drivers/staging/mt7621-pci/pci-mt7621.c

// SPDX-License-Identifier: GPL-2.0+
/*
 * BRIEF MODULE DESCRIPTION
 *     PCI init for Ralink RT2880 solution
 *
 * Copyright 2007 Ralink Inc. (bruce_chang@ralinktech.com.tw)
 *
 * May 2007 Bruce Chang
 * Initial Release
 *
 * May 2009 Bruce Chang
 * support RT2880/RT3883 PCIe
 *
 * May 2011 Bruce Chang
 * support RT6855/MT7620 PCIe
 */

#include <linux/bitops.h>
#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
#include <linux/of_pci.h>
#include <linux/of_platform.h>
#include <linux/pci.h>
#include <linux/platform_device.h>
#include <linux/reset.h>
#include <mt7621.h>
#include <ralink_regs.h>

#include "../../pci/pci.h"

/*
 * These functions and structures provide the BIOS scan and mapping of the PCI
 * devices.
 */

/* sysctl */
#define MT7621_CHIP_REV_ID		0x0c
#define MT7621_GPIO_MODE		0x60
#define CHIP_REV_MT7621_E2		0x0101

/* pcie */
#define RALINK_PCIE0_CLK_EN		BIT(24)
#define RALINK_PCIE1_CLK_EN		BIT(25)
#define RALINK_PCIE2_CLK_EN		BIT(26)

#define RALINK_PCI_CONFIG_ADDR		0x20
#define RALINK_PCI_CONFIG_DATA		0x24
#define RALINK_PCI_MEMBASE		0x28
#define RALINK_PCI_IOBASE		0x2C

/* RALINK_RSTCTRL bits */
#define RALINK_PCIE_RST			BIT(23)
#define RALINK_PCIE0_RST		BIT(24)
#define RALINK_PCIE1_RST		BIT(25)
#define RALINK_PCIE2_RST		BIT(26)

#define RALINK_PCI_PCICFG_ADDR		0x0000
#define RALINK_PCI_PCIMSK_ADDR		0x000C

#define RT6855_PCIE0_OFFSET		0x2000
#define RT6855_PCIE1_OFFSET		0x3000
#define RT6855_PCIE2_OFFSET		0x4000

#define RALINK_PCI_BAR0SETUP_ADDR	0x0010
#define RALINK_PCI_IMBASEBAR0_ADDR	0x0018
#define RALINK_PCI_ID			0x0030
#define RALINK_PCI_CLASS		0x0034
#define RALINK_PCI_SUBID		0x0038
#define RALINK_PCI_STATUS		0x0050

#define RALINK_PCI_MM_MAP_BASE		0x60000000
#define RALINK_PCI_IO_MAP_BASE		0x1e160000

#define RALINK_CLKCFG1			0x30
#define RALINK_RSTCTRL			0x34
#define RALINK_GPIOMODE			0x60
#define RALINK_PCIE_CLK_GEN		0x7c
#define RALINK_PCIE_CLK_GEN1		0x80

#define MEMORY_BASE 0x0

static int pcie_link_status;

/* pcie phy related macros */
#define RALINK_PCIEPHY_P0P1_CTL_OFFSET	0x9000
#define RALINK_PCIEPHY_P2_CTL_OFFSET	0xA000

#define RG_P0_TO_P1_WIDTH		0x100

#define RG_PE1_PIPE_REG			0x02c
#define RG_PE1_PIPE_RST			BIT(12)
#define RG_PE1_PIPE_CMD_FRC		BIT(4)

#define RG_PE1_H_LCDDS_REG		0x49c
#define RG_PE1_H_LCDDS_PCW		GENMASK(30, 0)
#define RG_PE1_H_LCDDS_PCW_VAL(x)	((0x7fffffff & (x)) << 0)

#define RG_PE1_FRC_H_XTAL_REG		0x400
#define RG_PE1_FRC_H_XTAL_TYPE          BIT(8)
#define RG_PE1_H_XTAL_TYPE              GENMASK(10, 9)
#define RG_PE1_H_XTAL_TYPE_VAL(x)       ((0x3 & (x)) << 9)

#define RG_PE1_FRC_PHY_REG		0x000
#define RG_PE1_FRC_PHY_EN               BIT(4)
#define RG_PE1_PHY_EN                   BIT(5)

