000-0x5fffffff]
  ftpci100 50000000.pci:
    DMA MEM1 BASE: 0x0000000000000000 -> 0x0000000007ffffff config 00070000
  ftpci100 50000000.pci:
    DMA MEM2 BASE: 0x0000000000000000 -> 0x0000000003ffffff config 00060000
  ftpci100 50000000.pci:
    DMA MEM3 BASE: 0x0000000000000000 -> 0x0000000003ffffff config 00060000
  PCI: bus0: Fast back to back transfers disabled
  pci 0000:00:00.0: of_irq_parse_pci() failed with rc=-22
  pci 0000:00:0c.0: BAR 0: assigned [mem 0x58000000-0x58007fff]
  pci 0000:00:09.2: BAR 0: assigned [mem 0x58008000-0x580080ff]
  pci 0000:00:09.0: BAR 4: assigned [io  0x1000-0x101f]
  pci 0000:00:09.1: BAR 4: assigned [io  0x1020-0x103f]
  pci 0000:00:09.0: enabling device (0140 -> 0141)
  pci 0000:00:09.0: HCRESET not completed yet!
  pci 0000:00:09.1: enabling device (0140 -> 0141)
  pci 0000:00:09.1: HCRESET not completed yet!
  pci 0000:00:09.2: enabling device (0140 -> 0142)
  rt61pci 0000:00:0c.0: enabling device (0140 -> 0142)
  ieee80211 phy0: rt2x00_set_chip: Info - Chipset detected -
     rt: 2561, rf: 0003, rev: 000c
  ehci_hcd: USB 2.0 'Enhanced' Host Controller (EHCI) Driver
  ehci-pci: EHCI PCI platform driver
  ehci-pci 0000:00:09.2: EHCI Host Controller
  ehci-pci 0000:00:09.2: new USB bus registered, assigned bus number 1
  ehci-pci 0000:00:09.2: irq 125, io mem 0x58008000
  ehci-pci 0000:00:09.2: USB 2.0 started, EHCI 1.00
  hub 1-0:1.0: USB hub found
  hub 1-0:1.0: 4 ports detected
  uhci_hcd: USB Universal Host Controller Interface driver
  uhci_hcd 0000:00:09.0: UHCI Host Controller
  uhci_hcd 0000:00:09.0: new USB bus registered, assigned bus number 2
  uhci_hcd 0000:00:09.0: HCRESET not completed yet!
  uhci_hcd 0000:00:09.0: irq 123, io base 0x00001000
  hub 2-0:1.0: USB hub found
  hub 2-0:1.0: config failed, hub doesn't have any ports! (err -19)
  uhci_hcd 0000:00:09.1: UHCI Host Controller
  uhci_hcd 0000:00:09.1: new USB bus registered, assigned bus number 3
  uhci_hcd 0000:00:09.1: HCRESET not completed yet!
  uhci_hcd 0000:00:09.1: irq 124, io base 0x00001020
  hub 3-0:1.0: USB hub found
  hub 3-0:1.0: config failed, hub doesn't have any ports! (err -19)
  scsi 0:0:0:0: Direct-Access     USB      Flash Disk       1.00 PQ: 0 ANSI: 2
  sd 0:0:0:0: [sda] 7900336 512-byte logical blocks: (4.04 GB/3.77 GiB)
  sd 0:0:0:0: [sda] Write Protect is off
  sd 0:0:0:0: [sda] No Caching mode page found
  sd 0:0:0:0: [sda] Assuming drive cache: write through
   sda: sda1 sda2 sda3
  sd 0:0:0:0: [sda] Attached SCSI removable disk
  ieee80211 phy0: rt2x00lib_request_firmware: Info -
     Loading firmware file 'rt2561s.bin'
  ieee80211 phy0: rt2x00lib_request_firmware: Info -
     Firmware detected - version: 0.8
  IPv6: ADDRCONF(NETDEV_UP): wlan0: link is not ready

  $ lspci
  00:00.0 Class 0600: 159b:4321
  00:09.2 Class 0c03: 1106:3104
  00:09.0 Class 0c03: 1106:3038
  00:09.1 Class 0c03: 1106:3038
  00:0c.0 Class 0280: 1814:0301

