Add ARM support into xf86drm.h

This provides support for Xorg interface.  Without this the vivante
samples will hang during close requiring a reboot

[Adapted from yocto project]
Upstream-Status: Pending
Signed-off-by: Lauren Post <lauren.post@freescale.com>
Signed-off-by: Evan Kotara <evan.kotara@freescale.com>
[Thomas: change CAS code to only be used on ARMv6/ARMv7, and not
ARMv4/ARMv5, which don't support ldrex/strex. If no CAS implementation
is provided libdrm falls back to a system call for locking/unlocking.]
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Peter Seiderer <ps.report@gmx.net>
Acked-by: Eric Engestrom <eric.engestrom@intel.com>
---
Changes v1 -> v2:
  - add comment explaining exclusion of ARMv4/ARMv5 and lower

diff --git a/xf86drm.h b/xf86drm.h
index 3805139..7b85079 100644 (file)
--- a/xf86drm.h
+++ b/xf86drm.h
@@ -481,6 +481,29 @@ do {       register unsigned int __old __asm("o0");                \
                : "cr0", "memory");                     \
        } while (0)
 
+# elif defined (__ARM_ARCH_6__) || defined(__ARM_ARCH_6J__) \
+       || defined (__ARM_ARCH_6Z__) || defined(__ARM_ARCH_6ZK__) \
+       || defined (__ARM_ARCH_6K__) || defined(__ARM_ARCH_6T2__) \
+       || defined (__ARM_ARCH_7__) || defined(__ARM_ARCH_7A__) \
+       || defined(__ARM_ARCH_7R__) || defined(__ARM_ARCH_7M__) \
+       || defined(__ARM_ARCH_7EM__)
+       /* excluding ARMv4/ARMv5 and lower (lacking ldrex/strex support) */
+       #undef DRM_DEV_MODE
+       #define DRM_DEV_MODE     (S_IRUSR|S_IWUSR|S_IRGRP|S_IWGRP|S_IROTH|S_IWOTH)
+
+       #define DRM_CAS(lock,old,new,__ret)             \
+       do {                                            \
+               __asm__ __volatile__ (                  \
+                       "1: ldrex %0, [%1]\n"           \
+                       "   teq %0, %2\n"               \
+                       "   ite eq\n"                   \
+                       "   strexeq %0, %3, [%1]\n"     \
+                       "   movne   %0, #1\n"           \
+               : "=&r" (__ret)                         \
+               : "r" (lock), "r" (old), "r" (new)      \
+               : "cc","memory");                       \
+       } while (0)
+
 #endif /* architecture */
 #endif /* __GNUC__ >= 2 */