[PATCH] powerpc: Experimental support for new G5 Macs (#2)

[deliverable/linux.git] / arch / powerpc / kernel / prom.c

/*
 * Procedures for creating, accessing and interpreting the device tree.
 *
 * 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 
 *
 *      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.
 */

#undef DEBUG

#include <stdarg.h>
#include <linux/config.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/init.h>
#include <linux/threads.h>
#include <linux/spinlock.h>
#include <linux/types.h>
#include <linux/pci.h>
#include <linux/stringify.h>
#include <linux/delay.h>
#include <linux/initrd.h>
#include <linux/bitops.h>
#include <linux/module.h>
#include <linux/kexec.h>

#include <asm/prom.h>
#include <asm/rtas.h>
#include <asm/lmb.h>
#include <asm/page.h>
#include <asm/processor.h>
#include <asm/irq.h>
#include <asm/io.h>
#include <asm/kdump.h>
#include <asm/smp.h>
#include <asm/system.h>
#include <asm/mmu.h>
#include <asm/pgtable.h>
#include <asm/pci.h>
#include <asm/iommu.h>
#include <asm/btext.h>
#include <asm/sections.h>
#include <asm/machdep.h>
#include <asm/pSeries_reconfig.h>
#include <asm/pci-bridge.h>

#ifdef DEBUG
#define DBG(fmt...) printk(KERN_ERR fmt)
#else
#define DBG(fmt...)
#endif


static int __initdata dt_root_addr_cells;
static int __initdata dt_root_size_cells;

#ifdef CONFIG_PPC64
static int __initdata iommu_is_off;
int __initdata iommu_force_on;
unsigned long tce_alloc_start, tce_alloc_end;
#endif

typedef u32 cell_t;

#if 0
static struct boot_param_header *initial_boot_params __initdata;
#else
struct boot_param_header *initial_boot_params;
#endif

static struct device_node *allnodes = NULL;

/* use when traversing tree through the allnext, child, sibling,
 * or parent members of struct device_node.
 */
static DEFINE_RWLOCK(devtree_lock);

/* export that to outside world */
struct device_node *of_chosen;

struct device_node *dflt_interrupt_controller;
int num_interrupt_controllers;

/*
 * Wrapper for allocating memory for various data that needs to be
 * attached to device nodes as they are processed at boot or when
 * added to the device tree later (e.g. DLPAR).  At boot there is
 * already a region reserved so we just increment *mem_start by size;
 * otherwise we call kmalloc.
 */
static void * prom_alloc(unsigned long size, unsigned long *mem_start)
{
        unsigned long tmp;

        if (!mem_start)
                return kmalloc(size, GFP_KERNEL);

        tmp = *mem_start;
        *mem_start += size;
        return (void *)tmp;
}

/*
 * Find the device_node with a given phandle.
 */
static struct device_node * find_phandle(phandle ph)
{
        struct device_node *np;

        for (np = allnodes; np != 0; np = np->allnext)
                if (np->linux_phandle == ph)
                        return np;
        return NULL;
}

/*
 * Find the interrupt parent of a node.
 */
static struct device_node * __devinit intr_parent(struct device_node *p)
{
        phandle *parp;

        parp = (phandle *) get_property(p, "interrupt-parent", NULL);
        if (parp == NULL)
                return p->parent;
        p = find_phandle(*parp);
        if (p != NULL)
                return p;
        /*
         * On a powermac booted with BootX, we don't get to know the
         * phandles for any nodes, so find_phandle will return NULL.
         * Fortunately these machines only have one interrupt controller
         * so there isn't in fact any ambiguity.  -- paulus
         */
        if (num_interrupt_controllers == 1)
                p = dflt_interrupt_controller;
        return p;
}

/*
 * Find out the size of each entry of the interrupts property
 * for a node.
 */
int __devinit prom_n_intr_cells(struct device_node *np)
{
        struct device_node *p;
        unsigned int *icp;

        for (p = np; (p = intr_parent(p)) != NULL; ) {
                icp = (unsigned int *)
                        get_property(p, "#interrupt-cells", NULL);
                if (icp != NULL)
                        return *icp;
                if (get_property(p, "interrupt-controller", NULL) != NULL
                    || get_property(p, "interrupt-map", NULL) != NULL) {
                        printk("oops, node %s doesn't have #interrupt-cells\n",
                               p->full_name);
                        return 1;
                }
        }
#ifdef DEBUG_IRQ
        printk("prom_n_intr_cells failed for %s\n", np->full_name);
#endif
        return 1;
}

/*
 * Map an interrupt from a device up to the platform interrupt
 * descriptor.
 */
static int __devinit map_interrupt(unsigned int **irq, struct device_node **ictrler,
                                   struct device_node *np, unsigned int *ints,
                                   int nintrc)
{
        struct device_node *p, *ipar;
        unsigned int *imap, *imask, *ip;
        int i, imaplen, match;
        int newintrc = 0, newaddrc = 0;
        unsigned int *reg;
        int naddrc;

        reg = (unsigned int *) get_property(np, "reg", NULL);
        naddrc = prom_n_addr_cells(np);
        p = intr_parent(np);
        while (p != NULL) {
                if (get_property(p, "interrupt-controller", NULL) != NULL)
                        /* this node is an interrupt controller, stop here */
                        break;
                imap = (unsigned int *)
                        get_property(p, "interrupt-map", &imaplen);
                if (imap == NULL) {
                        p = intr_parent(p);
                        continue;
                }
                imask = (unsigned int *)
                        get_property(p, "interrupt-map-mask", NULL);
                if (imask == NULL) {
                        printk("oops, %s has interrupt-map but no mask\n",
                               p->full_name);
                        return 0;
                }
                imaplen /= sizeof(unsigned int);
                match = 0;
                ipar = NULL;
                while (imaplen > 0 && !match) {
                        /* check the child-interrupt field */
                        match = 1;
                        for (i = 0; i < naddrc && match; ++i)
                                match = ((reg[i] ^ imap[i]) & imask[i]) == 0;
                        for (; i < naddrc + nintrc && match; ++i)
                                match = ((ints[i-naddrc] ^ imap[i]) & imask[i]) == 0;
                        imap += naddrc + nintrc;
                        imaplen -= naddrc + nintrc;
                        /* grab the interrupt parent */
                        ipar = find_phandle((phandle) *imap++);
                        --imaplen;
                        if (ipar == NULL && num_interrupt_controllers == 1)
                                /* cope with BootX not giving us phandles */
                                ipar = dflt_interrupt_controller;
                        if (ipar == NULL) {
                                printk("oops, no int parent %x in map of %s\n",
                                       imap[-1], p->full_name);
                                return 0;
                        }
                        /* find the parent's # addr and intr cells */
                        ip = (unsigned int *)
                                get_property(ipar, "#interrupt-cells", NULL);
                        if (ip == NULL) {
                                printk("oops, no #interrupt-cells on %s\n",
                                       ipar->full_name);
                                return 0;
                        }
                        newintrc = *ip;
                        ip = (unsigned int *)
                                get_property(ipar, "#address-cells", NULL);
                        newaddrc = (ip == NULL)? 0: *ip;
                        imap += newaddrc + newintrc;
                        imaplen -= newaddrc + newintrc;
                }
                if (imaplen < 0) {
                        printk("oops, error decoding int-map on %s, len=%d\n",
                               p->full_name, imaplen);
                        return 0;
                }
                if (!match) {
#ifdef DEBUG_IRQ
                        printk("oops, no match in %s int-map for %s\n",
                               p->full_name, np->full_name);
#endif
                        return 0;
                }
                p = ipar;
                naddrc = newaddrc;
                nintrc = newintrc;
                ints = imap - nintrc;
                reg = ints - naddrc;
        }
        if (p == NULL) {
#ifdef DEBUG_IRQ
                printk("hmmm, int tree for %s doesn't have ctrler\n",
                       np->full_name);
#endif
                return 0;
        }
        *irq = ints;
        *ictrler = p;
        return nintrc;
}

