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irqchip: mips-gic: Use pcpu_masks to avoid reading GIC_SH_MASK*

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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@imgtec.com>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/17109/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
This commit is contained in:
Paul Burton 2017-08-18 14:02:21 -07:00 committed by Ralf Baechle
parent aa493737d8
commit 7778c4b27c
1 changed files with 31 additions and 21 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

52
drivers/irqchip/irq-mips-gic.c
View File

@ -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;