/*
 * Copyright (C) 2015-2017 Netronome Systems, Inc.
 *
 * This software is dual licensed under the GNU General License Version 2,
 * June 1991 as shown in the file COPYING in the top-level directory of this
 * source tree or the BSD 2-Clause License provided below.  You have the
 * option to license this software under the complete terms of either license.
 *
 * The BSD 2-Clause License:
 *
 *     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.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

/* Parse the hwinfo table that the ARM firmware builds in the ARM scratch SRAM
 * after chip reset.
 *
 * Examples of the fields:
 *   me.count = 40
 *   me.mask = 0x7f_ffff_ffff
 *
 *   me.count is the total number of MEs on the system.
 *   me.mask is the bitmask of MEs that are available for application usage.
 *
 *   (ie, in this example, ME 39 has been reserved by boardconfig.)
 */

#include <asm/byteorder.h>
#include <asm/unaligned.h>
#include <linux/delay.h>
#include <linux/log2.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>

#define NFP_SUBSYS "nfp_hwinfo"

#include "crc32.h"
#include "nfp.h"
#include "nfp_cpp.h"
#include "nfp6000/nfp6000.h"

#define HWINFO_SIZE_MIN 0x100
#define HWINFO_WAIT     20      /* seconds */

/* The Hardware Info Table defines the properties of the system.
 *
 * HWInfo v1 Table (fixed size)
 *
 * 0x0000: u32 version          Hardware Info Table version (1.0)
 * 0x0004: u32 size             Total size of the table, including
 *                              the CRC32 (IEEE 802.3)
 * 0x0008: u32 jumptab          Offset of key/value table
 * 0x000c: u32 keys             Total number of keys in the key/value table
 * NNNNNN:                      Key/value jump table and string data
 * (size - 4): u32 crc32        CRC32 (same as IEEE 802.3, POSIX csum, etc)
 *                              CRC32("",0) = ~0, CRC32("a",1) = 0x48C279FE
 *
 * HWInfo v2 Table (variable size)
 *
 * 0x0000: u32 version          Hardware Info Table version (2.0)
 * 0x0004: u32 size             Current size of the data area, excluding CRC32
 * 0x0008: u32 limit            Maximum size of the table
 * 0x000c: u32 reserved         Unused, set to zero
 * NNNNNN:                      Key/value data
 * (size - 4): u32 crc32        CRC32 (same as IEEE 802.3, POSIX csum, etc)
 *                              CRC32("",0) = ~0, CRC32("a",1) = 0x48C279FE
 *
 * If the HWInfo table is in the process of being updated, the low bit
 * of version will be set.
 *
 * HWInfo v1 Key/Value Table
 * -------------------------
 *
 *  The key/value table is a set of offsets to ASCIIZ strings which have
 *  been strcmp(3) sorted (yes, please use bsearch(3) on the table).
 *
 *  All keys are guaranteed to be unique.
 *
 * N+0: u32 key_1               Offset to the first key
 * N+4: u32 val_1               Offset to the first value
 * N+8: u32 key_2               Offset to the second key
 * N+c: u32 val_2               Offset to the second value
 * ...
 *
 * HWInfo v2 Key/Value Table
 * -------------------------
 *
 * Packed UTF8Z strings, ie 'key1\000value1\000key2\000value2\000'
 *
 * Unsorted.
 */

#define NFP_HWINFO_VERSION_1 ('H' << 24 | 'I' << 16 | 1 << 8 | 0 << 1 | 0)
#define NFP_HWINFO_VERSION_2 ('H' << 24 | 'I' << 16 | 2 << 8 | 0 << 1 | 0)
#define NFP_HWINFO_VERSION_UPDATING     BIT(0)

struct nfp_hwinfo {
        u8 start[0];

        __le32 version;
        __le32 size;

        /* v2 specific fields */
        __le32 limit;
        __le32 resv;

        char data[];
};

static bool nfp_hwinfo_is_updating(struct nfp_hwinfo *hwinfo)
{
        return le32_to_cpu(hwinfo->version) & NFP_HWINFO_VERSION_UPDATING;
}

static int
hwinfo_db_walk(struct nfp_cpp *cpp, struct nfp_hwinfo *hwinfo, u32 size)
{
        const char *key, *val, *end = hwinfo->data + size;

        for (key = hwinfo->data; *key && key < end;
             key = val + strlen(val) + 1) {

                val = key + strlen(key) + 1;
                if (val >= end) {
                        nfp_warn(cpp, "Bad HWINFO - overflowing key\n");
                        return -EINVAL;
                }

                if (val + strlen(val) + 1 > end) {
                        nfp_warn(cpp, "Bad HWINFO - overflowing value\n");
                        return -EINVAL;
                }
        }