#define RG_PE1_H_PLL_REG		0x490
#define RG_PE1_H_PLL_BC			GENMASK(23, 22)
#define RG_PE1_H_PLL_BC_VAL(x)		((0x3 & (x)) << 22)
#define RG_PE1_H_PLL_BP			GENMASK(21, 18)
#define RG_PE1_H_PLL_BP_VAL(x)		((0xf & (x)) << 18)
#define RG_PE1_H_PLL_IR			GENMASK(15, 12)
#define RG_PE1_H_PLL_IR_VAL(x)		((0xf & (x)) << 12)
#define RG_PE1_H_PLL_IC			GENMASK(11, 8)
#define RG_PE1_H_PLL_IC_VAL(x)		((0xf & (x)) << 8)
#define RG_PE1_H_PLL_PREDIV             GENMASK(7, 6)
#define RG_PE1_H_PLL_PREDIV_VAL(x)      ((0x3 & (x)) << 6)
#define RG_PE1_PLL_DIVEN		GENMASK(3, 1)
#define RG_PE1_PLL_DIVEN_VAL(x)		((0x7 & (x)) << 1)

#define RG_PE1_H_PLL_FBKSEL_REG		0x4bc
#define RG_PE1_H_PLL_FBKSEL             GENMASK(5, 4)
#define RG_PE1_H_PLL_FBKSEL_VAL(x)      ((0x3 & (x)) << 4)

#define	RG_PE1_H_LCDDS_SSC_PRD_REG	0x4a4
#define RG_PE1_H_LCDDS_SSC_PRD          GENMASK(15, 0)
#define RG_PE1_H_LCDDS_SSC_PRD_VAL(x)   ((0xffff & (x)) << 0)

#define RG_PE1_H_LCDDS_SSC_DELTA_REG	0x4a8
#define RG_PE1_H_LCDDS_SSC_DELTA        GENMASK(11, 0)
#define RG_PE1_H_LCDDS_SSC_DELTA_VAL(x) ((0xfff & (x)) << 0)
#define RG_PE1_H_LCDDS_SSC_DELTA1       GENMASK(27, 16)
#define RG_PE1_H_LCDDS_SSC_DELTA1_VAL(x) ((0xff & (x)) << 16)

#define RG_PE1_LCDDS_CLK_PH_INV_REG	0x4a0
#define RG_PE1_LCDDS_CLK_PH_INV		BIT(5)

#define RG_PE1_H_PLL_BR_REG		0x4ac
#define RG_PE1_H_PLL_BR			GENMASK(18, 16)
#define RG_PE1_H_PLL_BR_VAL(x)		((0x7 & (x)) << 16)

#define	RG_PE1_MSTCKDIV_REG		0x414
#define RG_PE1_MSTCKDIV			GENMASK(7, 6)
#define RG_PE1_MSTCKDIV_VAL(x)		((0x3 & (x)) << 6)

#define RG_PE1_FRC_MSTCKDIV		BIT(5)

/**
 * struct mt7621_pcie_port - PCIe port information
 * @base: I/O mapped register base
 * @list: port list
 * @pcie: pointer to PCIe host info
 * @phy_reg_offset: offset to related phy registers
 * @pcie_rst: pointer to port reset control
 * @pcie_clk: PCIe clock
 * @slot: port slot
 */
struct mt7621_pcie_port {
	void __iomem *base;
	struct list_head list;
	struct mt7621_pcie *pcie;
	u32 phy_reg_offset;
	struct reset_control *pcie_rst;
	struct clk *pcie_clk;
	u32 slot;
};

/**
 * struct mt7621_pcie - PCIe host information
 * @base: IO Mapped Register Base
 * @sysctl: system control mapped register base
 * @io: IO resource
 * @mem: non-prefetchable memory resource
 * @busn: bus range
 * @offset: IO / Memory offset
 * @dev: Pointer to PCIe device
 * @ports: pointer to PCIe port information
 */
struct mt7621_pcie {
	void __iomem *base;
	void __iomem *sysctl;
	struct device *dev;
	struct resource io;
	struct resource mem;
	struct resource busn;
	struct {
		resource_size_t mem;
		resource_size_t io;
	} offset;
	struct list_head ports;
};

static inline u32 pcie_read(struct mt7621_pcie *pcie, u32 reg)
{
	return readl(pcie->base + reg);
}

static inline void pcie_write(struct mt7621_pcie *pcie, u32 val, u32 reg)
{
	writel(val, pcie->base + reg);
}