static unsigned char map_isa_senses[4] = {
        IRQ_SENSE_LEVEL | IRQ_POLARITY_NEGATIVE,
        IRQ_SENSE_LEVEL | IRQ_POLARITY_POSITIVE,
        IRQ_SENSE_EDGE  | IRQ_POLARITY_NEGATIVE,
        IRQ_SENSE_EDGE  | IRQ_POLARITY_POSITIVE
};

static unsigned char map_mpic_senses[4] = {
        IRQ_SENSE_EDGE  | IRQ_POLARITY_POSITIVE,
        IRQ_SENSE_LEVEL | IRQ_POLARITY_NEGATIVE,
        /* 2 seems to be used for the 8259 cascade... */
        IRQ_SENSE_LEVEL | IRQ_POLARITY_POSITIVE,
        IRQ_SENSE_EDGE  | IRQ_POLARITY_NEGATIVE,
};

static int __devinit finish_node_interrupts(struct device_node *np,
                                            unsigned long *mem_start,
                                            int measure_only)
{
        unsigned int *ints;
        int intlen, intrcells, intrcount;
        int i, j, n, sense;
        unsigned int *irq, virq;
        struct device_node *ic;
        int trace = 0;

        //#define TRACE(fmt...) do { if (trace) { printk(fmt); mdelay(1000); } } while(0)
#define TRACE(fmt...)

        if (!strcmp(np->name, "smu-doorbell"))
                trace = 1;

        TRACE("Finishing SMU doorbell ! num_interrupt_controllers = %d\n",
              num_interrupt_controllers);

        if (num_interrupt_controllers == 0) {
                /*
                 * Old machines just have a list of interrupt numbers
                 * and no interrupt-controller nodes.
                 */
                ints = (unsigned int *) get_property(np, "AAPL,interrupts",
                                                     &intlen);
                /* XXX old interpret_pci_props looked in parent too */
                /* XXX old interpret_macio_props looked for interrupts
                   before AAPL,interrupts */
                if (ints == NULL)
                        ints = (unsigned int *) get_property(np, "interrupts",
                                                             &intlen);
                if (ints == NULL)
                        return 0;

                np->n_intrs = intlen / sizeof(unsigned int);
                np->intrs = prom_alloc(np->n_intrs * sizeof(np->intrs[0]),
                                       mem_start);
                if (!np->intrs)
                        return -ENOMEM;
                if (measure_only)
                        return 0;

                for (i = 0; i < np->n_intrs; ++i) {
                        np->intrs[i].line = *ints++;
                        np->intrs[i].sense = IRQ_SENSE_LEVEL
                                | IRQ_POLARITY_NEGATIVE;
                }
                return 0;
        }

        ints = (unsigned int *) get_property(np, "interrupts", &intlen);
        TRACE("ints=%p, intlen=%d\n", ints, intlen);
        if (ints == NULL)
                return 0;
        intrcells = prom_n_intr_cells(np);
        intlen /= intrcells * sizeof(unsigned int);
        TRACE("intrcells=%d, new intlen=%d\n", intrcells, intlen);
        np->intrs = prom_alloc(intlen * sizeof(*(np->intrs)), mem_start);
        if (!np->intrs)
                return -ENOMEM;

        if (measure_only)
                return 0;

        intrcount = 0;
        for (i = 0; i < intlen; ++i, ints += intrcells) {
                n = map_interrupt(&irq, &ic, np, ints, intrcells);
                TRACE("map, irq=%d, ic=%p, n=%d\n", irq, ic, n);
                if (n <= 0)
                        continue;

                /* don't map IRQ numbers under a cascaded 8259 controller */
                if (ic && device_is_compatible(ic, "chrp,iic")) {
                        np->intrs[intrcount].line = irq[0];
                        sense = (n > 1)? (irq[1] & 3): 3;
                        np->intrs[intrcount].sense = map_isa_senses[sense];
                } else {
                        virq = virt_irq_create_mapping(irq[0]);
                        TRACE("virq=%d\n", virq);
#ifdef CONFIG_PPC64
                        if (virq == NO_IRQ) {
                                printk(KERN_CRIT "Could not allocate interrupt"
                                       " number for %s\n", np->full_name);
                                continue;
                        }
#endif
                        np->intrs[intrcount].line = irq_offset_up(virq);
                        sense = (n > 1)? (irq[1] & 3): 1;

                        /* Apple uses bits in there in a different way, let's
                         * only keep the real sense bit on macs
                         */
                        if (_machine == PLATFORM_POWERMAC)
                                sense &= 0x1;
                        np->intrs[intrcount].sense = map_mpic_senses[sense];
                }

#ifdef CONFIG_PPC64
                /* We offset irq numbers for the u3 MPIC by 128 in PowerMac */
                if (_machine == PLATFORM_POWERMAC && ic && ic->parent) {
                        char *name = get_property(ic->parent, "name", NULL);
                        if (name && !strcmp(name, "u3"))
                                np->intrs[intrcount].line += 128;
                        else if (!(name && (!strcmp(name, "mac-io") ||
                                            !strcmp(name, "u4"))))
                                /* ignore other cascaded controllers, such as
                                   the k2-sata-root */
                                break;
                }
#endif /* CONFIG_PPC64 */
                if (n > 2) {
                        printk("hmmm, got %d intr cells for %s:", n,
                               np->full_name);
                        for (j = 0; j < n; ++j)
                                printk(" %d", irq[j]);
                        printk("\n");
                }
                ++intrcount;
        }
        np->n_intrs = intrcount;

        return 0;
}

static int __devinit finish_node(struct device_node *np,
                                 unsigned long *mem_start,
                                 int measure_only)
{
        struct device_node *child;
        int rc = 0;

        rc = finish_node_interrupts(np, mem_start, measure_only);
        if (rc)
                goto out;

        for (child = np->child; child != NULL; child = child->sibling) {
                rc = finish_node(child, mem_start, measure_only);
                if (rc)
                        goto out;
        }
out:
        return rc;
}

static void __init scan_interrupt_controllers(void)
{
        struct device_node *np;
        int n = 0;
        char *name, *ic;
        int iclen;

        for (np = allnodes; np != NULL; np = np->allnext) {
                ic = get_property(np, "interrupt-controller", &iclen);
                name = get_property(np, "name", NULL);
                /* checking iclen makes sure we don't get a false
                   match on /chosen.interrupt_controller */
                if ((name != NULL
                     && strcmp(name, "interrupt-controller") == 0)
                    || (ic != NULL && iclen == 0
                        && strcmp(name, "AppleKiwi"))) {
                        if (n == 0)
                                dflt_interrupt_controller = np;
                        ++n;
                }
        }
        num_interrupt_controllers = n;
}

