// SPDX-License-Identifier: GPL-2.0
/*
 * AMD Family 10h mmconfig enablement
 */

#include <linux/types.h>
#include <linux/mm.h>
#include <linux/string.h>
#include <linux/pci.h>
#include <linux/dmi.h>
#include <linux/range.h>

#include <asm/pci-direct.h>
#include <linux/sort.h>
#include <asm/io.h>
#include <asm/msr.h>
#include <asm/acpi.h>
#include <asm/mmconfig.h>
#include <asm/pci_x86.h>

struct pci_hostbridge_probe {
        u32 bus;
        u32 slot;
        u32 vendor;
        u32 device;
};

static u64 fam10h_pci_mmconf_base;

static struct pci_hostbridge_probe pci_probes[] = {
        { 0, 0x18, PCI_VENDOR_ID_AMD, 0x1200 },
        { 0xff, 0, PCI_VENDOR_ID_AMD, 0x1200 },
};

static int cmp_range(const void *x1, const void *x2)
{
        const struct range *r1 = x1;
        const struct range *r2 = x2;
        int start1, start2;

        start1 = r1->start >> 32;
        start2 = r2->start >> 32;

        return start1 - start2;
}

#define MMCONF_UNIT (1ULL << FAM10H_MMIO_CONF_BASE_SHIFT)
#define MMCONF_MASK (~(MMCONF_UNIT - 1))
#define MMCONF_SIZE (MMCONF_UNIT << 8)
/* need to avoid (0xfd<<32), (0xfe<<32), and (0xff<<32), ht used space */
#define FAM10H_PCI_MMCONF_BASE (0xfcULL<<32)
#define BASE_VALID(b) ((b) + MMCONF_SIZE <= (0xfdULL<<32) || (b) >= (1ULL<<40))
static void get_fam10h_pci_mmconf_base(void)
{
        int i;
        unsigned bus;
        unsigned slot;
        int found;

        u64 val;
        u32 address;
        u64 tom2;
        u64 base = FAM10H_PCI_MMCONF_BASE;

        int hi_mmio_num;
        struct range range[8];

        /* only try to get setting from BSP */
        if (fam10h_pci_mmconf_base)
                return;

        if (!early_pci_allowed())
                return;

        found = 0;
        for (i = 0; i < ARRAY_SIZE(pci_probes); i++) {
                u32 id;
                u16 device;
                u16 vendor;

                bus = pci_probes[i].bus;
                slot = pci_probes[i].slot;
                id = read_pci_config(bus, slot, 0, PCI_VENDOR_ID);

                vendor = id & 0xffff;
                device = (id>>16) & 0xffff;
                if (pci_probes[i].vendor == vendor &&
                    pci_probes[i].device == device) {
                        found = 1;
                        break;
                }
        }

        if (!found)
                return;

        /* SYS_CFG */
        address = MSR_K8_SYSCFG;
        rdmsrl(address, val);

        /* TOP_MEM2 is not enabled? */
        if (!(val & (1<<21))) {
                tom2 = 1ULL << 32;
        } else {
                /* TOP_MEM2 */
                address = MSR_K8_TOP_MEM2;
                rdmsrl(address, val);
                tom2 = max(val & 0xffffff800000ULL, 1ULL << 32);
        }

        if (base <= tom2)
                base = (tom2 + 2 * MMCONF_UNIT - 1) & MMCONF_MASK;

        /*
         * need to check if the range is in the high mmio range that is
         * above 4G
         */
        hi_mmio_num = 0;
        for (i = 0; i < 8; i++) {
                u32 reg;
                u64 start;
                u64 end;
                reg = read_pci_config(bus, slot, 1, 0x80 + (i << 3));
                if (!(reg & 3))
                        continue;

                start = (u64)(reg & 0xffffff00) << 8; /* 39:16 on 31:8*/
                reg = read_pci_config(bus, slot, 1, 0x84 + (i << 3));
                end = ((u64)(reg & 0xffffff00) << 8) | 0xffff; /* 39:16 on 31:8*/

                if (end < tom2)
                        continue;

                range[hi_mmio_num].start = start;
                range[hi_mmio_num].end = end;
                hi_mmio_num++;
        }

        if (!hi_mmio_num)
                goto out;

