alistair23-linux/drivers/pci/host/pcie-iproc.c

/*
 * Copyright (C) 2014 Hauke Mehrtens <hauke@hauke-m.de>
 * Copyright (C) 2015 Broadcom Corporation
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation version 2.
 *
 * This program is distributed "as is" WITHOUT ANY WARRANTY of any
 * kind, whether express or implied; without even the implied warranty
 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

#include <linux/kernel.h>
#include <linux/pci.h>
#include <linux/msi.h>
#include <linux/clk.h>
#include <linux/module.h>
#include <linux/mbus.h>
#include <linux/slab.h>
#include <linux/delay.h>
#include <linux/interrupt.h>
#include <linux/irqchip/arm-gic-v3.h>
#include <linux/platform_device.h>
#include <linux/of_address.h>
#include <linux/of_pci.h>
#include <linux/of_irq.h>
#include <linux/of_platform.h>
#include <linux/phy/phy.h>

#include "pcie-iproc.h"

#define EP_PERST_SOURCE_SELECT_SHIFT 2
#define EP_PERST_SOURCE_SELECT       BIT(EP_PERST_SOURCE_SELECT_SHIFT)
#define EP_MODE_SURVIVE_PERST_SHIFT  1
#define EP_MODE_SURVIVE_PERST        BIT(EP_MODE_SURVIVE_PERST_SHIFT)
#define RC_PCIE_RST_OUTPUT_SHIFT     0
#define RC_PCIE_RST_OUTPUT           BIT(RC_PCIE_RST_OUTPUT_SHIFT)
#define PAXC_RESET_MASK              0x7f

#define GIC_V3_CFG_SHIFT             0
#define GIC_V3_CFG                   BIT(GIC_V3_CFG_SHIFT)

#define MSI_ENABLE_CFG_SHIFT         0
#define MSI_ENABLE_CFG               BIT(MSI_ENABLE_CFG_SHIFT)

#define CFG_IND_ADDR_MASK            0x00001ffc

#define CFG_ADDR_BUS_NUM_SHIFT       20
#define CFG_ADDR_BUS_NUM_MASK        0x0ff00000
#define CFG_ADDR_DEV_NUM_SHIFT       15
#define CFG_ADDR_DEV_NUM_MASK        0x000f8000
#define CFG_ADDR_FUNC_NUM_SHIFT      12
#define CFG_ADDR_FUNC_NUM_MASK       0x00007000
#define CFG_ADDR_REG_NUM_SHIFT       2
#define CFG_ADDR_REG_NUM_MASK        0x00000ffc
#define CFG_ADDR_CFG_TYPE_SHIFT      0
#define CFG_ADDR_CFG_TYPE_MASK       0x00000003

#define SYS_RC_INTX_MASK             0xf

#define PCIE_PHYLINKUP_SHIFT         3
#define PCIE_PHYLINKUP               BIT(PCIE_PHYLINKUP_SHIFT)
#define PCIE_DL_ACTIVE_SHIFT         2
#define PCIE_DL_ACTIVE               BIT(PCIE_DL_ACTIVE_SHIFT)

#define APB_ERR_EN_SHIFT             0
#define APB_ERR_EN                   BIT(APB_ERR_EN_SHIFT)

/* derive the enum index of the outbound/inbound mapping registers */
#define MAP_REG(base_reg, index)      ((base_reg) + (index) * 2)

/*
 * Maximum number of outbound mapping window sizes that can be supported by any
 * OARR/OMAP mapping pair
 */
#define MAX_NUM_OB_WINDOW_SIZES      4

#define OARR_VALID_SHIFT             0
#define OARR_VALID                   BIT(OARR_VALID_SHIFT)
#define OARR_SIZE_CFG_SHIFT          1

#define PCI_EXP_CAP			0xac

#define IPROC_PCIE_REG_INVALID 0xffff

/**
 * iProc PCIe outbound mapping controller specific parameters
 *
 * @window_sizes: list of supported outbound mapping window sizes in MB
 * @nr_sizes: number of supported outbound mapping window sizes
 */
struct iproc_pcie_ob_map {
	resource_size_t window_sizes[MAX_NUM_OB_WINDOW_SIZES];
	unsigned int nr_sizes;
};

static const struct iproc_pcie_ob_map paxb_ob_map[] = {
	{
		/* OARR0/OMAP0 */
		.window_sizes = { 128, 256 },
		.nr_sizes = 2,
	},
	{
		/* OARR1/OMAP1 */
		.window_sizes = { 128, 256 },
		.nr_sizes = 2,
	},
};