/**
 * finish_device_tree is called once things are running normally
 * (i.e. with text and data mapped to the address they were linked at).
 * It traverses the device tree and fills in some of the additional,
 * fields in each node like {n_}addrs and {n_}intrs, the virt interrupt
 * mapping is also initialized at this point.
 */
void __init finish_device_tree(void)
{
        unsigned long start, end, size = 0;

        DBG(" -> finish_device_tree\n");

#ifdef CONFIG_PPC64
        /* Initialize virtual IRQ map */
        virt_irq_init();
#endif
        scan_interrupt_controllers();

        /*
         * Finish device-tree (pre-parsing some properties etc...)
         * We do this in 2 passes. One with "measure_only" set, which
         * will only measure the amount of memory needed, then we can
         * allocate that memory, and call finish_node again. However,
         * we must be careful as most routines will fail nowadays when
         * prom_alloc() returns 0, so we must make sure our first pass
         * doesn't start at 0. We pre-initialize size to 16 for that
         * reason and then remove those additional 16 bytes
         */
        size = 16;
        finish_node(allnodes, &size, 1);
        size -= 16;
        end = start = (unsigned long) __va(lmb_alloc(size, 128));
        finish_node(allnodes, &end, 0);
        BUG_ON(end != start + size);

        DBG(" <- finish_device_tree\n");
}

static inline char *find_flat_dt_string(u32 offset)
{
        return ((char *)initial_boot_params) +
                initial_boot_params->off_dt_strings + offset;
}

/**
 * This function is used to scan the flattened device-tree, it is
 * used to extract the memory informations at boot before we can
 * unflatten the tree
 */
int __init of_scan_flat_dt(int (*it)(unsigned long node,
                                     const char *uname, int depth,
                                     void *data),
                           void *data)
{
        unsigned long p = ((unsigned long)initial_boot_params) +
                initial_boot_params->off_dt_struct;
        int rc = 0;
        int depth = -1;

        do {
                u32 tag = *((u32 *)p);
                char *pathp;
                
                p += 4;
                if (tag == OF_DT_END_NODE) {
                        depth --;
                        continue;
                }
                if (tag == OF_DT_NOP)
                        continue;
                if (tag == OF_DT_END)
                        break;
                if (tag == OF_DT_PROP) {
                        u32 sz = *((u32 *)p);
                        p += 8;
                        if (initial_boot_params->version < 0x10)
                                p = _ALIGN(p, sz >= 8 ? 8 : 4);
                        p += sz;
                        p = _ALIGN(p, 4);
                        continue;
                }
                if (tag != OF_DT_BEGIN_NODE) {
                        printk(KERN_WARNING "Invalid tag %x scanning flattened"
                               " device tree !\n", tag);
                        return -EINVAL;
                }
                depth++;
                pathp = (char *)p;
                p = _ALIGN(p + strlen(pathp) + 1, 4);
                if ((*pathp) == '/') {
                        char *lp, *np;
                        for (lp = NULL, np = pathp; *np; np++)
                                if ((*np) == '/')
                                        lp = np+1;
                        if (lp != NULL)
                                pathp = lp;
                }
                rc = it(p, pathp, depth, data);
                if (rc != 0)
                        break;          
        } while(1);

        return rc;
}

/**
 * This  function can be used within scan_flattened_dt callback to get
 * access to properties
 */
void* __init of_get_flat_dt_prop(unsigned long node, const char *name,
                                 unsigned long *size)
{
        unsigned long p = node;

        do {
                u32 tag = *((u32 *)p);
                u32 sz, noff;
                const char *nstr;

                p += 4;
                if (tag == OF_DT_NOP)
                        continue;
                if (tag != OF_DT_PROP)
                        return NULL;

                sz = *((u32 *)p);
                noff = *((u32 *)(p + 4));
                p += 8;
                if (initial_boot_params->version < 0x10)
                        p = _ALIGN(p, sz >= 8 ? 8 : 4);

                nstr = find_flat_dt_string(noff);
                if (nstr == NULL) {
                        printk(KERN_WARNING "Can't find property index"
                               " name !\n");
                        return NULL;
                }
                if (strcmp(name, nstr) == 0) {
                        if (size)
                                *size = sz;
                        return (void *)p;
                }
                p += sz;
                p = _ALIGN(p, 4);
        } while(1);
}

static void *__init unflatten_dt_alloc(unsigned long *mem, unsigned long size,
                                       unsigned long align)
{
        void *res;

        *mem = _ALIGN(*mem, align);
        res = (void *)*mem;
        *mem += size;

        return res;
}

static unsigned long __init unflatten_dt_node(unsigned long mem,
                                              unsigned long *p,
                                              struct device_node *dad,
                                              struct device_node ***allnextpp,
                                              unsigned long fpsize)
{
        struct device_node *np;
        struct property *pp, **prev_pp = NULL;
        char *pathp;
        u32 tag;
        unsigned int l, allocl;
        int has_name = 0;
        int new_format = 0;

        tag = *((u32 *)(*p));
        if (tag != OF_DT_BEGIN_NODE) {
                printk("Weird tag at start of node: %x\n", tag);
                return mem;
        }
        *p += 4;
        pathp = (char *)*p;
        l = allocl = strlen(pathp) + 1;
        *p = _ALIGN(*p + l, 4);

