/*-
 * Copyright (c) 2015 Nathan Whitehorn
 * Copyright (c) 2017-2018 Semihalf
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/bus.h>
#include <sys/pcpu.h>
#include <sys/proc.h>
#include <sys/smp.h>
#include <vm/vm.h>
#include <vm/pmap.h>

#include <machine/bus.h>
#include <machine/cpu.h>
#include <machine/hid.h>
#include <machine/platformvar.h>
#include <machine/pmap.h>
#include <machine/rtas.h>
#include <machine/smp.h>
#include <machine/spr.h>
#include <machine/trap.h>

#include <dev/ofw/openfirm.h>
#include <dev/ofw/ofw_bus.h>
#include <dev/ofw/ofw_bus_subr.h>
#include <machine/ofw_machdep.h>
#include <powerpc/aim/mmu_oea64.h>

#include "platform_if.h"
#include "opal.h"

#ifdef SMP
extern void *ap_pcpu;
#endif

void (*powernv_smp_ap_extra_init)(void);

static int powernv_probe(platform_t);
static int powernv_attach(platform_t);
void powernv_mem_regions(platform_t, struct mem_region *phys, int *physsz,
    struct mem_region *avail, int *availsz);
static void powernv_numa_mem_regions(platform_t plat, struct numa_mem_region *phys, int *physsz);
static u_long powernv_timebase_freq(platform_t, struct cpuref *cpuref);
static int powernv_smp_first_cpu(platform_t, struct cpuref *cpuref);
static int powernv_smp_next_cpu(platform_t, struct cpuref *cpuref);
static int powernv_smp_get_bsp(platform_t, struct cpuref *cpuref);
static void powernv_smp_ap_init(platform_t);
#ifdef SMP
static int powernv_smp_start_cpu(platform_t, struct pcpu *cpu);
static void powernv_smp_probe_threads(platform_t);
static struct cpu_group *powernv_smp_topo(platform_t plat);
#endif
static void powernv_reset(platform_t);
static void powernv_cpu_idle(sbintime_t sbt);
static int powernv_cpuref_init(void);
static int powernv_node_numa_domain(platform_t platform, phandle_t node);

static platform_method_t powernv_methods[] = {
        PLATFORMMETHOD(platform_probe,          powernv_probe),
        PLATFORMMETHOD(platform_attach,         powernv_attach),
        PLATFORMMETHOD(platform_mem_regions,    powernv_mem_regions),
        PLATFORMMETHOD(platform_numa_mem_regions,       powernv_numa_mem_regions),
        PLATFORMMETHOD(platform_timebase_freq,  powernv_timebase_freq),

        PLATFORMMETHOD(platform_smp_ap_init,    powernv_smp_ap_init),
        PLATFORMMETHOD(platform_smp_first_cpu,  powernv_smp_first_cpu),
        PLATFORMMETHOD(platform_smp_next_cpu,   powernv_smp_next_cpu),
        PLATFORMMETHOD(platform_smp_get_bsp,    powernv_smp_get_bsp),
#ifdef SMP
        PLATFORMMETHOD(platform_smp_start_cpu,  powernv_smp_start_cpu),
        PLATFORMMETHOD(platform_smp_probe_threads,      powernv_smp_probe_threads),
        PLATFORMMETHOD(platform_smp_topo,       powernv_smp_topo),
#endif
        PLATFORMMETHOD(platform_node_numa_domain,       powernv_node_numa_domain),

        PLATFORMMETHOD(platform_reset,          powernv_reset),
        { 0, 0 }
};

static platform_def_t powernv_platform = {
        "powernv",
        powernv_methods,
        0
};

static struct cpuref platform_cpuref[MAXCPU];
static int platform_cpuref_cnt;
static int platform_cpuref_valid;
static int platform_associativity;