static inline u32 pcie_port_read(struct mt7621_pcie_port *port, u32 reg)
{
	return readl(port->base + reg);
}

static inline void pcie_port_write(struct mt7621_pcie_port *port,
				   u32 val, u32 reg)
{
	writel(val, port->base + reg);
}

static inline u32 mt7621_pci_get_cfgaddr(unsigned int bus, unsigned int slot,
					 unsigned int func, unsigned int where)
{
	return (((where & 0xF00) >> 8) << 24) | (bus << 16) | (slot << 11) |
		(func << 8) | (where & 0xfc) | 0x80000000;
}

static void __iomem *mt7621_pcie_map_bus(struct pci_bus *bus,
					 unsigned int devfn, int where)
{
	struct mt7621_pcie *pcie = bus->sysdata;
	u32 address = mt7621_pci_get_cfgaddr(bus->number, PCI_SLOT(devfn),
					     PCI_FUNC(devfn), where);

	writel(address, pcie->base + RALINK_PCI_CONFIG_ADDR);

	return pcie->base + RALINK_PCI_CONFIG_DATA + (where & 3);
}

struct pci_ops mt7621_pci_ops = {
	.map_bus	= mt7621_pcie_map_bus,
	.read		= pci_generic_config_read,
	.write		= pci_generic_config_write,
};

static u32
read_config(struct mt7621_pcie *pcie, unsigned int dev, u32 reg)
{
	u32 address = mt7621_pci_get_cfgaddr(0, dev, 0, reg);

	pcie_write(pcie, address, RALINK_PCI_CONFIG_ADDR);
	return pcie_read(pcie, RALINK_PCI_CONFIG_DATA);
}

static void
write_config(struct mt7621_pcie *pcie, unsigned int dev, u32 reg, u32 val)
{
	u32 address = mt7621_pci_get_cfgaddr(0, dev, 0, reg);

	pcie_write(pcie, address, RALINK_PCI_CONFIG_ADDR);
	pcie_write(pcie, val, RALINK_PCI_CONFIG_DATA);
}

static void
bypass_pipe_rst(struct mt7621_pcie_port *port)
{
	struct mt7621_pcie *pcie = port->pcie;
	u32 phy_offset = port->phy_reg_offset;
	u32 offset = (port->slot != 1) ?
		phy_offset + RG_PE1_PIPE_REG :
		phy_offset + RG_PE1_PIPE_REG + RG_P0_TO_P1_WIDTH;
	u32 reg = pcie_read(pcie, offset);

	reg &= ~(RG_PE1_PIPE_RST | RG_PE1_PIPE_CMD_FRC);
	reg |= (RG_PE1_PIPE_RST | RG_PE1_PIPE_CMD_FRC);
	pcie_write(pcie, reg, offset);
}

static void
set_phy_for_ssc(struct mt7621_pcie_port *port)
{
	struct mt7621_pcie *pcie = port->pcie;
	struct device *dev = pcie->dev;
	u32 phy_offset = port->phy_reg_offset;
	u32 reg = rt_sysc_r32(SYSC_REG_SYSTEM_CONFIG0);
	u32 offset;
	u32 val;

	reg = (reg >> 6) & 0x7;
	/* Set PCIe Port PHY to disable SSC */
	/* Debug Xtal Type */
	offset = phy_offset + RG_PE1_FRC_H_XTAL_REG;
	val = pcie_read(pcie, offset);
	val &= ~(RG_PE1_FRC_H_XTAL_TYPE | RG_PE1_H_XTAL_TYPE);
	val |= RG_PE1_FRC_H_XTAL_TYPE;
	val |= RG_PE1_H_XTAL_TYPE_VAL(0x00);
	pcie_write(pcie, val, offset);

	/* disable port */
	offset = (port->slot != 1) ?
		phy_offset + RG_PE1_FRC_PHY_REG :
		phy_offset + RG_PE1_FRC_PHY_REG + RG_P0_TO_P1_WIDTH;
	val = pcie_read(pcie, offset);
	val &= ~(RG_PE1_FRC_PHY_EN | RG_PE1_PHY_EN);
	val |= RG_PE1_FRC_PHY_EN;
	pcie_write(pcie, val, offset);

