/*
 * Designware application register space functions for Keystone PCI controller
 *
 * Copyright (C) 2013-2014 Texas Instruments., Ltd.
 *		http://www.ti.com
 *
 * Author: Murali Karicheri <m-karicheri2@ti.com>
 *
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/irq.h>
#include <linux/irqdomain.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_pci.h>
#include <linux/pci.h>
#include <linux/platform_device.h>

#include "pcie-designware.h"
#include "pci-keystone.h"

/* Application register defines */
#define LTSSM_EN_VAL		        1
#define LTSSM_STATE_MASK		0x1f
#define LTSSM_STATE_L0			0x11
#define DBI_CS2_EN_VAL			0x20
#define OB_XLAT_EN_VAL		        2

/* Application registers */
#define CMD_STATUS			0x004
#define CFG_SETUP			0x008
#define OB_SIZE				0x030
#define CFG_PCIM_WIN_SZ_IDX		3
#define CFG_PCIM_WIN_CNT		32
#define SPACE0_REMOTE_CFG_OFFSET	0x1000
#define OB_OFFSET_INDEX(n)		(0x200 + (8 * n))
#define OB_OFFSET_HI(n)			(0x204 + (8 * n))

/* IRQ register defines */
#define IRQ_EOI				0x050
#define IRQ_STATUS			0x184
#define IRQ_ENABLE_SET			0x188
#define IRQ_ENABLE_CLR			0x18c

#define MSI_IRQ				0x054
#define MSI0_IRQ_STATUS			0x104
#define MSI0_IRQ_ENABLE_SET		0x108
#define MSI0_IRQ_ENABLE_CLR		0x10c
#define IRQ_STATUS			0x184
#define MSI_IRQ_OFFSET			4

/* Config space registers */
#define DEBUG0				0x728

#define to_keystone_pcie(x)	container_of(x, struct keystone_pcie, pp)

static inline struct pcie_port *sys_to_pcie(struct pci_sys_data *sys)
{
	return sys->private_data;
}

static inline void update_reg_offset_bit_pos(u32 offset, u32 *reg_offset,
					     u32 *bit_pos)
{
	*reg_offset = offset % 8;
	*bit_pos = offset >> 3;
}

u32 ks_dw_pcie_get_msi_addr(struct pcie_port *pp)
{
	struct keystone_pcie *ks_pcie = to_keystone_pcie(pp);

	return ks_pcie->app.start + MSI_IRQ;
}

void ks_dw_pcie_handle_msi_irq(struct keystone_pcie *ks_pcie, int offset)
{
	struct pcie_port *pp = &ks_pcie->pp;
	u32 pending, vector;
	int src, virq;

	pending = readl(ks_pcie->va_app_base + MSI0_IRQ_STATUS + (offset << 4));

	/*
	 * MSI0 status bit 0-3 shows vectors 0, 8, 16, 24, MSI1 status bit
	 * shows 1, 9, 17, 25 and so forth
	 */
	for (src = 0; src < 4; src++) {
		if (BIT(src) & pending) {
			vector = offset + (src << 3);
			virq = irq_linear_revmap(pp->irq_domain, vector);
			dev_dbg(pp->dev, "irq: bit %d, vector %d, virq %d\n",
				src, vector, virq);
			generic_handle_irq(virq);
		}
	}
}

static void ks_dw_pcie_msi_irq_ack(struct irq_data *d)
{
	u32 offset, reg_offset, bit_pos;
	struct keystone_pcie *ks_pcie;
	unsigned int irq = d->irq;
	struct msi_desc *msi;
	struct pcie_port *pp;

	msi = irq_get_msi_desc(irq);
	pp = sys_to_pcie(msi->dev->bus->sysdata);
	ks_pcie = to_keystone_pcie(pp);
	offset = irq - irq_linear_revmap(pp->irq_domain, 0);
	update_reg_offset_bit_pos(offset, &reg_offset, &bit_pos);