  $ cat /proc/interrupts
	     CPU0
  123:          0       PCI   0 Edge      uhci_hcd:usb2
  124:          0       PCI   1 Edge      uhci_hcd:usb3
  125:        159       PCI   2 Edge      ehci_hcd:usb1
  126:       1082       PCI   3 Edge      rt61pci

  $ cat /proc/iomem
  50000000-500000ff : /soc/pci@50000000
  58000000-5fffffff : Gemini PCI MEM
    58000000-58007fff : 0000:00:0c.0
      58000000-58007fff : 0000:00:0c.0
    58008000-580080ff : 0000:00:09.2
      58008000-580080ff : ehci_hcd

The EHCI USB hub works fine; I can mount and manage files and the IRQs just
keep ticking up.  I can issue iwlist wlan0 scanning and see all the WLANs
here.  I don't have wpa_supplicant so have not tried connecting to them.

[bhelgaas: fold in %pap change from Arnd Bergmann <arnd@arndb.de>]
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
CC: Janos Laube <janos.dev@gmail.com>
CC: Paulius Zaleckas <paulius.zaleckas@gmail.com>
CC: Hans Ulli Kroll <ulli.kroll@googlemail.com>
CC: Florian Fainelli <f.fainelli@gmail.com>
CC: Feng-Hsin Chiang <john453@faraday-tech.com>
CC: Greentime Hu <green.hu@gmail.com>

drivers/pci/host/Kconfig

@@ -27,6 +27,12 @@ config PCIE_XILINX_NWL
 	 or End Point. The current option selection will only
 	 support root port enabling.
 
+config PCI_FTPCI100
+	bool "Faraday Technology FTPCI100 PCI controller"
+	depends on OF
+	depends on ARM
+	default ARCH_GEMINI
+
 config PCI_TEGRA
 	bool "NVIDIA Tegra PCIe controller"
 	depends on ARCH_TEGRA

drivers/pci/host/Makefile

+obj-$(CONFIG_PCI_FTPCI100) += pci-ftpci100.o
 obj-$(CONFIG_PCI_HYPERV) += pci-hyperv.o
 obj-$(CONFIG_PCI_MVEBU) += pci-mvebu.o
 obj-$(CONFIG_PCI_AARDVARK) += pci-aardvark.o