	/* Set Pre-divider ratio (for host mode) */
	offset =  phy_offset + RG_PE1_H_PLL_REG;
	val = pcie_read(pcie, offset);
	val &= ~(RG_PE1_H_PLL_PREDIV);

	if (reg <= 5 && reg >= 3) { /* 40MHz Xtal */
		val |= RG_PE1_H_PLL_PREDIV_VAL(0x01);
		pcie_write(pcie, val, offset);
		dev_info(dev, "Xtal is 40MHz\n");
	} else { /* 25MHz | 20MHz Xtal */
		val |= RG_PE1_H_PLL_PREDIV_VAL(0x00);
		pcie_write(pcie, val, offset);
		if (reg >= 6) {
			dev_info(dev, "Xtal is 25MHz\n");

			/* Select feedback clock */
			offset = phy_offset + RG_PE1_H_PLL_FBKSEL_REG;
			val = pcie_read(pcie, offset);
			val &= ~(RG_PE1_H_PLL_FBKSEL);
			val |= RG_PE1_H_PLL_FBKSEL_VAL(0x01);
			pcie_write(pcie, val, offset);

			/* DDS NCPO PCW (for host mode) */
			offset = phy_offset + RG_PE1_H_LCDDS_SSC_PRD_REG;
			val = pcie_read(pcie, offset);
			val &= ~(RG_PE1_H_LCDDS_SSC_PRD);
			val |= RG_PE1_H_LCDDS_SSC_PRD_VAL(0x18000000);
			pcie_write(pcie, val, offset);

			/* DDS SSC dither period control */
			offset = phy_offset + RG_PE1_H_LCDDS_SSC_PRD_REG;
			val = pcie_read(pcie, offset);
			val &= ~(RG_PE1_H_LCDDS_SSC_PRD);
			val |= RG_PE1_H_LCDDS_SSC_PRD_VAL(0x18d);
			pcie_write(pcie, val, offset);

			/* DDS SSC dither amplitude control */
			offset = phy_offset + RG_PE1_H_LCDDS_SSC_DELTA_REG;
			val = pcie_read(pcie, offset);
			val &= ~(RG_PE1_H_LCDDS_SSC_DELTA |
				 RG_PE1_H_LCDDS_SSC_DELTA1);
			val |= RG_PE1_H_LCDDS_SSC_DELTA_VAL(0x4a);
			val |= RG_PE1_H_LCDDS_SSC_DELTA1_VAL(0x4a);
			pcie_write(pcie, val, offset);
		} else {
			dev_info(dev, "Xtal is 20MHz\n");
		}
	}

	/* DDS clock inversion */
	offset = phy_offset + RG_PE1_LCDDS_CLK_PH_INV_REG;
	val = pcie_read(pcie, offset);
	val &= ~(RG_PE1_LCDDS_CLK_PH_INV);
	val |= RG_PE1_LCDDS_CLK_PH_INV;
	pcie_write(pcie, val, offset);

	/* Set PLL bits */
	offset = phy_offset + RG_PE1_H_PLL_REG;
	val = pcie_read(pcie, offset);
	val &= ~(RG_PE1_H_PLL_BC | RG_PE1_H_PLL_BP | RG_PE1_H_PLL_IR |
		 RG_PE1_H_PLL_IC | RG_PE1_PLL_DIVEN);
	val |= RG_PE1_H_PLL_BC_VAL(0x02);
	val |= RG_PE1_H_PLL_BP_VAL(0x06);
	val |= RG_PE1_H_PLL_IR_VAL(0x02);
	val |= RG_PE1_H_PLL_IC_VAL(0x01);
	val |= RG_PE1_PLL_DIVEN_VAL(0x02);
	pcie_write(pcie, val, offset);

	offset = phy_offset + RG_PE1_H_PLL_BR_REG;
	val = pcie_read(pcie, offset);
	val &= ~(RG_PE1_H_PLL_BR);
	val |= RG_PE1_H_PLL_BR_VAL(0x00);
	pcie_write(pcie, val, offset);

	if (reg <= 5 && reg >= 3) { /* 40MHz Xtal */
		/* set force mode enable of da_pe1_mstckdiv */
		offset = phy_offset + RG_PE1_MSTCKDIV_REG;
		val = pcie_read(pcie, offset);
		val &= ~(RG_PE1_MSTCKDIV | RG_PE1_FRC_MSTCKDIV);
		val |= (RG_PE1_MSTCKDIV_VAL(0x01) | RG_PE1_FRC_MSTCKDIV);
		pcie_write(pcie, val, offset);
	}

