This patch avoids the need to read the GIC_SH_MASK* registers when
decoding shared interrupts by setting & clearing the interrupt's bit in
the appropriate CPU's pcpu_masks entry when masking or unmasking the
interrupt.
This effectively means that whilst an interrupt is masked we clear its
bit in all pcpu_masks, which causes gic_handle_shared_int() to ignore it
on all CPUs without needing to check GIC_SH_MASK*.
In essence, we add a little overhead to masking or unmasking interrupts
but in return reduce the overhead of the far more common task of
decoding interrupts.
Signed-off-by: Paul Burton <paul.burton@xxxxxxxxxx>
Cc: Jason Cooper <jason@xxxxxxxxxxxxxx>
Cc: Marc Zyngier <marc.zyngier@xxxxxxx>
Cc: Ralf Baechle <ralf@xxxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: linux-mips@xxxxxxxxxxxxxx
---
Changes in v2:
- Split pcpu_masks bit setting out of gic_setup_pcpu_masks() & rename to
gic_clear_pcpu_masks(), avoiding confusing use of NR_CPUS.
drivers/irqchip/irq-mips-gic.c | 52 +++++++++++++++++++++++++-----------------
1 file changed, 31 insertions(+), 21 deletions(-)
diff --git a/drivers/irqchip/irq-mips-gic.c b/drivers/irqchip/irq-mips-gic.c
index 00153231376a..e2ab0cee9ff2 100644
--- a/drivers/irqchip/irq-mips-gic.c
+++ b/drivers/irqchip/irq-mips-gic.c
@@ -55,6 +55,15 @@ static struct irq_chip gic_level_irq_controller, gic_edge_irq_controller;
DECLARE_BITMAP(ipi_resrv, GIC_MAX_INTRS);
DECLARE_BITMAP(ipi_available, GIC_MAX_INTRS);
+static void gic_clear_pcpu_masks(unsigned int intr)
+{
+ unsigned int i;
+
+ /* Clear the interrupt's bit in all pcpu_masks */
+ for_each_possible_cpu(i)
+ clear_bit(intr, per_cpu_ptr(pcpu_masks, i));
+}
+
static bool gic_local_irq_is_routable(int intr)
{
u32 vpe_ctl;
@@ -133,24 +142,17 @@ static void gic_handle_shared_int(bool chained)
unsigned int intr, virq;
unsigned long *pcpu_mask;
DECLARE_BITMAP(pending, GIC_MAX_INTRS);
- DECLARE_BITMAP(intrmask, GIC_MAX_INTRS);
/* Get per-cpu bitmaps */
pcpu_mask = this_cpu_ptr(pcpu_masks);
- if (mips_cm_is64) {
+ if (mips_cm_is64)
__ioread64_copy(pending, addr_gic_pend(),
DIV_ROUND_UP(gic_shared_intrs, 64));
- __ioread64_copy(intrmask, addr_gic_mask(),
- DIV_ROUND_UP(gic_shared_intrs, 64));
- } else {
+ else
__ioread32_copy(pending, addr_gic_pend(),
DIV_ROUND_UP(gic_shared_intrs, 32));
- __ioread32_copy(intrmask, addr_gic_mask(),
- DIV_ROUND_UP(gic_shared_intrs, 32));
- }
- bitmap_and(pending, pending, intrmask, gic_shared_intrs);
bitmap_and(pending, pending, pcpu_mask, gic_shared_intrs);
for_each_set_bit(intr, pending, gic_shared_intrs) {
@@ -165,12 +167,23 @@ static void gic_handle_shared_int(bool chained)
static void gic_mask_irq(struct irq_data *d)
{
- write_gic_rmask(BIT(GIC_HWIRQ_TO_SHARED(d->hwirq)));
+ unsigned int intr = GIC_HWIRQ_TO_SHARED(d->hwirq);
+
+ write_gic_rmask(BIT(intr));
+ gic_clear_pcpu_masks(intr);
}
static void gic_unmask_irq(struct irq_data *d)
{
- write_gic_smask(BIT(GIC_HWIRQ_TO_SHARED(d->hwirq)));
+ struct cpumask *affinity = irq_data_get_affinity_mask(d);
+ unsigned int intr = GIC_HWIRQ_TO_SHARED(d->hwirq);
+ unsigned int cpu;
+
+ write_gic_smask(BIT(intr));
+
+ gic_clear_pcpu_masks(intr);
+ cpu = cpumask_first_and(affinity, cpu_online_mask);
+ set_bit(intr, per_cpu_ptr(pcpu_masks, cpu));
}
static void gic_ack_irq(struct irq_data *d)
@@ -239,7 +252,6 @@ static int gic_set_affinity(struct irq_data *d, const struct cpumask *cpumask,
unsigned int irq = GIC_HWIRQ_TO_SHARED(d->hwirq);
cpumask_t tmp = CPU_MASK_NONE;
unsigned long flags;
- int i;
cpumask_and(&tmp, cpumask, cpu_online_mask);
if (cpumask_empty(&tmp))
@@ -252,9 +264,9 @@ static int gic_set_affinity(struct irq_data *d, const struct cpumask *cpumask,
write_gic_map_vp(irq, BIT(mips_cm_vp_id(cpumask_first(&tmp))));
/* Update the pcpu_masks */
- for (i = 0; i < min(gic_vpes, NR_CPUS); i++)
- clear_bit(irq, per_cpu_ptr(pcpu_masks, i));
- set_bit(irq, per_cpu_ptr(pcpu_masks, cpumask_first(&tmp)));
+ gic_clear_pcpu_masks(irq);
+ if (read_gic_mask(irq))
+ set_bit(irq, per_cpu_ptr(pcpu_masks, cpumask_first(&tmp)));
cpumask_copy(irq_data_get_affinity_mask(d), cpumask);
spin_unlock_irqrestore(&gic_lock, flags);
@@ -405,18 +417,16 @@ static int gic_local_irq_domain_map(struct irq_domain *d, unsigned int virq,
}
static int gic_shared_irq_domain_map(struct irq_domain *d, unsigned int virq,
- irq_hw_number_t hw, unsigned int vpe)
+ irq_hw_number_t hw, unsigned int cpu)
{
int intr = GIC_HWIRQ_TO_SHARED(hw);
unsigned long flags;
- int i;
spin_lock_irqsave(&gic_lock, flags);
write_gic_map_pin(intr, GIC_MAP_PIN_MAP_TO_PIN | gic_cpu_pin);
- write_gic_map_vp(intr, BIT(mips_cm_vp_id(vpe)));
- for (i = 0; i < min(gic_vpes, NR_CPUS); i++)
- clear_bit(intr, per_cpu_ptr(pcpu_masks, i));
- set_bit(intr, per_cpu_ptr(pcpu_masks, vpe));
+ write_gic_map_vp(intr, BIT(mips_cm_vp_id(cpu)));
+ gic_clear_pcpu_masks(intr);
+ set_bit(intr, per_cpu_ptr(pcpu_masks, cpu));
spin_unlock_irqrestore(&gic_lock, flags);
return 0;
--
2.14.1
