// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * OLPC-specific OFW device tree support code.
 *
 * Paul Mackerras       August 1996.
 * Copyright (C) 1996-2005 Paul Mackerras.
 *
 *  Adapted for 64bit PowerPC by Dave Engebretsen and Peter Bergner.
 *    {engebret|bergner}@us.ibm.com
 *
 *  Adapted for sparc by David S. Miller davem@davemloft.net
 *  Adapted for x86/OLPC by Andres Salomon <dilinger@queued.net>
 */

#include <linux/kernel.h>
#include <linux/memblock.h>
#include <linux/of.h>
#include <linux/of_pdt.h>
#include <asm/olpc.h>
#include <asm/olpc_ofw.h>

static phandle __init olpc_dt_getsibling(phandle node)
{
        const void *args[] = { (void *)node };
        void *res[] = { &node };

        if ((s32)node == -1)
                return 0;

        if (olpc_ofw("peer", args, res) || (s32)node == -1)
                return 0;

        return node;
}

static phandle __init olpc_dt_getchild(phandle node)
{
        const void *args[] = { (void *)node };
        void *res[] = { &node };

        if ((s32)node == -1)
                return 0;

        if (olpc_ofw("child", args, res) || (s32)node == -1) {
                pr_err("PROM: %s: fetching child failed!\n", __func__);
                return 0;
        }

        return node;
}

static int __init olpc_dt_getproplen(phandle node, const char *prop)
{
        const void *args[] = { (void *)node, prop };
        int len;
        void *res[] = { &len };

        if ((s32)node == -1)
                return -1;

        if (olpc_ofw("getproplen", args, res)) {
                pr_err("PROM: %s: getproplen failed!\n", __func__);
                return -1;
        }

        return len;
}

static int __init olpc_dt_getproperty(phandle node, const char *prop,
                char *buf, int bufsize)
{
        int plen;

        plen = olpc_dt_getproplen(node, prop);
        if (plen > bufsize || plen < 1) {
                return -1;
        } else {
                const void *args[] = { (void *)node, prop, buf, (void *)plen };
                void *res[] = { &plen };

                if (olpc_ofw("getprop", args, res)) {
                        pr_err("PROM: %s: getprop failed!\n", __func__);
                        return -1;
                }
        }

        return plen;
}

static int __init olpc_dt_nextprop(phandle node, char *prev, char *buf)
{
        const void *args[] = { (void *)node, prev, buf };
        int success;
        void *res[] = { &success };

        buf[0] = '\0';

        if ((s32)node == -1)
                return -1;

        if (olpc_ofw("nextprop", args, res) || success != 1)
                return -1;

        return 0;
}

static int __init olpc_dt_pkg2path(phandle node, char *buf,
                const int buflen, int *len)
{
        const void *args[] = { (void *)node, buf, (void *)buflen };
        void *res[] = { len };

        if ((s32)node == -1)
                return -1;

        if (olpc_ofw("package-to-path", args, res) || *len < 1)
                return -1;

        return 0;
}

static unsigned int prom_early_allocated __initdata;

void * __init prom_early_alloc(unsigned long size)
{
        static u8 *mem;
        static size_t free_mem;
        void *res;

        if (free_mem < size) {
                const size_t chunk_size = max(PAGE_SIZE, size);

                /*
                 * To minimize the number of allocations, grab at least
                 * PAGE_SIZE of memory (that's an arbitrary choice that's
                 * fast enough on the platforms we care about while minimizing
                 * wasted bootmem) and hand off chunks of it to callers.
                 */
                res = memblock_alloc_or_panic(chunk_size, SMP_CACHE_BYTES);
                prom_early_allocated += chunk_size;
                memset(res, 0, chunk_size);
                free_mem = chunk_size;
                mem = res;
        }

        /* allocate from the local cache */
        free_mem -= size;
        res = mem;
        mem += size;
        return res;
}

static struct of_pdt_ops prom_olpc_ops __initdata = {
        .nextprop = olpc_dt_nextprop,
        .getproplen = olpc_dt_getproplen,
        .getproperty = olpc_dt_getproperty,
        .getchild = olpc_dt_getchild,
        .getsibling = olpc_dt_getsibling,
        .pkg2path = olpc_dt_pkg2path,
};

static phandle __init olpc_dt_finddevice(const char *path)
{
        phandle node;
        const void *args[] = { path };
        void *res[] = { &node };