	/* Enable PHY and disable force mode */
	offset = (port->slot != 1) ?
		phy_offset + RG_PE1_FRC_PHY_REG :
		phy_offset + RG_PE1_FRC_PHY_REG + RG_P0_TO_P1_WIDTH;
	val = pcie_read(pcie, offset);
	val &= ~(RG_PE1_FRC_PHY_EN | RG_PE1_PHY_EN);
	val |= (RG_PE1_FRC_PHY_EN | RG_PE1_PHY_EN);
	pcie_write(pcie, val, offset);
}

static void mt7621_enable_phy(struct mt7621_pcie_port *port)
{
	struct mt7621_pcie *pcie = port->pcie;
	u32 chip_rev_id = ioread32(pcie->sysctl + MT7621_CHIP_REV_ID);

	if ((chip_rev_id & 0xFFFF) == CHIP_REV_MT7621_E2)
		bypass_pipe_rst(port);
	set_phy_for_ssc(port);
}

static void setup_cm_memory_region(struct resource *mem_resource)
{
	resource_size_t mask;

	if (mips_cps_numiocu(0)) {
		/*
		 * FIXME: hardware doesn't accept mask values with 1s after
		 * 0s (e.g. 0xffef), so it would be great to warn if that's
		 * about to happen
		 */
		mask = ~(mem_resource->end - mem_resource->start);

		write_gcr_reg1_base(mem_resource->start);
		write_gcr_reg1_mask(mask | CM_GCR_REGn_MASK_CMTGT_IOCU0);
		printk("PCI coherence region base: 0x%08llx, mask/settings: 0x%08llx\n",
			(unsigned long long)read_gcr_reg1_base(),
			(unsigned long long)read_gcr_reg1_mask());
	}
}

static int mt7621_pci_parse_request_of_pci_ranges(struct mt7621_pcie *pcie)
{
	struct device *dev = pcie->dev;
	struct device_node *node = dev->of_node;
	struct of_pci_range_parser parser;
	struct of_pci_range range;
	int err;

	if (of_pci_range_parser_init(&parser, node)) {
		dev_err(dev, "missing \"ranges\" property\n");
		return -EINVAL;
	}

	for_each_of_pci_range(&parser, &range) {
		struct resource *res = NULL;

		switch (range.flags & IORESOURCE_TYPE_BITS) {
		case IORESOURCE_IO:
			ioremap(range.cpu_addr, range.size);
			res = &pcie->io;
			pcie->offset.io = 0x00000000UL;
			break;
		case IORESOURCE_MEM:
			res = &pcie->mem;
			pcie->offset.mem = 0x00000000UL;
			break;
		}

		if (res != NULL)
			of_pci_range_to_resource(&range, node, res);
	}

	err = of_pci_parse_bus_range(node, &pcie->busn);
	if (err < 0) {
		dev_err(dev, "failed to parse bus ranges property: %d\n", err);
		pcie->busn.name = node->name;
		pcie->busn.start = 0;
		pcie->busn.end = 0xff;
		pcie->busn.flags = IORESOURCE_BUS;
	}

	return 0;
}

static int mt7621_pcie_parse_port(struct mt7621_pcie *pcie,
				  struct device_node *node,
				  int slot)
{
	struct mt7621_pcie_port *port;
	struct device *dev = pcie->dev;
	struct device_node *pnode = dev->of_node;
	struct resource regs;
	char name[6];
	int err;

	port = devm_kzalloc(dev, sizeof(*port), GFP_KERNEL);
	if (!port)
		return -ENOMEM;

	err = of_address_to_resource(pnode, slot + 1, &regs);
	if (err) {
		dev_err(dev, "missing \"reg\" property\n");
		return err;
	}

	port->base = devm_ioremap_resource(dev, &regs);
	if (IS_ERR(port->base))
		return PTR_ERR(port->base);

	snprintf(name, sizeof(name), "pcie%d", slot);
	port->pcie_clk = devm_clk_get(dev, name);
	if (IS_ERR(port->pcie_clk)) {
		dev_err(dev, "failed to get pcie%d clock\n", slot);
		return PTR_ERR(port->pcie_clk);
	}

	port->pcie_rst = devm_reset_control_get_exclusive(dev, name);
	if (PTR_ERR(port->pcie_rst) == -EPROBE_DEFER) {
		dev_err(dev, "failed to get pcie%d reset control\n", slot);
		return PTR_ERR(port->pcie_rst);
	}

	port->slot = slot;
	port->pcie = pcie;
	port->phy_reg_offset = (slot != 2) ?
				RALINK_PCIEPHY_P0P1_CTL_OFFSET :
				RALINK_PCIEPHY_P2_CTL_OFFSET;

