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ARM: EXYNOS: Fix CPU idle clock down after CPU off

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On Exynos4 USE_DELAYED_RESET_ASSERTION must be set in
ARM_COREx_OPTION register during CPU power down. This is the proper way
of powering down CPU on Exynos4.

Additionally on Exynos4212 without this the CPU clock down feature won't
work after powering down some CPU and the online CPUs will work at full
frequency chosen by CPUfreq governor.

Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Reviewed-by: Tomasz Figa <t.figa@samsung.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>
This commit is contained in:
Krzysztof Kozlowski 2014-09-14 02:49:32 +09:00 committed by Kukjin Kim
parent 27b9ee852c
commit 13cfa6c4f7
2 changed files with 44 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

43
arch/arm/mach-exynos/platsmp.c
View File

@ -34,8 +34,32 @@
extern void exynos4_secondary_startup(void);
/*
* Set or clear the USE_DELAYED_RESET_ASSERTION option, set on Exynos4 SoCs
* during hot-(un)plugging CPUx.
*
* The feature can be cleared safely during first boot of secondary CPU.
*
* Exynos4 SoCs require setting USE_DELAYED_RESET_ASSERTION during powering
* down a CPU so the CPU idle clock down feature could properly detect global
* idle state when CPUx is off.
*/
static void exynos_set_delayed_reset_assertion(u32 core_id, bool enable)
{
if (soc_is_exynos4()) {
unsigned int tmp;
tmp = pmu_raw_readl(EXYNOS_ARM_CORE_OPTION(core_id));
if (enable)
tmp |= S5P_USE_DELAYED_RESET_ASSERTION;
else
tmp &= ~(S5P_USE_DELAYED_RESET_ASSERTION);
pmu_raw_writel(tmp, EXYNOS_ARM_CORE_OPTION(core_id));
}
}
#ifdef CONFIG_HOTPLUG_CPU
static inline void cpu_leave_lowpower(void)
static inline void cpu_leave_lowpower(u32 core_id)
{
unsigned int v;
@ -49,6 +73,8 @@ static inline void cpu_leave_lowpower(void)
: "=&r" (v)
: "Ir" (CR_C), "Ir" (0x40)
: "cc");
exynos_set_delayed_reset_assertion(core_id, false);
}
static inline void platform_do_lowpower(unsigned int cpu, int *spurious)
@ -61,6 +87,14 @@ static inline void platform_do_lowpower(unsigned int cpu, int *spurious)
/* Turn the CPU off on next WFI instruction. */
exynos_cpu_power_down(core_id);
/*
* Exynos4 SoCs require setting
* USE_DELAYED_RESET_ASSERTION so the CPU idle
* clock down feature could properly detect
* global idle state when CPUx is off.
*/
exynos_set_delayed_reset_assertion(core_id, true);
wfi();
if (pen_release == core_id) {
@ -286,6 +320,9 @@ static int exynos_boot_secondary(unsigned int cpu, struct task_struct *idle)
udelay(10);
}
/* No harm if this is called during first boot of secondary CPU */
exynos_set_delayed_reset_assertion(core_id, false);
/*
* now the secondary core is starting up let it run its
* calibrations, then wait for it to finish
@ -376,6 +413,8 @@ static void __init exynos_smp_prepare_cpus(unsigned int max_cpus)
static void exynos_cpu_die(unsigned int cpu)
{
int spurious = 0;
u32 mpidr = cpu_logical_map(cpu);
u32 core_id = MPIDR_AFFINITY_LEVEL(mpidr, 0);
v7_exit_coherency_flush(louis);
@ -385,7 +424,7 @@ static void exynos_cpu_die(unsigned int cpu)
* bring this CPU back into the world of cache
* coherency, and then restore interrupts
*/
cpu_leave_lowpower();
cpu_leave_lowpower(core_id);
if (spurious)
pr_warn("CPU%u: %u spurious wakeup calls\n", cpu, spurious);

3
arch/arm/mach-exynos/regs-pmu.h
View File

@ -20,6 +20,7 @@
#define S5P_USE_STANDBY_WFI0 (1 << 16)
#define S5P_USE_STANDBY_WFE0 (1 << 24)
#define S5P_USE_DELAYED_RESET_ASSERTION BIT(12)
#define EXYNOS_SWRESET 0x0400
#define EXYNOS5440_SWRESET 0x00C4
@ -106,6 +107,8 @@
(EXYNOS_ARM_CORE0_CONFIGURATION + (0x80 * (_nr)))
#define EXYNOS_ARM_CORE_STATUS(_nr) \
(EXYNOS_ARM_CORE_CONFIGURATION(_nr) + 0x4)
#define EXYNOS_ARM_CORE_OPTION(_nr) \
(EXYNOS_ARM_CORE_CONFIGURATION(_nr) + 0x8)
#define EXYNOS_ARM_COMMON_CONFIGURATION 0x2500
#define EXYNOS_COMMON_CONFIGURATION(_nr) \