buildroot

Fix build on big endian systems

​

The usb_linux_client.c file defines cpu_to_le16/32 by using the C

library htole16/32 function calls. However, cpu_to_le16/32 are used

when initializing structures, i.e in a context where a function call

is not allowed.

​

It works fine on little endian systems because htole16/32 are defined

by the C library as no-ops. But on big-endian systems, they are

actually doing something, which might involve calling a function,

causing build failures.

​

To solve this, we simply open-code cpu_to_le16/32 in a way that allows

them to be used when initializing structures.

​

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

​

Index: b/core/adb/usb_linux_client.c

===================================================================

--- a/core/adb/usb_linux_client.c

+++ b/core/adb/usb_linux_client.c

@@ -34,8 +34,15 @@

 #define MAX_PACKET_SIZE_FS 64

 #define MAX_PACKET_SIZE_HS 512

-#define cpu_to_le16(x)  htole16(x)

-#define cpu_to_le32(x)  htole32(x)

+#if __BYTE_ORDER == __LITTLE_ENDIAN

+# define cpu_to_le16(x) (x)

+# define cpu_to_le32(x) (x)

+#else

+# define cpu_to_le16(x) ((((x) >> 8) & 0xffu) | (((x) & 0xffu) << 8))

+# define cpu_to_le32(x) \

+   ((((x) & 0xff000000u) >> 24) | (((x) & 0x00ff0000u) >>  8) | \

+    (((x) & 0x0000ff00u) <<  8) | (((x) & 0x000000ffu) << 24))

+#endif

 struct usb_handle

 {

Index: b/core/adbd/usb_linux_client.c

===================================================================

--- a/core/adbd/usb_linux_client.c

+++ b/core/adbd/usb_linux_client.c

@@ -34,8 +34,15 @@

 #define MAX_PACKET_SIZE_FS 64

 #define MAX_PACKET_SIZE_HS 512

-#define cpu_to_le16(x)  htole16(x)

-#define cpu_to_le32(x)  htole32(x)

+#if __BYTE_ORDER == __LITTLE_ENDIAN

+# define cpu_to_le16(x) (x)

+# define cpu_to_le32(x) (x)

+#else

+# define cpu_to_le16(x) ((((x) >> 8) & 0xffu) | (((x) & 0xffu) << 8))

+# define cpu_to_le32(x) \

+   ((((x) & 0xff000000u) >> 24) | (((x) & 0x00ff0000u) >>  8) | \

+    (((x) & 0x0000ff00u) <<  8) | (((x) & 0x000000ffu) << 24))

+#endif

 struct usb_handle

 {