- 根目录:
- drivers
- of
- fdt.c
/*
* Functions for working with the Flattened Device Tree data format
*
* Copyright 2009 Benjamin Herrenschmidt, IBM Corp
* benh@kernel.crashing.org
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* version 2 as published by the Free Software Foundation.
*/
#include <linux/kernel.h>
#include <linux/initrd.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_fdt.h>
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/slab.h>
#include <asm/setup.h> /* for COMMAND_LINE_SIZE */
#ifdef CONFIG_PPC
#include <asm/machdep.h>
#endif /* CONFIG_PPC */
#include <asm/page.h>
char *of_fdt_get_string(struct boot_param_header *blob, u32 offset)
{
return ((char *)blob) +
be32_to_cpu(blob->off_dt_strings) + offset;
}
/**
* of_fdt_get_property - Given a node in the given flat blob, return
* the property ptr
*/
void *of_fdt_get_property(struct boot_param_header *blob,
unsigned long node, const char *name,
unsigned long *size)
{
unsigned long p = node;
do {
u32 tag = be32_to_cpup((__be32 *)p);
u32 sz, noff;
const char *nstr;
p += 4;
if (tag == OF_DT_NOP)
continue;
if (tag != OF_DT_PROP)
return NULL;
sz = be32_to_cpup((__be32 *)p);
noff = be32_to_cpup((__be32 *)(p + 4));
p += 8;
if (be32_to_cpu(blob->version) < 0x10)
p = ALIGN(p, sz >= 8 ? 8 : 4);
nstr = of_fdt_get_string(blob, noff);
if (nstr == NULL) {
pr_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);
}
/**
* of_fdt_is_compatible - Return true if given node from the given blob has
* compat in its compatible list
* @blob: A device tree blob
* @node: node to test
* @compat: compatible string to compare with compatible list.
*
* On match, returns a non-zero value with smaller values returned for more
* specific compatible values.
*/
int of_fdt_is_compatible(struct boot_param_header *blob,
unsigned long node, const char *compat)
{
const char *cp;
unsigned long cplen, l, score = 0;
cp = of_fdt_get_property(blob, node, "compatible", &cplen);
if (cp == NULL)
return 0;
while (cplen > 0) {
score++;
if (of_compat_cmp(cp, compat, strlen(compat)) == 0)
return score;
l = strlen(cp) + 1;
cp += l;
cplen -= l;
}
return 0;
}
/**
* of_fdt_match - Return true if node matches a list of compatible values
*/
int of_fdt_match(struct boot_param_header *blob, unsigned long node,
const char *const *compat)
{
unsigned int tmp, score = 0;
if (!compat)
return 0;
while (*compat) {
tmp = of_fdt_is_compatible(blob, node, *compat);
if (tmp && (score == 0 || (tmp < score)))
score = tmp;
compat++;
}
return score;
}
static void *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;
}
/**
* unflatten_dt_node - Alloc and populate a device_node from the flat tree
* @blob: The parent device tree blob
* @mem: Memory chunk to use for allocating device nodes and properties
* @p: pointer to node in flat tree
* @dad: Parent struct device_node
* @allnextpp: pointer to ->allnext from last allocated device_node
* @fpsize: Size of the node path up at the current depth.
