From 69c31b7a6e9cd4654ed0bfc7e70b4d7076a5cdb3 Mon Sep 17 00:00:00 2001
From: Shawn Guo <shawn.guo@linaro.org>
Date: Tue, 6 Sep 2011 14:59:40 +0800
Subject: arm/imx6q: add smp and cpu hotplug support

It adds smp and cpu hotplug support for imx6q.

Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
---
 arch/arm/mach-imx/head-v7.S | 71 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 71 insertions(+)
 create mode 100644 arch/arm/mach-imx/head-v7.S

(limited to 'arch/arm/mach-imx/head-v7.S')

diff --git a/arch/arm/mach-imx/head-v7.S b/arch/arm/mach-imx/head-v7.S
new file mode 100644
index 000000000000..ede908bca7d5
--- /dev/null
+++ b/arch/arm/mach-imx/head-v7.S
@@ -0,0 +1,71 @@
+/*
+ * Copyright 2011 Freescale Semiconductor, Inc.
+ * Copyright 2011 Linaro Ltd.
+ *
+ * The code contained herein is licensed under the GNU General Public
+ * License. You may obtain a copy of the GNU General Public License
+ * Version 2 or later at the following locations:
+ *
+ * http://www.opensource.org/licenses/gpl-license.html
+ * http://www.gnu.org/copyleft/gpl.html
+ */
+
+#include <linux/linkage.h>
+#include <linux/init.h>
+#include <asm/hardware/cache-l2x0.h>
+
+	.section ".text.head", "ax"
+	__CPUINIT
+
+/*
+ * The secondary kernel init calls v7_flush_dcache_all before it enables
+ * the L1; however, the L1 comes out of reset in an undefined state, so
+ * the clean + invalidate performed by v7_flush_dcache_all causes a bunch
+ * of cache lines with uninitialized data and uninitialized tags to get
+ * written out to memory, which does really unpleasant things to the main
+ * processor.  We fix this by performing an invalidate, rather than a
+ * clean + invalidate, before jumping into the kernel.
+ *
+ * This funciton is cloned from arch/arm/mach-tegra/headsmp.S, and needs
+ * to be called for both secondary cores startup and primary core resume
+ * procedures.  Ideally, it should be moved into arch/arm/mm/cache-v7.S.
+ */
+ENTRY(v7_invalidate_l1)
+	mov	r0, #0
+	mcr	p15, 2, r0, c0, c0, 0
+	mrc	p15, 1, r0, c0, c0, 0
+
+	ldr	r1, =0x7fff
+	and	r2, r1, r0, lsr #13
+
+	ldr	r1, =0x3ff
+
+	and	r3, r1, r0, lsr #3	@ NumWays - 1
+	add	r2, r2, #1		@ NumSets
+
+	and	r0, r0, #0x7
+	add	r0, r0, #4	@ SetShift
+
+	clz	r1, r3		@ WayShift
+	add	r4, r3, #1	@ NumWays
+1:	sub	r2, r2, #1	@ NumSets--
+	mov	r3, r4		@ Temp = NumWays
+2:	subs	r3, r3, #1	@ Temp--
+	mov	r5, r3, lsl r1
+	mov	r6, r2, lsl r0
+	orr	r5, r5, r6	@ Reg = (Temp<<WayShift)|(NumSets<<SetShift)
+	mcr	p15, 0, r5, c7, c6, 2
+	bgt	2b
+	cmp	r2, #0
+	bgt	1b
+	dsb
+	isb
+	mov	pc, lr
+ENDPROC(v7_invalidate_l1)
+
+#ifdef CONFIG_SMP
+ENTRY(v7_secondary_startup)
+	bl	v7_invalidate_l1
+	b	secondary_startup
+ENDPROC(v7_secondary_startup)
+#endif
-- 
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