[PATCH] flattened device tree changes

This patch updates the format of the flattened device-tree passed
between the boot trampoline and the kernel to support a more compact
representation, for use by embedded systems mostly.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>

3 files changed, 209 insertions, 68 deletions

diff --git a/arch/ppc64/kernel/prom.c b/arch/ppc64/kernel/prom.c
index 5aca01ddd81f..255c39ae1b48 100644
--- a/arch/ppc64/kernel/prom.c
+++ b/arch/ppc64/kernel/prom.c
@@ -625,8 +625,8 @@ void __init finish_device_tree(void)
 
 static inline char *find_flat_dt_string(u32 offset)
 {
-        return ((char *)initial_boot_params) + initial_boot_params->off_dt_strings
-                + offset;
+        return ((char *)initial_boot_params) +
+                initial_boot_params->off_dt_strings + offset;
 }
 
 /**
@@ -635,26 +635,33 @@ static inline char *find_flat_dt_string(u32 offset)
  * unflatten the tree
  */
 static int __init scan_flat_dt(int (*it)(unsigned long node,
-                                         const char *full_path, void *data),
+                                         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)
+                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;
-                        p = _ALIGN(p, sz >= 8 ? 8 : 4);
+                        if (initial_boot_params->version < 0x10)
+                                p = _ALIGN(p, sz >= 8 ? 8 : 4);
                         p += sz;
                         p = _ALIGN(p, 4);
                         continue;
@@ -664,9 +671,18 @@ static int __init scan_flat_dt(int (*it)(unsigned long node,
                                " device tree !\n", tag);
                         return -EINVAL;
                 }
+                depth++;
                 pathp = (char *)p;
                 p = _ALIGN(p + strlen(pathp) + 1, 4);
-                rc = it(p, pathp, data);
+                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);
@@ -689,17 +705,21 @@ static void* __init get_flat_dt_prop(unsigned long node, const char *name,
                 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;
-                p = _ALIGN(p, sz >= 8 ? 8 : 4);
+                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");
+                        printk(KERN_WARNING "Can't find property index"
+                               " name !\n");
                         return NULL;
                 }
                 if (strcmp(name, nstr) == 0) {
@@ -713,7 +733,7 @@ static void* __init get_flat_dt_prop(unsigned long node, const char *name,
 }
 
 static void *__init unflatten_dt_alloc(unsigned long *mem, unsigned long size,
-                                               unsigned long align)
+                                       unsigned long align)
 {
         void *res;
 
@@ -727,13 +747,16 @@ static void *__init unflatten_dt_alloc(unsigned long *mem, unsigned long size,
 static unsigned long __init unflatten_dt_node(unsigned long mem,
                                               unsigned long *p,
                                               struct device_node *dad,
-                                              struct device_node ***allnextpp)
+                                              struct device_node ***allnextpp,
+                                              unsigned long fpsize)
 {
         struct device_node *np;
         struct property *pp, **prev_pp = NULL;
         char *pathp;
         u32 tag;
-        unsigned int l;
+        unsigned int l, allocl;
+        int has_name = 0;
+        int new_format = 0;
 
         tag = *((u32 *)(*p));
         if (tag != OF_DT_BEGIN_NODE) {
@@ -742,21 +765,62 @@ static unsigned long __init unflatten_dt_node(unsigned long mem,
         }
         *p += 4;
         pathp = (char *)*p;
-        l = strlen(pathp) + 1;
+        l = allocl = strlen(pathp) + 1;
         *p = _ALIGN(*p + l, 4);
 