PLATFORM_DEF(powernv_platform);

static uint64_t powernv_boot_pir;

static int
powernv_probe(platform_t plat)
{
        if (opal_check() == 0)
                return (BUS_PROBE_SPECIFIC);

        return (ENXIO);
}

static int
powernv_attach(platform_t plat)
{
        uint32_t nptlp, shift = 0, slb_encoding = 0;
        int32_t lp_size, lp_encoding;
        char buf[255];
        pcell_t refpoints[3];
        pcell_t prop;
        phandle_t cpu;
        phandle_t opal;
        int res, len, idx;
        register_t msr;
        register_t fscr;
        bool has_lp;

        /* Ping OPAL again just to make sure */
        opal_check();

#if BYTE_ORDER == LITTLE_ENDIAN
        opal_call(OPAL_REINIT_CPUS, 2 /* Little endian */);
#else
        opal_call(OPAL_REINIT_CPUS, 1 /* Big endian */);
#endif
        opal = OF_finddevice("/ibm,opal");

        platform_associativity = 4; /* Skiboot default. */
        if (OF_getencprop(opal, "ibm,associativity-reference-points", refpoints,
            sizeof(refpoints)) > 0) {
                platform_associativity = refpoints[0];
        }

       if (cpu_idle_hook == NULL)
                cpu_idle_hook = powernv_cpu_idle;

        powernv_boot_pir = mfspr(SPR_PIR);

        /* LPID must not be altered when PSL_DR or PSL_IR is set */
        msr = mfmsr();
        mtmsr(msr & ~(PSL_DR | PSL_IR));

        /* Direct interrupts to SRR instead of HSRR and reset LPCR otherwise */
        mtspr(SPR_LPID, 0);
        isync();

        if (cpu_features2 & PPC_FEATURE2_ARCH_3_00)
                lpcr |= LPCR_HVICE;

#if BYTE_ORDER == LITTLE_ENDIAN
        lpcr |= LPCR_ILE;
#endif

        mtspr(SPR_LPCR, lpcr);
        isync();

        fscr = mfspr(SPR_HFSCR);
        fscr |= FSCR_TAR | FSCR_EBB | HFSCR_BHRB | HFSCR_PM |
            HFSCR_VECVSX | HFSCR_FP | FSCR_MSGP | FSCR_DSCR;
        mtspr(SPR_HFSCR, fscr);

        mtmsr(msr);

        powernv_cpuref_init();

        /* Set SLB count from device tree */
        cpu = OF_peer(0);
        cpu = OF_child(cpu);
        while (cpu != 0) {
                res = OF_getprop(cpu, "name", buf, sizeof(buf));
                if (res > 0 && strcmp(buf, "cpus") == 0)
                        break;
                cpu = OF_peer(cpu);
        }
        if (cpu == 0)
                goto out;

        cpu = OF_child(cpu);
        while (cpu != 0) {
                res = OF_getprop(cpu, "device_type", buf, sizeof(buf));
                if (res > 0 && strcmp(buf, "cpu") == 0)
                        break;
                cpu = OF_peer(cpu);
        }
        if (cpu == 0)
                goto out;

        res = OF_getencprop(cpu, "ibm,slb-size", &prop, sizeof(prop));
        if (res > 0)
                n_slbs = prop;

        /*
         * Scan the large page size property for PAPR compatible machines.
         * See PAPR D.5 Changes to Section 5.1.4, 'CPU Node Properties'
         * for the encoding of the property.
         */

        len = OF_getproplen(cpu, "ibm,segment-page-sizes");
        if (len > 0) {
                /*
                 * We have to use a variable length array on the stack
                 * since we have very limited stack space.
                 */
                pcell_t arr[len/sizeof(cell_t)];
                res = OF_getencprop(cpu, "ibm,segment-page-sizes", arr,
                    sizeof(arr));
                len /= 4;
                idx = 0;
                has_lp = false;
                while (len > 0) {
                        shift = arr[idx];
                        slb_encoding = arr[idx + 1];
                        nptlp = arr[idx + 2];
                        idx += 3;
                        len -= 3;
                        while (len > 0 && nptlp) {
                                lp_size = arr[idx];
                                lp_encoding = arr[idx+1];
                                if (slb_encoding == SLBV_L && lp_encoding == 0)
                                        has_lp = true;

