There is a need to be able to specify some options when building an FDT
with the SW interface. This can be accomplished with minimal changes by
storing intermediate data in the fdt header itself, in fields that are
not otherwise needed during the creation process and can be set by
fdt_finish().
The fdt.magic field is already used exactly this way, as a state to
check with callers that the FDT has been created but not yet finished.
fdt.version and fdt.last_comp_version are used to make room for more
intermediate state. These are adjacent and unused during the building
process. last_comp_version is not yet used for intermediate state, but
it is zeroed and treated as used, so as to allow future growth easily.
A new interface, fdt_create_with_flags() is added, which takes 32-bit
flag value to control creation.
Signed-off-by: Nicholas Piggin <npiggin@xxxxxxxxx>
---
This is a different approach to the problem than the previous [PATCH]
libfdt: Add fdt_property_nocompress variants that trade size for speed.
Hopefully a nicer interface that's more extensible.
Note, I was not able to get the python tests working on my distro, but
I ran the program by hand a few times and tried to add some sane tests,
so apologies in advance for submitting the un-tested test code.
libfdt/fdt_sw.c | 27 +++++++++++++++++++++++++--
libfdt/libfdt.h | 1 +
libfdt/version.lds | 1 +
3 files changed, 27 insertions(+), 2 deletions(-)
diff --git a/libfdt/fdt_sw.c b/libfdt/fdt_sw.c
index 9fa4a94..f162579 100644
--- a/libfdt/fdt_sw.c
+++ b/libfdt/fdt_sw.c
@@ -121,6 +121,12 @@ static int fdt_sw_probe_struct_(void *fdt)
return err; \
}
+static inline uint32_t fdt_sw_create_flags(void *fdt)
+{
+ /* assert: (fdt_magic(fdt) == FDT_SW_MAGIC) */
+ return fdt_last_comp_version(fdt);
+}
+
/* 'complete' state: Enter this state after fdt_finish()
*
* Allowed functions: none
@@ -141,7 +147,7 @@ static void *fdt_grab_space_(void *fdt, size_t len)
return fdt_offset_ptr_w_(fdt, offset);
}
-int fdt_create(void *buf, int bufsize)
+int fdt_create_with_flags(void *buf, int bufsize, uint32_t flags)
{
const size_t hdrsize = FDT_ALIGN(sizeof(struct fdt_header),
sizeof(struct fdt_reserve_entry));
@@ -152,9 +158,17 @@ int fdt_create(void *buf, int bufsize)
memset(buf, 0, bufsize);
+ /*
+ * magic and last_comp_version keep intermediate state during the fdt
+ * creation process, which is replaced with the proper FDT format by
+ * fdt_finish().
+ *
+ * flags should be accessed with fdt_sw_create_flags().
+ */
fdt_set_magic(fdt, FDT_SW_MAGIC);
fdt_set_version(fdt, FDT_LAST_SUPPORTED_VERSION);
- fdt_set_last_comp_version(fdt, FDT_FIRST_SUPPORTED_VERSION);
+ fdt_set_last_comp_version(fdt, flags);
+
fdt_set_totalsize(fdt, bufsize);
fdt_set_off_mem_rsvmap(fdt, hdrsize);
@@ -164,6 +178,11 @@ int fdt_create(void *buf, int bufsize)
return 0;
}
+int fdt_create(void *buf, int bufsize)
+{
+ return fdt_create_with_flags(buf, bufsize, 0);
+}
+
int fdt_resize(void *fdt, void *buf, int bufsize)
{
size_t headsize, tailsize;
@@ -360,6 +379,10 @@ int fdt_finish(void *fdt)
/* Finally, adjust the header */
fdt_set_totalsize(fdt, newstroffset + fdt_size_dt_strings(fdt));
+
+ /* And fix up fields that were keeping intermediate state. */
+ fdt_set_last_comp_version(fdt, FDT_FIRST_SUPPORTED_VERSION);
fdt_set_magic(fdt, FDT_MAGIC);
+
return 0;
}
diff --git a/libfdt/libfdt.h b/libfdt/libfdt.h
index 1f44177..574904d 100644
--- a/libfdt/libfdt.h
+++ b/libfdt/libfdt.h
@@ -1430,6 +1430,7 @@ int fdt_nop_node(void *fdt, int nodeoffset);
/**********************************************************************/
int fdt_create(void *buf, int bufsize);
+int fdt_create_with_flags(void *buf, int bufsize, uint32_t flags);
int fdt_resize(void *fdt, void *buf, int bufsize);
int fdt_add_reservemap_entry(void *fdt, uint64_t addr, uint64_t size);
int fdt_finish_reservemap(void *fdt);
diff --git a/libfdt/version.lds b/libfdt/version.lds
index 9a92652..0d52217 100644
--- a/libfdt/version.lds
+++ b/libfdt/version.lds
@@ -74,6 +74,7 @@ LIBFDT_1.2 {
fdt_header_size_;
fdt_appendprop_addrrange;
fdt_setprop_inplace_namelen_partial;
+ fdt_create_with_flags;
local:
*;
};
--
2.20.1
