// SPDX-License-Identifier: GPL-2.0
/*
 * ACPI Platform Firmware Runtime Telemetry driver
 *
 * Copyright (C) 2021 Intel Corporation
 * Author: Chen Yu <yu.c.chen@intel.com>
 *
 * This driver allows user space to fetch telemetry data from the
 * firmware with the help of the Platform Firmware Runtime Telemetry
 * interface.
 */
#include <linux/acpi.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/errno.h>
#include <linux/file.h>
#include <linux/fs.h>
#include <linux/miscdevice.h>
#include <linux/module.h>
#include <linux/mm.h>
#include <linux/platform_device.h>
#include <linux/string.h>
#include <linux/uaccess.h>
#include <linux/uio.h>
#include <linux/uuid.h>

#include <uapi/linux/pfrut.h>

#define PFRT_LOG_EXEC_IDX       0
#define PFRT_LOG_HISTORY_IDX    1

#define PFRT_LOG_ERR            0
#define PFRT_LOG_WARN   1
#define PFRT_LOG_INFO   2
#define PFRT_LOG_VERB   4

#define PFRT_FUNC_SET_LEV               1
#define PFRT_FUNC_GET_LEV               2
#define PFRT_FUNC_GET_DATA              3

#define PFRT_REVID_1            1
#define PFRT_REVID_2            2
#define PFRT_DEFAULT_REV_ID     PFRT_REVID_1

enum log_index {
        LOG_STATUS_IDX = 0,
        LOG_EXT_STATUS_IDX = 1,
        LOG_MAX_SZ_IDX = 2,
        LOG_CHUNK1_LO_IDX = 3,
        LOG_CHUNK1_HI_IDX = 4,
        LOG_CHUNK1_SZ_IDX = 5,
        LOG_CHUNK2_LO_IDX = 6,
        LOG_CHUNK2_HI_IDX = 7,
        LOG_CHUNK2_SZ_IDX = 8,
        LOG_ROLLOVER_CNT_IDX = 9,
        LOG_RESET_CNT_IDX = 10,
        LOG_NR_IDX
};

struct pfrt_log_device {
        int index;
        struct pfrt_log_info info;
        struct device *parent_dev;
        struct miscdevice miscdev;
};

/* pfrt_guid is the parameter for _DSM method */
static const guid_t pfrt_log_guid =
        GUID_INIT(0x75191659, 0x8178, 0x4D9D, 0xB8, 0x8F, 0xAC, 0x5E,
                  0x5E, 0x93, 0xE8, 0xBF);

static DEFINE_IDA(pfrt_log_ida);

static inline struct pfrt_log_device *to_pfrt_log_dev(struct file *file)
{
        return container_of(file->private_data, struct pfrt_log_device, miscdev);
}

static int get_pfrt_log_data_info(struct pfrt_log_data_info *data_info,
                                  struct pfrt_log_device *pfrt_log_dev)
{
        acpi_handle handle = ACPI_HANDLE(pfrt_log_dev->parent_dev);
        union acpi_object *out_obj, in_obj, in_buf;
        int ret = -EBUSY;

        memset(data_info, 0, sizeof(*data_info));
        memset(&in_obj, 0, sizeof(in_obj));
        memset(&in_buf, 0, sizeof(in_buf));
        in_obj.type = ACPI_TYPE_PACKAGE;
        in_obj.package.count = 1;
        in_obj.package.elements = &in_buf;
        in_buf.type = ACPI_TYPE_INTEGER;
        in_buf.integer.value = pfrt_log_dev->info.log_type;

        out_obj = acpi_evaluate_dsm_typed(handle, &pfrt_log_guid,
                                          pfrt_log_dev->info.log_revid, PFRT_FUNC_GET_DATA,
                                          &in_obj, ACPI_TYPE_PACKAGE);
        if (!out_obj)
                return -EINVAL;

