olpc_dt.c

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/*
 * 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 [email protected]
 *  Adapted for x86/OLPC by Andres Salomon <[email protected]>
 *
 *      This program is free software; you can redistribute it and/or
 *      modify it under the terms of the GNU General Public License
 *      as published by the Free Software Foundation; either version
 *      2 of the License, or (at your option) any later version.
 */

#include <linux/kernel.h>
#include <linux/bootmem.h>
#include <linux/of.h>
#include <linux/of_platform.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 mimimize 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 = alloc_bootmem(chunk_size);
        BUG_ON(!res);
        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);
}

void __init olpc_dt_fixup(void)
{
    int r;
    char buf[64];
    phandle node;
    u32 board_rev;

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

    /*
     * If the battery node has a compatible property, we are running a new
     * enough firmware and don't have fixups to make.
     */
    r = olpc_dt_getproperty(node, "compatible", buf, sizeof(buf));
    if (r > 0)
        return;

    pr_info("PROM DT: Old firmware detected, applying fixes\n");

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

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

    if (board_rev >= olpc_board_pre(0xd0)) {
        /* XO-1.5: add dcon device */
        olpc_dt_interpret("\" /pci/display@1\" find-device"
            " new-device"
            " \" dcon\" device-name \" olpc,xo1-dcon\" +compatible"
            " finish-device device-end");
    } else {
        /* XO-1: add dcon device, mark RTC as olpc,xo1-rtc */
        olpc_dt_interpret("\" /pci/display@1,1\" find-device"
            " new-device"
            " \" dcon\" device-name \" olpc,xo1-dcon\" +compatible"
            " finish-device device-end"
            " \" /rtc\" find-device"
            " \" olpc,xo1-rtc\" +compatible"
            " 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);
}

/* A list of DT node/bus matches that we want to expose as platform devices */
static struct of_device_id __initdata of_ids[] = {
    { .compatible = "olpc,xo1-battery" },
    { .compatible = "olpc,xo1-dcon" },
    { .compatible = "olpc,xo1-rtc" },
    {},
};

static int __init olpc_create_platform_devices(void)
{
    if (machine_is_olpc())
        return of_platform_bus_probe(NULL, of_ids, NULL);
    else
        return 0;
}
device_initcall(olpc_create_platform_devices);