From 50c7960a4517d6c93226351cd8c43c86f104c919 Mon Sep 17 00:00:00 2001 From: Soren Brinkmann Date: Tue, 2 Sep 2014 14:19:12 -0700 Subject: ARM: zynq: Synchronise zynq_cpu_die/kill 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 Signed-off-by: Michal Simek --- 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(-) (limited to 'arch/arm/mach-zynq') diff --git a/arch/arm/mach-zynq/common.h b/arch/arm/mach-zynq/common.h index 0edbb6997b1c..24d6340d3fb6 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 6c7843108c7f..06415eeba7e6 100644 --- a/arch/arm/mach-zynq/platsmp.c +++ b/arch/arm/mach-zynq/platsmp.c @@ -127,6 +127,12 @@ 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. -- cgit v1.2.3