[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>

1 files changed, 55 insertions, 33 deletions

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;