                                if (slb_encoding == SLB_PGSZ_4K_4K &&
                                    lp_encoding == LP_4K_16M)
                                        moea64_has_lp_4k_16m = true;

                                idx += 2;
                                len -= 2;
                                nptlp--;
                        }
                        if (has_lp && moea64_has_lp_4k_16m)
                                break;
                }

                if (!has_lp)
                        panic("Standard large pages (SLB[L] = 1, PTE[LP] = 0) "
                            "not supported by this system.");

                moea64_large_page_shift = shift;
                moea64_large_page_size = 1ULL << lp_size;
        }

out:
        return (0);
}

void
powernv_mem_regions(platform_t plat, struct mem_region *phys, int *physsz,
    struct mem_region *avail, int *availsz)
{

        ofw_mem_regions(phys, physsz, avail, availsz);
}

static void
powernv_numa_mem_regions(platform_t plat, struct numa_mem_region *phys, int *physsz)
{

        ofw_numa_mem_regions(phys, physsz);
}

static u_long
powernv_timebase_freq(platform_t plat, struct cpuref *cpuref)
{
        char buf[8];
        phandle_t cpu, dev, root;
        int res;
        int32_t ticks = -1;

        root = OF_peer(0);
        dev = OF_child(root);
        while (dev != 0) {
                res = OF_getprop(dev, "name", buf, sizeof(buf));
                if (res > 0 && strcmp(buf, "cpus") == 0)
                        break;
                dev = OF_peer(dev);
        }

        for (cpu = OF_child(dev); cpu != 0; cpu = OF_peer(cpu)) {
                res = OF_getprop(cpu, "device_type", buf, sizeof(buf));
                if (res > 0 && strcmp(buf, "cpu") == 0)
                        break;
        }
        if (cpu == 0)
                return (512000000);

        OF_getencprop(cpu, "timebase-frequency", &ticks, sizeof(ticks));

        if (ticks <= 0)
                panic("Unable to determine timebase frequency!");

        return (ticks);

}

static int
powernv_cpuref_init(void)
{
        phandle_t cpu, dev;
        char buf[32];
        int a, res, tmp_cpuref_cnt;
        static struct cpuref tmp_cpuref[MAXCPU];
        cell_t interrupt_servers[32];
        uint64_t bsp;

        if (platform_cpuref_valid)
                return (0);

        dev = OF_peer(0);
        dev = OF_child(dev);
        while (dev != 0) {
                res = OF_getprop(dev, "name", buf, sizeof(buf));
                if (res > 0 && strcmp(buf, "cpus") == 0)
                        break;
                dev = OF_peer(dev);
        }

        bsp = 0;
        tmp_cpuref_cnt = 0;
        for (cpu = OF_child(dev); cpu != 0; cpu = OF_peer(cpu)) {
                res = OF_getprop(cpu, "device_type", buf, sizeof(buf));
                if (res > 0 && strcmp(buf, "cpu") == 0) {
                        if (!ofw_bus_node_status_okay(cpu))
                                continue;
                        res = OF_getproplen(cpu, "ibm,ppc-interrupt-server#s");
                        if (res > 0) {
                                OF_getencprop(cpu, "ibm,ppc-interrupt-server#s",
                                    interrupt_servers, res);

                                for (a = 0; a < res/sizeof(cell_t); a++) {
                                        tmp_cpuref[tmp_cpuref_cnt].cr_hwref = interrupt_servers[a];
                                        tmp_cpuref[tmp_cpuref_cnt].cr_cpuid = tmp_cpuref_cnt;
                                        tmp_cpuref[tmp_cpuref_cnt].cr_domain =
                                            powernv_node_numa_domain(NULL, cpu);
                                        if (interrupt_servers[a] == (uint32_t)powernv_boot_pir)
                                                bsp = tmp_cpuref_cnt;

                                        tmp_cpuref_cnt++;
                                }
                        }
                }
        }