drivers/pci/host/pci-ftpci100.c

+/*
+ * Support for Faraday Technology FTPC100 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>
+
+/*
+ * Special configuration registers directly in the first few words
+ * in I/O space.
+ */
+#define PCI_IOSIZE	0x00
+#define PCI_PROT	0x04 /* AHB protection */
+#define PCI_CTRL	0x08 /* PCI control signal */
+#define PCI_SOFTRST	0x10 /* Soft reset counter and response error enable */
+#define PCI_CONFIG	0x28 /* PCI configuration command register */
+#define PCI_DATA	0x2C
+
+#define FARADAY_PCI_PMC			0x40 /* Power management control */
+#define FARADAY_PCI_PMCSR		0x44 /* Power management status */
+#define FARADAY_PCI_CTRL1		0x48 /* Control register 1 */
+#define FARADAY_PCI_CTRL2		0x4C /* Control register 2 */
+#define FARADAY_PCI_MEM1_BASE_SIZE	0x50 /* Memory base and size #1 */
+#define FARADAY_PCI_MEM2_BASE_SIZE	0x54 /* Memory base and size #2 */
+#define FARADAY_PCI_MEM3_BASE_SIZE	0x58 /* Memory base and size #3 */
+
+/* Bits 31..28 gives INTD..INTA status */
+#define PCI_CTRL2_INTSTS_SHIFT		28
+#define PCI_CTRL2_INTMASK_CMDERR	BIT(27)
+#define PCI_CTRL2_INTMASK_PARERR	BIT(26)
+/* Bits 25..22 masks INTD..INTA */
+#define PCI_CTRL2_INTMASK_SHIFT		22
+#define PCI_CTRL2_INTMASK_MABRT_RX	BIT(21)
+#define PCI_CTRL2_INTMASK_TABRT_RX	BIT(20)
+#define PCI_CTRL2_INTMASK_TABRT_TX	BIT(19)
+#define PCI_CTRL2_INTMASK_RETRY4	BIT(18)
+#define PCI_CTRL2_INTMASK_SERR_RX	BIT(17)
+#define PCI_CTRL2_INTMASK_PERR_RX	BIT(16)
+/* Bit 15 reserved */
+#define PCI_CTRL2_MSTPRI_REQ6		BIT(14)
+#define PCI_CTRL2_MSTPRI_REQ5		BIT(13)
+#define PCI_CTRL2_MSTPRI_REQ4		BIT(12)
+#define PCI_CTRL2_MSTPRI_REQ3		BIT(11)
+#define PCI_CTRL2_MSTPRI_REQ2		BIT(10)
+#define PCI_CTRL2_MSTPRI_REQ1		BIT(9)
+#define PCI_CTRL2_MSTPRI_REQ0		BIT(8)
+/* Bits 7..4 reserved */
+/* Bits 3..0 TRDYW */
+
+/*
+ * Memory configs:
+ * Bit 31..20 defines the PCI side memory base
+ * Bit 19..16 (4 bits) defines the size per below
+ */
+#define FARADAY_PCI_MEMBASE_MASK	0xfff00000
+#define FARADAY_PCI_MEMSIZE_1MB		0x0
+#define FARADAY_PCI_MEMSIZE_2MB		0x1
+#define FARADAY_PCI_MEMSIZE_4MB		0x2
+#define FARADAY_PCI_MEMSIZE_8MB		0x3
+#define FARADAY_PCI_MEMSIZE_16MB	0x4
+#define FARADAY_PCI_MEMSIZE_32MB	0x5
+#define FARADAY_PCI_MEMSIZE_64MB	0x6
+#define FARADAY_PCI_MEMSIZE_128MB	0x7
+#define FARADAY_PCI_MEMSIZE_256MB	0x8
+#define FARADAY_PCI_MEMSIZE_512MB	0x9
+#define FARADAY_PCI_MEMSIZE_1GB		0xa
+#define FARADAY_PCI_MEMSIZE_2GB		0xb
+#define FARADAY_PCI_MEMSIZE_SHIFT	16
+
+/*
+ * The DMA base is set to 0x0 for all memory segments, it reflects the
+ * fact that the memory of the host system starts at 0x0.
+ */
+#define FARADAY_PCI_DMA_MEM1_BASE	0x00000000
+#define FARADAY_PCI_DMA_MEM2_BASE	0x00000000
+#define FARADAY_PCI_DMA_MEM3_BASE	0x00000000
+
+/* Defines for PCI configuration command register */
+#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)
+
+/**
+ * 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_res_to_memcfg(resource_size_t mem_base,
+				 resource_size_t mem_size, u32 *val)
+{
+	u32 outval;
+
+	switch (mem_size) {
+	case SZ_1M:
+		outval = FARADAY_PCI_MEMSIZE_1MB;
+		break;
+	case SZ_2M:
+		outval = FARADAY_PCI_MEMSIZE_2MB;
+		break;
+	case SZ_4M:
+		outval = FARADAY_PCI_MEMSIZE_4MB;
+		break;
+	case SZ_8M:
+		outval = FARADAY_PCI_MEMSIZE_8MB;
+		break;
+	case SZ_16M:
+		outval = FARADAY_PCI_MEMSIZE_16MB;
+		break;
+	case SZ_32M:
+		outval = FARADAY_PCI_MEMSIZE_32MB;
+		break;
+	case SZ_64M:
+		outval = FARADAY_PCI_MEMSIZE_64MB;
+		break;
+	case SZ_128M:
+		outval = FARADAY_PCI_MEMSIZE_128MB;
+		break;
+	case SZ_256M:
+		outval = FARADAY_PCI_MEMSIZE_256MB;
+		break;
+	case SZ_512M:
+		outval = FARADAY_PCI_MEMSIZE_512MB;
+		break;
+	case SZ_1G:
+		outval = FARADAY_PCI_MEMSIZE_1GB;
+		break;
