Commit-ID: d7eb4f2ecccd71f701bc8873bcf07c2d3b0375f6 Gitweb: http://git.kernel.org/tip/d7eb4f2ecccd71f701bc8873bcf07c2d3b0375f6 Author: Qais Yousef <qais.yousef@xxxxxxxxxx> AuthorDate: Mon, 19 Jan 2015 11:51:29 +0000 Committer: Thomas Gleixner <tglx@xxxxxxxxxxxxx> CommitDate: Mon, 26 Jan 2015 11:38:23 +0100 irqchip: mips-gic: Handle pending interrupts once in __gic_irq_dispatch() When an interrupt occurs __gic_irq_dispatch() continuously reads local and shared pending registers until all is serviced before returning. The problem with that is that it could introduce a long delay before returning if a piece of hardware keeps triggering while in one of these loops. To ensure fairness and priority doesn't get skewed a lot, read local and shared pending registers once to service each pending IRQ once. If another interupt triggers while servicing the current ones, then we shall re-enter the handler after we return. Signed-off-by: Qais Yousef <qais.yousef@xxxxxxxxxx> Cc: Jason Cooper <jason@xxxxxxxxxxxxxx> Cc: Andrew Bresticker <abrestic@xxxxxxxxxxxx> Cc: <linux-mips@xxxxxxxxxxxxxx> Link: http://lkml.kernel.org/r/1421668289-828-1-git-send-email-qais.yousef@xxxxxxxxxx Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx> --- drivers/irqchip/irq-mips-gic.c | 44 +++++++++++++++++++++++++----------------- 1 file changed, 26 insertions(+), 18 deletions(-) diff --git a/drivers/irqchip/irq-mips-gic.c b/drivers/irqchip/irq-mips-gic.c index 2b0468e..f3f9873 100644 --- a/drivers/irqchip/irq-mips-gic.c +++ b/drivers/irqchip/irq-mips-gic.c @@ -234,9 +234,9 @@ int gic_get_c0_perfcount_int(void) GIC_LOCAL_TO_HWIRQ(GIC_LOCAL_INT_PERFCTR)); } -static unsigned int gic_get_int(void) +static void gic_handle_shared_int(void) { - unsigned int i; + unsigned int i, intr, virq; unsigned long *pcpu_mask; unsigned long pending_reg, intrmask_reg; DECLARE_BITMAP(pending, GIC_MAX_INTRS); @@ -258,7 +258,16 @@ static unsigned int gic_get_int(void) bitmap_and(pending, pending, intrmask, gic_shared_intrs); bitmap_and(pending, pending, pcpu_mask, gic_shared_intrs); - return find_first_bit(pending, gic_shared_intrs); + intr = find_first_bit(pending, gic_shared_intrs); + while (intr != gic_shared_intrs) { + virq = irq_linear_revmap(gic_irq_domain, + GIC_SHARED_TO_HWIRQ(intr)); + do_IRQ(virq); + + /* go to next pending bit */ + bitmap_clear(pending, intr, 1); + intr = find_first_bit(pending, gic_shared_intrs); + } } static void gic_mask_irq(struct irq_data *d) @@ -385,16 +394,26 @@ static struct irq_chip gic_edge_irq_controller = { #endif }; -static unsigned int gic_get_local_int(void) +static void gic_handle_local_int(void) { unsigned long pending, masked; + unsigned int intr, virq; pending = gic_read(GIC_REG(VPE_LOCAL, GIC_VPE_PEND)); masked = gic_read(GIC_REG(VPE_LOCAL, GIC_VPE_MASK)); bitmap_and(&pending, &pending, &masked, GIC_NUM_LOCAL_INTRS); - return find_first_bit(&pending, GIC_NUM_LOCAL_INTRS); + intr = find_first_bit(&pending, GIC_NUM_LOCAL_INTRS); + while (intr != GIC_NUM_LOCAL_INTRS) { + virq = irq_linear_revmap(gic_irq_domain, + GIC_LOCAL_TO_HWIRQ(intr)); + do_IRQ(virq); + + /* go to next pending bit */ + bitmap_clear(&pending, intr, 1); + intr = find_first_bit(&pending, GIC_NUM_LOCAL_INTRS); + } } static void gic_mask_local_irq(struct irq_data *d) @@ -453,19 +472,8 @@ static struct irq_chip gic_all_vpes_local_irq_controller = { static void __gic_irq_dispatch(void) { - unsigned int intr, virq; - - while ((intr = gic_get_local_int()) != GIC_NUM_LOCAL_INTRS) { - virq = irq_linear_revmap(gic_irq_domain, - GIC_LOCAL_TO_HWIRQ(intr)); - do_IRQ(virq); - } - - while ((intr = gic_get_int()) != gic_shared_intrs) { - virq = irq_linear_revmap(gic_irq_domain, - GIC_SHARED_TO_HWIRQ(intr)); - do_IRQ(virq); - } + gic_handle_local_int(); + gic_handle_shared_int(); } static void gic_irq_dispatch(unsigned int irq, struct irq_desc *desc)
