Booting the Linux/ppc64 kernel without Open Firmware HOWTO (v3)
Benjamin Herrenschmidt
benh at kernel.crashing.org
Tue May 24 14:35:51 EST 2005
On Tue, 2005-05-24 at 14:34 +1000, Benjamin Herrenschmidt wrote:
> Hi !
>
> Here's revision 3 of the spec for the booting of linux/ppc64 with a
> flattened device-tree. The novelty is that I added a new more compact
> format. A followup mail will have the kernel patches to add support to
> this new format, I'll submit them upstream for after 2.6.12 I think.
>
> David and I are still working on sample code & tools. We have a
> prototype of a device-tree "compiler" that can build the flattened blob
> from a textual representation. We'll release that soon, hopefully this
> week.
And here is the patch:
Index: linux-work/arch/ppc64/kernel/prom_init.c
===================================================================
--- linux-work.orig/arch/ppc64/kernel/prom_init.c 2005-05-23 18:15:28.000000000 +1000
+++ linux-work/arch/ppc64/kernel/prom_init.c 2005-05-24 14:10:00.000000000 +1000
@@ -1514,7 +1514,14 @@
return 0;
}
-static void __init scan_dt_build_strings(phandle node, unsigned long *mem_start,
+/*
+ * The Open Firmware 1275 specification states properties must be 31 bytes or
+ * less, however not all firmwares obey this. Make it 64 bytes to be safe.
+ */
+#define MAX_PROPERTY_NAME 64
+
+static void __init scan_dt_build_strings(phandle node,
+ unsigned long *mem_start,
unsigned long *mem_end)
{
unsigned long offset = reloc_offset();
@@ -1527,14 +1534,19 @@
/* get and store all property names */
prev_name = RELOC("");
for (;;) {
-
- /* 32 is max len of name including nul. */
- namep = make_room(mem_start, mem_end, 32, 1);
+ namep = make_room(mem_start, mem_end, MAX_PROPERTY_NAME, 1);
if (call_prom("nextprop", 3, 1, node, prev_name, namep) <= 0) {
/* 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;
+ }
soff = dt_find_string(namep);
if (soff != 0) {
*mem_start = (unsigned long)namep;
@@ -1555,12 +1567,6 @@
}
}
-/*
- * The Open Firmware 1275 specification states properties must be 31 bytes or
- * less, however not all firmwares obey this. Make it 64 bytes to be safe.
- */
-#define MAX_PROPERTY_NAME 64
-
static void __init scan_dt_build_struct(phandle node, unsigned long *mem_start,
unsigned long *mem_end)
{
@@ -1570,10 +1576,8 @@
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] __initdata;
+ char *path, *p, *lp;
dt_push_token(OF_DT_BEGIN_NODE, mem_start, mem_end);
@@ -1588,10 +1592,20 @@
call_prom("package-to-path", 3, 1, node, namep, l);
}
namep[l] = '\0';
- *mem_start = _ALIGN(((unsigned long) namep) + strlen(namep) + 1, 4);
+ /* now try to find the unit name in that mess */
+ p = namep;
+ lp = NULL;
+ for (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);
@@ -1599,20 +1613,24 @@
prev_name = RELOC("");
sstart = (char *)RELOC(dt_string_start);
for (;;) {
- if (call_prom("nextprop", 3, 1, node, prev_name, pname) <= 0)
+ if (call_prom("nextprop", 3, 1, node, prev_name,
+ RELOC(pname)) <= 0)
break;
-
+ 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 < 0)
@@ -1621,7 +1639,7 @@
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;
}
@@ -1633,15 +1651,15 @@
/* 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);
+ 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);
@@ -1691,7 +1709,8 @@
/* 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);
@@ -1704,11 +1723,11 @@
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);
@@ -1723,9 +1742,11 @@
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
Index: linux-work/arch/ppc64/kernel/setup.c
===================================================================
--- linux-work.orig/arch/ppc64/kernel/setup.c 2005-05-23 18:15:28.000000000 +1000
+++ linux-work/arch/ppc64/kernel/setup.c 2005-05-23 18:16:09.000000000 +1000
@@ -10,7 +10,7 @@
* 2 of the License, or (at your option) any later version.
*/
-#undef DEBUG
+#define DEBUG
#include <linux/config.h>
#include <linux/module.h>
Index: linux-work/arch/ppc64/kernel/prom.c
===================================================================
--- linux-work.orig/arch/ppc64/kernel/prom.c 2005-05-23 18:15:28.000000000 +1000
+++ linux-work/arch/ppc64/kernel/prom.c 2005-05-24 14:12:35.000000000 +1000
@@ -15,7 +15,7 @@
* 2 of the License, or (at your option) any later version.
*/
-#undef DEBUG
+#define DEBUG
#include <stdarg.h>
#include <linux/config.h>
@@ -635,20 +635,23 @@
* 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_END)
break;
if (tag == OF_DT_PROP) {
@@ -664,9 +667,18 @@
" 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);
@@ -727,13 +739,16 @@
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 +757,56 @@
}
*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);
+ 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
@@ -782,6 +832,8 @@
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 +853,29 @@
}
*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;
+ int sz;
+
+ DBG("no name, building from %s\n", p);
+ while (*p && (*p) != '@')
+ p++;
+ sz = (p - pathp) + 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, pathp, sz - 1);
+ ((char *)pp->value)[sz - 1] = 0;
+ }
+ }
if (allnextpp) {
*prev_pp = NULL;
np->name = get_property(np, "name", NULL);
@@ -812,7 +887,7 @@
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) {
@@ -842,7 +917,7 @@
/* 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);
DBG(" size is %lx, allocating...\n", size);
@@ -854,7 +929,7 @@
/* 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));
*allnextp = NULL;
@@ -880,7 +955,7 @@
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;
@@ -933,13 +1008,15 @@
}
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 */
@@ -989,18 +1066,20 @@
}
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;
@@ -1028,7 +1107,7 @@
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;
@@ -1044,7 +1123,9 @@
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;
@@ -1455,10 +1536,11 @@
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;
}
Index: linux-work/include/asm-ppc64/prom.h
===================================================================
--- linux-work.orig/include/asm-ppc64/prom.h 2005-05-23 18:15:28.000000000 +1000
+++ linux-work/include/asm-ppc64/prom.h 2005-05-23 18:16:09.000000000 +1000
@@ -22,13 +22,14 @@
#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_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 +55,9 @@
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 */
};
@@ -169,17 +172,20 @@
*/
#define HAVE_ARCH_DEVTREE_FIXUPS
-static inline void set_node_proc_entry(struct device_node *dn, struct proc_dir_entry *de)
+static inline void set_node_proc_entry(struct device_node *dn,
+ struct proc_dir_entry *de)
{
dn->pde = de;
}
-static void inline set_node_name_link(struct device_node *dn, struct proc_dir_entry *de)
+static void inline set_node_name_link(struct device_node *dn,
+ struct proc_dir_entry *de)
{
dn->name_link = de;
}
-static void inline set_node_addr_link(struct device_node *dn, struct proc_dir_entry *de)
+static void inline set_node_addr_link(struct device_node *dn,
+ struct proc_dir_entry *de)
{
dn->addr_link = de;
}
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