-        np = unflatten_dt_alloc(&mem, sizeof(struct device_node) + l,
+        /* 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);
-                memcpy(np->full_name, pathp, l);
+                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'. */
+                        /* we temporarily use the next field as `last_child'*/
                         if (dad->next == 0)
                                 dad->child = np;
                         else
@@ -770,18 +834,26 @@ static unsigned long __init unflatten_dt_node(unsigned long mem,
                 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 = _ALIGN((*p) + 8, sz >= 8 ? 8 : 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));
@@ -801,6 +873,36 @@ static unsigned long __init unflatten_dt_node(unsigned long mem,
                 }
                 *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);
@@ -812,7 +914,7 @@ static unsigned long __init unflatten_dt_node(unsigned long mem,
                         np->type = "<NULL>";
         }
         while (tag == OF_DT_BEGIN_NODE) {
-                mem = unflatten_dt_node(mem, p, np, allnextpp);
+                mem = unflatten_dt_node(mem, p, np, allnextpp, fpsize);
                 tag = *((u32 *)(*p));
         }
         if (tag != OF_DT_END_NODE) {
@@ -842,21 +944,27 @@ void __init unflatten_device_tree(void)
         /* 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);
+        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 = (unsigned long)abs_to_virt(lmb_alloc(size,
+        mem = (unsigned long)abs_to_virt(lmb_alloc(size + 4,
                                                    __alignof__(struct device_node)));
+        ((u32 *)mem)[size / 4] = 0xdeadbeef;
+
         DBG("  unflattening...\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);
+        unflatten_dt_node(mem, &start, NULL, &allnextp, 0);
         if (*((u32 *)start) != OF_DT_END)
-                printk(KERN_WARNING "Weird tag at end of tree: %x\n", *((u32 *)start));
+                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 */
@@ -880,7 +988,7 @@ void __init unflatten_device_tree(void)
 
 
 static int __init early_init_dt_scan_cpus(unsigned long node,
-                                          const char *full_path, void *data)
+                                          const char *uname, int depth, void *data)
 {
         char *type = get_flat_dt_prop(node, "device_type", NULL);
         u32 *prop;
@@ -947,13 +1055,15 @@ static int __init early_init_dt_scan_cpus(unsigned long node,
 }
 
 static int __init early_init_dt_scan_chosen(unsigned long node,
-                                            const char *full_path, void *data)
+                                            const char *uname, int depth, void *data)
 {
         u32 *prop;
         u64 *prop64;
         extern unsigned long memory_limit, tce_alloc_start, tce_alloc_end;
 
-        if (strcmp(full_path, "/chosen") != 0)
+        DBG("search \"chosen\", depth: %d, uname: %s\n", depth, uname);
+
+        if (depth != 1 || strcmp(uname, "chosen") != 0)
                 return 0;
 
         /* get platform type */
@@ -1003,18 +1113,20 @@ static int __init early_init_dt_scan_chosen(unsigned long node,
 }
 
 static int __init early_init_dt_scan_root(unsigned long node,
-                                          const char *full_path, void *data)
+                                          const char *uname, int depth, void *data)
 {
         u32 *prop;
 
-        if (strcmp(full_path, "/") != 0)
+        if (depth != 0)
                 return 0;
 
         prop = (u32 *)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 = (u32 *)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;
@@ -1042,7 +1154,7 @@ static unsigned long __init dt_mem_next_cell(int s, cell_t **cellp)
 
 
 static int __init early_init_dt_scan_memory(unsigned long node,
-                                            const char *full_path, void *data)
+                                            const char *uname, int depth, void *data)
 {
         char *type = get_flat_dt_prop(node, "device_type", NULL);
         cell_t *reg, *endp;
@@ -1058,7 +1170,9 @@ static int __init early_init_dt_scan_memory(unsigned long node,
 
         endp = reg + (l / sizeof(cell_t));
 
-        DBG("memory scan node %s ...\n", full_path);
+        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;
 
@@ -1469,10 +1583,11 @@ 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)
+        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;
 }
diff --git a/arch/ppc64/kernel/prom_init.c b/arch/ppc64/kernel/prom_init.c
index dbbe6c79d8da..adcf972711fc 100644
--- a/arch/ppc64/kernel/prom_init.c
+++ b/arch/ppc64/kernel/prom_init.c
@@ -1534,7 +1534,8 @@ static unsigned long __init dt_find_string(char *str)
  */
 #define MAX_PROPERTY_NAME 64
 
