From f571eff0a24ed97a919f2b61bb4afdeab4b43002 Mon Sep 17 00:00:00 2001 From: "Kevin D. Kissell" Date: Fri, 3 Aug 2007 19:38:03 +0200 Subject: [MIPS] IRQ Affinity Support for SMTC on Malta Platform Signed-off-by: Kevin D. Kissell Signed-off-by: Ralf Baechle --- arch/mips/kernel/smtc.c | 63 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 63 insertions(+) (limited to 'arch/mips/kernel/smtc.c') diff --git a/arch/mips/kernel/smtc.c b/arch/mips/kernel/smtc.c index f09404377ef..fe22387d58b 100644 --- a/arch/mips/kernel/smtc.c +++ b/arch/mips/kernel/smtc.c @@ -606,6 +606,60 @@ int setup_irq_smtc(unsigned int irq, struct irqaction * new, return setup_irq(irq, new); } +#ifdef CONFIG_MIPS_MT_SMTC_IRQAFF +/* + * Support for IRQ affinity to TCs + */ + +void smtc_set_irq_affinity(unsigned int irq, cpumask_t affinity) +{ + /* + * If a "fast path" cache of quickly decodable affinity state + * is maintained, this is where it gets done, on a call up + * from the platform affinity code. + */ +} + +void smtc_forward_irq(unsigned int irq) +{ + int target; + + /* + * OK wise guy, now figure out how to get the IRQ + * to be serviced on an authorized "CPU". + * + * Ideally, to handle the situation where an IRQ has multiple + * eligible CPUS, we would maintain state per IRQ that would + * allow a fair distribution of service requests. Since the + * expected use model is any-or-only-one, for simplicity + * and efficiency, we just pick the easiest one to find. + */ + + target = first_cpu(irq_desc[irq].affinity); + + /* + * We depend on the platform code to have correctly processed + * IRQ affinity change requests to ensure that the IRQ affinity + * mask has been purged of bits corresponding to nonexistent and + * offline "CPUs", and to TCs bound to VPEs other than the VPE + * connected to the physical interrupt input for the interrupt + * in question. Otherwise we have a nasty problem with interrupt + * mask management. This is best handled in non-performance-critical + * platform IRQ affinity setting code, to minimize interrupt-time + * checks. + */ + + /* If no one is eligible, service locally */ + if (target >= NR_CPUS) { + do_IRQ_no_affinity(irq); + return; + } + + smtc_send_ipi(target, IRQ_AFFINITY_IPI, irq); +} + +#endif /* CONFIG_MIPS_MT_SMTC_IRQAFF */ + /* * IPI model for SMTC is tricky, because interrupts aren't TC-specific. * Within a VPE one TC can interrupt another by different approaches. @@ -830,6 +884,15 @@ void ipi_decode(struct smtc_ipi *pipi) break; } break; +#ifdef CONFIG_MIPS_MT_SMTC_IRQAFF + case IRQ_AFFINITY_IPI: + /* + * Accept a "forwarded" interrupt that was initially + * taken by a TC who doesn't have affinity for the IRQ. + */ + do_IRQ_no_affinity((int)arg_copy); + break; +#endif /* CONFIG_MIPS_MT_SMTC_IRQAFF */ default: printk("Impossible SMTC IPI Type 0x%x\n", type_copy); break; -- cgit v1.2.3