pylibfdt: Use an unsigned type for fdt32_t

The members of struct fdt_header are declared as fdt32_t which is a
32-bit, big-endian, unsigned integer. These fields are accessed by macros
in libfdt.h so no return type is declared. But the correct return type is
uint32_t, not fdt32_t, since the endianness conversion is done within the
macro before returning the value.

The macros are re-declared as normal functions in pylibfdt since swig does
not support macros. The return type is currently int. Change it to
uint32_t, which allows us to drop the work-around mask in Fdt.magic().

Also change the typedef for fdt32_t to uint32_t. The currently has no
obvious effect, since use of big-endian values should always be internal
to pylibfdt, but it is more correct.

Signed-off-by: Simon Glass <sjg@chromium.org>
Suggested-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>

1 files changed, 16 insertions, 13 deletions

diff --git a/pylibfdt/libfdt.i b/pylibfdt/libfdt.i
index 3abcf32..520911e 100644
--- a/pylibfdt/libfdt.i
+++ b/pylibfdt/libfdt.i
@@ -240,8 +240,7 @@ class Fdt:
         Returns:
             Magic word
         """
-        # Use a mask to ensure that this does not return a -ve number
-        return fdt_magic(self._fdt) & 0xffffffff
+        return fdt_magic(self._fdt)
 
     def totalsize(self):
         """Return the total size of the device tree
@@ -628,7 +627,11 @@ class Property(bytearray):
 
 %rename(fdt_property) fdt_property_func;
 
-typedef int fdt32_t;
+/*
+ * fdt32_t is a big-endian 32-bit value defined to uint32_t in libfdt_env.h
+ * so use the same type here.
+ */
+typedef uint32_t fdt32_t;
 
 %include "libfdt/fdt.h"
 
@@ -716,15 +719,15 @@ typedef int fdt32_t;
 %warnfilter(302) fdt_property;
 
 /* These are macros in the header so have to be redefined here */
-int fdt_magic(const void *fdt);
-int fdt_totalsize(const void *fdt);
-int fdt_off_dt_struct(const void *fdt);
-int fdt_off_dt_strings(const void *fdt);
-int fdt_off_mem_rsvmap(const void *fdt);
-int fdt_version(const void *fdt);
-int fdt_last_comp_version(const void *fdt);
-int fdt_boot_cpuid_phys(const void *fdt);
-int fdt_size_dt_strings(const void *fdt);
-int fdt_size_dt_struct(const void *fdt);
+uint32_t fdt_magic(const void *fdt);
+uint32_t fdt_totalsize(const void *fdt);
+uint32_t fdt_off_dt_struct(const void *fdt);
+uint32_t fdt_off_dt_strings(const void *fdt);
+uint32_t fdt_off_mem_rsvmap(const void *fdt);
+uint32_t fdt_version(const void *fdt);
+uint32_t fdt_last_comp_version(const void *fdt);
+uint32_t fdt_boot_cpuid_phys(const void *fdt);
+uint32_t fdt_size_dt_strings(const void *fdt);
+uint32_t fdt_size_dt_struct(const void *fdt);
 
 %include <../libfdt/libfdt.h>