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authorNicolas Pitre <nicolas.pitre@linaro.org>2012-11-27 21:54:41 -0500
committerNicolas Pitre <nicolas.pitre@linaro.org>2013-05-13 19:03:37 -0400
commit418e151df738a7a0ddfdeaf0ea389dad7f4a3b70 (patch)
tree91ae9f8151a9c18e99b3362c799e1b1e24097bfb
parente5ec0e38d6b3cca881b125db20dddd50d7eecbbf (diff)
downloadvexpress-lsk-418e151df738a7a0ddfdeaf0ea389dad7f4a3b70.tar.gz
ARM: SMP: basic IPI triggered completion support
We need a mechanism to let an inbound CPU signal that it is alive before even getting into the kernel environment i.e. from early assembly code. Using an IPI is the simplest way to achieve that. This adds some basic infrastructure to register a struct completion pointer to be "completed" when the dedicated IPI for this task is received. Signed-off-by: Nicolas Pitre <nico@linaro.org>
-rw-r--r--arch/arm/include/asm/hardirq.h2
-rw-r--r--arch/arm/include/asm/smp.h2
-rw-r--r--arch/arm/kernel/smp.c21
3 files changed, 24 insertions, 1 deletions
diff --git a/arch/arm/include/asm/hardirq.h b/arch/arm/include/asm/hardirq.h
index 2740c2a2df6..3d7351c844a 100644
--- a/arch/arm/include/asm/hardirq.h
+++ b/arch/arm/include/asm/hardirq.h
@@ -5,7 +5,7 @@
#include <linux/threads.h>
#include <asm/irq.h>
-#define NR_IPI 6
+#define NR_IPI 7
typedef struct {
unsigned int __softirq_pending;
diff --git a/arch/arm/include/asm/smp.h b/arch/arm/include/asm/smp.h
index d3a22bebe6c..610ccf33f5e 100644
--- a/arch/arm/include/asm/smp.h
+++ b/arch/arm/include/asm/smp.h
@@ -81,6 +81,8 @@ extern void arch_send_call_function_single_ipi(int cpu);
extern void arch_send_call_function_ipi_mask(const struct cpumask *mask);
extern void arch_send_wakeup_ipi_mask(const struct cpumask *mask);
+extern int register_ipi_completion(struct completion *completion, int cpu);
+
struct smp_operations {
#ifdef CONFIG_SMP
/*
diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c
index 79078edbb9b..668c8863ab4 100644
--- a/arch/arm/kernel/smp.c
+++ b/arch/arm/kernel/smp.c
@@ -66,6 +66,7 @@ enum ipi_msg_type {
IPI_CALL_FUNC,
IPI_CALL_FUNC_SINGLE,
IPI_CPU_STOP,
+ IPI_COMPLETION,
};
static DECLARE_COMPLETION(cpu_running);
@@ -429,6 +430,7 @@ static const char *ipi_types[NR_IPI] = {
S(IPI_CALL_FUNC, "Function call interrupts"),
S(IPI_CALL_FUNC_SINGLE, "Single function call interrupts"),
S(IPI_CPU_STOP, "CPU stop interrupts"),
+ S(IPI_COMPLETION, "completion interrupts"),
};
void show_ipi_list(struct seq_file *p, int prec)
@@ -554,6 +556,19 @@ static void ipi_cpu_stop(unsigned int cpu)
cpu_relax();
}
+static DEFINE_PER_CPU(struct completion *, cpu_completion);
+
+int register_ipi_completion(struct completion *completion, int cpu)
+{
+ per_cpu(cpu_completion, cpu) = completion;
+ return IPI_COMPLETION;
+}
+
+static void ipi_complete(unsigned int cpu)
+{
+ complete(per_cpu(cpu_completion, cpu));
+}
+
/*
* Main handler for inter-processor interrupts
*/
@@ -604,6 +619,12 @@ void handle_IPI(int ipinr, struct pt_regs *regs)
irq_exit();
break;
+ case IPI_COMPLETION:
+ irq_enter();
+ ipi_complete(cpu);
+ irq_exit();
+ break;
+
default:
printk(KERN_CRIT "CPU%u: Unknown IPI message 0x%x\n",
cpu, ipinr);