// SPDX-License-Identifier: MIT
/*
 * Copyright © 2023 Intel Corporation
 */

#include <linux/debugfs.h>
#include <linux/kernel.h>

#include <drm/drm_drv.h>

#include "intel_display_core.h"
#include "intel_display_debugfs_params.h"
#include "intel_display_params.h"

/* int param */
static int intel_display_param_int_show(struct seq_file *m, void *data)
{
        int *value = m->private;

        seq_printf(m, "%d\n", *value);

        return 0;
}

static int intel_display_param_int_open(struct inode *inode, struct file *file)
{
        return single_open(file, intel_display_param_int_show, inode->i_private);
}

static ssize_t intel_display_param_int_write(struct file *file,
                                             const char __user *ubuf, size_t len,
                                             loff_t *offp)
{
        struct seq_file *m = file->private_data;
        int *value = m->private;
        int ret;

        ret = kstrtoint_from_user(ubuf, len, 0, value);
        if (ret) {
                /* support boolean values too */
                bool b;

                ret = kstrtobool_from_user(ubuf, len, &b);
                if (!ret)
                        *value = b;
        }

        return ret ?: len;
}

static const struct file_operations intel_display_param_int_fops = {
        .owner = THIS_MODULE,
        .open = intel_display_param_int_open,
        .read = seq_read,
        .write = intel_display_param_int_write,
        .llseek = default_llseek,
        .release = single_release,
};

static const struct file_operations intel_display_param_int_fops_ro = {
        .owner = THIS_MODULE,
        .open = intel_display_param_int_open,
        .read = seq_read,
        .llseek = default_llseek,
        .release = single_release,
};

/* unsigned int param */
static int intel_display_param_uint_show(struct seq_file *m, void *data)
{
        unsigned int *value = m->private;

        seq_printf(m, "%u\n", *value);

        return 0;
}

static int intel_display_param_uint_open(struct inode *inode, struct file *file)
{
        return single_open(file, intel_display_param_uint_show, inode->i_private);
}

static ssize_t intel_display_param_uint_write(struct file *file,
                                              const char __user *ubuf, size_t len,
                                              loff_t *offp)
{
        struct seq_file *m = file->private_data;
        unsigned int *value = m->private;
        int ret;

        ret = kstrtouint_from_user(ubuf, len, 0, value);
        if (ret) {
                /* support boolean values too */
                bool b;

                ret = kstrtobool_from_user(ubuf, len, &b);
                if (!ret)
                        *value = b;
        }

        return ret ?: len;
}

static const struct file_operations intel_display_param_uint_fops = {
        .owner = THIS_MODULE,
        .open = intel_display_param_uint_open,
        .read = seq_read,
        .write = intel_display_param_uint_write,
        .llseek = default_llseek,
        .release = single_release,
};

static const struct file_operations intel_display_param_uint_fops_ro = {
        .owner = THIS_MODULE,
        .open = intel_display_param_uint_open,
        .read = seq_read,
        .llseek = default_llseek,
        .release = single_release,
};

#define RO(mode) (((mode) & 0222) == 0)

__maybe_unused static struct dentry *
intel_display_debugfs_create_int(const char *name, umode_t mode,
                        struct dentry *parent, int *value)
{
        return debugfs_create_file_unsafe(name, mode, parent, value,
                                          RO(mode) ? &intel_display_param_int_fops_ro :
                                          &intel_display_param_int_fops);
}

__maybe_unused static struct dentry *
intel_display_debugfs_create_uint(const char *name, umode_t mode,
                         struct dentry *parent, unsigned int *value)
{
        return debugfs_create_file_unsafe(name, mode, parent, value,
                                          RO(mode) ? &intel_display_param_uint_fops_ro :
                                          &intel_display_param_uint_fops);
}

#define _intel_display_param_create_file(parent, name, mode, valp)      \
        do {                                                            \
                if (mode)                                               \
                        _Generic(valp,                                  \
                                 bool * : debugfs_create_bool,          \
                                 int * : intel_display_debugfs_create_int, \
                                 unsigned int * : intel_display_debugfs_create_uint, \
                                 unsigned long * : debugfs_create_ulong, \
                                 char ** : debugfs_create_str) \
                                (name, mode, parent, valp);             \
        } while (0)

/* add a subdirectory with files for each intel display param */
void intel_display_debugfs_params(struct intel_display *display)
{
        struct dentry *debugfs_root = display->drm->debugfs_root;
        struct dentry *dir;
        char dirname[16];

        snprintf(dirname, sizeof(dirname), "%s_params", display->drm->driver->name);
        dir = debugfs_lookup(dirname, debugfs_root);
        if (!dir)
                dir = debugfs_create_dir(dirname, debugfs_root);
        if (IS_ERR(dir))
                return;

        /*
         * Note: We could create files for params needing special handling
         * here. Set mode in params to 0 to skip the generic create file, or
         * just let the generic create file fail silently with -EEXIST.
         */

#define REGISTER(T, x, unused, mode, ...) _intel_display_param_create_file( \
                dir, #x, mode, &display->params.x);
        INTEL_DISPLAY_PARAMS_FOR_EACH(REGISTER);
#undef REGISTER
}