        /* version 0x10 has a more compact unit name here instead of the full
         * path. we accumulate the full path size using "fpsize", we'll rebuild
         * it later. We detect this because the first character of the name is
         * not '/'.
         */
        if ((*pathp) != '/') {
                new_format = 1;
                if (fpsize == 0) {
                        /* root node: special case. fpsize accounts for path
                         * plus terminating zero. root node only has '/', so
                         * fpsize should be 2, but we want to avoid the first
                         * level nodes to have two '/' so we use fpsize 1 here
                         */
                        fpsize = 1;
                        allocl = 2;
                } else {
                        /* account for '/' and path size minus terminal 0
                         * already in 'l'
                         */
                        fpsize += l;
                        allocl = fpsize;
                }
        }


        np = unflatten_dt_alloc(&mem, sizeof(struct device_node) + allocl,
                                __alignof__(struct device_node));
        if (allnextpp) {
                memset(np, 0, sizeof(*np));
                np->full_name = ((char*)np) + sizeof(struct device_node);
                if (new_format) {
                        char *p = np->full_name;
                        /* rebuild full path for new format */
                        if (dad && dad->parent) {
                                strcpy(p, dad->full_name);
#ifdef DEBUG
                                if ((strlen(p) + l + 1) != allocl) {
                                        DBG("%s: p: %d, l: %d, a: %d\n",
                                            pathp, strlen(p), l, allocl);
                                }
#endif
                                p += strlen(p);
                        }
                        *(p++) = '/';
                        memcpy(p, pathp, l);
                } else
                        memcpy(np->full_name, pathp, l);
                prev_pp = &np->properties;
                **allnextpp = np;
                *allnextpp = &np->allnext;
                if (dad != NULL) {
                        np->parent = dad;
                        /* we temporarily use the next field as `last_child'*/
                        if (dad->next == 0)
                                dad->child = np;
                        else
                                dad->next->sibling = np;
                        dad->next = np;
                }
                kref_init(&np->kref);
        }
        while(1) {
                u32 sz, noff;
                char *pname;

                tag = *((u32 *)(*p));
                if (tag == OF_DT_NOP) {
                        *p += 4;
                        continue;
                }
                if (tag != OF_DT_PROP)
                        break;
                *p += 4;
                sz = *((u32 *)(*p));
                noff = *((u32 *)((*p) + 4));
                *p += 8;
                if (initial_boot_params->version < 0x10)
                        *p = _ALIGN(*p, sz >= 8 ? 8 : 4);

                pname = find_flat_dt_string(noff);
                if (pname == NULL) {
                        printk("Can't find property name in list !\n");
                        break;
                }
                if (strcmp(pname, "name") == 0)
                        has_name = 1;
                l = strlen(pname) + 1;
                pp = unflatten_dt_alloc(&mem, sizeof(struct property),
                                        __alignof__(struct property));
                if (allnextpp) {
                        if (strcmp(pname, "linux,phandle") == 0) {
                                np->node = *((u32 *)*p);
                                if (np->linux_phandle == 0)
                                        np->linux_phandle = np->node;
                        }
                        if (strcmp(pname, "ibm,phandle") == 0)
                                np->linux_phandle = *((u32 *)*p);
                        pp->name = pname;
                        pp->length = sz;
                        pp->value = (void *)*p;
                        *prev_pp = pp;
                        prev_pp = &pp->next;
                }
                *p = _ALIGN((*p) + sz, 4);
        }
        /* with version 0x10 we may not have the name property, recreate
         * it here from the unit name if absent
         */
        if (!has_name) {
                char *p = pathp, *ps = pathp, *pa = NULL;
                int sz;

                while (*p) {
                        if ((*p) == '@')
                                pa = p;
                        if ((*p) == '/')
                                ps = p + 1;
                        p++;
                }
                if (pa < ps)
                        pa = p;
                sz = (pa - ps) + 1;
                pp = unflatten_dt_alloc(&mem, sizeof(struct property) + sz,
                                        __alignof__(struct property));
                if (allnextpp) {
                        pp->name = "name";
                        pp->length = sz;
                        pp->value = (unsigned char *)(pp + 1);
                        *prev_pp = pp;
                        prev_pp = &pp->next;
                        memcpy(pp->value, ps, sz - 1);
                        ((char *)pp->value)[sz - 1] = 0;
                        DBG("fixed up name for %s -> %s\n", pathp, pp->value);
                }
        }
        if (allnextpp) {
                *prev_pp = NULL;
                np->name = get_property(np, "name", NULL);
                np->type = get_property(np, "device_type", NULL);

                if (!np->name)
                        np->name = "<NULL>";
                if (!np->type)
                        np->type = "<NULL>";
        }
        while (tag == OF_DT_BEGIN_NODE) {
                mem = unflatten_dt_node(mem, p, np, allnextpp, fpsize);
                tag = *((u32 *)(*p));
        }
        if (tag != OF_DT_END_NODE) {
                printk("Weird tag at end of node: %x\n", tag);
                return mem;
        }
        *p += 4;
        return mem;
}


/**
 * unflattens the device-tree passed by the firmware, creating the
 * tree of struct device_node. It also fills the "name" and "type"
 * pointers of the nodes so the normal device-tree walking functions
 * can be used (this used to be done by finish_device_tree)
 */
void __init unflatten_device_tree(void)
{
        unsigned long start, mem, size;
        struct device_node **allnextp = &allnodes;
        char *p = NULL;
        int l = 0;

        DBG(" -> unflatten_device_tree()\n");

        /* First pass, scan for size */
        start = ((unsigned long)initial_boot_params) +
                initial_boot_params->off_dt_struct;
        size = unflatten_dt_node(0, &start, NULL, NULL, 0);
        size = (size | 3) + 1;

        DBG("  size is %lx, allocating...\n", size);

        /* Allocate memory for the expanded device tree */
        mem = lmb_alloc(size + 4, __alignof__(struct device_node));
        if (!mem) {
                DBG("Couldn't allocate memory with lmb_alloc()!\n");
                panic("Couldn't allocate memory with lmb_alloc()!\n");
        }
        mem = (unsigned long) __va(mem);

        ((u32 *)mem)[size / 4] = 0xdeadbeef;

        DBG("  unflattening %lx...\n", mem);

        /* Second pass, do actual unflattening */
        start = ((unsigned long)initial_boot_params) +
                initial_boot_params->off_dt_struct;
        unflatten_dt_node(mem, &start, NULL, &allnextp, 0);
        if (*((u32 *)start) != OF_DT_END)
                printk(KERN_WARNING "Weird tag at end of tree: %08x\n", *((u32 *)start));
        if (((u32 *)mem)[size / 4] != 0xdeadbeef)
                printk(KERN_WARNING "End of tree marker overwritten: %08x\n",
                       ((u32 *)mem)[size / 4] );
        *allnextp = NULL;

        /* Get pointer to OF "/chosen" node for use everywhere */
        of_chosen = of_find_node_by_path("/chosen");
        if (of_chosen == NULL)
                of_chosen = of_find_node_by_path("/chosen@0");

        /* Retreive command line */
        if (of_chosen != NULL) {
                p = (char *)get_property(of_chosen, "bootargs", &l);
                if (p != NULL && l > 0)
                        strlcpy(cmd_line, p, min(l, COMMAND_LINE_SIZE));
        }
#ifdef CONFIG_CMDLINE
        if (l == 0 || (l == 1 && (*p) == 0))
                strlcpy(cmd_line, CONFIG_CMDLINE, COMMAND_LINE_SIZE);
#endif /* CONFIG_CMDLINE */

