// SPDX-License-Identifier: GPL-2.0-only
/*
 * NVIDIA GHES vendor record handler
 *
 * Copyright (c) 2026, NVIDIA CORPORATION & AFFILIATES. All rights reserved.
 */

#include <linux/acpi.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/types.h>
#include <linux/uuid.h>
#include <acpi/ghes.h>

static const guid_t nvidia_sec_guid =
        GUID_INIT(0x6d5244f2, 0x2712, 0x11ec,
                  0xbe, 0xa7, 0xcb, 0x3f, 0xdb, 0x95, 0xc7, 0x86);

struct cper_sec_nvidia {
        char    signature[16];
        __le16  error_type;
        __le16  error_instance;
        u8      severity;
        u8      socket;
        u8      number_regs;
        u8      reserved;
        __le64  instance_base;
        struct {
                __le64  addr;
                __le64  val;
        } regs[] __counted_by(number_regs);
};

struct nvidia_ghes_private {
        struct notifier_block   nb;
        struct device           *dev;
};

static void nvidia_ghes_print_error(struct device *dev,
                                    const struct cper_sec_nvidia *nvidia_err,
                                    size_t error_data_length, bool fatal)
{
        const char *level = fatal ? KERN_ERR : KERN_INFO;
        size_t min_size;

        dev_printk(level, dev, "signature: %.16s\n", nvidia_err->signature);
        dev_printk(level, dev, "error_type: %u\n", le16_to_cpu(nvidia_err->error_type));
        dev_printk(level, dev, "error_instance: %u\n", le16_to_cpu(nvidia_err->error_instance));
        dev_printk(level, dev, "severity: %u\n", nvidia_err->severity);
        dev_printk(level, dev, "socket: %u\n", nvidia_err->socket);
        dev_printk(level, dev, "number_regs: %u\n", nvidia_err->number_regs);
        dev_printk(level, dev, "instance_base: 0x%016llx\n",
                   le64_to_cpu(nvidia_err->instance_base));

        if (nvidia_err->number_regs == 0)
                return;

        /*
         * Validate that all registers fit within error_data_length.
         * Each register pair is two little-endian u64s.
         */
        min_size = struct_size(nvidia_err, regs, nvidia_err->number_regs);
        if (error_data_length < min_size) {
                dev_err(dev, "Invalid number_regs %u (section size %zu, need %zu)\n",
                        nvidia_err->number_regs, error_data_length, min_size);
                return;
        }

        for (int i = 0; i < nvidia_err->number_regs; i++)
                dev_printk(level, dev, "register[%d]: address=0x%016llx value=0x%016llx\n",
                           i, le64_to_cpu(nvidia_err->regs[i].addr),
                           le64_to_cpu(nvidia_err->regs[i].val));
}

static int nvidia_ghes_notify(struct notifier_block *nb,
                              unsigned long event, void *data)
{
        struct acpi_hest_generic_data *gdata = data;
        struct nvidia_ghes_private *priv;
        const struct cper_sec_nvidia *nvidia_err;
        guid_t sec_guid;

        import_guid(&sec_guid, gdata->section_type);
        if (!guid_equal(&sec_guid, &nvidia_sec_guid))
                return NOTIFY_DONE;

        priv = container_of(nb, struct nvidia_ghes_private, nb);

        if (acpi_hest_get_error_length(gdata) < sizeof(*nvidia_err)) {
                dev_err(priv->dev, "Section too small (%d < %zu)\n",
                        acpi_hest_get_error_length(gdata), sizeof(*nvidia_err));
                return NOTIFY_OK;
        }

        nvidia_err = acpi_hest_get_payload(gdata);

        if (event >= GHES_SEV_RECOVERABLE)
                dev_err(priv->dev, "NVIDIA CPER section, error_data_length: %u\n",
                        acpi_hest_get_error_length(gdata));
        else
                dev_info(priv->dev, "NVIDIA CPER section, error_data_length: %u\n",
                         acpi_hest_get_error_length(gdata));

        nvidia_ghes_print_error(priv->dev, nvidia_err, acpi_hest_get_error_length(gdata),
                                event >= GHES_SEV_RECOVERABLE);

        return NOTIFY_OK;
}

static int nvidia_ghes_probe(struct platform_device *pdev)
{
        struct nvidia_ghes_private *priv;
        int ret;

        priv = devm_kmalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
        if (!priv)
                return -ENOMEM;

        *priv = (struct nvidia_ghes_private) {
                .nb.notifier_call = nvidia_ghes_notify,
                .dev = &pdev->dev,
        };

        ret = devm_ghes_register_vendor_record_notifier(&pdev->dev, &priv->nb);
        if (ret)
                return dev_err_probe(&pdev->dev, ret,
                                     "Failed to register NVIDIA GHES vendor record notifier\n");

        return 0;
}

static const struct acpi_device_id nvidia_ghes_acpi_match[] = {
        { "NVDA2012" },
        { }
};
MODULE_DEVICE_TABLE(acpi, nvidia_ghes_acpi_match);

static struct platform_driver nvidia_ghes_driver = {
        .driver = {
                .name = "nvidia-ghes",
                .acpi_match_table = nvidia_ghes_acpi_match,
        },
        .probe = nvidia_ghes_probe,
};
module_platform_driver(nvidia_ghes_driver);

MODULE_AUTHOR("Kai-Heng Feng <kaihengf@nvidia.com>");
MODULE_DESCRIPTION("NVIDIA GHES vendor CPER record handler");
MODULE_LICENSE("GPL");