        if (out_obj->package.count < LOG_NR_IDX ||
            out_obj->package.elements[LOG_STATUS_IDX].type != ACPI_TYPE_INTEGER ||
            out_obj->package.elements[LOG_EXT_STATUS_IDX].type != ACPI_TYPE_INTEGER ||
            out_obj->package.elements[LOG_MAX_SZ_IDX].type != ACPI_TYPE_INTEGER ||
            out_obj->package.elements[LOG_CHUNK1_LO_IDX].type != ACPI_TYPE_INTEGER ||
            out_obj->package.elements[LOG_CHUNK1_HI_IDX].type != ACPI_TYPE_INTEGER ||
            out_obj->package.elements[LOG_CHUNK1_SZ_IDX].type != ACPI_TYPE_INTEGER ||
            out_obj->package.elements[LOG_CHUNK2_LO_IDX].type != ACPI_TYPE_INTEGER ||
            out_obj->package.elements[LOG_CHUNK2_HI_IDX].type != ACPI_TYPE_INTEGER ||
            out_obj->package.elements[LOG_CHUNK2_SZ_IDX].type != ACPI_TYPE_INTEGER ||
            out_obj->package.elements[LOG_ROLLOVER_CNT_IDX].type != ACPI_TYPE_INTEGER ||
            out_obj->package.elements[LOG_RESET_CNT_IDX].type != ACPI_TYPE_INTEGER)
                goto free_acpi_buffer;

        data_info->status = out_obj->package.elements[LOG_STATUS_IDX].integer.value;
        data_info->ext_status =
                out_obj->package.elements[LOG_EXT_STATUS_IDX].integer.value;
        if (data_info->status != DSM_SUCCEED) {
                dev_dbg(pfrt_log_dev->parent_dev, "Error Status:%d\n", data_info->status);
                dev_dbg(pfrt_log_dev->parent_dev, "Error Extend Status:%d\n",
                        data_info->ext_status);
                goto free_acpi_buffer;
        }

        data_info->max_data_size =
                out_obj->package.elements[LOG_MAX_SZ_IDX].integer.value;
        data_info->chunk1_addr_lo =
                out_obj->package.elements[LOG_CHUNK1_LO_IDX].integer.value;
        data_info->chunk1_addr_hi =
                out_obj->package.elements[LOG_CHUNK1_HI_IDX].integer.value;
        data_info->chunk1_size =
                out_obj->package.elements[LOG_CHUNK1_SZ_IDX].integer.value;
        data_info->chunk2_addr_lo =
                out_obj->package.elements[LOG_CHUNK2_LO_IDX].integer.value;
        data_info->chunk2_addr_hi =
                out_obj->package.elements[LOG_CHUNK2_HI_IDX].integer.value;
        data_info->chunk2_size =
                out_obj->package.elements[LOG_CHUNK2_SZ_IDX].integer.value;
        data_info->rollover_cnt =
                out_obj->package.elements[LOG_ROLLOVER_CNT_IDX].integer.value;
        data_info->reset_cnt =
                out_obj->package.elements[LOG_RESET_CNT_IDX].integer.value;

        ret = 0;

free_acpi_buffer:
        ACPI_FREE(out_obj);

        return ret;
}

static int set_pfrt_log_level(int level, struct pfrt_log_device *pfrt_log_dev)
{
        acpi_handle handle = ACPI_HANDLE(pfrt_log_dev->parent_dev);
        union acpi_object *out_obj, *obj, in_obj, in_buf;
        enum pfru_dsm_status status, ext_status;
        int ret = 0;

        memset(&in_obj, 0, sizeof(in_obj));
        memset(&in_buf, 0, sizeof(in_buf));
        in_obj.type = ACPI_TYPE_PACKAGE;
        in_obj.package.count = 1;
        in_obj.package.elements = &in_buf;
        in_buf.type = ACPI_TYPE_INTEGER;
        in_buf.integer.value = level;

        out_obj = acpi_evaluate_dsm_typed(handle, &pfrt_log_guid,
                                          pfrt_log_dev->info.log_revid, PFRT_FUNC_SET_LEV,
                                          &in_obj, ACPI_TYPE_PACKAGE);
        if (!out_obj)
                return -EINVAL;

        obj = &out_obj->package.elements[0];
        status = obj->integer.value;
        if (status != DSM_SUCCEED) {
                obj = &out_obj->package.elements[1];
                ext_status = obj->integer.value;
                dev_dbg(pfrt_log_dev->parent_dev, "Error Status:%d\n", status);
                dev_dbg(pfrt_log_dev->parent_dev, "Error Extend Status:%d\n", ext_status);
                ret = -EBUSY;
        }

