/*
 * PCIe host controller driver for Freescale Layerscape SoCs
 *
 * Copyright (C) 2014 Freescale Semiconductor.
 *
 * Author: Minghuan Lian <Minghuan.Lian@freescale.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/kernel.h>
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/of_pci.h>
#include <linux/of_platform.h>
#include <linux/of_irq.h>
#include <linux/of_address.h>
#include <linux/pci.h>
#include <linux/platform_device.h>
#include <linux/resource.h>
#include <linux/mfd/syscon.h>
#include <linux/regmap.h>

#include "pcie-designware.h"

/* PEX1/2 Misc Ports Status Register */
#define SCFG_PEXMSCPORTSR(pex_idx)      (0x94 + (pex_idx) * 4)
#define LTSSM_STATE_SHIFT       20
#define LTSSM_STATE_MASK        0x3f
#define LTSSM_PCIE_L0           0x11 /* L0 state */

/* PEX Internal Configuration Registers */
#define PCIE_STRFMR1            0x71c /* Symbol Timer & Filter Mask Register1 */
#define PCIE_DBI_RO_WR_EN       0x8bc /* DBI Read-Only Write Enable Register */

/* PEX LUT registers */
#define PCIE_LUT_DBG            0x7FC /* PEX LUT Debug Register */

struct ls_pcie_drvdata {
        u32 lut_offset;
        u32 ltssm_shift;
        struct pcie_host_ops *ops;
};

struct ls_pcie {
        void __iomem *dbi;
        void __iomem *lut;
        struct regmap *scfg;
        struct pcie_port pp;
        const struct ls_pcie_drvdata *drvdata;
        int index;
};

#define to_ls_pcie(x)   container_of(x, struct ls_pcie, pp)

static bool ls_pcie_is_bridge(struct ls_pcie *pcie)
{
        u32 header_type;

        header_type = ioread8(pcie->dbi + PCI_HEADER_TYPE);
        header_type &= 0x7f;

        return header_type == PCI_HEADER_TYPE_BRIDGE;
}

/* Clear multi-function bit */
static void ls_pcie_clear_multifunction(struct ls_pcie *pcie)
{
        iowrite8(PCI_HEADER_TYPE_BRIDGE, pcie->dbi + PCI_HEADER_TYPE);
}

/* Fix class value */
static void ls_pcie_fix_class(struct ls_pcie *pcie)
{
        iowrite16(PCI_CLASS_BRIDGE_PCI, pcie->dbi + PCI_CLASS_DEVICE);
}

/* Drop MSG TLP except for Vendor MSG */
static void ls_pcie_drop_msg_tlp(struct ls_pcie *pcie)
{
        u32 val;

        val = ioread32(pcie->dbi + PCIE_STRFMR1);
        val &= 0xDFFFFFFF;
        iowrite32(val, pcie->dbi + PCIE_STRFMR1);
}

static int ls1021_pcie_link_up(struct pcie_port *pp)
{
        u32 state;
        struct ls_pcie *pcie = to_ls_pcie(pp);

        if (!pcie->scfg)
                return 0;

        regmap_read(pcie->scfg, SCFG_PEXMSCPORTSR(pcie->index), &state);
        state = (state >> LTSSM_STATE_SHIFT) & LTSSM_STATE_MASK;

        if (state < LTSSM_PCIE_L0)
                return 0;

        return 1;
}

static void ls1021_pcie_host_init(struct pcie_port *pp)
{
        struct ls_pcie *pcie = to_ls_pcie(pp);
        u32 index[2];

        pcie->scfg = syscon_regmap_lookup_by_phandle(pp->dev->of_node,
                                                     "fsl,pcie-scfg");
        if (IS_ERR(pcie->scfg)) {
                dev_err(pp->dev, "No syscfg phandle specified\n");
                pcie->scfg = NULL;
                return;
        }

        if (of_property_read_u32_array(pp->dev->of_node,
                                       "fsl,pcie-scfg", index, 2)) {
                pcie->scfg = NULL;
                return;
        }
        pcie->index = index[1];

        dw_pcie_setup_rc(pp);

        ls_pcie_drop_msg_tlp(pcie);
}

static int ls_pcie_link_up(struct pcie_port *pp)
{
        struct ls_pcie *pcie = to_ls_pcie(pp);
        u32 state;

        state = (ioread32(pcie->lut + PCIE_LUT_DBG) >>
                 pcie->drvdata->ltssm_shift) &
                 LTSSM_STATE_MASK;

        if (state < LTSSM_PCIE_L0)
                return 0;

        return 1;
}

static void ls_pcie_host_init(struct pcie_port *pp)
{
        struct ls_pcie *pcie = to_ls_pcie(pp);

        iowrite32(1, pcie->dbi + PCIE_DBI_RO_WR_EN);
        ls_pcie_fix_class(pcie);
        ls_pcie_clear_multifunction(pcie);
        ls_pcie_drop_msg_tlp(pcie);
        iowrite32(0, pcie->dbi + PCIE_DBI_RO_WR_EN);
}

static int ls_pcie_msi_host_init(struct pcie_port *pp,
                                 struct msi_controller *chip)
{
        struct device_node *msi_node;
        struct device_node *np = pp->dev->of_node;