/*
 * iProc PCIe host registers
 */
enum iproc_pcie_reg {
	/* clock/reset signal control */
	IPROC_PCIE_CLK_CTRL = 0,

	/*
	 * To allow MSI to be steered to an external MSI controller (e.g., ARM
	 * GICv3 ITS)
	 */
	IPROC_PCIE_MSI_GIC_MODE,

	/*
	 * IPROC_PCIE_MSI_BASE_ADDR and IPROC_PCIE_MSI_WINDOW_SIZE define the
	 * window where the MSI posted writes are written, for the writes to be
	 * interpreted as MSI writes.
	 */
	IPROC_PCIE_MSI_BASE_ADDR,
	IPROC_PCIE_MSI_WINDOW_SIZE,

	/*
	 * To hold the address of the register where the MSI writes are
	 * programed.  When ARM GICv3 ITS is used, this should be programmed
	 * with the address of the GITS_TRANSLATER register.
	 */
	IPROC_PCIE_MSI_ADDR_LO,
	IPROC_PCIE_MSI_ADDR_HI,

	/* enable MSI */
	IPROC_PCIE_MSI_EN_CFG,

	/* allow access to root complex configuration space */
	IPROC_PCIE_CFG_IND_ADDR,
	IPROC_PCIE_CFG_IND_DATA,

	/* allow access to device configuration space */
	IPROC_PCIE_CFG_ADDR,
	IPROC_PCIE_CFG_DATA,

	/* enable INTx */
	IPROC_PCIE_INTX_EN,

	/* outbound address mapping */
	IPROC_PCIE_OARR0,
	IPROC_PCIE_OMAP0,
	IPROC_PCIE_OARR1,
	IPROC_PCIE_OMAP1,
	IPROC_PCIE_OARR2,
	IPROC_PCIE_OMAP2,
	IPROC_PCIE_OARR3,
	IPROC_PCIE_OMAP3,

	/* link status */
	IPROC_PCIE_LINK_STATUS,

	/* enable APB error for unsupported requests */
	IPROC_PCIE_APB_ERR_EN,

	/* total number of core registers */
	IPROC_PCIE_MAX_NUM_REG,
};

/* iProc PCIe PAXB BCMA registers */
static const u16 iproc_pcie_reg_paxb_bcma[] = {
	[IPROC_PCIE_CLK_CTRL]         = 0x000,
	[IPROC_PCIE_CFG_IND_ADDR]     = 0x120,
	[IPROC_PCIE_CFG_IND_DATA]     = 0x124,
	[IPROC_PCIE_CFG_ADDR]         = 0x1f8,
	[IPROC_PCIE_CFG_DATA]         = 0x1fc,
	[IPROC_PCIE_INTX_EN]          = 0x330,
	[IPROC_PCIE_LINK_STATUS]      = 0xf0c,
};

/* iProc PCIe PAXB registers */
static const u16 iproc_pcie_reg_paxb[] = {
	[IPROC_PCIE_CLK_CTRL]         = 0x000,
	[IPROC_PCIE_CFG_IND_ADDR]     = 0x120,
	[IPROC_PCIE_CFG_IND_DATA]     = 0x124,
	[IPROC_PCIE_CFG_ADDR]         = 0x1f8,
	[IPROC_PCIE_CFG_DATA]         = 0x1fc,
	[IPROC_PCIE_INTX_EN]          = 0x330,
	[IPROC_PCIE_OARR0]            = 0xd20,
	[IPROC_PCIE_OMAP0]            = 0xd40,
	[IPROC_PCIE_OARR1]            = 0xd28,
	[IPROC_PCIE_OMAP1]            = 0xd48,
	[IPROC_PCIE_LINK_STATUS]      = 0xf0c,
	[IPROC_PCIE_APB_ERR_EN]       = 0xf40,
};

/* iProc PCIe PAXC v1 registers */
static const u16 iproc_pcie_reg_paxc[] = {
	[IPROC_PCIE_CLK_CTRL]         = 0x000,
	[IPROC_PCIE_CFG_IND_ADDR]     = 0x1f0,
	[IPROC_PCIE_CFG_IND_DATA]     = 0x1f4,
	[IPROC_PCIE_CFG_ADDR]         = 0x1f8,
	[IPROC_PCIE_CFG_DATA]         = 0x1fc,
};

