From 6538961d6ad079e5cff93361b4d907758ab5f9dd Mon Sep 17 00:00:00 2001 From: Felix Fietkau Date: Thu, 19 Jan 2017 12:31:34 +0100 Subject: [PATCH] lantiq: fix spurious irq storm Since the MIPS IRQ stack patches, lantiq devices were emitting a storm of messages like this: [ 567.872172] Spurious IRQ: CAUSE=0x1100c300 Fix this by reworking the IRQ dispatch code Signed-off-by: Felix Fietkau --- ...0-MIPS-Lantiq-Fix-cascaded-IRQ-setup.patch | 87 +++++++++++++++++++ 1 file changed, 87 insertions(+) create mode 100644 target/linux/lantiq/patches-4.4/0050-MIPS-Lantiq-Fix-cascaded-IRQ-setup.patch diff --git a/target/linux/lantiq/patches-4.4/0050-MIPS-Lantiq-Fix-cascaded-IRQ-setup.patch b/target/linux/lantiq/patches-4.4/0050-MIPS-Lantiq-Fix-cascaded-IRQ-setup.patch new file mode 100644 index 0000000000..c0d7afc541 --- /dev/null +++ b/target/linux/lantiq/patches-4.4/0050-MIPS-Lantiq-Fix-cascaded-IRQ-setup.patch @@ -0,0 +1,87 @@ +From: Felix Fietkau +Date: Thu, 19 Jan 2017 12:14:44 +0100 +Subject: [PATCH] MIPS: Lantiq: Fix cascaded IRQ setup + +With the IRQ stack changes integrated, the XRX200 devices started +emitting a constant stream of kernel messages like this: + +[ 565.415310] Spurious IRQ: CAUSE=0x1100c300 + +This appears to be caused by IP0 firing for some reason without being +handled. Fix this by setting up IP2-6 as a proper chained IRQ handler and +calling do_IRQ for all MIPS CPU interrupts. + +Cc: john@phrozen.org +Cc: stable@vger.kernel.org +Signed-off-by: Felix Fietkau +--- + +--- a/arch/mips/lantiq/irq.c ++++ b/arch/mips/lantiq/irq.c +@@ -271,6 +271,11 @@ static void ltq_hw5_irqdispatch(void) + DEFINE_HWx_IRQDISPATCH(5) + #endif + ++static void ltq_hw_irq_handler(struct irq_desc *desc) ++{ ++ ltq_hw_irqdispatch(irq_desc_get_irq(desc) - 2); ++} ++ + #ifdef CONFIG_MIPS_MT_SMP + void __init arch_init_ipiirq(int irq, struct irqaction *action) + { +@@ -315,23 +320,19 @@ static struct irqaction irq_call = { + asmlinkage void plat_irq_dispatch(void) + { + unsigned int pending = read_c0_status() & read_c0_cause() & ST0_IM; +- unsigned int i; ++ int irq; + +- if ((MIPS_CPU_TIMER_IRQ == 7) && (pending & CAUSEF_IP7)) { +- do_IRQ(MIPS_CPU_TIMER_IRQ); +- goto out; +- } else { +- for (i = 0; i < MAX_IM; i++) { +- if (pending & (CAUSEF_IP2 << i)) { +- ltq_hw_irqdispatch(i); +- goto out; +- } +- } ++ if (!pending) { ++ spurious_interrupt(); ++ return; + } +- pr_alert("Spurious IRQ: CAUSE=0x%08x\n", read_c0_status()); + +-out: +- return; ++ pending >>= CAUSEB_IP; ++ while (pending) { ++ irq = fls(pending) - 1; ++ do_IRQ(MIPS_CPU_IRQ_BASE + irq); ++ pending &= ~BIT(irq); ++ } + } + + static int icu_map(struct irq_domain *d, unsigned int irq, irq_hw_number_t hw) +@@ -356,11 +357,6 @@ static const struct irq_domain_ops irq_d + .map = icu_map, + }; + +-static struct irqaction cascade = { +- .handler = no_action, +- .name = "cascade", +-}; +- + int __init icu_of_init(struct device_node *node, struct device_node *parent) + { + struct device_node *eiu_node; +@@ -392,7 +388,7 @@ int __init icu_of_init(struct device_nod + mips_cpu_irq_init(); + + for (i = 0; i < MAX_IM; i++) +- setup_irq(i + 2, &cascade); ++ irq_set_chained_handler(i + 2, ltq_hw_irq_handler); + + if (cpu_has_vint) { + pr_info("Setting up vectored interrupts\n"); -- 2.25.1