        return 0;
}

static int
hwinfo_db_validate(struct nfp_cpp *cpp, struct nfp_hwinfo *db, u32 len)
{
        u32 size, crc;

        size = le32_to_cpu(db->size);
        if (size > len) {
                nfp_err(cpp, "Unsupported hwinfo size %u > %u\n", size, len);
                return -EINVAL;
        }

        size -= sizeof(u32);
        crc = crc32_posix(db, size);
        if (crc != get_unaligned_le32(db->start + size)) {
                nfp_err(cpp, "Corrupt hwinfo table (CRC mismatch), calculated 0x%x, expected 0x%x\n",
                        crc, get_unaligned_le32(db->start + size));

                return -EINVAL;
        }

        return hwinfo_db_walk(cpp, db, size);
}

static struct nfp_hwinfo *
hwinfo_try_fetch(struct nfp_cpp *cpp, size_t *cpp_size)
{
        struct nfp_hwinfo *header;
        struct nfp_resource *res;
        u64 cpp_addr;
        u32 cpp_id;
        int err;
        u8 *db;

        res = nfp_resource_acquire(cpp, NFP_RESOURCE_NFP_HWINFO);
        if (!IS_ERR(res)) {
                cpp_id = nfp_resource_cpp_id(res);
                cpp_addr = nfp_resource_address(res);
                *cpp_size = nfp_resource_size(res);

                nfp_resource_release(res);

                if (*cpp_size < HWINFO_SIZE_MIN)
                        return NULL;
        } else if (PTR_ERR(res) == -ENOENT) {
                /* Try getting the HWInfo table from the 'classic' location */
                cpp_id = NFP_CPP_ISLAND_ID(NFP_CPP_TARGET_MU,
                                           NFP_CPP_ACTION_RW, 0, 1);
                cpp_addr = 0x30000;
                *cpp_size = 0x0e000;
        } else {
                return NULL;
        }

        db = kmalloc(*cpp_size + 1, GFP_KERNEL);
        if (!db)
                return NULL;

        err = nfp_cpp_read(cpp, cpp_id, cpp_addr, db, *cpp_size);
        if (err != *cpp_size)
                goto exit_free;

        header = (void *)db;
        if (nfp_hwinfo_is_updating(header))
                goto exit_free;

        if (le32_to_cpu(header->version) != NFP_HWINFO_VERSION_2) {
                nfp_err(cpp, "Unknown HWInfo version: 0x%08x\n",
                        le32_to_cpu(header->version));
                goto exit_free;
        }

        /* NULL-terminate for safety */
        db[*cpp_size] = '\0';

        return (void *)db;
exit_free:
        kfree(db);
        return NULL;
}

static struct nfp_hwinfo *hwinfo_fetch(struct nfp_cpp *cpp, size_t *hwdb_size)
{
        const unsigned long wait_until = jiffies + HWINFO_WAIT * HZ;
        struct nfp_hwinfo *db;
        int err;

        for (;;) {
                const unsigned long start_time = jiffies;

                db = hwinfo_try_fetch(cpp, hwdb_size);
                if (db)
                        return db;

                err = msleep_interruptible(100);
                if (err || time_after(start_time, wait_until)) {
                        nfp_err(cpp, "NFP access error\n");
                        return NULL;
                }
        }
}

struct nfp_hwinfo *nfp_hwinfo_read(struct nfp_cpp *cpp)
{
        struct nfp_hwinfo *db;
        size_t hwdb_size = 0;
        int err;

        db = hwinfo_fetch(cpp, &hwdb_size);
        if (!db)
                return NULL;

        err = hwinfo_db_validate(cpp, db, hwdb_size);
        if (err) {
                kfree(db);
                return NULL;
        }

        return db;
}

/**
 * nfp_hwinfo_lookup() - Find a value in the HWInfo table by name
 * @hwinfo:     NFP HWinfo table
 * @lookup:     HWInfo name to search for
 *
 * Return: Value of the HWInfo name, or NULL
 */
const char *nfp_hwinfo_lookup(struct nfp_hwinfo *hwinfo, const char *lookup)
{
        const char *key, *val, *end;

        if (!hwinfo || !lookup)
                return NULL;

        end = hwinfo->data + le32_to_cpu(hwinfo->size) - sizeof(u32);

        for (key = hwinfo->data; *key && key < end;
             key = val + strlen(val) + 1) {

                val = key + strlen(key) + 1;

                if (strcmp(key, lookup) == 0)
                        return val;
        }

        return NULL;
}

char *nfp_hwinfo_get_packed_strings(struct nfp_hwinfo *hwinfo)
{
        return hwinfo->data;
}

u32 nfp_hwinfo_get_packed_str_size(struct nfp_hwinfo *hwinfo)
{
        return le32_to_cpu(hwinfo->size) - sizeof(u32);
}