	writel(BIT(bit_pos),
	       ks_pcie->va_app_base + MSI0_IRQ_STATUS + (reg_offset << 4));
	writel(reg_offset + MSI_IRQ_OFFSET, ks_pcie->va_app_base + IRQ_EOI);
}

void ks_dw_pcie_msi_set_irq(struct pcie_port *pp, int irq)
{
	u32 reg_offset, bit_pos;
	struct keystone_pcie *ks_pcie = to_keystone_pcie(pp);

	update_reg_offset_bit_pos(irq, &reg_offset, &bit_pos);
	writel(BIT(bit_pos),
	       ks_pcie->va_app_base + MSI0_IRQ_ENABLE_SET + (reg_offset << 4));
}

void ks_dw_pcie_msi_clear_irq(struct pcie_port *pp, int irq)
{
	u32 reg_offset, bit_pos;
	struct keystone_pcie *ks_pcie = to_keystone_pcie(pp);

	update_reg_offset_bit_pos(irq, &reg_offset, &bit_pos);
	writel(BIT(bit_pos),
	       ks_pcie->va_app_base + MSI0_IRQ_ENABLE_CLR + (reg_offset << 4));
}

static void ks_dw_pcie_msi_irq_mask(struct irq_data *d)
{
	struct keystone_pcie *ks_pcie;
	unsigned int irq = d->irq;
	struct msi_desc *msi;
	struct pcie_port *pp;
	u32 offset;

	msi = irq_get_msi_desc(irq);
	pp = sys_to_pcie(msi->dev->bus->sysdata);
	ks_pcie = to_keystone_pcie(pp);
	offset = irq - irq_linear_revmap(pp->irq_domain, 0);

	/* Mask the end point if PVM implemented */
	if (IS_ENABLED(CONFIG_PCI_MSI)) {
		if (msi->msi_attrib.maskbit)
			pci_msi_mask_irq(d);
	}

	ks_dw_pcie_msi_clear_irq(pp, offset);
}

static void ks_dw_pcie_msi_irq_unmask(struct irq_data *d)
{
	struct keystone_pcie *ks_pcie;
	unsigned int irq = d->irq;
	struct msi_desc *msi;
	struct pcie_port *pp;
	u32 offset;

	msi = irq_get_msi_desc(irq);
	pp = sys_to_pcie(msi->dev->bus->sysdata);
	ks_pcie = to_keystone_pcie(pp);
	offset = irq - irq_linear_revmap(pp->irq_domain, 0);

	/* Mask the end point if PVM implemented */
	if (IS_ENABLED(CONFIG_PCI_MSI)) {
		if (msi->msi_attrib.maskbit)
			pci_msi_unmask_irq(d);
	}

	ks_dw_pcie_msi_set_irq(pp, offset);
}

static struct irq_chip ks_dw_pcie_msi_irq_chip = {
	.name = "Keystone-PCIe-MSI-IRQ",
	.irq_ack = ks_dw_pcie_msi_irq_ack,
	.irq_mask = ks_dw_pcie_msi_irq_mask,
	.irq_unmask = ks_dw_pcie_msi_irq_unmask,
};

static int ks_dw_pcie_msi_map(struct irq_domain *domain, unsigned int irq,
			      irq_hw_number_t hwirq)
{
	irq_set_chip_and_handler(irq, &ks_dw_pcie_msi_irq_chip,
				 handle_level_irq);
	irq_set_chip_data(irq, domain->host_data);
	set_irq_flags(irq, IRQF_VALID);

	return 0;
}

static const struct irq_domain_ops ks_dw_pcie_msi_domain_ops = {
	.map = ks_dw_pcie_msi_map,
};

int ks_dw_pcie_msi_host_init(struct pcie_port *pp, struct msi_controller *chip)
{
	struct keystone_pcie *ks_pcie = to_keystone_pcie(pp);
	int i;

