powerpc/boot: Add mfdcrx

Needed for currituck support.

Signed-off-by: Tony Breeds <tony@bakeyournoodle.com>
Signed-off-by: Josh Boyer <jwboyer@gmail.com>

1 files changed, 6 insertions, 0 deletions

diff --git a/arch/powerpc/boot/dcr.h b/arch/powerpc/boot/dcr.h
index 645a7c964e5f..cc73f7a95e26 100644
--- a/arch/powerpc/boot/dcr.h
+++ b/arch/powerpc/boot/dcr.h
@@ -9,6 +9,12 @@
         })
 #define mtdcr(rn, val) \
         asm volatile("mtdcr %0,%1" : : "i"(rn), "r"(val))
+#define mfdcrx(rn) \
+        ({      \
+                unsigned long rval; \
+                asm volatile("mfdcrx %0,%1" : "=r"(rval) : "r"(rn)); \
+                rval; \
+        })
 
 /* 440GP/440GX SDRAM controller DCRs */
 #define DCRN_SDRAM0_CFGADDR                             0x010