/* iProc PCIe PAXC v2 registers */
static const u16 iproc_pcie_reg_paxc_v2[] = {
	[IPROC_PCIE_MSI_GIC_MODE]     = 0x050,
	[IPROC_PCIE_MSI_BASE_ADDR]    = 0x074,
	[IPROC_PCIE_MSI_WINDOW_SIZE]  = 0x078,
	[IPROC_PCIE_MSI_ADDR_LO]      = 0x07c,
	[IPROC_PCIE_MSI_ADDR_HI]      = 0x080,
	[IPROC_PCIE_MSI_EN_CFG]       = 0x09c,
	[IPROC_PCIE_CFG_IND_ADDR]     = 0x1f0,
	[IPROC_PCIE_CFG_IND_DATA]     = 0x1f4,
	[IPROC_PCIE_CFG_ADDR]         = 0x1f8,
	[IPROC_PCIE_CFG_DATA]         = 0x1fc,
};

static inline struct iproc_pcie *iproc_data(struct pci_bus *bus)
{
	struct iproc_pcie *pcie;
#ifdef CONFIG_ARM
	struct pci_sys_data *sys = bus->sysdata;

	pcie = sys->private_data;
#else
	pcie = bus->sysdata;
#endif
	return pcie;
}

static inline bool iproc_pcie_reg_is_invalid(u16 reg_offset)
{
	return !!(reg_offset == IPROC_PCIE_REG_INVALID);
}

static inline u16 iproc_pcie_reg_offset(struct iproc_pcie *pcie,
					enum iproc_pcie_reg reg)
{
	return pcie->reg_offsets[reg];
}

static inline u32 iproc_pcie_read_reg(struct iproc_pcie *pcie,
				      enum iproc_pcie_reg reg)
{
	u16 offset = iproc_pcie_reg_offset(pcie, reg);

	if (iproc_pcie_reg_is_invalid(offset))
		return 0;

	return readl(pcie->base + offset);
}

static inline void iproc_pcie_write_reg(struct iproc_pcie *pcie,
					enum iproc_pcie_reg reg, u32 val)
{
	u16 offset = iproc_pcie_reg_offset(pcie, reg);

	if (iproc_pcie_reg_is_invalid(offset))
		return;

	writel(val, pcie->base + offset);
}

/**
 * APB error forwarding can be disabled during access of configuration
 * registers of the endpoint device, to prevent unsupported requests
 * (typically seen during enumeration with multi-function devices) from
 * triggering a system exception.
 */
static inline void iproc_pcie_apb_err_disable(struct pci_bus *bus,
					      bool disable)
{
	struct iproc_pcie *pcie = iproc_data(bus);
	u32 val;

	if (bus->number && pcie->has_apb_err_disable) {
		val = iproc_pcie_read_reg(pcie, IPROC_PCIE_APB_ERR_EN);
		if (disable)
			val &= ~APB_ERR_EN;
		else
			val |= APB_ERR_EN;
		iproc_pcie_write_reg(pcie, IPROC_PCIE_APB_ERR_EN, val);
	}
}

/**
 * Note access to the configuration registers are protected at the higher layer
 * by 'pci_lock' in drivers/pci/access.c
 */
static void __iomem *iproc_pcie_map_cfg_bus(struct pci_bus *bus,
					    unsigned int devfn,
					    int where)
{
	struct iproc_pcie *pcie = iproc_data(bus);
	unsigned slot = PCI_SLOT(devfn);
	unsigned fn = PCI_FUNC(devfn);
	unsigned busno = bus->number;
	u32 val;
	u16 offset;

	/* root complex access */
	if (busno == 0) {
		if (slot > 0 || fn > 0)
			return NULL;

		iproc_pcie_write_reg(pcie, IPROC_PCIE_CFG_IND_ADDR,
				     where & CFG_IND_ADDR_MASK);
		offset = iproc_pcie_reg_offset(pcie, IPROC_PCIE_CFG_IND_DATA);
		if (iproc_pcie_reg_is_invalid(offset))
			return NULL;
		else
			return (pcie->base + offset);
	}

	/*
	 * PAXC is connected to an internally emulated EP within the SoC.  It
	 * allows only one device.
	 */
	if (pcie->ep_is_internal)
		if (slot > 0)
			return NULL;