        DBG("Command line is: %s\n", cmd_line);

        DBG(" <- unflatten_device_tree()\n");
}


static int __init early_init_dt_scan_cpus(unsigned long node,
                                          const char *uname, int depth, void *data)
{
        u32 *prop;
        unsigned long size;
        char *type = of_get_flat_dt_prop(node, "device_type", &size);

        /* We are scanning "cpu" nodes only */
        if (type == NULL || strcmp(type, "cpu") != 0)
                return 0;

        boot_cpuid = 0;
        boot_cpuid_phys = 0;
        if (initial_boot_params && initial_boot_params->version >= 2) {
                /* version 2 of the kexec param format adds the phys cpuid
                 * of booted proc.
                 */
                boot_cpuid_phys = initial_boot_params->boot_cpuid_phys;
        } else {
                /* Check if it's the boot-cpu, set it's hw index now */
                if (of_get_flat_dt_prop(node,
                                        "linux,boot-cpu", NULL) != NULL) {
                        prop = of_get_flat_dt_prop(node, "reg", NULL);
                        if (prop != NULL)
                                boot_cpuid_phys = *prop;
                }
        }
        set_hard_smp_processor_id(0, boot_cpuid_phys);

#ifdef CONFIG_ALTIVEC
        /* Check if we have a VMX and eventually update CPU features */
        prop = (u32 *)of_get_flat_dt_prop(node, "ibm,vmx", NULL);
        if (prop && (*prop) > 0) {
                cur_cpu_spec->cpu_features |= CPU_FTR_ALTIVEC;
                cur_cpu_spec->cpu_user_features |= PPC_FEATURE_HAS_ALTIVEC;
        }

        /* Same goes for Apple's "altivec" property */
        prop = (u32 *)of_get_flat_dt_prop(node, "altivec", NULL);
        if (prop) {
                cur_cpu_spec->cpu_features |= CPU_FTR_ALTIVEC;
                cur_cpu_spec->cpu_user_features |= PPC_FEATURE_HAS_ALTIVEC;
        }
#endif /* CONFIG_ALTIVEC */

#ifdef CONFIG_PPC_PSERIES
        /*
         * Check for an SMT capable CPU and set the CPU feature. We do
         * this by looking at the size of the ibm,ppc-interrupt-server#s
         * property
         */
        prop = (u32 *)of_get_flat_dt_prop(node, "ibm,ppc-interrupt-server#s",
                                       &size);
        cur_cpu_spec->cpu_features &= ~CPU_FTR_SMT;
        if (prop && ((size / sizeof(u32)) > 1))
                cur_cpu_spec->cpu_features |= CPU_FTR_SMT;
#endif

        return 0;
}

static int __init early_init_dt_scan_chosen(unsigned long node,
                                            const char *uname, int depth, void *data)
{
        u32 *prop;
        unsigned long *lprop;

        DBG("search \"chosen\", depth: %d, uname: %s\n", depth, uname);

        if (depth != 1 ||
            (strcmp(uname, "chosen") != 0 && strcmp(uname, "chosen@0") != 0))
                return 0;

        /* get platform type */
        prop = (u32 *)of_get_flat_dt_prop(node, "linux,platform", NULL);
        if (prop == NULL)
                return 0;
#ifdef CONFIG_PPC_MULTIPLATFORM
        _machine = *prop;
#endif

#ifdef CONFIG_PPC64
        /* check if iommu is forced on or off */
        if (of_get_flat_dt_prop(node, "linux,iommu-off", NULL) != NULL)
                iommu_is_off = 1;
        if (of_get_flat_dt_prop(node, "linux,iommu-force-on", NULL) != NULL)
                iommu_force_on = 1;
#endif

        lprop = of_get_flat_dt_prop(node, "linux,memory-limit", NULL);
        if (lprop)
                memory_limit = *lprop;

#ifdef CONFIG_PPC64
        lprop = of_get_flat_dt_prop(node, "linux,tce-alloc-start", NULL);
        if (lprop)
                tce_alloc_start = *lprop;
        lprop = of_get_flat_dt_prop(node, "linux,tce-alloc-end", NULL);
        if (lprop)
                tce_alloc_end = *lprop;
#endif

#ifdef CONFIG_PPC_RTAS
        /* To help early debugging via the front panel, we retreive a minimal
         * set of RTAS infos now if available
         */
        {
                u64 *basep, *entryp;

                basep = of_get_flat_dt_prop(node, "linux,rtas-base", NULL);
                entryp = of_get_flat_dt_prop(node, "linux,rtas-entry", NULL);
                prop = of_get_flat_dt_prop(node, "linux,rtas-size", NULL);
                if (basep && entryp && prop) {
                        rtas.base = *basep;
                        rtas.entry = *entryp;
                        rtas.size = *prop;
                }
        }
#endif /* CONFIG_PPC_RTAS */

#ifdef CONFIG_KEXEC
       lprop = (u64*)of_get_flat_dt_prop(node, "linux,crashkernel-base", NULL);
       if (lprop)
               crashk_res.start = *lprop;

       lprop = (u64*)of_get_flat_dt_prop(node, "linux,crashkernel-size", NULL);
       if (lprop)
               crashk_res.end = crashk_res.start + *lprop - 1;
#endif

        /* break now */
        return 1;
}

static int __init early_init_dt_scan_root(unsigned long node,
                                          const char *uname, int depth, void *data)
{
        u32 *prop;

        if (depth != 0)
                return 0;

        prop = of_get_flat_dt_prop(node, "#size-cells", NULL);
        dt_root_size_cells = (prop == NULL) ? 1 : *prop;
        DBG("dt_root_size_cells = %x\n", dt_root_size_cells);

        prop = of_get_flat_dt_prop(node, "#address-cells", NULL);
        dt_root_addr_cells = (prop == NULL) ? 2 : *prop;
        DBG("dt_root_addr_cells = %x\n", dt_root_addr_cells);
        
        /* break now */
        return 1;
}

static unsigned long __init dt_mem_next_cell(int s, cell_t **cellp)
{
        cell_t *p = *cellp;
        unsigned long r;

        /* Ignore more than 2 cells */
        while (s > sizeof(unsigned long) / 4) {
                p++;
                s--;
        }
        r = *p++;
#ifdef CONFIG_PPC64
        if (s > 1) {
                r <<= 32;
                r |= *(p++);
                s--;
        }
#endif

        *cellp = p;
        return r;
}


static int __init early_init_dt_scan_memory(unsigned long node,
                                            const char *uname, int depth, void *data)
{
        char *type = of_get_flat_dt_prop(node, "device_type", NULL);
        cell_t *reg, *endp;
        unsigned long l;

