[PATCH 7/9] ARM: zynq: Synchronise zynq_cpu_die/kill
From: Soren Brinkmann <hidden>
Date: 2014-08-20 20:42:50
Also in:
linux-devicetree, linux-pm, lkml
Subsystem:
arm port, arm/zynq architecture, the rest · Maintainers:
Russell King, Michal Simek, Linus Torvalds
Avoid races and add synchronisation between the arch specific kill and die routines. The same synchronisation issue was fixed on IMX platform by this commit: "ARM: imx: fix sync issue between imx_cpu_die and imx_cpu_kill" (sha1: 2f3edfd7e27ad4206acbc2ae99c9df5f46353024) Signed-off-by: Soren Brinkmann <redacted> Signed-off-by: Michal Simek <redacted> --- arch/arm/mach-zynq/common.h | 2 ++ arch/arm/mach-zynq/hotplug.c | 2 ++ arch/arm/mach-zynq/platsmp.c | 6 ++++++ arch/arm/mach-zynq/slcr.c | 43 ++++++++++++++++++++++++++++++++++++++++++- 4 files changed, 52 insertions(+), 1 deletion(-)
diff --git a/arch/arm/mach-zynq/common.h b/arch/arm/mach-zynq/common.h
index 87945fa2a179..c0773e87e83c 100644
--- a/arch/arm/mach-zynq/common.h
+++ b/arch/arm/mach-zynq/common.h@@ -24,6 +24,8 @@ extern int zynq_early_slcr_init(void); extern void zynq_slcr_system_reset(void); extern void zynq_slcr_cpu_stop(int cpu); extern void zynq_slcr_cpu_start(int cpu); +extern bool zynq_slcr_cpu_state_read(int cpu); +extern void zynq_slcr_cpu_state_write(int cpu, bool die); extern u32 zynq_slcr_get_device_id(void); #ifdef CONFIG_SMP
diff --git a/arch/arm/mach-zynq/hotplug.c b/arch/arm/mach-zynq/hotplug.c
index 366f46c91365..fe44a05677e2 100644
--- a/arch/arm/mach-zynq/hotplug.c
+++ b/arch/arm/mach-zynq/hotplug.c@@ -19,6 +19,8 @@ */ void zynq_platform_cpu_die(unsigned int cpu) { + zynq_slcr_cpu_state_write(cpu, true); + /* * 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
diff --git a/arch/arm/mach-zynq/platsmp.c b/arch/arm/mach-zynq/platsmp.c
index 616b99e07c60..f77f7ca4c45b 100644
--- a/arch/arm/mach-zynq/platsmp.c
+++ b/arch/arm/mach-zynq/platsmp.c@@ -123,6 +123,12 @@ static void zynq_secondary_init(unsigned int cpu) #ifdef CONFIG_HOTPLUG_CPU static int zynq_cpu_kill(unsigned cpu) { + unsigned long timeout = jiffies + msecs_to_jiffies(50); + + while (zynq_slcr_cpu_state_read(cpu)) + if (time_after(jiffies, timeout)) + return 0; + zynq_slcr_cpu_stop(cpu); return 1; }
diff --git a/arch/arm/mach-zynq/slcr.c b/arch/arm/mach-zynq/slcr.c
index c43a2d16e223..d4cb50cf97c0 100644
--- a/arch/arm/mach-zynq/slcr.c
+++ b/arch/arm/mach-zynq/slcr.c@@ -138,6 +138,8 @@ void zynq_slcr_cpu_start(int cpu) zynq_slcr_write(reg, SLCR_A9_CPU_RST_CTRL_OFFSET); reg &= ~(SLCR_A9_CPU_CLKSTOP << cpu); zynq_slcr_write(reg, SLCR_A9_CPU_RST_CTRL_OFFSET); + + zynq_slcr_cpu_state_write(cpu, false); } /**
@@ -154,8 +156,47 @@ void zynq_slcr_cpu_stop(int cpu) } /** - * zynq_slcr_init - Regular slcr driver init + * zynq_slcr_cpu_state - Read/write cpu state + * @cpu: cpu number * + * SLCR_REBOOT_STATUS save upper 2 bits (31/30 cpu states for cpu0 and cpu1) + * 0 means cpu is running, 1 cpu is going to die. + * + * Return: true if cpu is running, false if cpu is going to die + */ +bool zynq_slcr_cpu_state_read(int cpu) +{ + u32 state; + + state = readl(zynq_slcr_base + SLCR_REBOOT_STATUS_OFFSET); + state &= 1 << (31 - cpu); + + return !state; +} + +/** + * zynq_slcr_cpu_state - Read/write cpu state + * @cpu: cpu number + * @die: cpu state - true if cpu is going to die + * + * SLCR_REBOOT_STATUS save upper 2 bits (31/30 cpu states for cpu0 and cpu1) + * 0 means cpu is running, 1 cpu is going to die. + */ +void zynq_slcr_cpu_state_write(int cpu, bool die) +{ + u32 state, mask; + + state = readl(zynq_slcr_base + SLCR_REBOOT_STATUS_OFFSET); + mask = 1 << (31 - cpu); + if (die) + state |= mask; + else + state &= ~mask; + writel(state, zynq_slcr_base + SLCR_REBOOT_STATUS_OFFSET); +} + +/** + * zynq_slcr_init - Regular slcr driver init * Return: 0 on success, negative errno otherwise. * * Called early during boot from platform code to remap SLCR area.
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2.0.1.1.gfbfc394