	/* EP device access */
	val = (busno << CFG_ADDR_BUS_NUM_SHIFT) |
		(slot << CFG_ADDR_DEV_NUM_SHIFT) |
		(fn << CFG_ADDR_FUNC_NUM_SHIFT) |
		(where & CFG_ADDR_REG_NUM_MASK) |
		(1 & CFG_ADDR_CFG_TYPE_MASK);
	iproc_pcie_write_reg(pcie, IPROC_PCIE_CFG_ADDR, val);
	offset = iproc_pcie_reg_offset(pcie, IPROC_PCIE_CFG_DATA);
	if (iproc_pcie_reg_is_invalid(offset))
		return NULL;
	else
		return (pcie->base + offset);
}

static int iproc_pcie_config_read32(struct pci_bus *bus, unsigned int devfn,
				    int where, int size, u32 *val)
{
	int ret;

	iproc_pcie_apb_err_disable(bus, true);
	ret = pci_generic_config_read32(bus, devfn, where, size, val);
	iproc_pcie_apb_err_disable(bus, false);

	return ret;
}

static int iproc_pcie_config_write32(struct pci_bus *bus, unsigned int devfn,
				     int where, int size, u32 val)
{
	int ret;

	iproc_pcie_apb_err_disable(bus, true);
	ret = pci_generic_config_write32(bus, devfn, where, size, val);
	iproc_pcie_apb_err_disable(bus, false);

	return ret;
}

static struct pci_ops iproc_pcie_ops = {
	.map_bus = iproc_pcie_map_cfg_bus,
	.read = iproc_pcie_config_read32,
	.write = iproc_pcie_config_write32,
};

static void iproc_pcie_reset(struct iproc_pcie *pcie)
{
	u32 val;

	/*
	 * PAXC and the internal emulated endpoint device downstream should not
	 * be reset.  If firmware has been loaded on the endpoint device at an
	 * earlier boot stage, reset here causes issues.
	 */
	if (pcie->ep_is_internal)
		return;

	/*
	 * Select perst_b signal as reset source. Put the device into reset,
	 * and then bring it out of reset
	 */
	val = iproc_pcie_read_reg(pcie, IPROC_PCIE_CLK_CTRL);
	val &= ~EP_PERST_SOURCE_SELECT & ~EP_MODE_SURVIVE_PERST &
		~RC_PCIE_RST_OUTPUT;
	iproc_pcie_write_reg(pcie, IPROC_PCIE_CLK_CTRL, val);
	udelay(250);

	val |= RC_PCIE_RST_OUTPUT;
	iproc_pcie_write_reg(pcie, IPROC_PCIE_CLK_CTRL, val);
	msleep(100);
}

static int iproc_pcie_check_link(struct iproc_pcie *pcie, struct pci_bus *bus)
{
	struct device *dev = pcie->dev;
	u8 hdr_type;
	u32 link_ctrl, class, val;
	u16 pos = PCI_EXP_CAP, link_status;
	bool link_is_active = false;

	/*
	 * PAXC connects to emulated endpoint devices directly and does not
	 * have a Serdes.  Therefore skip the link detection logic here.
	 */
	if (pcie->ep_is_internal)
		return 0;

	val = iproc_pcie_read_reg(pcie, IPROC_PCIE_LINK_STATUS);
	if (!(val & PCIE_PHYLINKUP) || !(val & PCIE_DL_ACTIVE)) {
		dev_err(dev, "PHY or data link is INACTIVE!\n");
		return -ENODEV;
	}

	/* make sure we are not in EP mode */
	pci_bus_read_config_byte(bus, 0, PCI_HEADER_TYPE, &hdr_type);
	if ((hdr_type & 0x7f) != PCI_HEADER_TYPE_BRIDGE) {
		dev_err(dev, "in EP mode, hdr=%#02x\n", hdr_type);
		return -EFAULT;
	}

	/* force class to PCI_CLASS_BRIDGE_PCI (0x0604) */
#define PCI_BRIDGE_CTRL_REG_OFFSET 0x43c
#define PCI_CLASS_BRIDGE_MASK      0xffff00
#define PCI_CLASS_BRIDGE_SHIFT     8
	pci_bus_read_config_dword(bus, 0, PCI_BRIDGE_CTRL_REG_OFFSET, &class);
	class &= ~PCI_CLASS_BRIDGE_MASK;
	class |= (PCI_CLASS_BRIDGE_PCI << PCI_CLASS_BRIDGE_SHIFT);
	pci_bus_write_config_dword(bus, 0, PCI_BRIDGE_CTRL_REG_OFFSET, class);

