// SPDX-License-Identifier: GPL-2.0
/*
 * Alchemy PCI host mode support.
 *
 * Copyright 2001-2003, 2007-2008 MontaVista Software Inc.
 * Author: MontaVista Software, Inc. <source@mvista.com>
 *
 * Support for all devices (greater than 16) added by David Gathright.
 */

#include <linux/clk.h>
#include <linux/export.h>
#include <linux/types.h>
#include <linux/pci.h>
#include <linux/platform_device.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/syscore_ops.h>
#include <linux/vmalloc.h>

#include <asm/dma-coherence.h>
#include <asm/mach-au1x00/au1000.h>
#include <asm/tlbmisc.h>

#ifdef CONFIG_PCI_DEBUG
#define DBG(x...) printk(KERN_DEBUG x)
#else
#define DBG(x...) do {} while (0)
#endif

#define PCI_ACCESS_READ         0
#define PCI_ACCESS_WRITE        1

struct alchemy_pci_context {
        struct pci_controller alchemy_pci_ctrl; /* leave as first member! */
        void __iomem *regs;                     /* ctrl base */
        /* tools for wired entry for config space access */
        unsigned long last_elo0;
        unsigned long last_elo1;
        int wired_entry;
        struct vm_struct *pci_cfg_vm;

        unsigned long pm[12];

        int (*board_map_irq)(const struct pci_dev *d, u8 slot, u8 pin);
        int (*board_pci_idsel)(unsigned int devsel, int assert);
};

/* for syscore_ops. There's only one PCI controller on Alchemy chips, so this
 * should suffice for now.
 */
static struct alchemy_pci_context *__alchemy_pci_ctx;


/* IO/MEM resources for PCI. Keep the memres in sync with fixup_bigphys_addr
 * in arch/mips/alchemy/common/setup.c
 */
static struct resource alchemy_pci_def_memres = {
        .start  = ALCHEMY_PCI_MEMWIN_START,
        .end    = ALCHEMY_PCI_MEMWIN_END,
        .name   = "PCI memory space",
        .flags  = IORESOURCE_MEM
};

static struct resource alchemy_pci_def_iores = {
        .start  = ALCHEMY_PCI_IOWIN_START,
        .end    = ALCHEMY_PCI_IOWIN_END,
        .name   = "PCI IO space",
        .flags  = IORESOURCE_IO
};

static void mod_wired_entry(int entry, unsigned long entrylo0,
                unsigned long entrylo1, unsigned long entryhi,
                unsigned long pagemask)
{
        unsigned long old_pagemask;
        unsigned long old_ctx;

        /* Save old context and create impossible VPN2 value */
        old_ctx = read_c0_entryhi() & MIPS_ENTRYHI_ASID;
        old_pagemask = read_c0_pagemask();
        write_c0_index(entry);
        write_c0_pagemask(pagemask);
        write_c0_entryhi(entryhi);
        write_c0_entrylo0(entrylo0);
        write_c0_entrylo1(entrylo1);
        tlb_write_indexed();
        write_c0_entryhi(old_ctx);
        write_c0_pagemask(old_pagemask);
}

static void alchemy_pci_wired_entry(struct alchemy_pci_context *ctx)
{
        ctx->wired_entry = read_c0_wired();
        add_wired_entry(0, 0, (unsigned long)ctx->pci_cfg_vm->addr, PM_4K);
        ctx->last_elo0 = ctx->last_elo1 = ~0;
}

static int config_access(unsigned char access_type, struct pci_bus *bus,
                         unsigned int dev_fn, unsigned char where, u32 *data)
{
        struct alchemy_pci_context *ctx = bus->sysdata;
        unsigned int device = PCI_SLOT(dev_fn);
        unsigned int function = PCI_FUNC(dev_fn);
        unsigned long offset, status, cfg_base, flags, entryLo0, entryLo1, r;
        int error = PCIBIOS_SUCCESSFUL;

        if (device > 19) {
                *data = 0xffffffff;
                return -1;
        }

        local_irq_save(flags);
        r = __raw_readl(ctx->regs + PCI_REG_STATCMD) & 0x0000ffff;
        r |= PCI_STATCMD_STATUS(0x2000);
        __raw_writel(r, ctx->regs + PCI_REG_STATCMD);
        wmb();

