diff options
author | Nathan Whitehorn <nwhitehorn@freebsd.org> | 2018-01-25 05:13:40 +0000 |
---|---|---|
committer | David Gibson <david@gibson.dropbear.id.au> | 2018-01-27 18:43:21 +1100 |
commit | f1879e1a50ebc3786540a075701ccaead2bfbe1f (patch) | |
tree | bfc6f37f2055cb4d253254701f43391c5b563abe | |
parent | 37dea76e9700fa4799b4cb1abfd74b121f6e3dd8 (diff) | |
download | device-tree-compiler-f1879e1a50ebc3786540a075701ccaead2bfbe1f.tar.gz |
Add limited read-only support for older (V2 and V3) device tree to libfdt.
This can be useful in particular in the kernel when booting on systems
with FDT-emitting firmware that is out of date. Releases of kexec-tools
on ppc64 prior to the end of 2014 are notable examples of such.
Signed-off-by: Nathan Whitehorn <nwhitehorn@freebsd.org>
[dwg: Some whitespace cleanups]
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
-rw-r--r-- | fdtget.c | 4 | ||||
-rw-r--r-- | libfdt/fdt.c | 3 | ||||
-rw-r--r-- | libfdt/fdt_ro.c | 100 | ||||
-rw-r--r-- | libfdt/libfdt.h | 5 |
4 files changed, 93 insertions, 19 deletions
@@ -140,7 +140,6 @@ static int show_data(struct display_info *disp, const char *data, int len) */ static int list_properties(const void *blob, int node) { - const struct fdt_property *data; const char *name; int prop; @@ -149,8 +148,7 @@ static int list_properties(const void *blob, int node) /* Stop silently when there are no more properties */ if (prop < 0) return prop == -FDT_ERR_NOTFOUND ? 0 : prop; - data = fdt_get_property_by_offset(blob, prop, NULL); - name = fdt_string(blob, fdt32_to_cpu(data->nameoff)); + fdt_getprop_by_offset(blob, prop, &name, NULL); if (name) puts(name); prop = fdt_next_property_offset(blob, prop); diff --git a/libfdt/fdt.c b/libfdt/fdt.c index fd13236..7855a17 100644 --- a/libfdt/fdt.c +++ b/libfdt/fdt.c @@ -123,6 +123,9 @@ uint32_t fdt_next_tag(const void *fdt, int startoffset, int *nextoffset) /* skip-name offset, length and value */ offset += sizeof(struct fdt_property) - FDT_TAGSIZE + fdt32_to_cpu(*lenp); + if (fdt_version(fdt) < 0x10 && fdt32_to_cpu(*lenp) >= 8 && + ((offset - fdt32_to_cpu(*lenp)) % 8) != 0) + offset += 4; break; case FDT_END: diff --git a/libfdt/fdt_ro.c b/libfdt/fdt_ro.c index ce17814..dfb3236 100644 --- a/libfdt/fdt_ro.c +++ b/libfdt/fdt_ro.c @@ -58,9 +58,10 @@ static int fdt_nodename_eq_(const void *fdt, int offset, const char *s, int len) { - const char *p = fdt_offset_ptr(fdt, offset + FDT_TAGSIZE, len+1); + int olen; + const char *p = fdt_get_name(fdt, offset, &olen); - if (!p) + if (!p || olen < len) /* short match */ return 0; @@ -233,16 +234,34 @@ int fdt_path_offset(const void *fdt, const char *path) const char *fdt_get_name(const void *fdt, int nodeoffset, int *len) { const struct fdt_node_header *nh = fdt_offset_ptr_(fdt, nodeoffset); + const char *nameptr; int err; if (((err = fdt_check_header(fdt)) != 0) || ((err = fdt_check_node_offset_(fdt, nodeoffset)) < 0)) goto fail; + nameptr = nh->name; + + if (fdt_version(fdt) < 0x10) { + /* + * For old FDT versions, match the naming conventions of V16: + * give only the leaf name (after all /). The actual tree + * contents are loosely checked. + */ + const char *leaf; + leaf = strrchr(nameptr, '/'); + if (leaf == NULL) { + err = -FDT_ERR_BADSTRUCTURE; + goto fail; + } + nameptr = leaf+1; + } + if (len) - *len = strlen(nh->name); + *len = strlen(nameptr); - return nh->name; + return nameptr; fail: if (len) @@ -268,9 +287,9 @@ int fdt_next_property_offset(const void *fdt, int offset) return nextprop_(fdt, offset); } -const struct fdt_property *fdt_get_property_by_offset(const void *fdt, - int offset, - int *lenp) +static const struct fdt_property *fdt_get_property_by_offset_(const void *fdt, + int offset, + int *lenp) { int err; const struct fdt_property *prop; @@ -289,23 +308,44 @@ const struct fdt_property *fdt_get_property_by_offset(const void *fdt, return prop; } -const struct fdt_property *fdt_get_property_namelen(const void *fdt, - int offset, - const char *name, - int namelen, int *lenp) +const struct fdt_property *fdt_get_property_by_offset(const void *fdt, + int offset, + int *lenp) +{ + /* Prior to version 16, properties may need realignment + * and this API does not work. fdt_getprop_*() will, however. */ + + if (fdt_version(fdt) < 0x10) { + if (lenp) + *lenp = -FDT_ERR_BADVERSION; + return NULL; + } + + return fdt_get_property_by_offset_(fdt, offset, lenp); +} + +static const struct fdt_property *fdt_get_property_namelen_(const void *fdt, + int offset, + const char *name, + int namelen, + int *lenp, + int *poffset) { for (offset = fdt_first_property_offset(fdt, offset); (offset >= 0); (offset = fdt_next_property_offset(fdt, offset))) { const struct fdt_property *prop; - if (!(prop = fdt_get_property_by_offset(fdt, offset, lenp))) { + if (!(prop = fdt_get_property_by_offset_(fdt, offset, lenp))) { offset = -FDT_ERR_INTERNAL; break; } if (fdt_string_eq_(fdt, fdt32_to_cpu(prop->nameoff), - name, namelen)) + name, namelen)) { + if (poffset) + *poffset = offset; return prop; + } } if (lenp) @@ -313,6 +353,25 @@ const struct fdt_property *fdt_get_property_namelen(const void *fdt, return NULL; } + +const struct fdt_property *fdt_get_property_namelen(const void *fdt, + int offset, + const char *name, + int namelen, int *lenp) +{ + /* Prior to version 16, properties may need realignment + * and this API does not work. fdt_getprop_*() will, however. */ + if (fdt_version(fdt) < 0x10) { + if (lenp) + *lenp = -FDT_ERR_BADVERSION; + return NULL; + } + + return fdt_get_property_namelen_(fdt, offset, name, namelen, lenp, + NULL); +} + + const struct fdt_property *fdt_get_property(const void *fdt, int nodeoffset, const char *name, int *lenp) @@ -324,12 +383,18 @@ const struct fdt_property *fdt_get_property(const void *fdt, const void *fdt_getprop_namelen(const void *fdt, int nodeoffset, const char *name, int namelen, int *lenp) { + int poffset; const struct fdt_property *prop; - prop = fdt_get_property_namelen(fdt, nodeoffset, name, namelen, lenp); + prop = fdt_get_property_namelen_(fdt, nodeoffset, name, namelen, lenp, + &poffset); if (!prop) return NULL; + /* Handle realignment */ + if (fdt_version(fdt) < 0x10 && (poffset + sizeof(*prop)) % 8 && + fdt32_to_cpu(prop->len) >= 8) + return prop->data + 4; return prop->data; } @@ -338,11 +403,16 @@ const void *fdt_getprop_by_offset(const void *fdt, int offset, { const struct fdt_property *prop; - prop = fdt_get_property_by_offset(fdt, offset, lenp); + prop = fdt_get_property_by_offset_(fdt, offset, lenp); if (!prop) return NULL; if (namep) *namep = fdt_string(fdt, fdt32_to_cpu(prop->nameoff)); + + /* Handle realignment */ + if (fdt_version(fdt) < 0x10 && (offset + sizeof(*prop)) % 8 && + fdt32_to_cpu(prop->len) >= 8) + return prop->data + 4; return prop->data; } diff --git a/libfdt/libfdt.h b/libfdt/libfdt.h index baa882c..c8c00fa 100644 --- a/libfdt/libfdt.h +++ b/libfdt/libfdt.h @@ -54,7 +54,7 @@ #include <libfdt_env.h> #include <fdt.h> -#define FDT_FIRST_SUPPORTED_VERSION 0x10 +#define FDT_FIRST_SUPPORTED_VERSION 0x02 #define FDT_LAST_SUPPORTED_VERSION 0x11 /* Error codes: informative error codes */ @@ -527,6 +527,9 @@ int fdt_next_property_offset(const void *fdt, int offset); * offset. If lenp is non-NULL, the length of the property value is * also returned, in the integer pointed to by lenp. * + * Note that this code only works on device tree versions >= 16. fdt_getprop() + * works on all versions. + * * returns: * pointer to the structure representing the property * if lenp is non-NULL, *lenp contains the length of the property |