        /* sort the range */
        sort(range, hi_mmio_num, sizeof(struct range), cmp_range, NULL);

        if (range[hi_mmio_num - 1].end < base)
                goto out;
        if (range[0].start > base + MMCONF_SIZE)
                goto out;

        /* need to find one window */
        base = (range[0].start & MMCONF_MASK) - MMCONF_UNIT;
        if ((base > tom2) && BASE_VALID(base))
                goto out;
        base = (range[hi_mmio_num - 1].end + MMCONF_UNIT) & MMCONF_MASK;
        if (BASE_VALID(base))
                goto out;
        /* need to find window between ranges */
        for (i = 1; i < hi_mmio_num; i++) {
                base = (range[i - 1].end + MMCONF_UNIT) & MMCONF_MASK;
                val = range[i].start & MMCONF_MASK;
                if (val >= base + MMCONF_SIZE && BASE_VALID(base))
                        goto out;
        }
        return;

out:
        fam10h_pci_mmconf_base = base;
}

void fam10h_check_enable_mmcfg(void)
{
        u64 val;
        u32 address;

        if (!(pci_probe & PCI_CHECK_ENABLE_AMD_MMCONF))
                return;

        address = MSR_FAM10H_MMIO_CONF_BASE;
        rdmsrl(address, val);

        /* try to make sure that AP's setting is identical to BSP setting */
        if (val & FAM10H_MMIO_CONF_ENABLE) {
                unsigned busnbits;
                busnbits = (val >> FAM10H_MMIO_CONF_BUSRANGE_SHIFT) &
                        FAM10H_MMIO_CONF_BUSRANGE_MASK;

                /* only trust the one handle 256 buses, if acpi=off */
                if (!acpi_pci_disabled || busnbits >= 8) {
                        u64 base = val & MMCONF_MASK;

                        if (!fam10h_pci_mmconf_base) {
                                fam10h_pci_mmconf_base = base;
                                return;
                        } else if (fam10h_pci_mmconf_base ==  base)
                                return;
                }
        }

        /*
         * if it is not enabled, try to enable it and assume only one segment
         * with 256 buses
         */
        get_fam10h_pci_mmconf_base();
        if (!fam10h_pci_mmconf_base) {
                pci_probe &= ~PCI_CHECK_ENABLE_AMD_MMCONF;
                return;
        }

        printk(KERN_INFO "Enable MMCONFIG on AMD Family 10h\n");
        val &= ~((FAM10H_MMIO_CONF_BASE_MASK<<FAM10H_MMIO_CONF_BASE_SHIFT) |
             (FAM10H_MMIO_CONF_BUSRANGE_MASK<<FAM10H_MMIO_CONF_BUSRANGE_SHIFT));
        val |= fam10h_pci_mmconf_base | (8 << FAM10H_MMIO_CONF_BUSRANGE_SHIFT) |
               FAM10H_MMIO_CONF_ENABLE;
        wrmsrl(address, val);
}

static int __init set_check_enable_amd_mmconf(const struct dmi_system_id *d)
{
        pci_probe |= PCI_CHECK_ENABLE_AMD_MMCONF;
        return 0;
}

static const struct dmi_system_id __initconst mmconf_dmi_table[] = {
        {
                .callback = set_check_enable_amd_mmconf,
                .ident = "Sun Microsystems Machine",
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "Sun Microsystems"),
                },
        },
        {}
};

/* Called from a non __init function, but only on the BSP. */
void __ref check_enable_amd_mmconf_dmi(void)
{
        dmi_check_system(mmconf_dmi_table);
}