        /* Map IDs, so BSP has CPUID 0 regardless of hwref */
        for (a = bsp; a < tmp_cpuref_cnt; a++) {
                platform_cpuref[platform_cpuref_cnt].cr_hwref = tmp_cpuref[a].cr_hwref;
                platform_cpuref[platform_cpuref_cnt].cr_cpuid = platform_cpuref_cnt;
                platform_cpuref[platform_cpuref_cnt].cr_domain = tmp_cpuref[a].cr_domain;
                platform_cpuref_cnt++;
        }
        for (a = 0; a < bsp; a++) {
                platform_cpuref[platform_cpuref_cnt].cr_hwref = tmp_cpuref[a].cr_hwref;
                platform_cpuref[platform_cpuref_cnt].cr_cpuid = platform_cpuref_cnt;
                platform_cpuref[platform_cpuref_cnt].cr_domain = tmp_cpuref[a].cr_domain;
                platform_cpuref_cnt++;
        }

        platform_cpuref_valid = 1;

        return (0);
}

static int
powernv_smp_first_cpu(platform_t plat, struct cpuref *cpuref)
{
        if (platform_cpuref_valid == 0)
                return (EINVAL);

        cpuref->cr_cpuid = 0;
        cpuref->cr_hwref = platform_cpuref[0].cr_hwref;
        cpuref->cr_domain = platform_cpuref[0].cr_domain;

        return (0);
}

static int
powernv_smp_next_cpu(platform_t plat, struct cpuref *cpuref)
{
        int id;

        if (platform_cpuref_valid == 0)
                return (EINVAL);

        id = cpuref->cr_cpuid + 1;
        if (id >= platform_cpuref_cnt)
                return (ENOENT);

        cpuref->cr_cpuid = platform_cpuref[id].cr_cpuid;
        cpuref->cr_hwref = platform_cpuref[id].cr_hwref;
        cpuref->cr_domain = platform_cpuref[id].cr_domain;

        return (0);
}

static int
powernv_smp_get_bsp(platform_t plat, struct cpuref *cpuref)
{

        cpuref->cr_cpuid = platform_cpuref[0].cr_cpuid;
        cpuref->cr_hwref = platform_cpuref[0].cr_hwref;
        cpuref->cr_domain = platform_cpuref[0].cr_domain;
        return (0);
}

#ifdef SMP
static int
powernv_smp_start_cpu(platform_t plat, struct pcpu *pc)
{
        int result;

        ap_pcpu = pc;
        powerpc_sync();

        result = opal_call(OPAL_START_CPU, pc->pc_hwref, EXC_RST);
        if (result != OPAL_SUCCESS) {
                printf("OPAL error (%d): unable to start AP %d\n",
                    result, (int)pc->pc_hwref);
                return (ENXIO);
        }

        return (0);
}

static void
powernv_smp_probe_threads(platform_t plat)
{
        char buf[8];
        phandle_t cpu, dev, root;
        int res, nthreads;

        root = OF_peer(0);

        dev = OF_child(root);
        while (dev != 0) {
                res = OF_getprop(dev, "name", buf, sizeof(buf));
                if (res > 0 && strcmp(buf, "cpus") == 0)
                        break;
                dev = OF_peer(dev);
        }

        nthreads = 1;
        for (cpu = OF_child(dev); cpu != 0; cpu = OF_peer(cpu)) {
                res = OF_getprop(cpu, "device_type", buf, sizeof(buf));
                if (res <= 0 || strcmp(buf, "cpu") != 0)
                        continue;

                res = OF_getproplen(cpu, "ibm,ppc-interrupt-server#s");

                if (res >= 0)
                        nthreads = res / sizeof(cell_t);
                else
                        nthreads = 1;
                break;
        }

        smp_threads_per_core = nthreads;
        if (mp_ncpus % nthreads == 0)
                mp_ncores = mp_ncpus / nthreads;
}

static struct cpu_group *
cpu_group_init(struct cpu_group *group, struct cpu_group *parent,
    const cpuset_t *cpus, int children, int level, int flags)
{
        struct cpu_group *child;

        child = children != 0 ? smp_topo_alloc(children) : NULL;