        if (olpc_ofw("finddevice", args, res)) {
                pr_err("olpc_dt: finddevice failed!\n");
                return 0;
        }

        if ((s32) node == -1)
                return 0;

        return node;
}

static int __init olpc_dt_interpret(const char *words)
{
        int result;
        const void *args[] = { words };
        void *res[] = { &result };

        if (olpc_ofw("interpret", args, res)) {
                pr_err("olpc_dt: interpret failed!\n");
                return -1;
        }

        return result;
}

/*
 * Extract board revision directly from OFW device tree.
 * We can't use olpc_platform_info because that hasn't been set up yet.
 */
static u32 __init olpc_dt_get_board_revision(void)
{
        phandle node;
        __be32 rev;
        int r;

        node = olpc_dt_finddevice("/");
        if (!node)
                return 0;

        r = olpc_dt_getproperty(node, "board-revision-int",
                                (char *) &rev, sizeof(rev));
        if (r < 0)
                return 0;

        return be32_to_cpu(rev);
}

static int __init olpc_dt_compatible_match(phandle node, const char *compat)
{
        char buf[64], *p;
        int plen;

        plen = olpc_dt_getproperty(node, "compatible", buf, sizeof(buf));
        if (plen <= 0)
                return 0;

        for (p = buf; p < buf + plen; p += strlen(p) + 1) {
                if (strcmp(p, compat) == 0)
                        return 1;
        }

        return 0;
}

static void __init olpc_dt_fixup(void)
{
        phandle node;
        u32 board_rev;

        node = olpc_dt_finddevice("/battery@0");
        if (!node)
                return;

        board_rev = olpc_dt_get_board_revision();
        if (!board_rev)
                return;

        if (board_rev >= olpc_board_pre(0xd0)) {
                /* XO-1.5 */

                if (olpc_dt_compatible_match(node, "olpc,xo1.5-battery"))
                        return;

                /* Add olpc,xo1.5-battery compatible marker to battery node */
                olpc_dt_interpret("\" /battery@0\" find-device");
                olpc_dt_interpret("  \" olpc,xo1.5-battery\" +compatible");
                olpc_dt_interpret("device-end");

                if (olpc_dt_compatible_match(node, "olpc,xo1-battery")) {
                        /*
                         * If we have a olpc,xo1-battery compatible, then we're
                         * running a new enough firmware that already has
                         * the dcon node.
                         */
                        return;
                }

                /* Add dcon device */
                olpc_dt_interpret("\" /pci/display@1\" find-device");
                olpc_dt_interpret("  new-device");
                olpc_dt_interpret("    \" dcon\" device-name");
                olpc_dt_interpret("    \" olpc,xo1-dcon\" +compatible");
                olpc_dt_interpret("  finish-device");
                olpc_dt_interpret("device-end");
        } else {
                /* XO-1 */

                if (olpc_dt_compatible_match(node, "olpc,xo1-battery")) {
                        /*
                         * If we have a olpc,xo1-battery compatible, then we're
                         * running a new enough firmware that already has
                         * the dcon and RTC nodes.
                         */
                        return;
                }

                /* Add dcon device, mark RTC as olpc,xo1-rtc */
                olpc_dt_interpret("\" /pci/display@1,1\" find-device");
                olpc_dt_interpret("  new-device");
                olpc_dt_interpret("    \" dcon\" device-name");
                olpc_dt_interpret("    \" olpc,xo1-dcon\" +compatible");
                olpc_dt_interpret("  finish-device");
                olpc_dt_interpret("device-end");

                olpc_dt_interpret("\" /rtc\" find-device");
                olpc_dt_interpret(" \" olpc,xo1-rtc\" +compatible");
                olpc_dt_interpret("device-end");
        }

        /* Add olpc,xo1-battery compatible marker to battery node */
        olpc_dt_interpret("\" /battery@0\" find-device");
        olpc_dt_interpret("  \" olpc,xo1-battery\" +compatible");
        olpc_dt_interpret("device-end");
}

void __init olpc_dt_build_devicetree(void)
{
        phandle root;

        if (!olpc_ofw_is_installed())
                return;

        olpc_dt_fixup();

        root = olpc_dt_getsibling(0);
        if (!root) {
                pr_err("PROM: unable to get root node from OFW!\n");
                return;
        }
        of_pdt_build_devicetree(root, &prom_olpc_ops);

        pr_info("PROM DT: Built device tree with %u bytes of memory.\n",
                        prom_early_allocated);
}