// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (c) 2019-2020 Linaro Ltd.
 */
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/of_address.h>
#include "qcom_pil_info.h"

/*
 * The PIL relocation information region is used to communicate memory regions
 * occupied by co-processor firmware for post mortem crash analysis.
 *
 * It consists of an array of entries with an 8 byte textual identifier of the
 * region followed by a 64 bit base address and 32 bit size, both little
 * endian.
 */
#define PIL_RELOC_NAME_LEN      8
#define PIL_RELOC_ENTRY_SIZE    (PIL_RELOC_NAME_LEN + sizeof(__le64) + sizeof(__le32))

struct pil_reloc {
        void __iomem *base;
        size_t num_entries;
};

static struct pil_reloc _reloc __read_mostly;
static DEFINE_MUTEX(pil_reloc_lock);

static int qcom_pil_info_init(void)
{
        struct device_node *np;
        struct resource imem;
        void __iomem *base;
        int ret;

        /* Already initialized? */
        if (_reloc.base)
                return 0;

        np = of_find_compatible_node(NULL, NULL, "qcom,pil-reloc-info");
        if (!np)
                return -ENOENT;

        ret = of_address_to_resource(np, 0, &imem);
        of_node_put(np);
        if (ret < 0)
                return ret;

        base = ioremap(imem.start, resource_size(&imem));
        if (!base) {
                pr_err("failed to map PIL relocation info region\n");
                return -ENOMEM;
        }

        memset_io(base, 0, resource_size(&imem));

        _reloc.base = base;
        _reloc.num_entries = (u32)resource_size(&imem) / PIL_RELOC_ENTRY_SIZE;

        return 0;
}

/**
 * qcom_pil_info_store() - store PIL information of image in IMEM
 * @image:      name of the image
 * @base:       base address of the loaded image
 * @size:       size of the loaded image
 *
 * Return: 0 on success, negative errno on failure
 */
int qcom_pil_info_store(const char *image, phys_addr_t base, size_t size)
{
        char buf[PIL_RELOC_NAME_LEN];
        void __iomem *entry;
        int ret;
        int i;

        mutex_lock(&pil_reloc_lock);
        ret = qcom_pil_info_init();
        if (ret < 0) {
                mutex_unlock(&pil_reloc_lock);
                return ret;
        }

        for (i = 0; i < _reloc.num_entries; i++) {
                entry = _reloc.base + i * PIL_RELOC_ENTRY_SIZE;

                memcpy_fromio(buf, entry, PIL_RELOC_NAME_LEN);

                /*
                 * An empty record means we didn't find it, given that the
                 * records are packed.
                 */
                if (!buf[0])
                        goto found_unused;

                if (!strncmp(buf, image, PIL_RELOC_NAME_LEN))
                        goto found_existing;
        }

        pr_warn("insufficient PIL info slots\n");
        mutex_unlock(&pil_reloc_lock);
        return -ENOMEM;

found_unused:
        memcpy_toio(entry, image, strnlen(image, PIL_RELOC_NAME_LEN));
found_existing:
        /* Use two writel() as base is only aligned to 4 bytes on odd entries */
        writel(base, entry + PIL_RELOC_NAME_LEN);
        writel((u64)base >> 32, entry + PIL_RELOC_NAME_LEN + 4);
        writel(size, entry + PIL_RELOC_NAME_LEN + sizeof(__le64));
        mutex_unlock(&pil_reloc_lock);

        return 0;
}
EXPORT_SYMBOL_GPL(qcom_pil_info_store);

static void __exit pil_reloc_exit(void)
{
        mutex_lock(&pil_reloc_lock);
        iounmap(_reloc.base);
        _reloc.base = NULL;
        mutex_unlock(&pil_reloc_lock);
}
module_exit(pil_reloc_exit);

MODULE_DESCRIPTION("Qualcomm PIL relocation info");
MODULE_LICENSE("GPL v2");