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Subject[PATCH v2] [ARM] gic: Unmask private interrupts on all cores during IRQ enable
Date
Some multi-core ARM chips designate a unique IRQ number for each core for
private peripheral interrupts (PPIs). Others designate a common IRQ number
for all cores. In the latter case, requesting/freeing private peripheral
interrupts currently unmasks/masks the interrupt for only the
executing core, respectively.

With this change, request_irq will unmask a PPI on all cores so a separate
call to enable_irq on the other cores is not required. Likewise, free_irq
will mask a PPI on the other cores. Also, shutdown is implemented instead
of disable to allow for lazy IRQ disabling.

Signed-off-by: Stephen Caudle <scaudle@codeaurora.org>
---
arch/arm/Kconfig | 5 +++
arch/arm/common/gic.c | 86 +++++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 91 insertions(+), 0 deletions(-)
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 30ddd06..7f11e31 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -1153,6 +1153,11 @@ config SMP

If you don't know what to do here, say N.

+config IRQ_PER_CPU
+ bool
+ depends on SMP
+ default n
+
config HAVE_ARM_SCU
bool
depends on SMP
diff --git a/arch/arm/common/gic.c b/arch/arm/common/gic.c
index 886daaf..937a33a 100644
--- a/arch/arm/common/gic.c
+++ b/arch/arm/common/gic.c
@@ -44,12 +44,25 @@ struct gic_chip_data {
unsigned int wakeup_irqs[32];
unsigned int enabled_irqs[32];
#endif
+#ifdef CONFIG_IRQ_PER_CPU
+ struct call_single_data ppi_data[NR_CPUS];
+#endif
};

#ifndef MAX_GIC_NR
#define MAX_GIC_NR 1
#endif

+#ifdef CONFIG_IRQ_PER_CPU
+#ifndef GIC_PPI_FIRST
+#define GIC_PPI_FIRST 16
+#endif
+
+#ifndef GIC_PPI_LAST
+#define GIC_PPI_LAST 31
+#endif
+#endif
+
static struct gic_chip_data gic_data[MAX_GIC_NR];

static inline void __iomem *gic_dist_base(unsigned int irq)
@@ -272,6 +285,75 @@ static int gic_set_type(unsigned int irq, unsigned int type)
return 0;
}

+#ifdef CONFIG_IRQ_PER_CPU
+static inline void gic_smp_call_function(struct call_single_data *data)
+{
+ int cpu;
+
+ /* Make sure data is visible */
+ smp_mb();
+
+ /*
+ * Since this function is called with interrupts disabled,
+ * smp_call_function can't be used here because it warns (even
+ * if wait = 0) when interrupts are disabled.
+ *
+ * __smp_call_function_single doesn't warn when interrupts are
+ * disabled and not waiting, so use it instead.
+ */
+ for_each_online_cpu(cpu)
+ if (cpu != smp_processor_id())
+ __smp_call_function_single(cpu, data, 0);
+}
+
+static void gic_mask_ppi(void *info)
+{
+ struct irq_desc *desc = info;
+ gic_mask_irq(desc->irq);
+}
+
+static void gic_unmask_ppi(void *info)
+{
+ struct irq_desc *desc = info;
+ gic_unmask_irq(desc->irq);
+}
+
+static void gic_enable_irq(unsigned int irq)
+{
+ struct irq_desc *desc = irq_to_desc(irq);
+ struct gic_chip_data *gic_data = get_irq_chip_data(irq);
+ int cpu = smp_processor_id();
+
+ if (irq >= GIC_PPI_FIRST && irq <= GIC_PPI_LAST) {
+ gic_data->ppi_data[cpu].func = gic_unmask_ppi;
+ gic_data->ppi_data[cpu].info = desc;
+
+ /* Unmask PPIs on all cores during enable. */
+ gic_smp_call_function(&gic_data->ppi_data[cpu]);
+ }
+
+ desc->chip->unmask(irq);
+ desc->status &= ~IRQ_MASKED;
+}
+
+static void gic_shutdown_irq(unsigned int irq)
+{
+ struct irq_desc *desc = irq_to_desc(irq);
+ struct gic_chip_data *gic_data = get_irq_chip_data(irq);
+ int cpu = smp_processor_id();
+
+ if (irq >= GIC_PPI_FIRST && irq <= GIC_PPI_LAST) {
+ gic_data->ppi_data[cpu].func = gic_mask_ppi;
+ gic_data->ppi_data[cpu].info = desc;
+
+ /* Mask PPIs on all cores during disable. */
+ gic_smp_call_function(&gic_data->ppi_data[cpu]);
+ }
+
+ desc->chip->mask(irq);
+ desc->status |= IRQ_MASKED;
+}
+#endif

static struct irq_chip gic_chip = {
.name = "GIC",
@@ -283,6 +365,10 @@ static struct irq_chip gic_chip = {
#endif
.set_type = gic_set_type,
.set_wake = gic_set_wake,
+#ifdef CONFIG_IRQ_PER_CPU
+ .enable = gic_enable_irq,
+ .shutdown = gic_shutdown_irq,
+#endif
};

void __init gic_cascade_irq(unsigned int gic_nr, unsigned int irq)
--
1.7.3.2
--
Sent by an employee of the Qualcomm Innovation Center, Inc.
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum



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