	pp->irq_domain = irq_domain_add_linear(ks_pcie->msi_intc_np,
					MAX_MSI_IRQS,
					&ks_dw_pcie_msi_domain_ops,
					chip);
	if (!pp->irq_domain) {
		dev_err(pp->dev, "irq domain init failed\n");
		return -ENXIO;
	}

	for (i = 0; i < MAX_MSI_IRQS; i++)
		irq_create_mapping(pp->irq_domain, i);

	return 0;
}

void ks_dw_pcie_enable_legacy_irqs(struct keystone_pcie *ks_pcie)
{
	int i;

	for (i = 0; i < MAX_LEGACY_IRQS; i++)
		writel(0x1, ks_pcie->va_app_base + IRQ_ENABLE_SET + (i << 4));
}

void ks_dw_pcie_handle_legacy_irq(struct keystone_pcie *ks_pcie, int offset)
{
	struct pcie_port *pp = &ks_pcie->pp;
	u32 pending;
	int virq;

	pending = readl(ks_pcie->va_app_base + IRQ_STATUS + (offset << 4));

	if (BIT(0) & pending) {
		virq = irq_linear_revmap(ks_pcie->legacy_irq_domain, offset);
		dev_dbg(pp->dev, ": irq: irq_offset %d, virq %d\n", offset,
			virq);
		generic_handle_irq(virq);
	}

	/* EOI the INTx interrupt */
	writel(offset, ks_pcie->va_app_base + IRQ_EOI);
}

static void ks_dw_pcie_ack_legacy_irq(struct irq_data *d)
{
}

static void ks_dw_pcie_mask_legacy_irq(struct irq_data *d)
{
}

static void ks_dw_pcie_unmask_legacy_irq(struct irq_data *d)
{
}

static struct irq_chip ks_dw_pcie_legacy_irq_chip = {
	.name = "Keystone-PCI-Legacy-IRQ",
	.irq_ack = ks_dw_pcie_ack_legacy_irq,
	.irq_mask = ks_dw_pcie_mask_legacy_irq,
	.irq_unmask = ks_dw_pcie_unmask_legacy_irq,
};

static int ks_dw_pcie_init_legacy_irq_map(struct irq_domain *d,
				unsigned int irq, irq_hw_number_t hw_irq)
{
	irq_set_chip_and_handler(irq, &ks_dw_pcie_legacy_irq_chip,
				 handle_level_irq);
	irq_set_chip_data(irq, d->host_data);
	set_irq_flags(irq, IRQF_VALID);

	return 0;
}

static const struct irq_domain_ops ks_dw_pcie_legacy_irq_domain_ops = {
	.map = ks_dw_pcie_init_legacy_irq_map,
	.xlate = irq_domain_xlate_onetwocell,
};

/**
 * ks_dw_pcie_set_dbi_mode() - Set DBI mode to access overlaid BAR mask
 * registers
 *
 * Since modification of dbi_cs2 involves different clock domain, read the
 * status back to ensure the transition is complete.
 */
static void ks_dw_pcie_set_dbi_mode(void __iomem *reg_virt)
{
	u32 val;

	writel(DBI_CS2_EN_VAL | readl(reg_virt + CMD_STATUS),
	       reg_virt + CMD_STATUS);

	do {
		val = readl(reg_virt + CMD_STATUS);
	} while (!(val & DBI_CS2_EN_VAL));
}

/**
 * ks_dw_pcie_clear_dbi_mode() - Disable DBI mode
 *
 * Since modification of dbi_cs2 involves different clock domain, read the
 * status back to ensure the transition is complete.
 */
static void ks_dw_pcie_clear_dbi_mode(void __iomem *reg_virt)
{
	u32 val;

	writel(~DBI_CS2_EN_VAL & readl(reg_virt + CMD_STATUS),
		     reg_virt + CMD_STATUS);

	do {
		val = readl(reg_virt + CMD_STATUS);
	} while (val & DBI_CS2_EN_VAL);
}

void ks_dw_pcie_setup_rc_app_regs(struct keystone_pcie *ks_pcie)
{
	struct pcie_port *pp = &ks_pcie->pp;
	u32 start = pp->mem.start, end = pp->mem.end;
	int i, tr_size;