        /* We are scanning "memory" nodes only */
        if (type == NULL) {
                /*
                 * The longtrail doesn't have a device_type on the
                 * /memory node, so look for the node called /memory@0.
                 */
                if (depth != 1 || strcmp(uname, "memory@0") != 0)
                        return 0;
        } else if (strcmp(type, "memory") != 0)
                return 0;

        reg = (cell_t *)of_get_flat_dt_prop(node, "linux,usable-memory", &l);
        if (reg == NULL)
                reg = (cell_t *)of_get_flat_dt_prop(node, "reg", &l);
        if (reg == NULL)
                return 0;

        endp = reg + (l / sizeof(cell_t));

        DBG("memory scan node %s, reg size %ld, data: %x %x %x %x,\n",
            uname, l, reg[0], reg[1], reg[2], reg[3]);

        while ((endp - reg) >= (dt_root_addr_cells + dt_root_size_cells)) {
                unsigned long base, size;

                base = dt_mem_next_cell(dt_root_addr_cells, &reg);
                size = dt_mem_next_cell(dt_root_size_cells, &reg);

                if (size == 0)
                        continue;
                DBG(" - %lx ,  %lx\n", base, size);
#ifdef CONFIG_PPC64
                if (iommu_is_off) {
                        if (base >= 0x80000000ul)
                                continue;
                        if ((base + size) > 0x80000000ul)
                                size = 0x80000000ul - base;
                }
#endif
                lmb_add(base, size);
        }
        return 0;
}

static void __init early_reserve_mem(void)
{
        unsigned long base, size;
        unsigned long *reserve_map;

        reserve_map = (unsigned long *)(((unsigned long)initial_boot_params) +
                                        initial_boot_params->off_mem_rsvmap);
        while (1) {
                base = *(reserve_map++);
                size = *(reserve_map++);
                if (size == 0)
                        break;
                DBG("reserving: %lx -> %lx\n", base, size);
                lmb_reserve(base, size);
        }

#if 0
        DBG("memory reserved, lmbs :\n");
        lmb_dump_all();
#endif
}

void __init early_init_devtree(void *params)
{
        DBG(" -> early_init_devtree()\n");

        /* Setup flat device-tree pointer */
        initial_boot_params = params;

        /* Retrieve various informations from the /chosen node of the
         * device-tree, including the platform type, initrd location and
         * size, TCE reserve, and more ...
         */
        of_scan_flat_dt(early_init_dt_scan_chosen, NULL);

        /* Scan memory nodes and rebuild LMBs */
        lmb_init();
        of_scan_flat_dt(early_init_dt_scan_root, NULL);
        of_scan_flat_dt(early_init_dt_scan_memory, NULL);
        lmb_enforce_memory_limit(memory_limit);
        lmb_analyze();

        DBG("Phys. mem: %lx\n", lmb_phys_mem_size());

        /* Reserve LMB regions used by kernel, initrd, dt, etc... */
        lmb_reserve(PHYSICAL_START, __pa(klimit) - PHYSICAL_START);
#ifdef CONFIG_CRASH_DUMP
        lmb_reserve(0, KDUMP_RESERVE_LIMIT);
#endif
        early_reserve_mem();

        DBG("Scanning CPUs ...\n");

        /* Retreive CPU related informations from the flat tree
         * (altivec support, boot CPU ID, ...)
         */
        of_scan_flat_dt(early_init_dt_scan_cpus, NULL);

        DBG(" <- early_init_devtree()\n");
}

#undef printk

int
prom_n_addr_cells(struct device_node* np)
{
        int* ip;
        do {
                if (np->parent)
                        np = np->parent;
                ip = (int *) get_property(np, "#address-cells", NULL);
                if (ip != NULL)
                        return *ip;
        } while (np->parent);
        /* No #address-cells property for the root node, default to 1 */
        return 1;
}
EXPORT_SYMBOL(prom_n_addr_cells);

int
prom_n_size_cells(struct device_node* np)
{
        int* ip;
        do {
                if (np->parent)
                        np = np->parent;
                ip = (int *) get_property(np, "#size-cells", NULL);
                if (ip != NULL)
                        return *ip;
        } while (np->parent);
        /* No #size-cells property for the root node, default to 1 */
        return 1;
}
EXPORT_SYMBOL(prom_n_size_cells);

/**
 * Work out the sense (active-low level / active-high edge)
 * of each interrupt from the device tree.
 */
void __init prom_get_irq_senses(unsigned char *senses, int off, int max)
{
        struct device_node *np;
        int i, j;

        /* default to level-triggered */
        memset(senses, IRQ_SENSE_LEVEL | IRQ_POLARITY_NEGATIVE, max - off);

        for (np = allnodes; np != 0; np = np->allnext) {
                for (j = 0; j < np->n_intrs; j++) {
                        i = np->intrs[j].line;
                        if (i >= off && i < max)
                                senses[i-off] = np->intrs[j].sense;
                }
        }
}

/**
 * Construct and return a list of the device_nodes with a given name.
 */
struct device_node *find_devices(const char *name)
{
        struct device_node *head, **prevp, *np;

        prevp = &head;
        for (np = allnodes; np != 0; np = np->allnext) {
                if (np->name != 0 && strcasecmp(np->name, name) == 0) {
                        *prevp = np;
                        prevp = &np->next;
                }
        }
        *prevp = NULL;
        return head;
}
EXPORT_SYMBOL(find_devices);

/**
 * Construct and return a list of the device_nodes with a given type.
 */
struct device_node *find_type_devices(const char *type)
{
        struct device_node *head, **prevp, *np;

        prevp = &head;
        for (np = allnodes; np != 0; np = np->allnext) {
                if (np->type != 0 && strcasecmp(np->type, type) == 0) {
                        *prevp = np;
                        prevp = &np->next;
                }
        }
        *prevp = NULL;
        return head;
}
EXPORT_SYMBOL(find_type_devices);

/**
 * Returns all nodes linked together
 */
struct device_node *find_all_nodes(void)
{
        struct device_node *head, **prevp, *np;

        prevp = &head;
        for (np = allnodes; np != 0; np = np->allnext) {
                *prevp = np;
                prevp = &np->next;
        }
        *prevp = NULL;
        return head;
}
EXPORT_SYMBOL(find_all_nodes);

/** Checks if the given "compat" string matches one of the strings in
 * the device's "compatible" property
 */
int device_is_compatible(struct device_node *device, const char *compat)
{
        const char* cp;
        int cplen, l;

        cp = (char *) get_property(device, "compatible", &cplen);
        if (cp == NULL)
                return 0;
        while (cplen > 0) {
                if (strncasecmp(cp, compat, strlen(compat)) == 0)
                        return 1;
                l = strlen(cp) + 1;
                cp += l;
                cplen -= l;
        }

        return 0;
}
EXPORT_SYMBOL(device_is_compatible);


