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/Kconfig b/arch/mips/Kconfig
index fa344a7..47056b4 100644
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -318,6 +318,22 @@
config DYNAMIC_IO_PORT_BASE
bool
+config MIPS_CM
+ bool
+ help
+ Select this if your system contains a MIPS Coherence Manager and you
+ wish U-Boot to configure it or make use of it to retrieve system
+ information such as cache configuration.
+
+config MIPS_CM_BASE
+ hex
+ default 0x1fbf8000
+ help
+ The physical base address at which to map the MIPS Coherence Manager
+ Global Configuration Registers (GCRs). This should be set such that
+ the GCRs occupy a region of the physical address space which is
+ otherwise unused, or at minimum that software doesn't need to access.
+
endif
endmenu
diff --git a/arch/mips/cpu/Makefile b/arch/mips/cpu/Makefile
index fc6b455..429fd3a 100644
--- a/arch/mips/cpu/Makefile
+++ b/arch/mips/cpu/Makefile
@@ -7,3 +7,5 @@
obj-y += time.o
obj-y += interrupts.o
obj-y += cpu.o
+
+obj-$(CONFIG_MIPS_CM) += cm_init.o
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)
diff --git a/arch/mips/cpu/start.S b/arch/mips/cpu/start.S
index 6f1d219..c157d03 100644
--- a/arch/mips/cpu/start.S
+++ b/arch/mips/cpu/start.S
@@ -141,6 +141,12 @@
1:
PTR_L gp, 0(ra)
+#ifdef CONFIG_MIPS_CM
+ PTR_LA t9, mips_cm_map
+ jalr t9
+ nop
+#endif
+
#ifndef CONFIG_SKIP_LOWLEVEL_INIT
# ifdef CONFIG_SYS_MIPS_CACHE_INIT_RAM_LOAD
/* Initialize any external memory */
diff --git a/arch/mips/include/asm/cm.h b/arch/mips/include/asm/cm.h
new file mode 100644
index 0000000..0261733
--- /dev/null
+++ b/arch/mips/include/asm/cm.h
@@ -0,0 +1,19 @@
+/*
+ * MIPS Coherence Manager (CM) Register Definitions
+ *
+ * Copyright (c) 2016 Imagination Technologies Ltd.
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ */
+#ifndef __MIPS_ASM_CM_H__
+#define __MIPS_ASM_CM_H__
+
+/* Global Control Register (GCR) offsets */
+#define GCR_BASE 0x0008
+#define GCR_BASE_UPPER 0x000c
+#define GCR_REV 0x0030
+
+/* GCR_REV CM versions */
+#define GCR_REV_CM3 0x0800
+
+#endif /* __MIPS_ASM_CM_H__ */