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Subject[PATCH 04/10] irqchip/csky: Optimize remove unnecessary loop irq handle
Date
From: Guo Ren <ren_guo@c-sky.com>

Here is the previous interrupt processing flow:
while (pending) {
^^^^^^^^^^^^^^^ It's unnecessary!
get irq
handle_level/fasteoi_irq {
mask irq
driver irq handler
unmask irq
}
irq_exit {
preempt_count_sub(HARDIRQ_OFFSET);
if (!in_interrupt() && local_softirq_pending())
invoke_softirq();
Because: ^^^^^^^^^^^^^^^^ linux enable irq Here!
}
}

Because linux enable the irq in irq_exit() before ret, we needn't loop
read pending register again for next irq which is done during irq_exit().

Signed-off-by: Guo Ren <ren_guo@c-sky.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Marc Zyngier <marc.zyngier@arm.com>
---
drivers/irqchip/irq-csky-apb-intc.c | 36 ++++++++++++++++++------------------
drivers/irqchip/irq-csky-mpintc.c | 8 ++------
2 files changed, 20 insertions(+), 24 deletions(-)

diff --git a/drivers/irqchip/irq-csky-apb-intc.c b/drivers/irqchip/irq-csky-apb-intc.c
index fcc5444..ae4c59b 100644
--- a/drivers/irqchip/irq-csky-apb-intc.c
+++ b/drivers/irqchip/irq-csky-apb-intc.c
@@ -150,7 +150,7 @@ ck_intc_init_comm(struct device_node *node, struct device_node *parent)
return 0;
}

-static inline bool handle_irq_perbit(struct pt_regs *regs, u32 hwirq,
+static inline bool handle_irq_onebit(struct pt_regs *regs, u32 hwirq,
u32 irq_base)
{
if (hwirq == 0)
@@ -166,16 +166,15 @@ static void gx_irq_handler(struct pt_regs *regs)
{
bool ret;

-retry:
- ret = handle_irq_perbit(regs,
+ ret = handle_irq_onebit(regs,
readl(reg_base + GX_INTC_PEN63_32), 32);
if (ret)
- goto retry;
+ return;

- ret = handle_irq_perbit(regs,
+ ret = handle_irq_onebit(regs,
readl(reg_base + GX_INTC_PEN31_00), 0);
- if (ret)
- goto retry;
+ if (!ret)
+ pr_err("%s: none irq pending!\n", __func__);
}

static int __init
@@ -277,29 +276,30 @@ static void ck_irq_handler(struct pt_regs *regs)
void __iomem *reg_pen_lo = reg_base + CK_INTC_PEN31_00;
void __iomem *reg_pen_hi = reg_base + CK_INTC_PEN63_32;

-retry:
/* handle 0 - 63 irqs */
- ret = handle_irq_perbit(regs, readl(reg_pen_hi), 32);
+ ret = handle_irq_onebit(regs, readl(reg_pen_hi), 32);
if (ret)
- goto retry;
+ return;

- ret = handle_irq_perbit(regs, readl(reg_pen_lo), 0);
+ ret = handle_irq_onebit(regs, readl(reg_pen_lo), 0);
if (ret)
- goto retry;
+ return;

- if (nr_irq == INTC_IRQS)
+ if (nr_irq == INTC_IRQS) {
+ pr_err("%s: none irq pending!\n", __func__);
return;
+ }

/* handle 64 - 127 irqs */
- ret = handle_irq_perbit(regs,
+ ret = handle_irq_onebit(regs,
readl(reg_pen_hi + CK_INTC_DUAL_BASE), 96);
if (ret)
- goto retry;
+ return;

- ret = handle_irq_perbit(regs,
+ ret = handle_irq_onebit(regs,
readl(reg_pen_lo + CK_INTC_DUAL_BASE), 64);
- if (ret)
- goto retry;
+ if (!ret)
+ pr_err("%s: none irq pending!\n", __func__);
}

static int __init
diff --git a/drivers/irqchip/irq-csky-mpintc.c b/drivers/irqchip/irq-csky-mpintc.c
index c67c961..99d3f3f 100644
--- a/drivers/irqchip/irq-csky-mpintc.c
+++ b/drivers/irqchip/irq-csky-mpintc.c
@@ -33,7 +33,6 @@ static void __iomem *INTCL_base;

#define INTCL_PICTLR 0x0
#define INTCL_SIGR 0x60
-#define INTCL_HPPIR 0x68
#define INTCL_RDYIR 0x6c
#define INTCL_SENR 0xa0
#define INTCL_CENR 0xa4
@@ -45,11 +44,8 @@ static void csky_mpintc_handler(struct pt_regs *regs)
{
void __iomem *reg_base = this_cpu_read(intcl_reg);

- do {
- handle_domain_irq(root_domain,
- readl_relaxed(reg_base + INTCL_RDYIR),
- regs);
- } while (readl_relaxed(reg_base + INTCL_HPPIR) & BIT(31));
+ handle_domain_irq(root_domain,
+ readl_relaxed(reg_base + INTCL_RDYIR), regs);
}

static void csky_mpintc_enable(struct irq_data *d)
--
2.7.4
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