	/* Disable BARs for inbound access */
	ks_dw_pcie_set_dbi_mode(ks_pcie->va_app_base);
	writel(0, pp->dbi_base + PCI_BASE_ADDRESS_0);
	writel(0, pp->dbi_base + PCI_BASE_ADDRESS_1);
	ks_dw_pcie_clear_dbi_mode(ks_pcie->va_app_base);

	/* Set outbound translation size per window division */
	writel(CFG_PCIM_WIN_SZ_IDX & 0x7, ks_pcie->va_app_base + OB_SIZE);

	tr_size = (1 << (CFG_PCIM_WIN_SZ_IDX & 0x7)) * SZ_1M;

	/* Using Direct 1:1 mapping of RC <-> PCI memory space */
	for (i = 0; (i < CFG_PCIM_WIN_CNT) && (start < end); i++) {
		writel(start | 1, ks_pcie->va_app_base + OB_OFFSET_INDEX(i));
		writel(0, ks_pcie->va_app_base + OB_OFFSET_HI(i));
		start += tr_size;
	}

	/* Enable OB translation */
	writel(OB_XLAT_EN_VAL | readl(ks_pcie->va_app_base + CMD_STATUS),
	       ks_pcie->va_app_base + CMD_STATUS);
}

/**
 * ks_pcie_cfg_setup() - Set up configuration space address for a device
 *
 * @ks_pcie: ptr to keystone_pcie structure
 * @bus: Bus number the device is residing on
 * @devfn: device, function number info
 *
 * Forms and returns the address of configuration space mapped in PCIESS
 * address space 0.  Also configures CFG_SETUP for remote configuration space
 * access.
 *
 * The address space has two regions to access configuration - local and remote.
 * We access local region for bus 0 (as RC is attached on bus 0) and remote
 * region for others with TYPE 1 access when bus > 1.  As for device on bus = 1,
 * we will do TYPE 0 access as it will be on our secondary bus (logical).
 * CFG_SETUP is needed only for remote configuration access.
 */
static void __iomem *ks_pcie_cfg_setup(struct keystone_pcie *ks_pcie, u8 bus,
				       unsigned int devfn)
{
	u8 device = PCI_SLOT(devfn), function = PCI_FUNC(devfn);
	struct pcie_port *pp = &ks_pcie->pp;
	u32 regval;

	if (bus == 0)
		return pp->dbi_base;

	regval = (bus << 16) | (device << 8) | function;

	/*
	 * Since Bus#1 will be a virtual bus, we need to have TYPE0
	 * access only.
	 * TYPE 1
	 */
	if (bus != 1)
		regval |= BIT(24);

	writel(regval, ks_pcie->va_app_base + CFG_SETUP);
	return pp->va_cfg0_base;
}

int ks_dw_pcie_rd_other_conf(struct pcie_port *pp, struct pci_bus *bus,
			     unsigned int devfn, int where, int size, u32 *val)
{
	struct keystone_pcie *ks_pcie = to_keystone_pcie(pp);
	u8 bus_num = bus->number;
	void __iomem *addr;

	addr = ks_pcie_cfg_setup(ks_pcie, bus_num, devfn);

	return dw_pcie_cfg_read(addr + (where & ~0x3), where, size, val);
}

int ks_dw_pcie_wr_other_conf(struct pcie_port *pp, struct pci_bus *bus,
			     unsigned int devfn, int where, int size, u32 val)
{
	struct keystone_pcie *ks_pcie = to_keystone_pcie(pp);
	u8 bus_num = bus->number;
	void __iomem *addr;

	addr = ks_pcie_cfg_setup(ks_pcie, bus_num, devfn);

	return dw_pcie_cfg_write(addr + (where & ~0x3), where, size, val);
}

/**
 * ks_dw_pcie_v3_65_scan_bus() - keystone scan_bus post initialization
 *
 * This sets BAR0 to enable inbound access for MSI_IRQ register
 */
void ks_dw_pcie_v3_65_scan_bus(struct pcie_port *pp)
{
	struct keystone_pcie *ks_pcie = to_keystone_pcie(pp);