	INIT_LIST_HEAD(&port->list);
	list_add_tail(&port->list, &pcie->ports);

	return 0;
}

static int mt7621_pcie_parse_dt(struct mt7621_pcie *pcie)
{
	struct device *dev = pcie->dev;
	struct device_node *node = dev->of_node, *child;
	struct resource regs;
	int err;

	err = of_address_to_resource(node, 0, &regs);
	if (err) {
		dev_err(dev, "missing \"reg\" property\n");
		return err;
	}

	pcie->base = devm_ioremap_resource(dev, &regs);
	if (IS_ERR(pcie->base))
		return PTR_ERR(pcie->base);

	err = of_address_to_resource(node, 4, &regs);
	if (err) {
		dev_err(dev, "missing \"reg\" property\n");
		return err;
	}

	pcie->sysctl = devm_ioremap_resource(dev, &regs);
	if (IS_ERR(pcie->sysctl))
		return PTR_ERR(pcie->sysctl);

	for_each_available_child_of_node(node, child) {
		int slot;

		err = of_pci_get_devfn(child);
		if (err < 0) {
			dev_err(dev, "failed to parse devfn: %d\n", err);
			return err;
		}

		slot = PCI_SLOT(err);

		err = mt7621_pcie_parse_port(pcie, child, slot);
		if (err)
			return err;
	}

	return 0;
}

static int mt7621_pcie_init_port(struct mt7621_pcie_port *port)
{
	struct mt7621_pcie *pcie = port->pcie;
	struct device *dev = pcie->dev;
	u32 slot = port->slot;
	u32 val = 0;
	int err;

	err = clk_prepare_enable(port->pcie_clk);
	if (err) {
		dev_err(dev, "failed to enable pcie%d clock\n", slot);
		return err;
	}

	reset_control_assert(port->pcie_rst);
	reset_control_deassert(port->pcie_rst);

	if ((pcie_port_read(port, RALINK_PCI_STATUS) & 0x1) == 0) {
		dev_err(dev, "pcie%d no card, disable it (RST & CLK)\n", slot);
		reset_control_assert(port->pcie_rst);
		rt_sysc_m32(BIT(24 + slot), 0, RALINK_CLKCFG1);
		pcie_link_status &= ~(1 << slot);
	} else {
		pcie_link_status |= BIT(slot);
		val = pcie_read(pcie, RALINK_PCI_PCIMSK_ADDR);
		/* enable pcie interrupt */
		val |= BIT(20 + slot);
		pcie_write(pcie, val, RALINK_PCI_PCIMSK_ADDR);
	}

	mt7621_enable_phy(port);

	val = read_config(pcie, slot, 0x70c);
	dev_info(dev, "Port %d N_FTS = %x\n", (unsigned int)val, slot);

	return 0;
}

static int mt7621_pcie_request_resources(struct mt7621_pcie *pcie,
					 struct list_head *res)
{
	struct device *dev = pcie->dev;
	int err;

	pci_add_resource_offset(res, &pcie->io, pcie->offset.io);
	pci_add_resource_offset(res, &pcie->mem, pcie->offset.mem);
	pci_add_resource(res, &pcie->busn);

	err = devm_request_pci_bus_resources(dev, res);
	if (err < 0)
		return err;

	return 0;
}

static int mt7621_pcie_register_host(struct pci_host_bridge *host,
				     struct list_head *res)
{
	struct mt7621_pcie *pcie = pci_host_bridge_priv(host);

	list_splice_init(res, &host->windows);
	host->busnr = pcie->busn.start;
	host->dev.parent = pcie->dev;
	host->ops = &mt7621_pci_ops;
	host->map_irq = of_irq_parse_and_map_pci;
	host->swizzle_irq = pci_common_swizzle;
	host->sysdata = pcie;

	return pci_host_probe(host);
}

static void mt7621_set_gpio_mode(struct mt7621_pcie *pcie)
{
	u32 reg = ioread32(pcie->sysctl + MT7621_GPIO_MODE);

	reg &= ~(0x3 << 10 | 0x3 << 3);
	reg |= (BIT(10) | BIT(3));
	iowrite32(reg, pcie->sysctl + MT7621_GPIO_MODE);
	mdelay(100);
}

