// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2014 Texas Instruments
 * Author: Tomi Valkeinen <tomi.valkeinen@ti.com>
 */

/*
 * As omapdss panel drivers are omapdss specific, but we want to define the
 * DT-data in generic manner, we convert the compatible strings of the panel and
 * encoder nodes from "panel-foo" to "omapdss,panel-foo". This way we can have
 * both correct DT data and omapdss specific drivers.
 *
 * When we get generic panel drivers to the kernel, this file will be removed.
 */

#include <linux/kernel.h>
#include <linux/of.h>
#include <linux/of_graph.h>
#include <linux/slab.h>
#include <linux/list.h>

static struct list_head dss_conv_list __initdata;

static const char prefix[] __initconst = "omapdss,";

struct dss_conv_node {
        struct list_head list;
        struct device_node *node;
        bool root;
};

static int __init omapdss_count_strings(const struct property *prop)
{
        const char *p = prop->value;
        int l = 0, total = 0;
        int i;

        for (i = 0; total < prop->length; total += l, p += l, i++)
                l = strlen(p) + 1;

        return i;
}

static void __init omapdss_update_prop(struct device_node *node, char *compat,
        int len)
{
        struct property *prop;

        prop = kzalloc_obj(*prop);
        if (!prop)
                return;

        prop->name = "compatible";
        prop->value = compat;
        prop->length = len;

        of_update_property(node, prop);
}

static void __init omapdss_prefix_strcpy(char *dst, int dst_len,
        const char *src, int src_len)
{
        size_t total = 0;

        while (total < src_len) {
                size_t l = strlen(src) + 1;

                strcpy(dst, prefix);
                dst += strlen(prefix);

                strcpy(dst, src);
                dst += l;

                src += l;
                total += l;
        }
}

/* prepend compatible property strings with "omapdss," */
static void __init omapdss_omapify_node(struct device_node *node)
{
        struct property *prop;
        char *new_compat;
        int num_strs;
        int new_len;

        prop = of_find_property(node, "compatible", NULL);

        if (!prop || !prop->value)
                return;

        if (strnlen(prop->value, prop->length) >= prop->length)
                return;

        /* is it already prefixed? */
        if (strncmp(prefix, prop->value, strlen(prefix)) == 0)
                return;

        num_strs = omapdss_count_strings(prop);

        new_len = prop->length + strlen(prefix) * num_strs;
        new_compat = kmalloc(new_len, GFP_KERNEL);
        if (!new_compat)
                return;

        omapdss_prefix_strcpy(new_compat, new_len, prop->value, prop->length);

        omapdss_update_prop(node, new_compat, new_len);
}

static void __init omapdss_add_to_list(struct device_node *node, bool root)
{
        struct dss_conv_node *n = kmalloc_obj(struct dss_conv_node);
        if (n) {
                n->node = node;
                n->root = root;
                list_add(&n->list, &dss_conv_list);
        }
}

static bool __init omapdss_list_contains(const struct device_node *node)
{
        struct dss_conv_node *n;

        list_for_each_entry(n, &dss_conv_list, list) {
                if (n->node == node)
                        return true;
        }

        return false;
}

static void __init omapdss_walk_device(struct device_node *node, bool root)
{
        struct device_node *n;

        omapdss_add_to_list(node, root);

        /*
         * of_graph_get_remote_port_parent() prints an error if there is no
         * port/ports node. To avoid that, check first that there's the node.
         */
        n = of_get_child_by_name(node, "ports");
        if (!n)
                n = of_get_child_by_name(node, "port");
        if (!n)
                return;

        of_node_put(n);

        for_each_endpoint_of_node(node, n) {
                struct device_node *pn;

                pn = of_graph_get_remote_port_parent(n);

                if (!pn)
                        continue;

                if (!of_device_is_available(pn) || omapdss_list_contains(pn)) {
                        of_node_put(pn);
                        continue;
                }

                omapdss_walk_device(pn, false);
        }
}

static const struct of_device_id omapdss_of_match[] __initconst = {
        { .compatible = "ti,omap2-dss", },
        { .compatible = "ti,omap3-dss", },
        { .compatible = "ti,omap4-dss", },
        { .compatible = "ti,omap5-dss", },
        { .compatible = "ti,dra7-dss", },
        {},
};

static int __init omapdss_boot_init(void)
{
        struct device_node *dss, *child;

        INIT_LIST_HEAD(&dss_conv_list);

        dss = of_find_matching_node(NULL, omapdss_of_match);

        if (dss == NULL || !of_device_is_available(dss)) {
                of_node_put(dss);
                return 0;
        }

        omapdss_walk_device(dss, true);

        for_each_available_child_of_node(dss, child) {
                if (!of_property_present(child, "compatible"))
                        continue;

                omapdss_walk_device(child, true);
        }

        while (!list_empty(&dss_conv_list)) {
                struct dss_conv_node *n;

                n = list_first_entry(&dss_conv_list, struct dss_conv_node,
                        list);

                if (!n->root)
                        omapdss_omapify_node(n->node);

                list_del(&n->list);
                of_node_put(n->node);
                kfree(n);
        }

        return 0;
}

subsys_initcall(omapdss_boot_init);