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Koen Kooi
189ce92b4c
Signed-off-by: Koen Kooi <koen@dominion.thruhere.net> Signed-off-by: Denys Dmytriyenko <denys@ti.com>
99 lines
2.6 KiB
Diff
99 lines
2.6 KiB
Diff
From 863d8967cf0028dc6f7ca98d88f4e93045ec143e Mon Sep 17 00:00:00 2001
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From: Shawn Guo <shawn.guo@linaro.org>
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Date: Tue, 22 May 2012 22:13:46 +0800
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Subject: [PATCH 35/67] ARM: imx6: exit coherency when shutting down a cpu
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commit 602bf40971d7f9a1ec0b7ba2b7e6427849828651 upstream.
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There is a system hang issue on imx6q which can easily be seen with
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running a cpu hotplug stress testing (hotplug secondary cores from
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user space via sysfs interface for thousands iterations).
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It turns out that the issue is caused by coherency of the cpu that
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is being shut down. When shutting down a cpu, we need to have the
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cpu exit coherency to prevent it from receiving cache, TLB, or BTB
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maintenance operations broadcast by other CPUs in the cluster.
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Copy cpu_enter_lowpower() and cpu_leave_lowpower() from mach-vexpress
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to have coherency properly handled in platform_cpu_die(), thus fix
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the issue.
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Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
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Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
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---
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arch/arm/mach-imx/hotplug.c | 42 +++++++++++++++++++++++++++++++++++++++++-
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1 file changed, 41 insertions(+), 1 deletion(-)
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diff --git a/arch/arm/mach-imx/hotplug.c b/arch/arm/mach-imx/hotplug.c
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index 89493ab..20ed2d5 100644
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--- a/arch/arm/mach-imx/hotplug.c
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+++ b/arch/arm/mach-imx/hotplug.c
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@@ -12,6 +12,7 @@
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#include <linux/errno.h>
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#include <asm/cacheflush.h>
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+#include <asm/cp15.h>
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#include <mach/common.h>
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int platform_cpu_kill(unsigned int cpu)
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@@ -19,6 +20,44 @@ int platform_cpu_kill(unsigned int cpu)
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return 1;
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}
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+static inline void cpu_enter_lowpower(void)
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+{
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+ unsigned int v;
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+
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+ flush_cache_all();
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+ asm volatile(
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+ "mcr p15, 0, %1, c7, c5, 0\n"
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+ " mcr p15, 0, %1, c7, c10, 4\n"
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+ /*
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+ * Turn off coherency
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+ */
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+ " mrc p15, 0, %0, c1, c0, 1\n"
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+ " bic %0, %0, %3\n"
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+ " mcr p15, 0, %0, c1, c0, 1\n"
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+ " mrc p15, 0, %0, c1, c0, 0\n"
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+ " bic %0, %0, %2\n"
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+ " mcr p15, 0, %0, c1, c0, 0\n"
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+ : "=&r" (v)
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+ : "r" (0), "Ir" (CR_C), "Ir" (0x40)
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+ : "cc");
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+}
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+
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+static inline void cpu_leave_lowpower(void)
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+{
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+ unsigned int v;
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+
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+ asm volatile(
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+ "mrc p15, 0, %0, c1, c0, 0\n"
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+ " orr %0, %0, %1\n"
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+ " mcr p15, 0, %0, c1, c0, 0\n"
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+ " mrc p15, 0, %0, c1, c0, 1\n"
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+ " orr %0, %0, %2\n"
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+ " mcr p15, 0, %0, c1, c0, 1\n"
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+ : "=&r" (v)
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+ : "Ir" (CR_C), "Ir" (0x40)
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+ : "cc");
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+}
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+
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/*
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* platform-specific code to shutdown a CPU
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*
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@@ -26,9 +65,10 @@ int platform_cpu_kill(unsigned int cpu)
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*/
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void platform_cpu_die(unsigned int cpu)
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{
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- flush_cache_all();
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+ cpu_enter_lowpower();
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imx_enable_cpu(cpu, false);
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cpu_do_idle();
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+ cpu_leave_lowpower();
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/* We should never return from idle */
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panic("cpu %d unexpectedly exit from shutdown\n", cpu);
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--
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1.7.9.5
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