[kernel] map write combine buffers

Author: yuyichao

lib/nacs-kernel/devctl.cpp

@@ -48,6 +48,11 @@ NACS_EXPORT() void *allocOCMBuffer(size_t len)
     return mapFile(getFD(), page_size, len);
 }
 
+NACS_EXPORT() void *allocOCMBuffer(size_t len, bool writecombine)
+{
+    return mapFile(getFD(), writecombine ? page_size * 3 : page_size, len);
+}
+
 NACS_EXPORT() void freeOCMBuffer(void *buff, size_t old_size)
 {
     munmap(buff, old_size);
@@ -58,6 +63,11 @@ NACS_EXPORT() void *allocDMABuffer(size_t len)
     return mapFile(getFD(), page_size * 2, len);
 }
 
+NACS_EXPORT() void *allocDMABuffer(size_t len, bool writecombine)
+{
+    return mapFile(getFD(), writecombine ? page_size * 4 : page_size * 2, len);
+}
+
 NACS_EXPORT() void freeDMABuffer(void *buff, size_t old_size)
 {
     munmap(buff, old_size);

lib/nacs-kernel/devctl.h

@@ -29,9 +29,11 @@ knacs_version_t getDriverVersion();
 void *mapPulseCtrl();
 
 void *allocOCMBuffer(size_t);
+void *allocOCMBuffer(size_t, bool);
 void freeOCMBuffer(void*, size_t);
 
 void *allocDMABuffer(size_t);
+void *allocDMABuffer(size_t, bool);
 void freeDMABuffer(void*, size_t);
 
 void *bufferPhyAddr(void*);