-static void __init scan_dt_build_strings(phandle node, unsigned long *mem_start,
+static void __init scan_dt_build_strings(phandle node,
+                                         unsigned long *mem_start,
                                          unsigned long *mem_end)
 {
         unsigned long offset = reloc_offset();
@@ -1547,16 +1548,21 @@ static void __init scan_dt_build_strings(phandle node, unsigned long *mem_start,
         /* get and store all property names */
         prev_name = RELOC("");
         for (;;) {
-                int rc;
-
                 /* 64 is max len of name including nul. */
                 namep = make_room(mem_start, mem_end, MAX_PROPERTY_NAME, 1);
-                rc = call_prom("nextprop", 3, 1, node, prev_name, namep);
-                if (rc != 1) {
+                if (call_prom("nextprop", 3, 1, node, prev_name, namep) != 1) {
                         /* No more nodes: unwind alloc */
                         *mem_start = (unsigned long)namep;
                         break;
                 }
+
+                /* skip "name" */
+                if (strcmp(namep, RELOC("name")) == 0) {
+                        *mem_start = (unsigned long)namep;
+                        prev_name = RELOC("name");
+                        continue;
+                }
+                /* get/create string entry */
                 soff = dt_find_string(namep);
                 if (soff != 0) {
                         *mem_start = (unsigned long)namep;
@@ -1571,7 +1577,7 @@ static void __init scan_dt_build_strings(phandle node, unsigned long *mem_start,
 
         /* do all our children */
         child = call_prom("child", 1, 1, node);
-        while (child != (phandle)0) {
+        while (child != 0) {
                 scan_dt_build_strings(child, mem_start, mem_end);
                 child = call_prom("peer", 1, 1, child);
         }
@@ -1580,16 +1586,13 @@ static void __init scan_dt_build_strings(phandle node, unsigned long *mem_start,
 static void __init scan_dt_build_struct(phandle node, unsigned long *mem_start,
                                         unsigned long *mem_end)
 {
-        int l, align;
         phandle child;
-        char *namep, *prev_name, *sstart, *p, *ep;
+        char *namep, *prev_name, *sstart, *p, *ep, *lp, *path;
         unsigned long soff;
         unsigned char *valp;
         unsigned long offset = reloc_offset();
-        char pname[MAX_PROPERTY_NAME];
-        char *path;
-
-        path = RELOC(prom_scratch);
+        static char pname[MAX_PROPERTY_NAME];
+        int l;
 
         dt_push_token(OF_DT_BEGIN_NODE, mem_start, mem_end);
 
@@ -1599,23 +1602,33 @@ static void __init scan_dt_build_struct(phandle node, unsigned long *mem_start,
                       namep, *mem_end - *mem_start);
         if (l >= 0) {
                 /* Didn't fit?  Get more room. */
-                if (l+1 > *mem_end - *mem_start) {
+                if ((l+1) > (*mem_end - *mem_start)) {
                         namep = make_room(mem_start, mem_end, l+1, 1);
                         call_prom("package-to-path", 3, 1, node, namep, l);
                 }
                 namep[l] = '\0';
+
                 /* Fixup an Apple bug where they have bogus \0 chars in the
                  * middle of the path in some properties
                  */
                 for (p = namep, ep = namep + l; p < ep; p++)
                         if (*p == '\0') {
                                 memmove(p, p+1, ep - p);
-                                ep--; l--;
+                                ep--; l--; p--;
                         }
-                *mem_start = _ALIGN(((unsigned long) namep) + strlen(namep) + 1, 4);
+
+                /* now try to extract the unit name in that mess */
+                for (p = namep, lp = NULL; *p; p++)
+                        if (*p == '/')
+                                lp = p + 1;
+                if (lp != NULL)
+                        memmove(namep, lp, strlen(lp) + 1);
+                *mem_start = _ALIGN(((unsigned long) namep) +
+                                    strlen(namep) + 1, 4);
         }
 
