[U-Boot] [PATCH 1/3] arm64: mvebu: Add L3 cache flush functionality to A8K family

[kostap at marvell.com]

From: Konstantin Porotchkin <kostap at marvell.com>

Add missing L3 cache flush functionality which absence prevents
Linux kernel from normal boot in case the L3 cache is enabled
by ATF.
The L3 cache is named the "last level" cache in order to keep
the terminology similar to the ATF code.
This cache should not be disabled by u-boot since the Linux
kernel cannot activate it, so it is activates at ATF stage.
However the cache flush is required for preventing data corruption
after disabling the MMU and the data cache before passing control
to the loaded Linux image.

Signed-off-by: Konstantin Porotchkin <kostap at marvell.com>
Cc: Stefan Roese <sr at denx.de>
Cc: Nadav Haklai <nadavh at marvell.com>
Cc: Neta Zur Hershkovits <neta at marvell.com>
Cc: Omri Itach <omrii at marvell.com>
Cc: Igal Liberman <igall at marvell.com>
Cc: Haim Boot <hayim at marvell.com>
Cc: Hanna Hawa <hannah at marvell.com>
---
 arch/arm/include/asm/arch-armada8k/cache_llc.h | 21 ++++++++++++++
 arch/arm/mach-mvebu/armada8k/Makefile          |  1 +
 arch/arm/mach-mvebu/armada8k/cache_llc.S       | 39 ++++++++++++++++++++++++++
 3 files changed, 61 insertions(+)
 create mode 100644 arch/arm/include/asm/arch-armada8k/cache_llc.h
 create mode 100644 arch/arm/mach-mvebu/armada8k/cache_llc.S

diff --git a/arch/arm/include/asm/arch-armada8k/cache_llc.h b/arch/arm/include/asm/arch-armada8k/cache_llc.h
new file mode 100644
index 0000000..8f97e6d
--- /dev/null
+++ b/arch/arm/include/asm/arch-armada8k/cache_llc.h
@@ -0,0 +1,21 @@
+/*
+ * Copyright (C) 2016 Marvell International Ltd.
+ *
+ * SPDX-License-Identifier:	GPL-2.0
+ * https://spdx.org/licenses
+ */
+
+#ifndef _CACHE_LLC_H_
+#define _CACHE_LLC_H_
+
+/* Armada-7K/8K last level cache */
+
+#define MVEBU_A8K_REGS_BASE_MSB		0xf000
+#define LLC_BASE_ADDR			0x8000
+#define LLC_CACHE_SYNC			0x700
+#define LLC_CACHE_SYNC_COMPLETE		0x730
+#define LLC_FLUSH_BY_WAY		0x7fc
+#define LLC_WAY_MASK			0xffffffff
+#define LLC_CACHE_SYNC_MASK		0x1
+
+#endif	/* _CACHE_LLC_H_ */
diff --git a/arch/arm/mach-mvebu/armada8k/Makefile b/arch/arm/mach-mvebu/armada8k/Makefile
index 84c69d9..0facf14 100644
--- a/arch/arm/mach-mvebu/armada8k/Makefile
+++ b/arch/arm/mach-mvebu/armada8k/Makefile
@@ -5,3 +5,4 @@
 #
 
 obj-y = cpu.o
+obj-y += cache_llc.o
diff --git a/arch/arm/mach-mvebu/armada8k/cache_llc.S b/arch/arm/mach-mvebu/armada8k/cache_llc.S
new file mode 100644
index 0000000..71aecb2
--- /dev/null
+++ b/arch/arm/mach-mvebu/armada8k/cache_llc.S
@@ -0,0 +1,39 @@
+/*
+ * Copyright (C) 2016 Marvell International Ltd.
+ *
+ * SPDX-License-Identifier:	GPL-2.0
+ * https://spdx.org/licenses
+ */
+
+#include <asm/arch-armada8k/cache_llc.h>
+#include <linux/linkage.h>
+
+/*
+ * int __asm_flush_l3_dcache
+ *
+ * flush Armada-8K last level cache.
+ *
+ */
+ENTRY(__asm_flush_l3_dcache)
+	/* flush cache */
+	mov     x0, #LLC_BASE_ADDR
+	add	x0, x0, #LLC_FLUSH_BY_WAY
+	movk    x0, #MVEBU_A8K_REGS_BASE_MSB, lsl #16
+	mov     w1, #LLC_WAY_MASK
+	str     w1, [x0]
+	/* sync cache */
+	mov     x0, #LLC_BASE_ADDR
+	add	x0, x0, #LLC_CACHE_SYNC
+	movk    x0, #MVEBU_A8K_REGS_BASE_MSB, lsl #16
+	str     wzr, [x0]
+	/* check that cache sync completed */
+	mov     x0, #LLC_BASE_ADDR
+	add	x0, x0, #LLC_CACHE_SYNC_COMPLETE
+	movk    x0, #MVEBU_A8K_REGS_BASE_MSB, lsl #16
+1:	ldr	w1, [x0]
+	and	w1, w1, #LLC_CACHE_SYNC_MASK
+	cbnz	w1, 1b
+	/* return success */
+	mov	x0, #0
+	ret
+ENDPROC(__asm_flush_l3_dcache)
-- 
2.7.4