// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * BCM63XX CFE image tag parser
 *
 * Copyright © 2006-2008  Florian Fainelli <florian@openwrt.org>
 *                        Mike Albon <malbon@openwrt.org>
 * Copyright © 2009-2010  Daniel Dickinson <openwrt@cshore.neomailbox.net>
 * Copyright © 2011-2013  Jonas Gorski <jonas.gorski@gmail.com>
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/bcm963xx_tag.h>
#include <linux/crc32.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/sizes.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <linux/mtd/mtd.h>
#include <linux/mtd/partitions.h>
#include <linux/of.h>

/* Ensure strings read from flash structs are null terminated */
#define STR_NULL_TERMINATE(x) \
        do { char *_str = (x); _str[sizeof(x) - 1] = 0; } while (0)

static int bcm963xx_read_imagetag(struct mtd_info *master, const char *name,
        loff_t tag_offset, struct bcm_tag *buf)
{
        int ret;
        size_t retlen;
        u32 computed_crc;

        ret = mtd_read(master, tag_offset, sizeof(*buf), &retlen, (void *)buf);
        if (ret)
                return ret;

        if (retlen != sizeof(*buf))
                return -EIO;

        computed_crc = crc32_le(IMAGETAG_CRC_START, (u8 *)buf,
                                offsetof(struct bcm_tag, header_crc));
        if (computed_crc == buf->header_crc) {
                STR_NULL_TERMINATE(buf->board_id);
                STR_NULL_TERMINATE(buf->tag_version);

                pr_info("%s: CFE image tag found at 0x%llx with version %s, board type %s\n",
                        name, tag_offset, buf->tag_version, buf->board_id);

                return 0;
        }

        pr_warn("%s: CFE image tag at 0x%llx CRC invalid (expected %08x, actual %08x)\n",
                name, tag_offset, buf->header_crc, computed_crc);
        return -EINVAL;
}

static int bcm963xx_parse_imagetag_partitions(struct mtd_info *master,
                                        const struct mtd_partition **pparts,
                                        struct mtd_part_parser_data *data)
{
        /* CFE, NVRAM and global Linux are always present */
        int nrparts = 0, curpart = 0;
        struct bcm_tag *buf = NULL;
        struct mtd_partition *parts;
        int ret;
        unsigned int rootfsaddr, kerneladdr, spareaddr, offset;
        unsigned int rootfslen, kernellen, sparelen, totallen;
        int i;
        bool rootfs_first = false;

        buf = vmalloc(sizeof(struct bcm_tag));
        if (!buf)
                return -ENOMEM;

        /* Get the tag */
        ret = bcm963xx_read_imagetag(master, "rootfs", 0, buf);
        if (!ret) {
                STR_NULL_TERMINATE(buf->flash_image_start);
                if (kstrtouint(buf->flash_image_start, 10, &rootfsaddr) ||
                                rootfsaddr < BCM963XX_EXTENDED_SIZE) {
                        pr_err("invalid rootfs address: %*ph\n",
                                (int)sizeof(buf->flash_image_start),
                                buf->flash_image_start);
                        ret = -EINVAL;
                        goto out;
                }

                STR_NULL_TERMINATE(buf->kernel_address);
                if (kstrtouint(buf->kernel_address, 10, &kerneladdr) ||
                                kerneladdr < BCM963XX_EXTENDED_SIZE) {
                        pr_err("invalid kernel address: %*ph\n",
                                (int)sizeof(buf->kernel_address),
                                buf->kernel_address);
                        ret = -EINVAL;
                        goto out;
                }

                STR_NULL_TERMINATE(buf->kernel_length);
                if (kstrtouint(buf->kernel_length, 10, &kernellen)) {
                        pr_err("invalid kernel length: %*ph\n",
                                (int)sizeof(buf->kernel_length),
                                buf->kernel_length);
                        ret = -EINVAL;
                        goto out;
                }

                STR_NULL_TERMINATE(buf->total_length);
                if (kstrtouint(buf->total_length, 10, &totallen)) {
                        pr_err("invalid total length: %*ph\n",
                                (int)sizeof(buf->total_length),
                                buf->total_length);
                        ret = -EINVAL;
                        goto out;
                }

                /*
                 * Addresses are flash absolute, so convert to partition
                 * relative addresses. Assume either kernel or rootfs will
                 * directly follow the image tag.
                 */
                if (rootfsaddr < kerneladdr)
                        offset = rootfsaddr - sizeof(struct bcm_tag);
                else
                        offset = kerneladdr - sizeof(struct bcm_tag);

                kerneladdr = kerneladdr - offset;
                rootfsaddr = rootfsaddr - offset;
                spareaddr = roundup(totallen, master->erasesize);

                if (rootfsaddr < kerneladdr) {
                        /* default Broadcom layout */
                        rootfslen = kerneladdr - rootfsaddr;
                        rootfs_first = true;
                } else {
                        /* OpenWrt layout */
                        rootfsaddr = kerneladdr + kernellen;
                        rootfslen = spareaddr - rootfsaddr;
                }
        } else {
                goto out;
        }
        sparelen = master->size - spareaddr;

        /* Determine number of partitions */
        if (rootfslen > 0)
                nrparts++;

        if (kernellen > 0)
                nrparts++;

        parts = kzalloc(sizeof(*parts) * nrparts + 10 * nrparts, GFP_KERNEL);
        if (!parts) {
                ret = -ENOMEM;
                goto out;
        }

        /* Start building partition list */
        if (kernellen > 0) {
                int kernelpart = curpart;

                if (rootfslen > 0 && rootfs_first)
                        kernelpart++;
                parts[kernelpart].name = "kernel";
                parts[kernelpart].offset = kerneladdr;
                parts[kernelpart].size = kernellen;
                curpart++;
        }

        if (rootfslen > 0) {
                int rootfspart = curpart;

                if (kernellen > 0 && rootfs_first)
                        rootfspart--;
                parts[rootfspart].name = "rootfs";
                parts[rootfspart].offset = rootfsaddr;
                parts[rootfspart].size = rootfslen;
                if (sparelen > 0  && !rootfs_first)
                        parts[rootfspart].size += sparelen;
                curpart++;
        }

        for (i = 0; i < nrparts; i++)
                pr_info("Partition %d is %s offset %llx and length %llx\n", i,
                        parts[i].name, parts[i].offset, parts[i].size);

        pr_info("Spare partition is offset %x and length %x\n", spareaddr,
                sparelen);

        *pparts = parts;
        ret = 0;

out:
        vfree(buf);

        if (ret)
                return ret;

        return nrparts;
}

static const struct of_device_id parse_bcm963xx_imagetag_match_table[] = {
        { .compatible = "brcm,bcm963xx-imagetag" },
        {},
};
MODULE_DEVICE_TABLE(of, parse_bcm963xx_imagetag_match_table);

static struct mtd_part_parser bcm963xx_imagetag_parser = {
        .parse_fn = bcm963xx_parse_imagetag_partitions,
        .name = "bcm963xx-imagetag",
        .of_match_table = parse_bcm963xx_imagetag_match_table,
};
module_mtd_part_parser(bcm963xx_imagetag_parser);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Daniel Dickinson <openwrt@cshore.neomailbox.net>");
MODULE_AUTHOR("Florian Fainelli <florian@openwrt.org>");
MODULE_AUTHOR("Mike Albon <malbon@openwrt.org>");
MODULE_AUTHOR("Jonas Gorski <jonas.gorski@gmail.com>");
MODULE_DESCRIPTION("MTD parser for BCM963XX CFE Image Tag partitions");