	/* check link status to see if link is active */
	pci_bus_read_config_word(bus, 0, pos + PCI_EXP_LNKSTA, &link_status);
	if (link_status & PCI_EXP_LNKSTA_NLW)
		link_is_active = true;

	if (!link_is_active) {
		/* try GEN 1 link speed */
#define PCI_TARGET_LINK_SPEED_MASK    0xf
#define PCI_TARGET_LINK_SPEED_GEN2    0x2
#define PCI_TARGET_LINK_SPEED_GEN1    0x1
		pci_bus_read_config_dword(bus, 0,
					  pos + PCI_EXP_LNKCTL2,
					  &link_ctrl);
		if ((link_ctrl & PCI_TARGET_LINK_SPEED_MASK) ==
		    PCI_TARGET_LINK_SPEED_GEN2) {
			link_ctrl &= ~PCI_TARGET_LINK_SPEED_MASK;
			link_ctrl |= PCI_TARGET_LINK_SPEED_GEN1;
			pci_bus_write_config_dword(bus, 0,
					   pos + PCI_EXP_LNKCTL2,
					   link_ctrl);
			msleep(100);

			pci_bus_read_config_word(bus, 0, pos + PCI_EXP_LNKSTA,
						 &link_status);
			if (link_status & PCI_EXP_LNKSTA_NLW)
				link_is_active = true;
		}
	}

	dev_info(dev, "link: %s\n", link_is_active ? "UP" : "DOWN");

	return link_is_active ? 0 : -ENODEV;
}

static void iproc_pcie_enable(struct iproc_pcie *pcie)
{
	iproc_pcie_write_reg(pcie, IPROC_PCIE_INTX_EN, SYS_RC_INTX_MASK);
}

static inline bool iproc_pcie_ob_is_valid(struct iproc_pcie *pcie,
					  int window_idx)
{
	u32 val;

	val = iproc_pcie_read_reg(pcie, MAP_REG(IPROC_PCIE_OARR0, window_idx));

	return !!(val & OARR_VALID);
}

static inline int iproc_pcie_ob_write(struct iproc_pcie *pcie, int window_idx,
				      int size_idx, u64 axi_addr, u64 pci_addr)
{
	struct device *dev = pcie->dev;
	u16 oarr_offset, omap_offset;

	/*
	 * Derive the OARR/OMAP offset from the first pair (OARR0/OMAP0) based
	 * on window index.
	 */
	oarr_offset = iproc_pcie_reg_offset(pcie, MAP_REG(IPROC_PCIE_OARR0,
							  window_idx));
	omap_offset = iproc_pcie_reg_offset(pcie, MAP_REG(IPROC_PCIE_OMAP0,
							  window_idx));
	if (iproc_pcie_reg_is_invalid(oarr_offset) ||
	    iproc_pcie_reg_is_invalid(omap_offset))
		return -EINVAL;

	/*
	 * Program the OARR registers.  The upper 32-bit OARR register is
	 * always right after the lower 32-bit OARR register.
	 */
	writel(lower_32_bits(axi_addr) | (size_idx << OARR_SIZE_CFG_SHIFT) |
	       OARR_VALID, pcie->base + oarr_offset);
	writel(upper_32_bits(axi_addr), pcie->base + oarr_offset + 4);

	/* now program the OMAP registers */
	writel(lower_32_bits(pci_addr), pcie->base + omap_offset);
	writel(upper_32_bits(pci_addr), pcie->base + omap_offset + 4);

	dev_info(dev, "ob window [%d]: offset 0x%x axi %pap pci %pap\n",
		 window_idx, oarr_offset, &axi_addr, &pci_addr);
	dev_info(dev, "oarr lo 0x%x oarr hi 0x%x\n",
		 readl(pcie->base + oarr_offset),
		 readl(pcie->base + oarr_offset + 4));
	dev_info(dev, "omap lo 0x%x omap hi 0x%x\n",
		 readl(pcie->base + omap_offset),
		 readl(pcie->base + omap_offset + 4));

