// SPDX-License-Identifier: GPL-2.0
// Driver to instantiate Chromebook ramoops device.
//
// Copyright (C) 2013 Google, Inc.

#include <linux/acpi.h>
#include <linux/dmi.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/pstore_ram.h>

static int ecc_size;
module_param(ecc_size, int, 0400);
MODULE_PARM_DESC(ecc_size, "ECC parity data size in bytes. A positive value enables ECC for the ramoops region.");

static const struct dmi_system_id chromeos_pstore_dmi_table[] __initconst = {
        {
                /*
                 * Today all Chromebooks/boxes ship with Google_* as version and
                 * coreboot as bios vendor. No other systems with this
                 * combination are known to date.
                 */
                .matches = {
                        DMI_MATCH(DMI_BIOS_VENDOR, "coreboot"),
                        DMI_MATCH(DMI_BIOS_VERSION, "Google_"),
                },
        },
        {
                /* x86-alex, the first Samsung Chromebook. */
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD."),
                        DMI_MATCH(DMI_PRODUCT_NAME, "Alex"),
                },
        },
        {
                /* x86-mario, the Cr-48 pilot device from Google. */
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "IEC"),
                        DMI_MATCH(DMI_PRODUCT_NAME, "Mario"),
                },
        },
        {
                /* x86-zgb, the first Acer Chromebook. */
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "ACER"),
                        DMI_MATCH(DMI_PRODUCT_NAME, "ZGB"),
                },
        },
        { }
};
MODULE_DEVICE_TABLE(dmi, chromeos_pstore_dmi_table);

/*
 * On x86 chromebooks/boxes, the firmware will keep the legacy VGA memory
 * range untouched across reboots, so we use that to store our pstore
 * contents for panic logs, etc.
 */
static struct ramoops_platform_data chromeos_ramoops_data = {
        .mem_size       = 0x100000,
        .mem_address    = 0xf00000,
        .record_size    = 0x40000,
        .console_size   = 0x20000,
        .ftrace_size    = 0x20000,
        .pmsg_size      = 0x20000,
        .max_reason     = KMSG_DUMP_OOPS,
};

static struct platform_device chromeos_ramoops = {
        .name = "ramoops",
        .dev = {
                .platform_data = &chromeos_ramoops_data,
        },
};

#ifdef CONFIG_ACPI
static const struct acpi_device_id cros_ramoops_acpi_match[] = {
        { "GOOG9999", 0 },
        { }
};
MODULE_DEVICE_TABLE(acpi, cros_ramoops_acpi_match);

static struct platform_driver chromeos_ramoops_acpi = {
        .driver         = {
                .name   = "chromeos_pstore",
                .acpi_match_table = ACPI_PTR(cros_ramoops_acpi_match),
        },
};

static int __init chromeos_probe_acpi(struct platform_device *pdev)
{
        struct resource *res;
        resource_size_t len;

        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        if (!res)
                return -ENOMEM;

        len = resource_size(res);
        if (!res->start || !len)
                return -ENOMEM;

        pr_info("chromeos ramoops using acpi device.\n");

        chromeos_ramoops_data.mem_size = len;
        chromeos_ramoops_data.mem_address = res->start;

        return 0;
}

static bool __init chromeos_check_acpi(void)
{
        if (!platform_driver_probe(&chromeos_ramoops_acpi, chromeos_probe_acpi))
                return true;
        return false;
}
#else
static inline bool chromeos_check_acpi(void) { return false; }
#endif

static int __init chromeos_pstore_init(void)
{
        bool acpi_dev_found;

        if (ecc_size > 0)
                chromeos_ramoops_data.ecc_info.ecc_size = ecc_size;

        /* First check ACPI for non-hardcoded values from firmware. */
        acpi_dev_found = chromeos_check_acpi();

        if (acpi_dev_found || dmi_check_system(chromeos_pstore_dmi_table))
                return platform_device_register(&chromeos_ramoops);

        return -ENODEV;
}

static void __exit chromeos_pstore_exit(void)
{
        platform_device_unregister(&chromeos_ramoops);
}

module_init(chromeos_pstore_init);
module_exit(chromeos_pstore_exit);

MODULE_DESCRIPTION("ChromeOS pstore module");
MODULE_LICENSE("GPL v2");