/**
 * Indicates whether the root node has a given value in its
 * compatible property.
 */
int machine_is_compatible(const char *compat)
{
        struct device_node *root;
        int rc = 0;

        root = of_find_node_by_path("/");
        if (root) {
                rc = device_is_compatible(root, compat);
                of_node_put(root);
        }
        return rc;
}
EXPORT_SYMBOL(machine_is_compatible);

/**
 * Construct and return a list of the device_nodes with a given type
 * and compatible property.
 */
struct device_node *find_compatible_devices(const char *type,
                                            const char *compat)
{
        struct device_node *head, **prevp, *np;

        prevp = &head;
        for (np = allnodes; np != 0; np = np->allnext) {
                if (type != NULL
                    && !(np->type != 0 && strcasecmp(np->type, type) == 0))
                        continue;
                if (device_is_compatible(np, compat)) {
                        *prevp = np;
                        prevp = &np->next;
                }
        }
        *prevp = NULL;
        return head;
}
EXPORT_SYMBOL(find_compatible_devices);

/**
 * Find the device_node with a given full_name.
 */
struct device_node *find_path_device(const char *path)
{
        struct device_node *np;

        for (np = allnodes; np != 0; np = np->allnext)
                if (np->full_name != 0 && strcasecmp(np->full_name, path) == 0)
                        return np;
        return NULL;
}
EXPORT_SYMBOL(find_path_device);

/*******
 *
 * New implementation of the OF "find" APIs, return a refcounted
 * object, call of_node_put() when done.  The device tree and list
 * are protected by a rw_lock.
 *
 * Note that property management will need some locking as well,
 * this isn't dealt with yet.
 *
 *******/

/**
 *      of_find_node_by_name - Find a node by its "name" property
 *      @from:  The node to start searching from or NULL, the node
 *              you pass will not be searched, only the next one
 *              will; typically, you pass what the previous call
 *              returned. of_node_put() will be called on it
 *      @name:  The name string to match against
 *
 *      Returns a node pointer with refcount incremented, use
 *      of_node_put() on it when done.
 */
struct device_node *of_find_node_by_name(struct device_node *from,
        const char *name)
{
        struct device_node *np;

        read_lock(&devtree_lock);
        np = from ? from->allnext : allnodes;
        for (; np != 0; np = np->allnext)
                if (np->name != 0 && strcasecmp(np->name, name) == 0
                    && of_node_get(np))
                        break;
        if (from)
                of_node_put(from);
        read_unlock(&devtree_lock);
        return np;
}
EXPORT_SYMBOL(of_find_node_by_name);

/**
 *      of_find_node_by_type - Find a node by its "device_type" property
 *      @from:  The node to start searching from or NULL, the node
 *              you pass will not be searched, only the next one
 *              will; typically, you pass what the previous call
 *              returned. of_node_put() will be called on it
 *      @name:  The type string to match against
 *
 *      Returns a node pointer with refcount incremented, use
 *      of_node_put() on it when done.
 */
struct device_node *of_find_node_by_type(struct device_node *from,
        const char *type)
{
        struct device_node *np;

        read_lock(&devtree_lock);
        np = from ? from->allnext : allnodes;
        for (; np != 0; np = np->allnext)
                if (np->type != 0 && strcasecmp(np->type, type) == 0
                    && of_node_get(np))
                        break;
        if (from)
                of_node_put(from);
        read_unlock(&devtree_lock);
        return np;
}
EXPORT_SYMBOL(of_find_node_by_type);

/**
 *      of_find_compatible_node - Find a node based on type and one of the
 *                                tokens in its "compatible" property
 *      @from:          The node to start searching from or NULL, the node
 *                      you pass will not be searched, only the next one
 *                      will; typically, you pass what the previous call
 *                      returned. of_node_put() will be called on it
 *      @type:          The type string to match "device_type" or NULL to ignore
 *      @compatible:    The string to match to one of the tokens in the device
 *                      "compatible" list.
 *
 *      Returns a node pointer with refcount incremented, use
 *      of_node_put() on it when done.
 */
struct device_node *of_find_compatible_node(struct device_node *from,
        const char *type, const char *compatible)
{
        struct device_node *np;

        read_lock(&devtree_lock);
        np = from ? from->allnext : allnodes;
        for (; np != 0; np = np->allnext) {
                if (type != NULL
                    && !(np->type != 0 && strcasecmp(np->type, type) == 0))
                        continue;
                if (device_is_compatible(np, compatible) && of_node_get(np))
                        break;
        }
        if (from)
                of_node_put(from);
        read_unlock(&devtree_lock);
        return np;
}
EXPORT_SYMBOL(of_find_compatible_node);

/**
 *      of_find_node_by_path - Find a node matching a full OF path
 *      @path:  The full path to match
 *
 *      Returns a node pointer with refcount incremented, use
 *      of_node_put() on it when done.
 */
struct device_node *of_find_node_by_path(const char *path)
{
        struct device_node *np = allnodes;

        read_lock(&devtree_lock);
        for (; np != 0; np = np->allnext) {
                if (np->full_name != 0 && strcasecmp(np->full_name, path) == 0
                    && of_node_get(np))
                        break;
        }
        read_unlock(&devtree_lock);
        return np;
}
EXPORT_SYMBOL(of_find_node_by_path);

/**
 *      of_find_node_by_phandle - Find a node given a phandle
 *      @handle:        phandle of the node to find
 *
 *      Returns a node pointer with refcount incremented, use
 *      of_node_put() on it when done.
 */
struct device_node *of_find_node_by_phandle(phandle handle)
{
        struct device_node *np;

        read_lock(&devtree_lock);
        for (np = allnodes; np != 0; np = np->allnext)
                if (np->linux_phandle == handle)
                        break;
        if (np)
                of_node_get(np);
        read_unlock(&devtree_lock);
        return np;
}
EXPORT_SYMBOL(of_find_node_by_phandle);

/**
 *      of_find_all_nodes - Get next node in global list
 *      @prev:  Previous node or NULL to start iteration
 *              of_node_put() will be called on it
 *
 *      Returns a node pointer with refcount incremented, use
 *      of_node_put() on it when done.
 */
struct device_node *of_find_all_nodes(struct device_node *prev)
{
        struct device_node *np;

        read_lock(&devtree_lock);
        np = prev ? prev->allnext : allnodes;
        for (; np != 0; np = np->allnext)
                if (of_node_get(np))
                        break;
        if (prev)
                of_node_put(prev);
        read_unlock(&devtree_lock);
        return np;
}
EXPORT_SYMBOL(of_find_all_nodes);

/**
 *      of_get_parent - Get a node's parent if any
 *      @node:  Node to get parent
 *
 *      Returns a node pointer with refcount incremented, use
 *      of_node_put() on it when done.
 */
struct device_node *of_get_parent(const struct device_node *node)
{
        struct device_node *np;

        if (!node)
                return NULL;

        read_lock(&devtree_lock);
        np = of_node_get(node->parent);
        read_unlock(&devtree_lock);
        return np;
}
EXPORT_SYMBOL(of_get_parent);

