[PATCH 4.9 66/72] MIPS: Lantiq: Fix cascaded IRQ setup

Greg Kroah-Hartman
2017-04-06T08:43:28Z

From: Felix Fietkau <nbd@nbd.name>

commit 6c356eda225e3ee134ed4176b9ae3a76f793f4dd upstream.

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 is caused by IP0 getting handled by plat_irq_dispatch() rather than
its vectored interrupt handler, which is fixed by commit de856416e714
("MIPS: IRQ Stack: Fix erroneous jal to plat_irq_dispatch").

Fix plat_irq_dispatch() to handle non-vectored IPI interrupts correctly
by setting up IP2-6 as proper chained IRQ handlers and calling do_IRQ
for all MIPS CPU interrupts.

Signed-off-by: Felix Fietkau <nbd@nbd.name>
Acked-by: John Crispin <john@phrozen.org>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/15077/
[james.hogan@imgtec.com: tweaked commit message]
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Signed-off-by: Amit Pundir <amit.pundir@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
arch/mips/lantiq/irq.c | 36 ++++++++++++++++--------------------
1 file changed, 16 insertions(+), 20 deletions(-)

--- a/arch/mips/lantiq/irq.c
+++ b/arch/mips/lantiq/irq.c
@@ -269,6 +269,11 @@ 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)
{
@@ -313,23 +318,19 @@ 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)
@@ -354,11 +355,6 @@ 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;
@@ -390,7 +386,7 @@ 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");