        /* Allow board vendors to implement their own off-chip IDSEL.
         * If it doesn't succeed, may as well bail out at this point.
         */
        if (ctx->board_pci_idsel(device, 1) == 0) {
                *data = 0xffffffff;
                local_irq_restore(flags);
                return -1;
        }

        /* Setup the config window */
        if (bus->number == 0)
                cfg_base = (1 << device) << 11;
        else
                cfg_base = 0x80000000 | (bus->number << 16) | (device << 11);

        /* Setup the lower bits of the 36-bit address */
        offset = (function << 8) | (where & ~0x3);
        /* Pick up any address that falls below the page mask */
        offset |= cfg_base & ~PAGE_MASK;

        /* Page boundary */
        cfg_base = cfg_base & PAGE_MASK;

        /* To improve performance, if the current device is the same as
         * the last device accessed, we don't touch the TLB.
         */
        entryLo0 = (6 << 26) | (cfg_base >> 6) | (2 << 3) | 7;
        entryLo1 = (6 << 26) | (cfg_base >> 6) | (0x1000 >> 6) | (2 << 3) | 7;
        if ((entryLo0 != ctx->last_elo0) || (entryLo1 != ctx->last_elo1)) {
                mod_wired_entry(ctx->wired_entry, entryLo0, entryLo1,
                                (unsigned long)ctx->pci_cfg_vm->addr, PM_4K);
                ctx->last_elo0 = entryLo0;
                ctx->last_elo1 = entryLo1;
        }

        if (access_type == PCI_ACCESS_WRITE)
                __raw_writel(*data, ctx->pci_cfg_vm->addr + offset);
        else
                *data = __raw_readl(ctx->pci_cfg_vm->addr + offset);
        wmb();

        DBG("alchemy-pci: cfg access %d bus %u dev %u at %x dat %x conf %lx\n",
            access_type, bus->number, device, where, *data, offset);

        /* check for errors, master abort */
        status = __raw_readl(ctx->regs + PCI_REG_STATCMD);
        if (status & (1 << 29)) {
                *data = 0xffffffff;
                error = -1;
                DBG("alchemy-pci: master abort on cfg access %d bus %d dev %d\n",
                    access_type, bus->number, device);
        } else if ((status >> 28) & 0xf) {
                DBG("alchemy-pci: PCI ERR detected: dev %d, status %lx\n",
                    device, (status >> 28) & 0xf);

                /* clear errors */
                __raw_writel(status & 0xf000ffff, ctx->regs + PCI_REG_STATCMD);

                *data = 0xffffffff;
                error = -1;
        }

        /* Take away the IDSEL. */
        (void)ctx->board_pci_idsel(device, 0);

        local_irq_restore(flags);
        return error;
}

static int read_config_byte(struct pci_bus *bus, unsigned int devfn,
                            int where,  u8 *val)
{
        u32 data;
        int ret = config_access(PCI_ACCESS_READ, bus, devfn, where, &data);

        if (where & 1)
                data >>= 8;
        if (where & 2)
                data >>= 16;
        *val = data & 0xff;
        return ret;
}

static int read_config_word(struct pci_bus *bus, unsigned int devfn,
                            int where, u16 *val)
{
        u32 data;
        int ret = config_access(PCI_ACCESS_READ, bus, devfn, where, &data);

        if (where & 2)
                data >>= 16;
        *val = data & 0xffff;
        return ret;
}

static int read_config_dword(struct pci_bus *bus, unsigned int devfn,
                             int where, u32 *val)
{
        return config_access(PCI_ACCESS_READ, bus, devfn, where, val);
}