	/* Configure and set up BAR0 */
	ks_dw_pcie_set_dbi_mode(ks_pcie->va_app_base);

	/* Enable BAR0 */
	writel(1, pp->dbi_base + PCI_BASE_ADDRESS_0);
	writel(SZ_4K - 1, pp->dbi_base + PCI_BASE_ADDRESS_0);

	ks_dw_pcie_clear_dbi_mode(ks_pcie->va_app_base);

	 /*
	  * For BAR0, just setting bus address for inbound writes (MSI) should
	  * be sufficient.  Use physical address to avoid any conflicts.
	  */
	writel(ks_pcie->app.start, pp->dbi_base + PCI_BASE_ADDRESS_0);
}

/**
 * ks_dw_pcie_link_up() - Check if link up
 */
int ks_dw_pcie_link_up(struct pcie_port *pp)
{
	u32 val = readl(pp->dbi_base + DEBUG0);

	return (val & LTSSM_STATE_MASK) == LTSSM_STATE_L0;
}

void ks_dw_pcie_initiate_link_train(struct keystone_pcie *ks_pcie)
{
	u32 val;

	/* Disable Link training */
	val = readl(ks_pcie->va_app_base + CMD_STATUS);
	val &= ~LTSSM_EN_VAL;
	writel(LTSSM_EN_VAL | val,  ks_pcie->va_app_base + CMD_STATUS);

	/* Initiate Link Training */
	val = readl(ks_pcie->va_app_base + CMD_STATUS);
	writel(LTSSM_EN_VAL | val,  ks_pcie->va_app_base + CMD_STATUS);
}

/**
 * ks_dw_pcie_host_init() - initialize host for v3_65 dw hardware
 *
 * Ioremap the register resources, initialize legacy irq domain
 * and call dw_pcie_v3_65_host_init() API to initialize the Keystone
 * PCI host controller.
 */
int __init ks_dw_pcie_host_init(struct keystone_pcie *ks_pcie,
				struct device_node *msi_intc_np)
{
	struct pcie_port *pp = &ks_pcie->pp;
	struct platform_device *pdev = to_platform_device(pp->dev);
	struct resource *res;

	/* Index 0 is the config reg. space address */
	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	pp->dbi_base = devm_ioremap_resource(pp->dev, res);
	if (IS_ERR(pp->dbi_base))
		return PTR_ERR(pp->dbi_base);

	/*
	 * We set these same and is used in pcie rd/wr_other_conf
	 * functions
	 */
	pp->va_cfg0_base = pp->dbi_base + SPACE0_REMOTE_CFG_OFFSET;
	pp->va_cfg1_base = pp->va_cfg0_base;

	/* Index 1 is the application reg. space address */
	res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
	ks_pcie->va_app_base = devm_ioremap_resource(pp->dev, res);
	if (IS_ERR(ks_pcie->va_app_base))
		return PTR_ERR(ks_pcie->va_app_base);

	ks_pcie->app = *res;

	/* Create legacy IRQ domain */
	ks_pcie->legacy_irq_domain =
			irq_domain_add_linear(ks_pcie->legacy_intc_np,
					MAX_LEGACY_IRQS,
					&ks_dw_pcie_legacy_irq_domain_ops,
					NULL);
	if (!ks_pcie->legacy_irq_domain) {
		dev_err(pp->dev, "Failed to add irq domain for legacy irqs\n");
		return -EINVAL;
	}

	return dw_pcie_host_init(pp);
}