*/
static unsigned long unflatten_dt_node(struct boot_param_header *blob,
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 = be32_to_cpup((__be32 *)(*p));
if (tag != OF_DT_BEGIN_NODE) {
pr_err("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 *fn = np->full_name;
/* rebuild full path for new format */
if (dad && dad->parent) {
strcpy(fn, dad->full_name);
#ifdef DEBUG
if ((strlen(fn) + l + 1) != allocl) {
pr_debug("%s: p: %d, l: %d, a: %d\n",
pathp, (int)strlen(fn),
l, allocl);
}
#endif
fn += strlen(fn);
}
*(fn++) = '/';
memcpy(fn, 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 == NULL)
dad->child = np;
else
dad->next->sibling = np;
dad->next = np;
}
kref_init(&np->kref);
}
/* process properties */
while (1) {
u32 sz, noff;
char *pname;
tag = be32_to_cpup((__be32 *)(*p));
if (tag == OF_DT_NOP) {
*p += 4;
continue;
}
if (tag != OF_DT_PROP)
break;
*p += 4;
sz = be32_to_cpup((__be32 *)(*p));
noff = be32_to_cpup((__be32 *)((*p) + 4));
*p += 8;
if (be32_to_cpu(blob->version) < 0x10)
*p = ALIGN(*p, sz >= 8 ? 8 : 4);
pname = of_fdt_get_string(blob, noff);
if (pname == NULL) {
pr_info("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) {
/* We accept flattened tree phandles either in
* ePAPR-style "phandle" properties, or the
* legacy "linux,phandle" properties. If both
* appear and have different values, things
* will get weird. Don't do that. */
if ((strcmp(pname, "phandle") == 0) ||
(strcmp(pname, "linux,phandle") == 0)) {
if (np->phandle == 0)
np->phandle = be32_to_cpup((__be32*)*p);
}
/* And we process the "ibm,phandle" property
* used in pSeries dynamic device tree
* stuff */
if (strcmp(pname, "ibm,phandle") == 0)
np->phandle = be32_to_cpup((__be32 *)*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 *p1 = pathp, *ps = pathp, *pa = NULL;
int sz;
while (*p1) {
if ((*p1) == '@')
pa = p1;
if ((*p1) == '/')
ps = p1 + 1;
p1++;
}
if (pa < ps)
pa = p1;
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 = pp + 1;
*prev_pp = pp;
prev_pp = &pp->next;
memcpy(pp->value, ps, sz - 1);
((char *)pp->value)[sz - 1] = 0;
pr_debug("fixed up name for %s -> %s\n", pathp,
(char *)pp->value);
}
}
if (allnextpp) {
*prev_pp = NULL;
np->name = of_get_property(np, "name", NULL);
np->type = of_get_property(np, "device_type", NULL);
if (!np->name)
np->name = "<NULL>";
if (!np->type)
np->type = "<NULL>";
}
while (tag == OF_DT_BEGIN_NODE || tag == OF_DT_NOP) {
if (tag == OF_DT_NOP)
*p += 4;
else
mem = unflatten_dt_node(blob, mem, p, np, allnextpp,
fpsize);
tag = be32_to_cpup((__be32 *)(*p));
}
if (tag != OF_DT_END_NODE) {
pr_err("Weird tag at end of node: %x\n", tag);
return mem;
}
*p += 4;
return mem;
}
/**
* __unflatten_device_tree - create tree of device_nodes from flat blob
*
* unflattens a device-tree, 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.
* @blob: The blob to expand
* @mynodes: The device_node tree created by the call
* @dt_alloc: An allocator that provides a virtual address to memory
* for the resulting tree
*/
static void __unflatten_device_tree(struct boot_param_header *blob,
struct device_node **mynodes,
void * (*dt_alloc)(u64 size, u64 align))
{
unsigned long start, mem, size;
struct device_node **allnextp = mynodes;
pr_debug(" -> unflatten_device_tree()\n");
if (!blob) {
pr_debug("No device tree pointer\n");
return;
}
pr_debug("Unflattening device tree:\n");
pr_debug("magic: %08x\n", be32_to_cpu(blob->magic));
pr_debug("size: %08x\n", be32_to_cpu(blob->totalsize));
pr_debug("version: %08x\n", be32_to_cpu(blob->version));
if (be32_to_cpu(blob->magic) != OF_DT_HEADER) {
pr_err("Invalid device tree blob header\n");
return;
}
/* First pass, scan for size */
start = ((unsigned long)blob) +
be32_to_cpu(blob->off_dt_struct);
size = unflatten_dt_node(blob, 0, &start, NULL, NULL, 0);
size = (size | 3) + 1;
pr_debug(" size is %lx, allocating...\n", size);
/* Allocate memory for the expanded device tree */
mem = (unsigned long)
dt_alloc(size + 4, __alignof__(struct device_node));
memset((void *)mem, 0, size);
((__be32 *)mem)[size / 4] = cpu_to_be32(0xdeadbeef);
pr_debug(" unflattening %lx...\n", mem);
/* Second pass, do actual unflattening */
start = ((unsigned long)blob) +
be32_to_cpu(blob->off_dt_struct);
unflatten_dt_node(blob, mem, &start, NULL, &allnextp, 0);
if (be32_to_cpup((__be32 *)start) != OF_DT_END)
pr_warning("Weird tag at end of tree: %08x\n", *((u32 *)start));
if (be32_to_cpu(((__be32 *)mem)[size / 4]) != 0xdeadbeef)
pr_warning("End of tree marker overwritten: %08x\n",
be32_to_cpu(((__be32 *)mem)[size / 4]));
*allnextp = NULL;
pr_debug(" <- unflatten_device_tree()\n");
}
static void *kernel_tree_alloc(u64 size, u64 align)
{
return kzalloc(size, GFP_KERNEL);
}
/**
* of_fdt_unflatten_tree - create tree of device_nodes from flat blob
*
* 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.
