/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2006 IronPort Systems Inc. <ambrisko@ironport.com>
 * 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 AND CONTRIBUTORS ``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 OR CONTRIBUTORS 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/bus.h>
#include <sys/condvar.h>
#include <sys/eventhandler.h>
#include <sys/kernel.h>
#include <sys/selinfo.h>
#include <sys/efi.h>

#include <vm/vm.h>
#include <vm/pmap.h>
#if defined(__amd64__) || defined(__i386__)
#include <machine/pc/bios.h>
#endif
#include <dev/smbios/smbios.h>

#ifdef LOCAL_MODULE
#include <ipmi.h>
#include <ipmivars.h>
#else
#include <sys/ipmi.h>
#include <dev/ipmi/ipmivars.h>
#endif

struct ipmi_entry {
        uint8_t         type;
        uint8_t         length;
        uint16_t        handle;
        uint8_t         interface_type;
        uint8_t         spec_revision;
        uint8_t         i2c_slave_address;
        uint8_t         NV_storage_device_address;
        uint64_t        base_address;
        uint8_t         base_address_modifier;
        uint8_t         interrupt_number;
};

/* Fields in the base_address field of an IPMI entry. */
#define IPMI_BAR_MODE(ba)       ((ba) & 0x0000000000000001)
#define IPMI_BAR_ADDR(ba)       ((ba) & 0xfffffffffffffffe)

/* Fields in the base_address_modifier field of an IPMI entry. */
#define IPMI_BAM_IRQ_TRIGGER    0x01
#define IPMI_BAM_IRQ_POLARITY   0x02
#define IPMI_BAM_IRQ_VALID      0x08
#define IPMI_BAM_ADDR_LSB(bam)  (((bam) & 0x10) >> 4)
#define IPMI_BAM_REG_SPACING(bam) (((bam) & 0xc0) >> 6)
#define SPACING_8               0x0
#define SPACING_32              0x1
#define SPACING_16              0x2

static struct ipmi_get_info ipmi_info;
static int ipmi_probed;
static struct mtx ipmi_info_mtx;
MTX_SYSINIT(ipmi_info, &ipmi_info_mtx, "ipmi info", MTX_DEF);

static void     ipmi_smbios_probe(struct ipmi_get_info *);
static int      smbios_cksum(struct smbios_eps *);
static void     smbios_ipmi_info(struct smbios_structure_header *, void *);

static void
smbios_ipmi_info(struct smbios_structure_header *h, void *arg)
{
        struct ipmi_get_info *info;
        struct ipmi_entry *s;

        if (h->type != 38 || h->length <
            offsetof(struct ipmi_entry, interrupt_number))
                return;
        s = (struct ipmi_entry *)h;
        info = arg;
        bzero(info, sizeof(struct ipmi_get_info));
        switch (s->interface_type) {
        case KCS_MODE:
        case SMIC_MODE:
        case BT_MODE:
                info->address = IPMI_BAR_ADDR(s->base_address) |
                    IPMI_BAM_ADDR_LSB(s->base_address_modifier);
                info->io_mode = IPMI_BAR_MODE(s->base_address);
                switch (IPMI_BAM_REG_SPACING(s->base_address_modifier)) {
                case SPACING_8:
                        info->offset = 1;
                        break;
                case SPACING_32:
                        info->offset = 4;
                        break;
                case SPACING_16:
                        info->offset = 2;
                        break;
                default:
                        printf("SMBIOS: Invalid register spacing\n");
                        return;
                }
                break;
        case SSIF_MODE:
                if ((s->base_address & 0xffffffffffffff00) != 0) {
                        printf("SMBIOS: Invalid SSIF SMBus address, using BMC I2C slave address instead\n");
                        info->address = s->i2c_slave_address;
                        break;
                }
                info->address = IPMI_BAR_ADDR(s->base_address);
                break;
        default:
                return;
        }
        if (s->length > offsetof(struct ipmi_entry, interrupt_number)) {
                if (s->interrupt_number > 15)
                        printf("SMBIOS: Non-ISA IRQ %d for IPMI\n",
                            s->interrupt_number);
                else
                        info->irq = s->interrupt_number;
        }
        info->iface_type = s->interface_type;
}

/*
 * Walk the SMBIOS table looking for an IPMI (type 38) entry.  If we find
 * one, return the parsed data in the passed in ipmi_get_info structure and
 * return true.  If we don't find one, return false.
 */
static void
ipmi_smbios_probe(struct ipmi_get_info *info)
{
#ifdef ARCH_MAY_USE_EFI
        efi_guid_t efi_smbios = EFI_TABLE_SMBIOS;
        void *addr_efi;
#endif
        struct smbios_eps *header;
        void *table;
        u_int32_t addr;

        addr = 0;
        bzero(info, sizeof(struct ipmi_get_info));

#ifdef ARCH_MAY_USE_EFI
        if (!efi_get_table(&efi_smbios, &addr_efi))
                addr = (vm_paddr_t)addr_efi;
#endif

#if defined(__amd64__) || defined(__i386__)
        if (addr == 0)
                /* Find the SMBIOS table header. */
                addr = bios_sigsearch(SMBIOS_START, SMBIOS_SIG, SMBIOS_LEN,
                        SMBIOS_STEP, SMBIOS_OFF);
#endif
        if (addr == 0)
                return;

        /*
         * Map the header.  We first map a fixed size to get the actual
         * length and then map it a second time with the actual length so
         * we can verify the checksum.
         */
        header = pmap_mapbios(addr, sizeof(struct smbios_eps));
        table = pmap_mapbios(addr, header->length);
        pmap_unmapbios(header, sizeof(struct smbios_eps));
        header = table;
        if (smbios_cksum(header) != 0) {
                pmap_unmapbios(header, header->length);
                return;
        }

        /* Now map the actual table and walk it looking for an IPMI entry. */
        table = pmap_mapbios(header->structure_table_address,
            header->structure_table_length);
        smbios_walk_table(table, header->number_structures,
            header->structure_table_length, smbios_ipmi_info, info);

        /* Unmap everything. */
        pmap_unmapbios(table, header->structure_table_length);
        pmap_unmapbios(header, header->length);
}

/*
 * Return the SMBIOS IPMI table entry info to the caller.  If we haven't
 * searched the IPMI table yet, search it.  Otherwise, return a cached
 * copy of the data.
 */
int
ipmi_smbios_identify(struct ipmi_get_info *info)
{

        mtx_lock(&ipmi_info_mtx);
        switch (ipmi_probed) {
        case 0:
                /* Need to probe the SMBIOS table. */
                ipmi_probed++;
                mtx_unlock(&ipmi_info_mtx);
                ipmi_smbios_probe(&ipmi_info);
                mtx_lock(&ipmi_info_mtx);
                ipmi_probed++;
                wakeup(&ipmi_info);
                break;
        case 1:
                /* Another thread is currently probing the table, so wait. */
                while (ipmi_probed == 1)
                        msleep(&ipmi_info, &ipmi_info_mtx, 0, "ipmi info", 0);
                break;
        default:
                /* The cached data is available. */
                break;
        }

        bcopy(&ipmi_info, info, sizeof(ipmi_info));
        mtx_unlock(&ipmi_info_mtx);

        return (info->iface_type != 0);
}

static int
smbios_cksum(struct smbios_eps *e)
{
        u_int8_t *ptr;
        u_int8_t cksum;
        int i;

        ptr = (u_int8_t *)e;
        cksum = 0;
        for (i = 0; i < e->length; i++) {
                cksum += ptr[i];
        }

        return (cksum);
}