/*
 * Qualcomm Peripheral Image Loader
 *
 * Copyright (C) 2016 Linaro Ltd
 * Copyright (C) 2015 Sony Mobile Communications Inc
 * Copyright (c) 2012-2013, The Linux Foundation. All rights reserved.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * version 2 as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

#include <linux/device.h>
#include <linux/elf.h>
#include <linux/firmware.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/qcom_scm.h>
#include <linux/sizes.h>
#include <linux/slab.h>
#include <linux/soc/qcom/mdt_loader.h>

static bool mdt_phdr_valid(const struct elf32_phdr *phdr)
{
        if (phdr->p_type != PT_LOAD)
                return false;

        if ((phdr->p_flags & QCOM_MDT_TYPE_MASK) == QCOM_MDT_TYPE_HASH)
                return false;

        if (!phdr->p_memsz)
                return false;

        return true;
}

/**
 * qcom_mdt_get_size() - acquire size of the memory region needed to load mdt
 * @fw:         firmware object for the mdt file
 *
 * Returns size of the loaded firmware blob, or -EINVAL on failure.
 */
ssize_t qcom_mdt_get_size(const struct firmware *fw)
{
        const struct elf32_phdr *phdrs;
        const struct elf32_phdr *phdr;
        const struct elf32_hdr *ehdr;
        phys_addr_t min_addr = (phys_addr_t)ULLONG_MAX;
        phys_addr_t max_addr = 0;
        int i;

        ehdr = (struct elf32_hdr *)fw->data;
        phdrs = (struct elf32_phdr *)(ehdr + 1);

        for (i = 0; i < ehdr->e_phnum; i++) {
                phdr = &phdrs[i];

                if (!mdt_phdr_valid(phdr))
                        continue;

                if (phdr->p_paddr < min_addr)
                        min_addr = phdr->p_paddr;

                if (phdr->p_paddr + phdr->p_memsz > max_addr)
                        max_addr = ALIGN(phdr->p_paddr + phdr->p_memsz, SZ_4K);
        }

        return min_addr < max_addr ? max_addr - min_addr : -EINVAL;
}
EXPORT_SYMBOL_GPL(qcom_mdt_get_size);

/**
 * qcom_mdt_load() - load the firmware which header is loaded as fw
 * @dev:        device handle to associate resources with
 * @fw:         firmware object for the mdt file
 * @firmware:   name of the firmware, for construction of segment file names
 * @pas_id:     PAS identifier
 * @mem_region: allocated memory region to load firmware into
 * @mem_phys:   physical address of allocated memory region
 * @mem_size:   size of the allocated memory region
 *
 * Returns 0 on success, negative errno otherwise.
 */
int qcom_mdt_load(struct device *dev, const struct firmware *fw,
                  const char *firmware, int pas_id, void *mem_region,
                  phys_addr_t mem_phys, size_t mem_size)
{
        const struct elf32_phdr *phdrs;
        const struct elf32_phdr *phdr;
        const struct elf32_hdr *ehdr;
        const struct firmware *seg_fw;
        phys_addr_t mem_reloc;
        phys_addr_t min_addr = (phys_addr_t)ULLONG_MAX;
        phys_addr_t max_addr = 0;
        size_t fw_name_len;
        ssize_t offset;
        char *fw_name;
        bool relocate = false;
        void *ptr;
        int ret;
        int i;

        if (!fw || !mem_region || !mem_phys || !mem_size)
                return -EINVAL;

        ehdr = (struct elf32_hdr *)fw->data;
        phdrs = (struct elf32_phdr *)(ehdr + 1);

        fw_name_len = strlen(firmware);
        if (fw_name_len <= 4)
                return -EINVAL;

        fw_name = kstrdup(firmware, GFP_KERNEL);
        if (!fw_name)
                return -ENOMEM;

        ret = qcom_scm_pas_init_image(pas_id, fw->data, fw->size);
        if (ret) {
                dev_err(dev, "invalid firmware metadata\n");
                goto out;
        }

        for (i = 0; i < ehdr->e_phnum; i++) {
                phdr = &phdrs[i];

                if (!mdt_phdr_valid(phdr))
                        continue;

                if (phdr->p_flags & QCOM_MDT_RELOCATABLE)
                        relocate = true;

                if (phdr->p_paddr < min_addr)
                        min_addr = phdr->p_paddr;

                if (phdr->p_paddr + phdr->p_memsz > max_addr)
                        max_addr = ALIGN(phdr->p_paddr + phdr->p_memsz, SZ_4K);
        }

        if (relocate) {
                ret = qcom_scm_pas_mem_setup(pas_id, mem_phys, max_addr - min_addr);
                if (ret) {
                        dev_err(dev, "unable to setup relocation\n");
                        goto out;
                }

                /*
                 * The image is relocatable, so offset each segment based on
                 * the lowest segment address.
                 */
                mem_reloc = min_addr;
        } else {
                /*
                 * Image is not relocatable, so offset each segment based on
                 * the allocated physical chunk of memory.
                 */
                mem_reloc = mem_phys;
        }

        for (i = 0; i < ehdr->e_phnum; i++) {
                phdr = &phdrs[i];

                if (!mdt_phdr_valid(phdr))
                        continue;

                offset = phdr->p_paddr - mem_reloc;
                if (offset < 0 || offset + phdr->p_memsz > mem_size) {
                        dev_err(dev, "segment outside memory range\n");
                        ret = -EINVAL;
                        break;
                }

                ptr = mem_region + offset;

                if (phdr->p_filesz) {
                        sprintf(fw_name + fw_name_len - 3, "b%02d", i);
                        ret = request_firmware_into_buf(&seg_fw, fw_name, dev,
                                                        ptr, phdr->p_filesz);
                        if (ret) {
                                dev_err(dev, "failed to load %s\n", fw_name);
                                break;
                        }

                        release_firmware(seg_fw);
                }

                if (phdr->p_memsz > phdr->p_filesz)
                        memset(ptr + phdr->p_filesz, 0, phdr->p_memsz - phdr->p_filesz);
        }

out:
        kfree(fw_name);

        return ret;
}
EXPORT_SYMBOL_GPL(qcom_mdt_load);

MODULE_DESCRIPTION("Firmware parser for Qualcomm MDT format");
MODULE_LICENSE("GPL v2");