Revert "MIPS: Lantiq: Fix cascaded IRQ setup"

This reverts commit 362721c which is
commit 6c356ed upstream.

It shouldn't have been included in a stable release.

Reported-by: Amit Pundir <[email protected]>
Cc: Felix Fietkau <[email protected]>
Cc: John Crispin <[email protected]>
Cc: James Hogan <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

arch/mips/lantiq/irq.c

@@ -269,11 +269,6 @@ 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)
 {
@@ -318,19 +313,23 @@ static struct irqaction irq_call = {
 asmlinkage void plat_irq_dispatch(void)
 {
  unsigned int pending = read_c0_status() & read_c0_cause() & ST0_IM;
- int irq;
-
- if (!pending) {
- spurious_interrupt();
- return;
+ unsigned int i;
+
+ 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;
+ }
+ }
  }
+ pr_alert("Spurious IRQ: CAUSE=0x%08x\n", read_c0_status());
 
- pending >>= CAUSEB_IP;
- while (pending) {
- irq = fls(pending) - 1;
- do_IRQ(MIPS_CPU_IRQ_BASE + irq);
- pending &= ~BIT(irq);
- }
+out:
+ return;
 }
 
 static int icu_map(struct irq_domain *d, unsigned int irq, irq_hw_number_t hw)
@@ -355,6 +354,11 @@ static const struct irq_domain_ops irq_domain_ops = {
  .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;
@@ -386,7 +390,7 @@ int __init icu_of_init(struct device_node *node, struct device_node *parent)
  mips_cpu_irq_init();
 
  for (i = 0; i < MAX_IM; i++)
- irq_set_chained_handler(i + 2, ltq_hw_irq_handler);
+ setup_irq(i + 2, &cascade);
 
  if (cpu_has_vint) {
  pr_info("Setting up vectored interrupts\n");