*/
void of_fdt_unflatten_tree(unsigned long *blob,
struct device_node **mynodes)
{
struct boot_param_header *device_tree =
(struct boot_param_header *)blob;
__unflatten_device_tree(device_tree, mynodes, &kernel_tree_alloc);
}
EXPORT_SYMBOL_GPL(of_fdt_unflatten_tree);
/* Everything below here references initial_boot_params directly. */
int __initdata dt_root_addr_cells;
int __initdata dt_root_size_cells;
struct boot_param_header *initial_boot_params;
#ifdef CONFIG_OF_EARLY_FLATTREE
/**
* of_scan_flat_dt - scan flattened tree blob and call callback on each.
* @it: callback function
* @data: context data pointer
*
* This function is used to scan the flattened device-tree, it is
* used to extract the memory information 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) +
be32_to_cpu(initial_boot_params->off_dt_struct);
int rc = 0;
int depth = -1;
do {
u32 tag = be32_to_cpup((__be32 *)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 = be32_to_cpup((__be32 *)p);
p += 8;
if (be32_to_cpu(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) {
pr_err("Invalid tag %x in flat 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;
}
/**
* of_get_flat_dt_root - find the root node in the flat blob
*/
unsigned long __init of_get_flat_dt_root(void)
{
unsigned long p = ((unsigned long)initial_boot_params) +
be32_to_cpu(initial_boot_params->off_dt_struct);
while (be32_to_cpup((__be32 *)p) == OF_DT_NOP)
p += 4;
BUG_ON(be32_to_cpup((__be32 *)p) != OF_DT_BEGIN_NODE);
p += 4;
return ALIGN(p + strlen((char *)p) + 1, 4);
}
/**
* of_get_flat_dt_prop - Given a node in the flat blob, return the property ptr
*
* 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)
{
return of_fdt_get_property(initial_boot_params, node, name, size);
}
/**
* of_flat_dt_is_compatible - Return true if given node has compat in compatible list
* @node: node to test
* @compat: compatible string to compare with compatible list.