	return 0;
}

/**
 * Some iProc SoCs require the SW to configure the outbound address mapping
 *
 * Outbound address translation:
 *
 * iproc_pcie_address = axi_address - axi_offset
 * OARR = iproc_pcie_address
 * OMAP = pci_addr
 *
 * axi_addr -> iproc_pcie_address -> OARR -> OMAP -> pci_address
 */
static int iproc_pcie_setup_ob(struct iproc_pcie *pcie, u64 axi_addr,
			       u64 pci_addr, resource_size_t size)
{
	struct iproc_pcie_ob *ob = &pcie->ob;
	struct device *dev = pcie->dev;
	int ret = -EINVAL, window_idx, size_idx;

	if (axi_addr < ob->axi_offset) {
		dev_err(dev, "axi address %pap less than offset %pap\n",
			&axi_addr, &ob->axi_offset);
		return -EINVAL;
	}

	/*
	 * Translate the AXI address to the internal address used by the iProc
	 * PCIe core before programming the OARR
	 */
	axi_addr -= ob->axi_offset;

	/* iterate through all OARR/OMAP mapping windows */
	for (window_idx = ob->nr_windows - 1; window_idx >= 0; window_idx--) {
		const struct iproc_pcie_ob_map *ob_map =
			&pcie->ob_map[window_idx];

		/*
		 * If current outbound window is already in use, move on to the
		 * next one.
		 */
		if (iproc_pcie_ob_is_valid(pcie, window_idx))
			continue;

		/*
		 * Iterate through all supported window sizes within the
		 * OARR/OMAP pair to find a match.  Go through the window sizes
		 * in a descending order.
		 */
		for (size_idx = ob_map->nr_sizes - 1; size_idx >= 0;
		     size_idx--) {
			resource_size_t window_size =
				ob_map->window_sizes[size_idx] * SZ_1M;

			if (size < window_size)
				continue;

			if (!IS_ALIGNED(axi_addr, window_size) ||
			    !IS_ALIGNED(pci_addr, window_size)) {
				dev_err(dev,
					"axi %pap or pci %pap not aligned\n",
					&axi_addr, &pci_addr);
				return -EINVAL;
			}

			/*
			 * Match found!  Program both OARR and OMAP and mark
			 * them as a valid entry.
			 */
			ret = iproc_pcie_ob_write(pcie, window_idx, size_idx,
						  axi_addr, pci_addr);
			if (ret)
				goto err_ob;

			size -= window_size;
			if (size == 0)
				return 0;

			/*
			 * If we are here, we are done with the current window,
			 * but not yet finished all mappings.  Need to move on
			 * to the next window.
			 */
			axi_addr += window_size;
			pci_addr += window_size;
			break;
		}
	}

err_ob:
	dev_err(dev, "unable to configure outbound mapping\n");
	dev_err(dev,
		"axi %pap, axi offset %pap, pci %pap, res size %pap\n",
		&axi_addr, &ob->axi_offset, &pci_addr, &size);

	return ret;
}

static int iproc_pcie_map_ranges(struct iproc_pcie *pcie,
				 struct list_head *resources)
{
	struct device *dev = pcie->dev;
	struct resource_entry *window;
	int ret;

	resource_list_for_each_entry(window, resources) {
		struct resource *res = window->res;
		u64 res_type = resource_type(res);

		switch (res_type) {
		case IORESOURCE_IO:
		case IORESOURCE_BUS:
			break;
		case IORESOURCE_MEM:
			ret = iproc_pcie_setup_ob(pcie, res->start,
						  res->start - window->offset,
						  resource_size(res));
			if (ret)
				return ret;
			break;
		default:
			dev_err(dev, "invalid resource %pR\n", res);
			return -EINVAL;
		}
	}

	return 0;
}

static int iproce_pcie_get_msi(struct iproc_pcie *pcie,
			       struct device_node *msi_node,
			       u64 *msi_addr)
{
	struct device *dev = pcie->dev;
	int ret;
	struct resource res;

	/*
	 * Check if 'msi-map' points to ARM GICv3 ITS, which is the only
	 * supported external MSI controller that requires steering.
	 */
	if (!of_device_is_compatible(msi_node, "arm,gic-v3-its")) {
		dev_err(dev, "unable to find compatible MSI controller\n");
		return -ENODEV;
	}

	/* derive GITS_TRANSLATER address from GICv3 */
	ret = of_address_to_resource(msi_node, 0, &res);
	if (ret < 0) {
		dev_err(dev, "unable to obtain MSI controller resources\n");
		return ret;
	}