        ACPI_FREE(out_obj);

        return ret;
}

static int get_pfrt_log_level(struct pfrt_log_device *pfrt_log_dev)
{
        acpi_handle handle = ACPI_HANDLE(pfrt_log_dev->parent_dev);
        union acpi_object *out_obj, *obj;
        enum pfru_dsm_status status, ext_status;
        int ret = -EBUSY;

        out_obj = acpi_evaluate_dsm_typed(handle, &pfrt_log_guid,
                                          pfrt_log_dev->info.log_revid, PFRT_FUNC_GET_LEV,
                                          NULL, ACPI_TYPE_PACKAGE);
        if (!out_obj)
                return -EINVAL;

        obj = &out_obj->package.elements[0];
        if (obj->type != ACPI_TYPE_INTEGER)
                goto free_acpi_buffer;

        status = obj->integer.value;
        if (status != DSM_SUCCEED) {
                obj = &out_obj->package.elements[1];
                ext_status = obj->integer.value;
                dev_dbg(pfrt_log_dev->parent_dev, "Error Status:%d\n", status);
                dev_dbg(pfrt_log_dev->parent_dev, "Error Extend Status:%d\n", ext_status);
                goto free_acpi_buffer;
        }

        obj = &out_obj->package.elements[2];
        if (obj->type != ACPI_TYPE_INTEGER)
                goto free_acpi_buffer;

        ret = obj->integer.value;

free_acpi_buffer:
        ACPI_FREE(out_obj);

        return ret;
}

static int valid_log_level(u32 level)
{
        return level == PFRT_LOG_ERR || level == PFRT_LOG_WARN ||
               level == PFRT_LOG_INFO || level == PFRT_LOG_VERB;
}

static int valid_log_type(u32 type)
{
        return type == PFRT_LOG_EXEC_IDX || type == PFRT_LOG_HISTORY_IDX;
}

static inline int valid_log_revid(u32 id)
{
        return id == PFRT_REVID_1 || id == PFRT_REVID_2;
}

static long pfrt_log_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
        struct pfrt_log_device *pfrt_log_dev = to_pfrt_log_dev(file);
        struct pfrt_log_data_info data_info;
        struct pfrt_log_info info;
        void __user *p;
        int ret = 0;

        p = (void __user *)arg;

        switch (cmd) {
        case PFRT_LOG_IOC_SET_INFO:
                if (copy_from_user(&info, p, sizeof(info)))
                        return -EFAULT;

                if (valid_log_revid(info.log_revid))
                        pfrt_log_dev->info.log_revid = info.log_revid;

                if (valid_log_level(info.log_level)) {
                        ret = set_pfrt_log_level(info.log_level, pfrt_log_dev);
                        if (ret < 0)
                                return ret;

                        pfrt_log_dev->info.log_level = info.log_level;
                }

                if (valid_log_type(info.log_type))
                        pfrt_log_dev->info.log_type = info.log_type;

                return 0;

        case PFRT_LOG_IOC_GET_INFO:
                info.log_level = get_pfrt_log_level(pfrt_log_dev);
                info.log_type = pfrt_log_dev->info.log_type;
                info.log_revid = pfrt_log_dev->info.log_revid;
                if (copy_to_user(p, &info, sizeof(info)))
                        return -EFAULT;

                return 0;

        case PFRT_LOG_IOC_GET_DATA_INFO:
                ret = get_pfrt_log_data_info(&data_info, pfrt_log_dev);
                if (ret)
                        return ret;

                if (copy_to_user(p, &data_info, sizeof(struct pfrt_log_data_info)))
                        return -EFAULT;

                return 0;

        default:
                return -ENOTTY;
        }
}

static int
pfrt_log_mmap(struct file *file, struct vm_area_struct *vma)
{
        struct pfrt_log_device *pfrt_log_dev;
        struct pfrt_log_data_info info;
        unsigned long psize, vsize;
        phys_addr_t base_addr;
        int ret;

        if (vma->vm_flags & VM_WRITE)
                return -EROFS;