        group->cg_parent = parent;
        group->cg_child = child;
        CPU_COPY(cpus, &group->cg_mask);
        group->cg_count = CPU_COUNT(cpus);
        group->cg_children = children;
        group->cg_level = level;
        group->cg_flags = flags;

        return (child);
}

static struct cpu_group *
powernv_smp_topo(platform_t plat)
{
        struct cpu_group *core, *dom, *root;
        cpuset_t corecpus, domcpus;
        int cpuid, i, j, k, ncores;

        if (mp_ncpus % smp_threads_per_core != 0) {
                printf("%s: irregular SMP topology (%d threads, %d per core)\n",
                    __func__, mp_ncpus, smp_threads_per_core);
                return (smp_topo_none());
        }

        root = smp_topo_alloc(1);
        dom = cpu_group_init(root, NULL, &all_cpus, vm_ndomains, CG_SHARE_NONE,
            0);

        /*
         * Redundant layers will be collapsed by the caller so we don't need a
         * special case for a single domain.
         */
        for (i = 0; i < vm_ndomains; i++, dom++) {
                CPU_COPY(&cpuset_domain[i], &domcpus);
                ncores = CPU_COUNT(&domcpus) / smp_threads_per_core;
                KASSERT(CPU_COUNT(&domcpus) % smp_threads_per_core == 0,
                    ("%s: domain %d core count not divisible by thread count",
                    __func__, i));

                core = cpu_group_init(dom, root, &domcpus, ncores, CG_SHARE_L3,
                    0);
                for (j = 0; j < ncores; j++, core++) {
                        /*
                         * Assume that consecutive CPU IDs correspond to sibling
                         * threads.
                         */
                        CPU_ZERO(&corecpus);
                        for (k = 0; k < smp_threads_per_core; k++) {
                                cpuid = CPU_FFS(&domcpus) - 1;
                                CPU_CLR(cpuid, &domcpus);
                                CPU_SET(cpuid, &corecpus);
                        }
                        (void)cpu_group_init(core, dom, &corecpus, 0,
                            CG_SHARE_L1, CG_FLAG_SMT);
                }
        }

        return (root);
}

#endif

static void
powernv_reset(platform_t platform)
{

        opal_call(OPAL_CEC_REBOOT);
}

static void
powernv_smp_ap_init(platform_t platform)
{

        if (powernv_smp_ap_extra_init != NULL)
                powernv_smp_ap_extra_init();
}

static void
powernv_cpu_idle(sbintime_t sbt)
{
}

static int
powernv_node_numa_domain(platform_t platform, phandle_t node)
{
        /* XXX: Is locking necessary in here? */
        static int numa_domains[MAXMEMDOM];
        static int numa_max_domain;
        cell_t associativity[5];
        int i, res;

#ifndef NUMA
        return (0);
#endif
        i = 0;
        TUNABLE_INT_FETCH("vm.numa.disabled", &i);
        if (i)
                return (0);

        res = OF_getencprop(node, "ibm,associativity",
                associativity, sizeof(associativity));

        /*
         * If this node doesn't have associativity, or if there are not
         * enough elements in it, check its parent.
         */
        if (res < (int)(sizeof(cell_t) * (platform_associativity + 1))) {
                node = OF_parent(node);
                /* If already at the root, use default domain. */
                if (node == 0)
                        return (0);
                return (powernv_node_numa_domain(platform, node));
        }

        for (i = 0; i < numa_max_domain; i++) {
                if (numa_domains[i] == associativity[platform_associativity])
                        return (i);
        }
        if (i < MAXMEMDOM)
                numa_domains[numa_max_domain++] =
                    associativity[platform_associativity];
        else
                i = 0;

        return (i);
}

/* Set up the Nest MMU on POWER9 relatively early, but after pmap is setup. */
static void
powernv_setup_nmmu(void *unused)
{
        if (opal_check() != 0)
                return;
        opal_call(OPAL_NMMU_SET_PTCR, -1, mfspr(SPR_PTCR));
}

SYSINIT(powernv_setup_nmmu, SI_SUB_CPU, SI_ORDER_ANY, powernv_setup_nmmu, NULL);