	*msi_addr = res.start + GITS_TRANSLATER;
	return 0;
}

static void iproc_pcie_paxc_v2_msi_steer(struct iproc_pcie *pcie, u64 msi_addr)
{
	u32 val;

	/*
	 * Program bits [43:13] of address of GITS_TRANSLATER register into
	 * bits [30:0] of the MSI base address register.  In fact, in all iProc
	 * based SoCs, all I/O register bases are well below the 32-bit
	 * boundary, so we can safely assume bits [43:32] are always zeros.
	 */
	iproc_pcie_write_reg(pcie, IPROC_PCIE_MSI_BASE_ADDR,
			     (u32)(msi_addr >> 13));

	/* use a default 8K window size */
	iproc_pcie_write_reg(pcie, IPROC_PCIE_MSI_WINDOW_SIZE, 0);

	/* steering MSI to GICv3 ITS */
	val = iproc_pcie_read_reg(pcie, IPROC_PCIE_MSI_GIC_MODE);
	val |= GIC_V3_CFG;
	iproc_pcie_write_reg(pcie, IPROC_PCIE_MSI_GIC_MODE, val);

	/*
	 * Program bits [43:2] of address of GITS_TRANSLATER register into the
	 * iProc MSI address registers.
	 */
	msi_addr >>= 2;
	iproc_pcie_write_reg(pcie, IPROC_PCIE_MSI_ADDR_HI,
			     upper_32_bits(msi_addr));
	iproc_pcie_write_reg(pcie, IPROC_PCIE_MSI_ADDR_LO,
			     lower_32_bits(msi_addr));

	/* enable MSI */
	val = iproc_pcie_read_reg(pcie, IPROC_PCIE_MSI_EN_CFG);
	val |= MSI_ENABLE_CFG;
	iproc_pcie_write_reg(pcie, IPROC_PCIE_MSI_EN_CFG, val);
}

static int iproc_pcie_msi_steer(struct iproc_pcie *pcie,
				struct device_node *msi_node)
{
	struct device *dev = pcie->dev;
	int ret;
	u64 msi_addr;

	ret = iproce_pcie_get_msi(pcie, msi_node, &msi_addr);
	if (ret < 0) {
		dev_err(dev, "msi steering failed\n");
		return ret;
	}

	switch (pcie->type) {
	case IPROC_PCIE_PAXC_V2:
		iproc_pcie_paxc_v2_msi_steer(pcie, msi_addr);
		break;
	default:
		return -EINVAL;
	}

	return 0;
}

static int iproc_pcie_msi_enable(struct iproc_pcie *pcie)
{
	struct device_node *msi_node;
	int ret;

	/*
	 * Either the "msi-parent" or the "msi-map" phandle needs to exist
	 * for us to obtain the MSI node.
	 */

	msi_node = of_parse_phandle(pcie->dev->of_node, "msi-parent", 0);
	if (!msi_node) {
		const __be32 *msi_map = NULL;
		int len;
		u32 phandle;

		msi_map = of_get_property(pcie->dev->of_node, "msi-map", &len);
		if (!msi_map)
			return -ENODEV;

		phandle = be32_to_cpup(msi_map + 1);
		msi_node = of_find_node_by_phandle(phandle);
		if (!msi_node)
			return -ENODEV;
	}

	/*
	 * Certain revisions of the iProc PCIe controller require additional
	 * configurations to steer the MSI writes towards an external MSI
	 * controller.
	 */
	if (pcie->need_msi_steer) {
		ret = iproc_pcie_msi_steer(pcie, msi_node);
		if (ret)
			return ret;
	}

	/*
	 * If another MSI controller is being used, the call below should fail
	 * but that is okay
	 */
	return iproc_msi_init(pcie, msi_node);
}

static void iproc_pcie_msi_disable(struct iproc_pcie *pcie)
{
	iproc_msi_exit(pcie);
}

static int iproc_pcie_rev_init(struct iproc_pcie *pcie)
{
	struct device *dev = pcie->dev;
	unsigned int reg_idx;
	const u16 *regs;