*/
int __init of_flat_dt_is_compatible(unsigned long node, const char *compat)
{
return of_fdt_is_compatible(initial_boot_params, node, compat);
}
/**
* of_flat_dt_match - Return true if node matches a list of compatible values
*/
int __init of_flat_dt_match(unsigned long node, const char *const *compat)
{
return of_fdt_match(initial_boot_params, node, compat);
}
#ifdef CONFIG_BLK_DEV_INITRD
/**
* early_init_dt_check_for_initrd - Decode initrd location from flat tree
* @node: reference to node containing initrd location ('chosen')
*/
void __init early_init_dt_check_for_initrd(unsigned long node)
{
unsigned long start, end, len;
__be32 *prop;
pr_debug("Looking for initrd properties... ");
prop = of_get_flat_dt_prop(node, "linux,initrd-start", &len);
if (!prop)
return;
start = of_read_ulong(prop, len/4);
prop = of_get_flat_dt_prop(node, "linux,initrd-end", &len);
if (!prop)
return;
end = of_read_ulong(prop, len/4);
early_init_dt_setup_initrd_arch(start, end);
pr_debug("initrd_start=0x%lx initrd_end=0x%lx\n", start, end);
}
#else
inline void early_init_dt_check_for_initrd(unsigned long node)
{
}
#endif /* CONFIG_BLK_DEV_INITRD */
/**
* early_init_dt_scan_root - fetch the top level address and size cells
*/
int __init early_init_dt_scan_root(unsigned long node, const char *uname,
int depth, void *data)
{
__be32 *prop;
if (depth != 0)
return 0;
dt_root_size_cells = OF_ROOT_NODE_SIZE_CELLS_DEFAULT;
dt_root_addr_cells = OF_ROOT_NODE_ADDR_CELLS_DEFAULT;
prop = of_get_flat_dt_prop(node, "#size-cells", NULL);
if (prop)
dt_root_size_cells = be32_to_cpup(prop);
pr_debug("dt_root_size_cells = %x\n", dt_root_size_cells);
prop = of_get_flat_dt_prop(node, "#address-cells", NULL);
if (prop)
dt_root_addr_cells = be32_to_cpup(prop);
pr_debug("dt_root_addr_cells = %x\n", dt_root_addr_cells);
/* break now */
return 1;
}
u64 __init dt_mem_next_cell(int s, __be32 **cellp)
{
__be32 *p = *cellp;
*cellp = p + s;
return of_read_number(p, s);
}
/**
* early_init_dt_scan_memory - Look for an parse memory nodes
*/
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);
__be32 *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 = of_get_flat_dt_prop(node, "linux,usable-memory", &l);
if (reg == NULL)
reg = of_get_flat_dt_prop(node, "reg", &l);
if (reg == NULL)
return 0;
endp = reg + (l / sizeof(__be32));
pr_debug("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)) {
u64 base, size;
base = dt_mem_next_cell(dt_root_addr_cells, ®);
size = dt_mem_next_cell(dt_root_size_cells, ®);
if (size == 0)
continue;
pr_debug(" - %llx , %llx\n", (unsigned long long)base,
(unsigned long long)size);
early_init_dt_add_memory_arch(base, size);
}
return 0;
}
int __init early_init_dt_scan_chosen(unsigned long node, const char *uname,
int depth, void *data)
{
unsigned long l;
char *p;
pr_debug("search \"chosen\", depth: %d, uname: %s\n", depth, uname);
if (depth != 1 || !data ||
(strcmp(uname, "chosen") != 0 && strcmp(uname, "chosen@0") != 0))
return 0;
early_init_dt_check_for_initrd(node);
/* Retrieve command line */
p = of_get_flat_dt_prop(node, "bootargs", &l);
if (p != NULL && l > 0)
strlcpy(data, p, min((int)l, COMMAND_LINE_SIZE));
/*
* CONFIG_CMDLINE is meant to be a default in case nothing else
* managed to set the command line, unless CONFIG_CMDLINE_FORCE
* is set in which case we override whatever was found earlier.
*/
#ifdef CONFIG_CMDLINE
#ifndef CONFIG_CMDLINE_FORCE
if (!((char *)data)[0])
#endif
strlcpy(data, CONFIG_CMDLINE, COMMAND_LINE_SIZE);
#endif /* CONFIG_CMDLINE */
pr_debug("Command line is: %s\n", (char*)data);
/* break now */
return 1;
}
/**
* unflatten_device_tree - create tree of device_nodes from flat blob
*
* 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.
*/
void __init unflatten_device_tree(void)
{
__unflatten_device_tree(initial_boot_params, &allnodes,
early_init_dt_alloc_memory_arch);
/* Get pointer to "/chosen" and "/aliasas" nodes for use everywhere */
of_alias_scan(early_init_dt_alloc_memory_arch);
}
#endif /* CONFIG_OF_EARLY_FLATTREE */