        /* changing from read to write with mprotect is not allowed */
        vm_flags_clear(vma, VM_MAYWRITE);

        pfrt_log_dev = to_pfrt_log_dev(file);

        ret = get_pfrt_log_data_info(&info, pfrt_log_dev);
        if (ret)
                return ret;

        base_addr = (phys_addr_t)((info.chunk2_addr_hi << 32) | info.chunk2_addr_lo);
        /* pfrt update has not been launched yet */
        if (!base_addr)
                return -ENODEV;

        psize = info.max_data_size;
        /* base address and total buffer size must be page aligned */
        if (!PAGE_ALIGNED(base_addr) || !PAGE_ALIGNED(psize))
                return -ENODEV;

        vsize = vma->vm_end - vma->vm_start;
        if (vsize > psize)
                return -EINVAL;

        vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
        if (io_remap_pfn_range(vma, vma->vm_start, PFN_DOWN(base_addr),
                               vsize, vma->vm_page_prot))
                return -EAGAIN;

        return 0;
}

static const struct file_operations acpi_pfrt_log_fops = {
        .owner          = THIS_MODULE,
        .mmap           = pfrt_log_mmap,
        .unlocked_ioctl = pfrt_log_ioctl,
        .llseek         = noop_llseek,
};

static void acpi_pfrt_log_remove(struct platform_device *pdev)
{
        struct pfrt_log_device *pfrt_log_dev = platform_get_drvdata(pdev);

        misc_deregister(&pfrt_log_dev->miscdev);
}

static void pfrt_log_put_idx(void *data)
{
        struct pfrt_log_device *pfrt_log_dev = data;

        ida_free(&pfrt_log_ida, pfrt_log_dev->index);
}

static int acpi_pfrt_log_probe(struct platform_device *pdev)
{
        acpi_handle handle = ACPI_HANDLE(&pdev->dev);
        struct pfrt_log_device *pfrt_log_dev;
        int ret;

        if (!acpi_has_method(handle, "_DSM")) {
                dev_dbg(&pdev->dev, "Missing _DSM\n");
                return -ENODEV;
        }

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

        ret = ida_alloc(&pfrt_log_ida, GFP_KERNEL);
        if (ret < 0)
                return ret;

        pfrt_log_dev->index = ret;
        ret = devm_add_action_or_reset(&pdev->dev, pfrt_log_put_idx, pfrt_log_dev);
        if (ret)
                return ret;

        pfrt_log_dev->info.log_revid = PFRT_DEFAULT_REV_ID;
        pfrt_log_dev->parent_dev = &pdev->dev;

        pfrt_log_dev->miscdev.minor = MISC_DYNAMIC_MINOR;
        pfrt_log_dev->miscdev.name = devm_kasprintf(&pdev->dev, GFP_KERNEL,
                                                    "pfrt%d",
                                                    pfrt_log_dev->index);
        if (!pfrt_log_dev->miscdev.name)
                return -ENOMEM;

        pfrt_log_dev->miscdev.nodename = devm_kasprintf(&pdev->dev, GFP_KERNEL,
                                                        "acpi_pfr_telemetry%d",
                                                        pfrt_log_dev->index);
        if (!pfrt_log_dev->miscdev.nodename)
                return -ENOMEM;

        pfrt_log_dev->miscdev.fops = &acpi_pfrt_log_fops;
        pfrt_log_dev->miscdev.parent = &pdev->dev;

        ret = misc_register(&pfrt_log_dev->miscdev);
        if (ret)
                return ret;

        platform_set_drvdata(pdev, pfrt_log_dev);

        return 0;
}

static const struct acpi_device_id acpi_pfrt_log_ids[] = {
        {"INTC1081"},
        {}
};
MODULE_DEVICE_TABLE(acpi, acpi_pfrt_log_ids);

static struct platform_driver acpi_pfrt_log_driver = {
        .driver = {
                .name = "pfr_telemetry",
                .acpi_match_table = acpi_pfrt_log_ids,
        },
        .probe = acpi_pfrt_log_probe,
        .remove = acpi_pfrt_log_remove,
};
module_platform_driver(acpi_pfrt_log_driver);

MODULE_DESCRIPTION("Platform Firmware Runtime Update Telemetry driver");
MODULE_LICENSE("GPL v2");