	switch (pcie->type) {
	case IPROC_PCIE_PAXB_BCMA:
		regs = iproc_pcie_reg_paxb_bcma;
		break;
	case IPROC_PCIE_PAXB:
		regs = iproc_pcie_reg_paxb;
		pcie->has_apb_err_disable = true;
		if (pcie->need_ob_cfg) {
			pcie->ob_map = paxb_ob_map;
			pcie->ob.nr_windows = ARRAY_SIZE(paxb_ob_map);
		}
		break;
	case IPROC_PCIE_PAXC:
		regs = iproc_pcie_reg_paxc;
		pcie->ep_is_internal = true;
		break;
	case IPROC_PCIE_PAXC_V2:
		regs = iproc_pcie_reg_paxc_v2;
		pcie->ep_is_internal = true;
		pcie->need_msi_steer = true;
		break;
	default:
		dev_err(dev, "incompatible iProc PCIe interface\n");
		return -EINVAL;
	}

	pcie->reg_offsets = devm_kcalloc(dev, IPROC_PCIE_MAX_NUM_REG,
					 sizeof(*pcie->reg_offsets),
					 GFP_KERNEL);
	if (!pcie->reg_offsets)
		return -ENOMEM;

	/* go through the register table and populate all valid registers */
	pcie->reg_offsets[0] = (pcie->type == IPROC_PCIE_PAXC_V2) ?
		IPROC_PCIE_REG_INVALID : regs[0];
	for (reg_idx = 1; reg_idx < IPROC_PCIE_MAX_NUM_REG; reg_idx++)
		pcie->reg_offsets[reg_idx] = regs[reg_idx] ?
			regs[reg_idx] : IPROC_PCIE_REG_INVALID;

	return 0;
}

int iproc_pcie_setup(struct iproc_pcie *pcie, struct list_head *res)
{
	struct device *dev;
	int ret;
	void *sysdata;
	struct pci_bus *bus;

	dev = pcie->dev;

	ret = iproc_pcie_rev_init(pcie);
	if (ret) {
		dev_err(dev, "unable to initialize controller parameters\n");
		return ret;
	}

	ret = devm_request_pci_bus_resources(dev, res);
	if (ret)
		return ret;

	ret = phy_init(pcie->phy);
	if (ret) {
		dev_err(dev, "unable to initialize PCIe PHY\n");
		return ret;
	}

	ret = phy_power_on(pcie->phy);
	if (ret) {
		dev_err(dev, "unable to power on PCIe PHY\n");
		goto err_exit_phy;
	}

	iproc_pcie_reset(pcie);

	if (pcie->need_ob_cfg) {
		ret = iproc_pcie_map_ranges(pcie, res);
		if (ret) {
			dev_err(dev, "map failed\n");
			goto err_power_off_phy;
		}
	}

#ifdef CONFIG_ARM
	pcie->sysdata.private_data = pcie;
	sysdata = &pcie->sysdata;
#else
	sysdata = pcie;
#endif

	bus = pci_create_root_bus(dev, 0, &iproc_pcie_ops, sysdata, res);
	if (!bus) {
		dev_err(dev, "unable to create PCI root bus\n");
		ret = -ENOMEM;
		goto err_power_off_phy;
	}
	pcie->root_bus = bus;

	ret = iproc_pcie_check_link(pcie, bus);
	if (ret) {
		dev_err(dev, "no PCIe EP device detected\n");
		goto err_rm_root_bus;
	}

	iproc_pcie_enable(pcie);

	if (IS_ENABLED(CONFIG_PCI_MSI))
		if (iproc_pcie_msi_enable(pcie))
			dev_info(dev, "not using iProc MSI\n");

	pci_scan_child_bus(bus);
	pci_assign_unassigned_bus_resources(bus);
	pci_fixup_irqs(pci_common_swizzle, pcie->map_irq);
	pci_bus_add_devices(bus);

	return 0;

err_rm_root_bus:
	pci_stop_root_bus(bus);
	pci_remove_root_bus(bus);

err_power_off_phy:
	phy_power_off(pcie->phy);
err_exit_phy:
	phy_exit(pcie->phy);
	return ret;
}
EXPORT_SYMBOL(iproc_pcie_setup);

int iproc_pcie_remove(struct iproc_pcie *pcie)
{
	pci_stop_root_bus(pcie->root_bus);
	pci_remove_root_bus(pcie->root_bus);

	iproc_pcie_msi_disable(pcie);

	phy_power_off(pcie->phy);
	phy_exit(pcie->phy);

	return 0;
}
EXPORT_SYMBOL(iproc_pcie_remove);

MODULE_AUTHOR("Ray Jui <rjui@broadcom.com>");
MODULE_DESCRIPTION("Broadcom iPROC PCIe common driver");
MODULE_LICENSE("GPL v2");