Commit 34153fa3 authored by Benjamin Herrenschmidt's avatar Benjamin Herrenschmidt Committed by Paul Mackerras
Browse files

[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: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: default avatarPaul Mackerras <paulus@samba.org>
parent e28f7faf

arch/ppc64/kernel/prom.c

+145 −30
Original line number Diff line number Diff line
@@ -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;

}



/**
@@ -635,25 +635,32 @@ 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;

			if (initial_boot_params->version < 0x10)

				p = _ALIGN(p, sz >= 8 ? 8 : 4);

			p += sz;

			p = _ALIGN(p, 4);
@@ -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;

		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) {
@@ -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);

		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;

}

arch/ppc64/kernel/prom_init.c

+55 −33
Original line number Diff line number Diff line
@@ -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;

include/asm-ppc64/prom.h

+9 −5
Original line number Diff line number Diff line
@@ -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 */

};

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