Blackfin arch: Use DTEST rather than DMA to poke at L1 SRAM during exception context

Signed-off-by: Robin Getz <rgetz@blackfin.uclinux.org>
Signed-off-by: Bryan Wu <cooloney@kernel.org>

1 files changed, 10 insertions, 0 deletions

diff --git a/arch/blackfin/mach-common/head.S b/arch/blackfin/mach-common/head.S
index eb9eef0e23b7..3069df580729 100644
--- a/arch/blackfin/mach-common/head.S
+++ b/arch/blackfin/mach-common/head.S
@@ -68,6 +68,16 @@ ENTRY(__start)
         M2 = r0;
         M3 = r0;
 
+        /*
+         * Clear ITEST_COMMAND and DTEST_COMMAND registers,
+         * Leaving these as non-zero can confuse the emulator
+         */
+        p0.L = LO(DTEST_COMMAND);
+        p0.H = HI(DTEST_COMMAND);
+        [p0] = R0;
+        [p0 + (ITEST_COMMAND - DTEST_COMMAND)] = R0;
+        CSYNC;
+
         trace_buffer_init(p0,r0);
         P0 = R1;
         R0 = R1;