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 <soren.brinkmann@xxxxxxxxxx>
Signed-off-by: Michal Simek <michal.simek@xxxxxxxxxx>
---
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 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.
--
2.1.0.1.g27b9230
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