static int write_config_byte(struct pci_bus *bus, unsigned int devfn,
                             int where, u8 val)
{
        u32 data = 0;

        if (config_access(PCI_ACCESS_READ, bus, devfn, where, &data))
                return -1;

        data = (data & ~(0xff << ((where & 3) << 3))) |
               (val << ((where & 3) << 3));

        if (config_access(PCI_ACCESS_WRITE, bus, devfn, where, &data))
                return -1;

        return PCIBIOS_SUCCESSFUL;
}

static int write_config_word(struct pci_bus *bus, unsigned int devfn,
                             int where, u16 val)
{
        u32 data = 0;

        if (config_access(PCI_ACCESS_READ, bus, devfn, where, &data))
                return -1;

        data = (data & ~(0xffff << ((where & 3) << 3))) |
               (val << ((where & 3) << 3));

        if (config_access(PCI_ACCESS_WRITE, bus, devfn, where, &data))
                return -1;

        return PCIBIOS_SUCCESSFUL;
}

static int write_config_dword(struct pci_bus *bus, unsigned int devfn,
                              int where, u32 val)
{
        return config_access(PCI_ACCESS_WRITE, bus, devfn, where, &val);
}

static int alchemy_pci_read(struct pci_bus *bus, unsigned int devfn,
                       int where, int size, u32 *val)
{
        switch (size) {
        case 1: {
                        u8 _val;
                        int rc = read_config_byte(bus, devfn, where, &_val);

                        *val = _val;
                        return rc;
                }
        case 2: {
                        u16 _val;
                        int rc = read_config_word(bus, devfn, where, &_val);

                        *val = _val;
                        return rc;
                }
        default:
                return read_config_dword(bus, devfn, where, val);
        }
}

static int alchemy_pci_write(struct pci_bus *bus, unsigned int devfn,
                             int where, int size, u32 val)
{
        switch (size) {
        case 1:
                return write_config_byte(bus, devfn, where, (u8) val);
        case 2:
                return write_config_word(bus, devfn, where, (u16) val);
        default:
                return write_config_dword(bus, devfn, where, val);
        }
}

static struct pci_ops alchemy_pci_ops = {
        .read   = alchemy_pci_read,
        .write  = alchemy_pci_write,
};

static int alchemy_pci_def_idsel(unsigned int devsel, int assert)
{
        return 1;       /* success */
}

/* save PCI controller register contents. */
static int alchemy_pci_suspend(void)
{
        struct alchemy_pci_context *ctx = __alchemy_pci_ctx;
        if (!ctx)
                return 0;

        ctx->pm[0]  = __raw_readl(ctx->regs + PCI_REG_CMEM);
        ctx->pm[1]  = __raw_readl(ctx->regs + PCI_REG_CONFIG) & 0x0009ffff;
        ctx->pm[2]  = __raw_readl(ctx->regs + PCI_REG_B2BMASK_CCH);
        ctx->pm[3]  = __raw_readl(ctx->regs + PCI_REG_B2BBASE0_VID);
        ctx->pm[4]  = __raw_readl(ctx->regs + PCI_REG_B2BBASE1_SID);
        ctx->pm[5]  = __raw_readl(ctx->regs + PCI_REG_MWMASK_DEV);
        ctx->pm[6]  = __raw_readl(ctx->regs + PCI_REG_MWBASE_REV_CCL);
        ctx->pm[7]  = __raw_readl(ctx->regs + PCI_REG_ID);
        ctx->pm[8]  = __raw_readl(ctx->regs + PCI_REG_CLASSREV);
        ctx->pm[9]  = __raw_readl(ctx->regs + PCI_REG_PARAM);
        ctx->pm[10] = __raw_readl(ctx->regs + PCI_REG_MBAR);
        ctx->pm[11] = __raw_readl(ctx->regs + PCI_REG_TIMEOUT);

        return 0;
}

static void alchemy_pci_resume(void)
{
        struct alchemy_pci_context *ctx = __alchemy_pci_ctx;
        if (!ctx)
                return;

