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author | Kukjin Kim <kgene.kim@samsung.com> | 2011-02-14 16:33:10 +0900 |
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committer | Kukjin Kim <kgene.kim@samsung.com> | 2011-02-22 13:51:14 +0900 |
commit | 7d30e8b3815f804139271dfc31962ab74ce89650 (patch) | |
tree | 711d4830705e0147cb8184ca1a8e6e3c97bc02fe /arch/arm/mach-exynos4/hotplug.c | |
parent | f5412be599602124d2bdd49947b231dd77c0bf99 (diff) | |
download | op-kernel-dev-7d30e8b3815f804139271dfc31962ab74ce89650.zip op-kernel-dev-7d30e8b3815f804139271dfc31962ab74ce89650.tar.gz |
ARM: EXYNOS4: Add EXYNOS4 CPU initialization support
This patch adds EXYNOS4 CPU support files in mach-exynos4,
and basically they are moved from mach-s5pv310 so that it
can support Samsung's new CPU name, EXYNOS4.
The EXYNOS4 ingegrates a ARM Cortex A9 multi-core.
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>
Diffstat (limited to 'arch/arm/mach-exynos4/hotplug.c')
-rw-r--r-- | arch/arm/mach-exynos4/hotplug.c | 130 |
1 files changed, 130 insertions, 0 deletions
diff --git a/arch/arm/mach-exynos4/hotplug.c b/arch/arm/mach-exynos4/hotplug.c new file mode 100644 index 0000000..4c42f9c --- /dev/null +++ b/arch/arm/mach-exynos4/hotplug.c @@ -0,0 +1,130 @@ +/* linux arch/arm/mach-exynos4/hotplug.c + * + * Cloned from linux/arch/arm/mach-realview/hotplug.c + * + * Copyright (C) 2002 ARM Ltd. + * All Rights Reserved + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. +*/ + +#include <linux/kernel.h> +#include <linux/errno.h> +#include <linux/smp.h> + +#include <asm/cacheflush.h> + +extern volatile int pen_release; + +static inline void cpu_enter_lowpower(void) +{ + unsigned int v; + + flush_cache_all(); + asm volatile( + " mcr p15, 0, %1, c7, c5, 0\n" + " mcr p15, 0, %1, c7, c10, 4\n" + /* + * Turn off coherency + */ + " mrc p15, 0, %0, c1, c0, 1\n" + " bic %0, %0, #0x20\n" + " mcr p15, 0, %0, c1, c0, 1\n" + " mrc p15, 0, %0, c1, c0, 0\n" + " bic %0, %0, %2\n" + " mcr p15, 0, %0, c1, c0, 0\n" + : "=&r" (v) + : "r" (0), "Ir" (CR_C) + : "cc"); +} + +static inline void cpu_leave_lowpower(void) +{ + unsigned int v; + + asm volatile( + "mrc p15, 0, %0, c1, c0, 0\n" + " orr %0, %0, %1\n" + " mcr p15, 0, %0, c1, c0, 0\n" + " mrc p15, 0, %0, c1, c0, 1\n" + " orr %0, %0, #0x20\n" + " mcr p15, 0, %0, c1, c0, 1\n" + : "=&r" (v) + : "Ir" (CR_C) + : "cc"); +} + +static inline void platform_do_lowpower(unsigned int cpu, int *spurious) +{ + /* + * there is no power-control hardware on this platform, so all + * we can do is put the core into WFI; this is safe as the calling + * code will have already disabled interrupts + */ + for (;;) { + /* + * here's the WFI + */ + asm(".word 0xe320f003\n" + : + : + : "memory", "cc"); + + if (pen_release == cpu) { + /* + * OK, proper wakeup, we're done + */ + break; + } + + /* + * Getting here, means that we have come out of WFI without + * having been woken up - this shouldn't happen + * + * Just note it happening - when we're woken, we can report + * its occurrence. + */ + (*spurious)++; + } +} + +int platform_cpu_kill(unsigned int cpu) +{ + return 1; +} + +/* + * platform-specific code to shutdown a CPU + * + * Called with IRQs disabled + */ +void platform_cpu_die(unsigned int cpu) +{ + int spurious = 0; + + /* + * we're ready for shutdown now, so do it + */ + cpu_enter_lowpower(); + platform_do_lowpower(cpu, &spurious); + + /* + * bring this CPU back into the world of cache + * coherency, and then restore interrupts + */ + cpu_leave_lowpower(); + + if (spurious) + pr_warn("CPU%u: %u spurious wakeup calls\n", cpu, spurious); +} + +int platform_cpu_disable(unsigned int cpu) +{ + /* + * we don't allow CPU 0 to be shutdown (it is still too special + * e.g. clock tick interrupts) + */ + return cpu == 0 ? -EPERM : 0; +} |