         /* get it again for debugging */
+        path = RELOC(prom_scratch);
         memset(path, 0, PROM_SCRATCH_SIZE);
         call_prom("package-to-path", 3, 1, node, path, PROM_SCRATCH_SIZE-1);
 
@@ -1623,23 +1636,27 @@ static void __init scan_dt_build_struct(phandle node, unsigned long *mem_start,
         prev_name = RELOC("");
         sstart = (char *)RELOC(dt_string_start);
         for (;;) {
-                int rc;
-
-                rc = call_prom("nextprop", 3, 1, node, prev_name, pname);
-                if (rc != 1)
+                if (call_prom("nextprop", 3, 1, node, prev_name,
+                              RELOC(pname)) != 1)
                         break;
 
+                /* skip "name" */
+                if (strcmp(RELOC(pname), RELOC("name")) == 0) {
+                        prev_name = RELOC("name");
+                        continue;
+                }
+
                 /* find string offset */
-                soff = dt_find_string(pname);
+                soff = dt_find_string(RELOC(pname));
                 if (soff == 0) {
-                        prom_printf("WARNING: Can't find string index for <%s>, node %s\n",
-                                    pname, path);
+                        prom_printf("WARNING: Can't find string index for"
+                                    " <%s>, node %s\n", RELOC(pname), path);
                         break;
                 }
                 prev_name = sstart + soff;
 
                 /* get length */
-                l = call_prom("getproplen", 2, 1, node, pname);
+                l = call_prom("getproplen", 2, 1, node, RELOC(pname));
 
                 /* sanity checks */
                 if (l == PROM_ERROR)
@@ -1648,7 +1665,7 @@ static void __init scan_dt_build_struct(phandle node, unsigned long *mem_start,
                         prom_printf("WARNING: ignoring large property ");
                         /* It seems OF doesn't null-terminate the path :-( */
                         prom_printf("[%s] ", path);
-                        prom_printf("%s length 0x%x\n", pname, l);
+                        prom_printf("%s length 0x%x\n", RELOC(pname), l);
                         continue;
                 }
 
@@ -1658,17 +1675,16 @@ static void __init scan_dt_build_struct(phandle node, unsigned long *mem_start,
                 dt_push_token(soff, mem_start, mem_end);
 
                 /* push property content */
-                align = (l >= 8) ? 8 : 4;
-                valp = make_room(mem_start, mem_end, l, align);
-                call_prom("getprop", 4, 1, node, pname, valp, l);
+                valp = make_room(mem_start, mem_end, l, 4);
+                call_prom("getprop", 4, 1, node, RELOC(pname), valp, l);
                 *mem_start = _ALIGN(*mem_start, 4);
         }
 
         /* Add a "linux,phandle" property. */
         soff = dt_find_string(RELOC("linux,phandle"));
         if (soff == 0)
-                prom_printf("WARNING: Can't find string index for <linux-phandle>"
-                            " node %s\n", path);
+                prom_printf("WARNING: Can't find string index for"
+                            " <linux-phandle> node %s\n", path);
         else {
                 dt_push_token(OF_DT_PROP, mem_start, mem_end);
                 dt_push_token(4, mem_start, mem_end);
@@ -1679,7 +1695,7 @@ static void __init scan_dt_build_struct(phandle node, unsigned long *mem_start,
 
         /* do all our children */
         child = call_prom("child", 1, 1, node);
-        while (child != (phandle)0) {
+        while (child != 0) {
                 scan_dt_build_struct(child, mem_start, mem_end);
                 child = call_prom("peer", 1, 1, child);
         }
@@ -1718,7 +1734,8 @@ static void __init flatten_device_tree(void)
 