static int mt7621_pci_probe(struct platform_device *pdev)
{
	struct device *dev = &pdev->dev;
	struct mt7621_pcie *pcie;
	struct pci_host_bridge *bridge;
	struct mt7621_pcie_port *port, *tmp;
	int err;
	u32 val = 0;
	LIST_HEAD(res);

	if (!dev->of_node)
		return -ENODEV;

	bridge = devm_pci_alloc_host_bridge(dev, sizeof(*pcie));
	if (!bridge)
		return -ENOMEM;

	pcie = pci_host_bridge_priv(bridge);
	pcie->dev = dev;
	platform_set_drvdata(pdev, pcie);
	INIT_LIST_HEAD(&pcie->ports);

	err = mt7621_pcie_parse_dt(pcie);
	if (err) {
		dev_err(dev, "Parsing DT failed\n");
		return err;
	}

	/* set resources limits */
	iomem_resource.start = 0;
	iomem_resource.end = ~0UL; /* no limit */
	ioport_resource.start = 0;
	ioport_resource.end = ~0UL; /* no limit */

	mt7621_set_gpio_mode(pcie);
	*(unsigned int *)(0xbe000600) |= BIT(19) | BIT(8) | BIT(7); // use GPIO19/GPIO8/GPIO7 (PERST_N/UART_RXD3/UART_TXD3)
	mdelay(100);
	*(unsigned int *)(0xbe000620) &= ~(BIT(19) | BIT(8) | BIT(7));		// clear DATA

	mdelay(100);

	list_for_each_entry_safe(port, tmp, &pcie->ports, list) {
		u32 slot = port->slot;

		err = mt7621_pcie_init_port(port);
		if (err) {
			dev_err(dev, "enabling port %d failed\n", slot);
			list_del(&port->list);
		}
	}

	rt_sysc_m32(0, RALINK_PCIE_RST, RALINK_RSTCTRL);
	rt_sysc_m32(0x30, 2 << 4, SYSC_REG_SYSTEM_CONFIG1);

	rt_sysc_m32(0x80000000, 0, RALINK_PCIE_CLK_GEN);
	rt_sysc_m32(0x7f000000, 0xa << 24, RALINK_PCIE_CLK_GEN1);
	rt_sysc_m32(0, 0x80000000, RALINK_PCIE_CLK_GEN);

	mdelay(50);
	rt_sysc_m32(RALINK_PCIE_RST, 0, RALINK_RSTCTRL);

	/* Use GPIO control instead of PERST_N */
	*(unsigned int *)(0xbe000620) |= BIT(19) | BIT(8) | BIT(7);		// set DATA
	mdelay(1000);

	if (pcie_link_status == 0)
		return 0;

/*
pcie(2/1/0) link status	pcie2_num	pcie1_num	pcie0_num
3'b000			x		x		x
3'b001			x		x		0
3'b010			x		0		x
3'b011			x		1		0
3'b100			0		x		x
3'b101			1		x		0
3'b110			1		0		x
3'b111			2		1		0
*/
	switch (pcie_link_status) {
	case 2:
		val = pcie_read(pcie, RALINK_PCI_PCICFG_ADDR);
		val &= ~0x00ff0000;
		val |= 0x1 << 16;	// port 0
		val |= 0x0 << 20;	// port 1
		pcie_write(pcie, val, RALINK_PCI_PCICFG_ADDR);
		break;
	case 4:
		val = pcie_read(pcie, RALINK_PCI_PCICFG_ADDR);
		val &= ~0x0fff0000;
		val |= 0x1 << 16;	//port0
		val |= 0x2 << 20;	//port1
		val |= 0x0 << 24;	//port2
		pcie_write(pcie, val, RALINK_PCI_PCICFG_ADDR);
		break;
	case 5:
		val = pcie_read(pcie, RALINK_PCI_PCICFG_ADDR);
		val &= ~0x0fff0000;
		val |= 0x0 << 16;	//port0
		val |= 0x2 << 20;	//port1
		val |= 0x1 << 24;	//port2
		pcie_write(pcie, val, RALINK_PCI_PCICFG_ADDR);
		break;
	case 6:
		val = pcie_read(pcie, RALINK_PCI_PCICFG_ADDR);
		val &= ~0x0fff0000;
		val |= 0x2 << 16;	//port0
		val |= 0x0 << 20;	//port1
		val |= 0x1 << 24;	//port2
		pcie_write(pcie, val, RALINK_PCI_PCICFG_ADDR);
		break;
	}

	pcie_write(pcie, 0xffffffff, RALINK_PCI_MEMBASE);
	pcie_write(pcie, RALINK_PCI_IO_MAP_BASE, RALINK_PCI_IOBASE);