        __raw_writel(ctx->pm[0],  ctx->regs + PCI_REG_CMEM);
        __raw_writel(ctx->pm[2],  ctx->regs + PCI_REG_B2BMASK_CCH);
        __raw_writel(ctx->pm[3],  ctx->regs + PCI_REG_B2BBASE0_VID);
        __raw_writel(ctx->pm[4],  ctx->regs + PCI_REG_B2BBASE1_SID);
        __raw_writel(ctx->pm[5],  ctx->regs + PCI_REG_MWMASK_DEV);
        __raw_writel(ctx->pm[6],  ctx->regs + PCI_REG_MWBASE_REV_CCL);
        __raw_writel(ctx->pm[7],  ctx->regs + PCI_REG_ID);
        __raw_writel(ctx->pm[8],  ctx->regs + PCI_REG_CLASSREV);
        __raw_writel(ctx->pm[9],  ctx->regs + PCI_REG_PARAM);
        __raw_writel(ctx->pm[10], ctx->regs + PCI_REG_MBAR);
        __raw_writel(ctx->pm[11], ctx->regs + PCI_REG_TIMEOUT);
        wmb();
        __raw_writel(ctx->pm[1],  ctx->regs + PCI_REG_CONFIG);
        wmb();

        /* YAMON on all db1xxx boards wipes the TLB and writes zero to C0_wired
         * on resume, making it necessary to recreate it as soon as possible.
         */
        ctx->wired_entry = 8191;        /* impossibly high value */
        alchemy_pci_wired_entry(ctx);   /* install it */
}

static struct syscore_ops alchemy_pci_pmops = {
        .suspend        = alchemy_pci_suspend,
        .resume         = alchemy_pci_resume,
};

static int alchemy_pci_probe(struct platform_device *pdev)
{
        struct alchemy_pci_platdata *pd = pdev->dev.platform_data;
        struct alchemy_pci_context *ctx;
        void __iomem *virt_io;
        unsigned long val;
        struct resource *r;
        struct clk *c;
        int ret;

        /* need at least PCI IRQ mapping table */
        if (!pd) {
                dev_err(&pdev->dev, "need platform data for PCI setup\n");
                ret = -ENODEV;
                goto out;
        }

        ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
        if (!ctx) {
                dev_err(&pdev->dev, "no memory for pcictl context\n");
                ret = -ENOMEM;
                goto out;
        }

        r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        if (!r) {
                dev_err(&pdev->dev, "no  pcictl ctrl regs resource\n");
                ret = -ENODEV;
                goto out1;
        }

        if (!request_mem_region(r->start, resource_size(r), pdev->name)) {
                dev_err(&pdev->dev, "cannot claim pci regs\n");
                ret = -ENODEV;
                goto out1;
        }

        c = clk_get(&pdev->dev, "pci_clko");
        if (IS_ERR(c)) {
                dev_err(&pdev->dev, "unable to find PCI clock\n");
                ret = PTR_ERR(c);
                goto out2;
        }

        ret = clk_prepare_enable(c);
        if (ret) {
                dev_err(&pdev->dev, "cannot enable PCI clock\n");
                goto out6;
        }

        ctx->regs = ioremap(r->start, resource_size(r));
        if (!ctx->regs) {
                dev_err(&pdev->dev, "cannot map pci regs\n");
                ret = -ENODEV;
                goto out5;
        }

        /* map parts of the PCI IO area */
        /* REVISIT: if this changes with a newer variant (doubt it) make this
         * a platform resource.
         */
        virt_io = ioremap(AU1500_PCI_IO_PHYS_ADDR, 0x00100000);
        if (!virt_io) {
                dev_err(&pdev->dev, "cannot remap pci io space\n");
                ret = -ENODEV;
                goto out3;
        }
        ctx->alchemy_pci_ctrl.io_map_base = (unsigned long)virt_io;

