uint32_t fdt_next_tag(const void *fdt, int startoffset, int *nextoffset)
{
const fdt32_t *tagp, *lenp;
uint32_t tag;
int offset = startoffset;
const char *p;
*nextoffset = -FDT_ERR_TRUNCATED;
tagp = fdt_offset_ptr(fdt, offset, FDT_TAGSIZE);
if (!tagp)
return FDT_END; /* premature end */
tag = fdt32_to_cpu(*tagp);
offset += FDT_TAGSIZE;
*nextoffset = -FDT_ERR_BADSTRUCTURE;
switch (tag) {
case FDT_BEGIN_NODE:
/* skip name */
do {
p = fdt_offset_ptr(fdt, offset++, 1);
} while (p && (*p != '\0'));
if (!p)
return FDT_END; /* premature end */
break;
case FDT_PROP:
lenp = fdt_offset_ptr(fdt, offset, sizeof(*lenp));
if (!lenp)
return FDT_END; /* premature end */
/* skip-name offset, length and value */
offset += sizeof(struct fdt_property) - FDT_TAGSIZE
+ fdt32_to_cpu(*lenp);
break;
case FDT_END:
case FDT_END_NODE:
case FDT_NOP:
break;
default:
return FDT_END;
}
if (!fdt_offset_ptr(fdt, startoffset, offset - startoffset))
return FDT_END; /* premature end */
*nextoffset = FDT_TAGALIGN(offset);
return tag;
}
int fdt_begin_node(void *fdt, const char *name)
{
struct fdt_node_header *nh;
int namelen = strlen(name) + 1;
FDT_SW_CHECK_HEADER(fdt);
nh = _fdt_grab_space(fdt, sizeof(*nh) + FDT_TAGALIGN(namelen));
if (! nh)
return -FDT_ERR_NOSPACE;
nh->tag = cpu_to_fdt32(FDT_BEGIN_NODE);
memcpy(nh->name, name, namelen);
return 0;
}
int fdt_property(void *fdt, const char *name, const void *val, int len)
{
struct fdt_property *prop;
int nameoff;
FDT_SW_CHECK_HEADER(fdt);
nameoff = _fdt_find_add_string(fdt, name);
if (nameoff == 0)
return -FDT_ERR_NOSPACE;
prop = _fdt_grab_space(fdt, sizeof(*prop) + FDT_TAGALIGN(len));
if (! prop)
return -FDT_ERR_NOSPACE;
prop->tag = cpu_to_fdt32(FDT_PROP);
prop->nameoff = cpu_to_fdt32(nameoff);
prop->len = cpu_to_fdt32(len);
memcpy(prop->data, val, len);
return 0;
}
uint32_t fdt_next_tag(const void *fdt, int offset, int *nextoffset)
{
const uint32_t *tagp, *lenp;
uint32_t tag;
const char *p;
if (offset % FDT_TAGSIZE)
return -1;
tagp = fdt_offset_ptr(fdt, offset, FDT_TAGSIZE);
if (! tagp)
return FDT_END; /* premature end */
tag = fdt32_to_cpu(*tagp);
offset += FDT_TAGSIZE;
switch (tag) {
case FDT_BEGIN_NODE:
/* skip name */
do {
p = fdt_offset_ptr(fdt, offset++, 1);
} while (p && (*p != '\0'));
if (! p)
return FDT_END;
break;
case FDT_PROP:
lenp = fdt_offset_ptr(fdt, offset, sizeof(*lenp));
if (! lenp)
return FDT_END;
/* skip name offset, length and value */
offset += 2*FDT_TAGSIZE + fdt32_to_cpu(*lenp);
break;
}
if (nextoffset)
*nextoffset = FDT_TAGALIGN(offset);
return tag;
}
/*
* 다음 tag의 Offset를 찾는다.(nextoffset갱신)
* in startoffset 현재 시작 offset
* out nextoffset 다음 시작 offset
* return FDT_END 에러 혹은 현재의 tag값
* tag 구분값
* define FDT_BEGIN_NODE 0x1
* #define FDT_END_NODE 0x2
* #define FDT_PROP 0x3
*/
uint32_t fdt_next_tag(const void *fdt, int startoffset, int *nextoffset)
{
const uint32_t *tagp, *lenp;
uint32_t tag;
int offset = startoffset;
const char *p;
*nextoffset = -FDT_ERR_TRUNCATED;
/* FDT_TAGSIZE: sizeof(uint32_t) word사이즈 */
tagp = fdt_offset_ptr(fdt, offset, FDT_TAGSIZE);
if (!tagp)
return FDT_END; /* premature end */
tag = fdt32_to_cpu(*tagp);
offset += FDT_TAGSIZE;
*nextoffset = -FDT_ERR_BADSTRUCTURE;
switch (tag) {
/*
#define FDT_BEGIN_NODE 0x1
#define FDT_END_NODE 0x2
#define FDT_PROP 0x3
[2015-11-07 여기까지 함]
*/
case FDT_BEGIN_NODE:
/* skip name */
/*
struct fdt_node_header {
uint32_t tag;
char name[0];
};
*/
do {
p = fdt_offset_ptr(fdt, offset++, 1);
} while (p && (*p != '\0'));
if (!p)
return FDT_END; /* premature end */
break;
case FDT_PROP:
/*
struct fdt_property {
uint32_t tag;
uint32_t len;
uint32_t nameoff;
char data[0];
};
*/
lenp = fdt_offset_ptr(fdt, offset, sizeof(*lenp));
if (!lenp)
return FDT_END; /* premature end */
/* skip-name offset, length and value */
/* offset += 12 - 4 + (*lenp)
sizeof(struct fdt_property) 는 12이다.
*/
offset += sizeof(struct fdt_property) - FDT_TAGSIZE
+ fdt32_to_cpu(*lenp);
break;
case FDT_END:
case FDT_END_NODE:
case FDT_NOP:
break;
default:
return FDT_END;
}
// offset값 범위체크
if (!fdt_offset_ptr(fdt, startoffset, offset - startoffset))
return FDT_END; /* premature end */
/*
4 byte align을 맞추기위해
#define FDT_ALIGN(x, a) (((x) + (a) - 1) & ~((a) - 1))
#define FDT_TAGALIGN(x) (FDT_ALIGN((x), FDT_TAGSIZE))
ex) FDT_TAGALIGN(10)
FDT_ALIGN(10, 4)
((10 + 4 - 1) & ~(4 - 1)) = 12
(13 & ~3) = 0b1101 & ~0b0011 = 0b1100 = 12
*/
*nextoffset = FDT_TAGALIGN(offset);
return tag;
}