	//PCIe0
	if ((pcie_link_status & 0x1) != 0) {
		/* open 7FFF:2G; ENABLE */
		pcie_write(pcie, 0x7FFF0001,
			   RT6855_PCIE0_OFFSET + RALINK_PCI_BAR0SETUP_ADDR);
		pcie_write(pcie, MEMORY_BASE,
			   RT6855_PCIE0_OFFSET + RALINK_PCI_IMBASEBAR0_ADDR);
		pcie_write(pcie, 0x06040001,
			   RT6855_PCIE0_OFFSET + RALINK_PCI_CLASS);
		printk("PCIE0 enabled\n");
	}

	//PCIe1
	if ((pcie_link_status & 0x2) != 0) {
		/* open 7FFF:2G; ENABLE */
		pcie_write(pcie, 0x7FFF0001,
			   RT6855_PCIE1_OFFSET + RALINK_PCI_BAR0SETUP_ADDR);
		pcie_write(pcie, MEMORY_BASE,
			   RT6855_PCIE1_OFFSET + RALINK_PCI_IMBASEBAR0_ADDR);
		pcie_write(pcie, 0x06040001,
			   RT6855_PCIE1_OFFSET + RALINK_PCI_CLASS);
		printk("PCIE1 enabled\n");
	}

	//PCIe2
	if ((pcie_link_status & 0x4) != 0) {
		/* open 7FFF:2G; ENABLE */
		pcie_write(pcie, 0x7FFF0001,
			   RT6855_PCIE2_OFFSET + RALINK_PCI_BAR0SETUP_ADDR);
		pcie_write(pcie, MEMORY_BASE,
			   RT6855_PCIE2_OFFSET + RALINK_PCI_IMBASEBAR0_ADDR);
		pcie_write(pcie, 0x06040001,
			   RT6855_PCIE2_OFFSET + RALINK_PCI_CLASS);
		printk("PCIE2 enabled\n");
	}

	switch (pcie_link_status) {
	case 7:
		val = read_config(pcie, 2, 0x4);
		write_config(pcie, 2, 0x4, val | 0x4);
		val = read_config(pcie, 2, 0x70c);
		val &= ~(0xff) << 8;
		val |= 0x50 << 8;
		write_config(pcie, 2, 0x70c, val);
	case 3:
	case 5:
	case 6:
		val = read_config(pcie, 1, 0x4);
		write_config(pcie, 1, 0x4, val | 0x4);
		val = read_config(pcie, 1, 0x70c);
		val &= ~(0xff) << 8;
		val |= 0x50 << 8;
		write_config(pcie, 1, 0x70c, val);
	default:
		val = read_config(pcie, 0, 0x4);
		write_config(pcie, 0, 0x4, val | 0x4); //bus master enable
		val = read_config(pcie, 0, 0x70c);
		val &= ~(0xff) << 8;
		val |= 0x50 << 8;
		write_config(pcie, 0, 0x70c, val);
	}

	err = mt7621_pci_parse_request_of_pci_ranges(pcie);
	if (err) {
		dev_err(dev, "Error requesting pci resources from ranges");
		return err;
	}

	setup_cm_memory_region(&pcie->mem);

	err = mt7621_pcie_request_resources(pcie, &res);
	if (err) {
		dev_err(dev, "Error requesting resources\n");
		return err;
	}

	err = mt7621_pcie_register_host(bridge, &res);
	if (err) {
		dev_err(dev, "Error registering host\n");
		return err;
	}

	return 0;
}

static const struct of_device_id mt7621_pci_ids[] = {
	{ .compatible = "mediatek,mt7621-pci" },
	{},
};
MODULE_DEVICE_TABLE(of, mt7621_pci_ids);

static struct platform_driver mt7621_pci_driver = {
	.probe = mt7621_pci_probe,
	.driver = {
		.name = "mt7621-pci",
		.of_match_table = of_match_ptr(mt7621_pci_ids),
	},
};

static int __init mt7621_pci_init(void)
{
	return platform_driver_register(&mt7621_pci_driver);
}

arch_initcall(mt7621_pci_init);