/**
 *      of_get_next_child - Iterate a node childs
 *      @node:  parent node
 *      @prev:  previous child of the parent node, or NULL to get first
 *
 *      Returns a node pointer with refcount incremented, use
 *      of_node_put() on it when done.
 */
struct device_node *of_get_next_child(const struct device_node *node,
        struct device_node *prev)
{
        struct device_node *next;

        read_lock(&devtree_lock);
        next = prev ? prev->sibling : node->child;
        for (; next != 0; next = next->sibling)
                if (of_node_get(next))
                        break;
        if (prev)
                of_node_put(prev);
        read_unlock(&devtree_lock);
        return next;
}
EXPORT_SYMBOL(of_get_next_child);

/**
 *      of_node_get - Increment refcount of a node
 *      @node:  Node to inc refcount, NULL is supported to
 *              simplify writing of callers
 *
 *      Returns node.
 */
struct device_node *of_node_get(struct device_node *node)
{
        if (node)
                kref_get(&node->kref);
        return node;
}
EXPORT_SYMBOL(of_node_get);

static inline struct device_node * kref_to_device_node(struct kref *kref)
{
        return container_of(kref, struct device_node, kref);
}

/**
 *      of_node_release - release a dynamically allocated node
 *      @kref:  kref element of the node to be released
 *
 *      In of_node_put() this function is passed to kref_put()
 *      as the destructor.
 */
static void of_node_release(struct kref *kref)
{
        struct device_node *node = kref_to_device_node(kref);
        struct property *prop = node->properties;

        if (!OF_IS_DYNAMIC(node))
                return;
        while (prop) {
                struct property *next = prop->next;
                kfree(prop->name);
                kfree(prop->value);
                kfree(prop);
                prop = next;
        }
        kfree(node->intrs);
        kfree(node->full_name);
        kfree(node->data);
        kfree(node);
}

/**
 *      of_node_put - Decrement refcount of a node
 *      @node:  Node to dec refcount, NULL is supported to
 *              simplify writing of callers
 *
 */
void of_node_put(struct device_node *node)
{
        if (node)
                kref_put(&node->kref, of_node_release);
}
EXPORT_SYMBOL(of_node_put);

/*
 * Plug a device node into the tree and global list.
 */
void of_attach_node(struct device_node *np)
{
        write_lock(&devtree_lock);
        np->sibling = np->parent->child;
        np->allnext = allnodes;
        np->parent->child = np;
        allnodes = np;
        write_unlock(&devtree_lock);
}

/*
 * "Unplug" a node from the device tree.  The caller must hold
 * a reference to the node.  The memory associated with the node
 * is not freed until its refcount goes to zero.
 */
void of_detach_node(const struct device_node *np)
{
        struct device_node *parent;

        write_lock(&devtree_lock);

        parent = np->parent;

        if (allnodes == np)
                allnodes = np->allnext;
        else {
                struct device_node *prev;
                for (prev = allnodes;
                     prev->allnext != np;
                     prev = prev->allnext)
                        ;
                prev->allnext = np->allnext;
        }

        if (parent->child == np)
                parent->child = np->sibling;
        else {
                struct device_node *prevsib;
                for (prevsib = np->parent->child;
                     prevsib->sibling != np;
                     prevsib = prevsib->sibling)
                        ;
                prevsib->sibling = np->sibling;
        }

        write_unlock(&devtree_lock);
}

#ifdef CONFIG_PPC_PSERIES
/*
 * Fix up the uninitialized fields in a new device node:
 * name, type, n_addrs, addrs, n_intrs, intrs, and pci-specific fields
 *
 * A lot of boot-time code is duplicated here, because functions such
 * as finish_node_interrupts, interpret_pci_props, etc. cannot use the
 * slab allocator.
 *
 * This should probably be split up into smaller chunks.
 */

static int of_finish_dynamic_node(struct device_node *node)
{
        struct device_node *parent = of_get_parent(node);
        int err = 0;
        phandle *ibm_phandle;

        node->name = get_property(node, "name", NULL);
        node->type = get_property(node, "device_type", NULL);

        if (!parent) {
                err = -ENODEV;
                goto out;
        }

        /* We don't support that function on PowerMac, at least
         * not yet
         */
        if (_machine == PLATFORM_POWERMAC)
                return -ENODEV;

        /* fix up new node's linux_phandle field */
        if ((ibm_phandle = (unsigned int *)get_property(node,
                                                        "ibm,phandle", NULL)))
                node->linux_phandle = *ibm_phandle;

out:
        of_node_put(parent);
        return err;
}

static int prom_reconfig_notifier(struct notifier_block *nb,
                                  unsigned long action, void *node)
{
        int err;

        switch (action) {
        case PSERIES_RECONFIG_ADD:
                err = of_finish_dynamic_node(node);
                if (!err)
                        finish_node(node, NULL, 0);
                if (err < 0) {
                        printk(KERN_ERR "finish_node returned %d\n", err);
                        err = NOTIFY_BAD;
                }
                break;
        default:
                err = NOTIFY_DONE;
                break;
        }
        return err;
}

static struct notifier_block prom_reconfig_nb = {
        .notifier_call = prom_reconfig_notifier,
        .priority = 10, /* This one needs to run first */
};

static int __init prom_reconfig_setup(void)
{
        return pSeries_reconfig_notifier_register(&prom_reconfig_nb);
}
__initcall(prom_reconfig_setup);
#endif

/*
 * Find a property with a given name for a given node
 * and return the value.
 */
unsigned char *get_property(struct device_node *np, const char *name,
                            int *lenp)
{
        struct property *pp;

        for (pp = np->properties; pp != 0; pp = pp->next)
                if (strcmp(pp->name, name) == 0) {
                        if (lenp != 0)
                                *lenp = pp->length;
                        return pp->value;
                }
        return NULL;
}
EXPORT_SYMBOL(get_property);

/*
 * Add a property to a node
 */
int prom_add_property(struct device_node* np, struct property* prop)
{
        struct property **next;

        prop->next = NULL;      
        write_lock(&devtree_lock);
        next = &np->properties;
        while (*next) {
                if (strcmp(prop->name, (*next)->name) == 0) {
                        /* duplicate ! don't insert it */
                        write_unlock(&devtree_lock);
                        return -1;
                }
                next = &(*next)->next;
        }
        *next = prop;
        write_unlock(&devtree_lock);

#ifdef CONFIG_PROC_DEVICETREE
        /* try to add to proc as well if it was initialized */
        if (np->pde)
                proc_device_tree_add_prop(np->pde, prop);
#endif /* CONFIG_PROC_DEVICETREE */

        return 0;
}