+	case SZ_2G:
+		outval = FARADAY_PCI_MEMSIZE_2GB;
+		break;
+	default:
+		return -EINVAL;
+	}
+	outval <<= FARADAY_PCI_MEMSIZE_SHIFT;
+
+	/* This is probably not good */
+	if (mem_base & ~(FARADAY_PCI_MEMBASE_MASK))
+		pr_warn("truncated PCI memory base\n");
+	/* Translate to bridge side address space */
+	outval |= (mem_base & FARADAY_PCI_MEMBASE_MASK);
+	pr_debug("Translated pci base @%pap, size %pap to config %08x\n",
+		 &mem_base, &mem_size, outval);
+
+	*val = outval;
+	return 0;
+}
+
+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 pci_dma_range_parser_init(struct of_pci_range_parser *parser,
+				     struct device_node *node)
+{
+	const int na = 3, ns = 2;
+	int rlen;
+
+	parser->node = node;
+	parser->pna = of_n_addr_cells(node);
+	parser->np = parser->pna + na + ns;
+
+	parser->range = of_get_property(node, "dma-ranges", &rlen);
+	if (!parser->range)
+		return -ENOENT;
+	parser->end = parser->range + rlen / sizeof(__be32);
+
+	return 0;
+}
+
+static int faraday_pci_parse_map_dma_ranges(struct faraday_pci *p,
+					    struct device_node *np)
+{
+	struct of_pci_range range;
+	struct of_pci_range_parser parser;
+	struct device *dev = p->dev;
+	u32 confreg[3] = {
+		FARADAY_PCI_MEM1_BASE_SIZE,
+		FARADAY_PCI_MEM2_BASE_SIZE,
+		FARADAY_PCI_MEM3_BASE_SIZE,
+	};
+	int i = 0;
+	u32 val;
+
+	if (pci_dma_range_parser_init(&parser, np)) {
+		dev_err(dev, "missing dma-ranges property\n");
+		return -EINVAL;
+	}
+
+	/*
+	 * Get the dma-ranges from the device tree
+	 */
+	for_each_of_pci_range(&parser, &range) {
+		u64 end = range.pci_addr + range.size - 1;
+		int ret;
+
+		ret = faraday_res_to_memcfg(range.pci_addr, range.size, &val);
+		if (ret) {
+			dev_err(dev,
+				"DMA range %d: illegal MEM resource size\n", i);
+			return -EINVAL;
+		}
+
+		dev_info(dev, "DMA MEM%d BASE: 0x%016llx -> 0x%016llx config %08x\n",
+			 i + 1, range.pci_addr, end, val);
+		if (i <= 2) {
+			faraday_pci_write_config(p->bus, 0, confreg[i],
+						 4, val);
+		} else {
+			dev_err(dev, "ignore extraneous dma-range %d\n", i);
+			break;
+		}
+
+		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_host_bridge *host;
+	int ret;
+	u32 val;
+	LIST_HEAD(res);
+
+	host = pci_alloc_host_bridge(sizeof(*p));
+	if (!host)
+		return -ENOMEM;
+
+	host->dev.parent = dev;
+	host->ops = &faraday_pci_ops;
+	host->busnr = 0;
+	host->msi = NULL;
+	p = pci_host_bridge_priv(host);
+	host->sysdata = p;
+	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 (!faraday_res_to_memcfg(io->start - win->offset,
+						   resource_size(io), &val)) {
+				/* setup I/O space size */
+				writel(val, p->base + PCI_IOSIZE);
+			} else {
+				dev_err(dev, "illegal IO mem size\n");
+				return -EINVAL;
+			}
+			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);
+
+	list_splice_init(&res, &host->windows);
+	ret = pci_register_host_bridge(host);
+	if (ret) {
+		dev_err(dev, "failed to register host: %d\n", ret);
+		return ret;
+	}
+	p->bus = host->bus;
+
+	/* Mask and clear all interrupts */
+	faraday_pci_write_config(p->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;
+		}
+	}
+
+	ret = faraday_pci_parse_map_dma_ranges(p, dev->of_node);
+	if (ret)
+		return ret;
+
+	pci_scan_child_bus(p->bus);
+	pci_fixup_irqs(pci_common_swizzle, of_irq_parse_and_map_pci);
+	pci_bus_assign_resources(p->bus);
+	pci_bus_add_devices(p->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,ftpci100",
+		.data = &faraday_regular,
+	},
+	{
+		.compatible = "faraday,ftpci100-dual",
+		.data = &faraday_dual,
+	},
+	{},
+};
+
+static struct platform_driver faraday_pci_driver = {
+	.driver = {
+		.name = "ftpci100",
+		.of_match_table = of_match_ptr(faraday_pci_of_match),
+	},
+	.probe  = faraday_pci_probe,
+};
+builtin_platform_driver(faraday_pci_driver);