        /* Au1500 revisions older than AD have borked coherent PCI */
        if ((alchemy_get_cputype() == ALCHEMY_CPU_AU1500) &&
            (read_c0_prid() < 0x01030202) &&
            (coherentio == IO_COHERENCE_DISABLED)) {
                val = __raw_readl(ctx->regs + PCI_REG_CONFIG);
                val |= PCI_CONFIG_NC;
                __raw_writel(val, ctx->regs + PCI_REG_CONFIG);
                wmb();
                dev_info(&pdev->dev, "non-coherent PCI on Au1500 AA/AB/AC\n");
        }

        if (pd->board_map_irq)
                ctx->board_map_irq = pd->board_map_irq;

        if (pd->board_pci_idsel)
                ctx->board_pci_idsel = pd->board_pci_idsel;
        else
                ctx->board_pci_idsel = alchemy_pci_def_idsel;

        /* fill in relevant pci_controller members */
        ctx->alchemy_pci_ctrl.pci_ops = &alchemy_pci_ops;
        ctx->alchemy_pci_ctrl.mem_resource = &alchemy_pci_def_memres;
        ctx->alchemy_pci_ctrl.io_resource = &alchemy_pci_def_iores;

        /* we can't ioremap the entire pci config space because it's too large,
         * nor can we dynamically ioremap it because some drivers use the
         * PCI config routines from within atomic contex and that becomes a
         * problem in get_vm_area().  Instead we use one wired TLB entry to
         * handle all config accesses for all busses.
         */
        ctx->pci_cfg_vm = get_vm_area(0x2000, VM_IOREMAP);
        if (!ctx->pci_cfg_vm) {
                dev_err(&pdev->dev, "unable to get vm area\n");
                ret = -ENOMEM;
                goto out4;
        }
        ctx->wired_entry = 8191;        /* impossibly high value */
        alchemy_pci_wired_entry(ctx);   /* install it */

        set_io_port_base((unsigned long)ctx->alchemy_pci_ctrl.io_map_base);

        /* board may want to modify bits in the config register, do it now */
        val = __raw_readl(ctx->regs + PCI_REG_CONFIG);
        val &= ~pd->pci_cfg_clr;
        val |= pd->pci_cfg_set;
        val &= ~PCI_CONFIG_PD;          /* clear disable bit */
        __raw_writel(val, ctx->regs + PCI_REG_CONFIG);
        wmb();

        __alchemy_pci_ctx = ctx;
        platform_set_drvdata(pdev, ctx);
        register_syscore_ops(&alchemy_pci_pmops);
        register_pci_controller(&ctx->alchemy_pci_ctrl);

        dev_info(&pdev->dev, "PCI controller at %ld MHz\n",
                 clk_get_rate(c) / 1000000);

        return 0;

out4:
        iounmap(virt_io);
out3:
        iounmap(ctx->regs);
out5:
        clk_disable_unprepare(c);
out6:
        clk_put(c);
out2:
        release_mem_region(r->start, resource_size(r));
out1:
        kfree(ctx);
out:
        return ret;
}

static struct platform_driver alchemy_pcictl_driver = {
        .probe          = alchemy_pci_probe,
        .driver = {
                .name   = "alchemy-pci",
        },
};

static int __init alchemy_pci_init(void)
{
        /* Au1500/Au1550 have PCI */
        switch (alchemy_get_cputype()) {
        case ALCHEMY_CPU_AU1500:
        case ALCHEMY_CPU_AU1550:
                return platform_driver_register(&alchemy_pcictl_driver);
        }
        return 0;
}
arch_initcall(alchemy_pci_init);


int pcibios_map_irq(const struct pci_dev *dev, u8 slot, u8 pin)
{
        struct alchemy_pci_context *ctx = dev->sysdata;
        if (ctx && ctx->board_map_irq)
                return ctx->board_map_irq(dev, slot, pin);
        return -1;
}

int pcibios_plat_dev_init(struct pci_dev *dev)
{
        return 0;
}