        /*
         * The MSI domain is set by the generic of_msi_configure().  This
         * .msi_host_init() function keeps us from doing the default MSI
         * domain setup in dw_pcie_host_init() and also enforces the
         * requirement that "msi-parent" exists.
         */
        msi_node = of_parse_phandle(np, "msi-parent", 0);
        if (!msi_node) {
                dev_err(pp->dev, "failed to find msi-parent\n");
                return -EINVAL;
        }

        return 0;
}

static struct pcie_host_ops ls1021_pcie_host_ops = {
        .link_up = ls1021_pcie_link_up,
        .host_init = ls1021_pcie_host_init,
        .msi_host_init = ls_pcie_msi_host_init,
};

static struct pcie_host_ops ls_pcie_host_ops = {
        .link_up = ls_pcie_link_up,
        .host_init = ls_pcie_host_init,
        .msi_host_init = ls_pcie_msi_host_init,
};

static struct ls_pcie_drvdata ls1021_drvdata = {
        .ops = &ls1021_pcie_host_ops,
};

static struct ls_pcie_drvdata ls1043_drvdata = {
        .lut_offset = 0x10000,
        .ltssm_shift = 24,
        .ops = &ls_pcie_host_ops,
};

static struct ls_pcie_drvdata ls2080_drvdata = {
        .lut_offset = 0x80000,
        .ltssm_shift = 0,
        .ops = &ls_pcie_host_ops,
};

static const struct of_device_id ls_pcie_of_match[] = {
        { .compatible = "fsl,ls1021a-pcie", .data = &ls1021_drvdata },
        { .compatible = "fsl,ls1043a-pcie", .data = &ls1043_drvdata },
        { .compatible = "fsl,ls2080a-pcie", .data = &ls2080_drvdata },
        { .compatible = "fsl,ls2085a-pcie", .data = &ls2080_drvdata },
        { },
};
MODULE_DEVICE_TABLE(of, ls_pcie_of_match);

static int __init ls_add_pcie_port(struct pcie_port *pp,
                                   struct platform_device *pdev)
{
        int ret;
        struct ls_pcie *pcie = to_ls_pcie(pp);

        pp->dev = &pdev->dev;
        pp->dbi_base = pcie->dbi;
        pp->ops = pcie->drvdata->ops;

        ret = dw_pcie_host_init(pp);
        if (ret) {
                dev_err(pp->dev, "failed to initialize host\n");
                return ret;
        }

        return 0;
}

static int __init ls_pcie_probe(struct platform_device *pdev)
{
        const struct of_device_id *match;
        struct ls_pcie *pcie;
        struct resource *dbi_base;
        int ret;

        match = of_match_device(ls_pcie_of_match, &pdev->dev);
        if (!match)
                return -ENODEV;

        pcie = devm_kzalloc(&pdev->dev, sizeof(*pcie), GFP_KERNEL);
        if (!pcie)
                return -ENOMEM;

        dbi_base = platform_get_resource_byname(pdev, IORESOURCE_MEM, "regs");
        pcie->dbi = devm_ioremap_resource(&pdev->dev, dbi_base);
        if (IS_ERR(pcie->dbi)) {
                dev_err(&pdev->dev, "missing *regs* space\n");
                return PTR_ERR(pcie->dbi);
        }

        pcie->drvdata = match->data;
        pcie->lut = pcie->dbi + pcie->drvdata->lut_offset;

        if (!ls_pcie_is_bridge(pcie))
                return -ENODEV;

        ret = ls_add_pcie_port(&pcie->pp, pdev);
        if (ret < 0)
                return ret;

        platform_set_drvdata(pdev, pcie);

        return 0;
}

static struct platform_driver ls_pcie_driver = {
        .driver = {
                .name = "layerscape-pcie",
                .of_match_table = ls_pcie_of_match,
        },
};

module_platform_driver_probe(ls_pcie_driver, ls_pcie_probe);

MODULE_AUTHOR("Minghuan Lian <Minghuan.Lian@freescale.com>");
MODULE_DESCRIPTION("Freescale Layerscape PCIe host controller driver");
MODULE_LICENSE("GPL v2");