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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 <nbd@nbd.name>
lede-17.01
Felix Fietkau 2017-01-19 12:31:34 +01:00
parent c76da77573
commit 6538961d6a
1 changed files with 87 additions and 0 deletions
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87
target/linux/lantiq/patches-4.4/0050-MIPS-Lantiq-Fix-cascaded-IRQ-setup.patch Normal file
View File

@ -0,0 +1,87 @@
From: Felix Fietkau <nbd@nbd.name>
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 <nbd@nbd.name>
---
--- 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");