         /* Build header and make room for mem rsv map */ 
         mem_start = _ALIGN(mem_start, 4);
-        hdr = make_room(&mem_start, &mem_end, sizeof(struct boot_param_header), 4);
+        hdr = make_room(&mem_start, &mem_end,
+                        sizeof(struct boot_param_header), 4);
         RELOC(dt_header_start) = (unsigned long)hdr;
         rsvmap = make_room(&mem_start, &mem_end, sizeof(mem_reserve_map), 8);
 
@@ -1731,11 +1748,11 @@ static void __init flatten_device_tree(void)
         namep = make_room(&mem_start, &mem_end, 16, 1);
         strcpy(namep, RELOC("linux,phandle"));
         mem_start = (unsigned long)namep + strlen(namep) + 1;
-        RELOC(dt_string_end) = mem_start;
 
         /* Build string array */
         prom_printf("Building dt strings...\n"); 
         scan_dt_build_strings(root, &mem_start, &mem_end);
+        RELOC(dt_string_end) = mem_start;
 
         /* Build structure */
         mem_start = PAGE_ALIGN(mem_start);
@@ -1750,9 +1767,11 @@ static void __init flatten_device_tree(void)
         hdr->totalsize = RELOC(dt_struct_end) - RELOC(dt_header_start);
         hdr->off_dt_struct = RELOC(dt_struct_start) - RELOC(dt_header_start);
         hdr->off_dt_strings = RELOC(dt_string_start) - RELOC(dt_header_start);
+        hdr->dt_strings_size = RELOC(dt_string_end) - RELOC(dt_string_start);
         hdr->off_mem_rsvmap = ((unsigned long)rsvmap) - RELOC(dt_header_start);
         hdr->version = OF_DT_VERSION;
-        hdr->last_comp_version = 1;
+        /* Version 16 is not backward compatible */
+        hdr->last_comp_version = 0x10;
 
         /* Reserve the whole thing and copy the reserve map in, we
          * also bump mem_reserve_cnt to cause further reservations to
@@ -1808,6 +1827,9 @@ static void __init fixup_device_tree(void)
         /* does it need fixup ? */
         if (prom_getproplen(i2c, "interrupts") > 0)
                 return;
+
+        prom_printf("fixing up bogus interrupts for u3 i2c...\n");
+
         /* interrupt on this revision of u3 is number 0 and level */
         interrupts[0] = 0;
         interrupts[1] = 1;
diff --git a/include/asm-ppc64/prom.h b/include/asm-ppc64/prom.h
index 04b1a84f7ca3..dc5330b39509 100644
--- a/include/asm-ppc64/prom.h
+++ b/include/asm-ppc64/prom.h
@@ -22,13 +22,15 @@
 #define RELOC(x)        (*PTRRELOC(&(x)))
 
 /* Definitions used by the flattened device tree */
-#define OF_DT_HEADER            0xd00dfeed      /* 4: version, 4: total size */
-#define OF_DT_BEGIN_NODE        0x1             /* Start node: full name */
+#define OF_DT_HEADER            0xd00dfeed      /* marker */
+#define OF_DT_BEGIN_NODE        0x1             /* Start of node, full name */
 #define OF_DT_END_NODE          0x2             /* End node */
-#define OF_DT_PROP              0x3             /* Property: name off, size, content */
+#define OF_DT_PROP              0x3             /* Property: name off, size,
+                                                 * content */
+#define OF_DT_NOP               0x4             /* nop */
 #define OF_DT_END               0x9
 
-#define OF_DT_VERSION           1
+#define OF_DT_VERSION           0x10
 
 /*
  * This is what gets passed to the kernel by prom_init or kexec
@@ -54,7 +56,9 @@ struct boot_param_header
         u32     version;                /* format version */
         u32     last_comp_version;      /* last compatible version */
         /* version 2 fields below */
-        u32     boot_cpuid_phys;        /* Which physical CPU id we're booting on */
+        u32     boot_cpuid_phys;        /* Physical CPU id we're booting on */
+        /* version 3 fields below */
+        u32     dt_strings_size;        /* size of the DT strings block */
 };