MIPS: Map CM Global Control Registers
Map the Global Control Registers (GCRs) provided by the MIPS Coherence
Manager (CM) in preparation for using some of them in later patches.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
diff --git a/arch/mips/cpu/cm_init.S b/arch/mips/cpu/cm_init.S
new file mode 100644
index 0000000..ddcaa49
--- /dev/null
+++ b/arch/mips/cpu/cm_init.S
@@ -0,0 +1,45 @@
+/*
+ * MIPS Coherence Manager (CM) Initialisation
+ *
+ * Copyright (c) 2016 Imagination Technologies Ltd.
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ */
+
+#include <asm/addrspace.h>
+#include <asm/asm.h>
+#include <asm/cm.h>
+#include <asm/mipsregs.h>
+#include <asm/regdef.h>
+
+LEAF(mips_cm_map)
+ /* Config3 must exist for a CM to be present */
+ mfc0 t0, CP0_CONFIG, 1
+ bgez t0, 2f
+ mfc0 t0, CP0_CONFIG, 2
+ bgez t0, 2f
+
+ /* Check Config3.CMGCR to determine CM presence */
+ mfc0 t0, CP0_CONFIG, 3
+ and t0, t0, MIPS_CONF3_CMGCR
+ beqz t0, 2f
+
+ /* Find the current physical GCR base address */
+1: MFC0 t0, CP0_CMGCRBASE
+ PTR_SLL t0, t0, 4
+
+ /* If the GCRs are where we want, we're done */
+ PTR_LI t1, CONFIG_MIPS_CM_BASE
+ beq t0, t1, 2f
+
+ /* Move the GCRs to our configured base address */
+ PTR_LI t2, CKSEG1
+ PTR_ADDU t0, t0, t2
+ sw zero, GCR_BASE_UPPER(t0)
+ sw t1, GCR_BASE(t0)
+
+ /* Re-check the GCR base */
+ b 1b
+
+2: jr ra
+ END(mips_cm_map)