Commit e9de688dac65 ("irqchip: mips-gic: Support local interrupts")
changed the GIC irqchip driver so that all local interrupts were routed
to the same CPU pin used for external interrupts. Unfortunately this
causes a regression when smp-cmp is used. The CPUs are started by the
bootloader and put in a timer based waiting poll loop, but when their
timer interrupts are rerouted to a different IRQ pin which is not
unmasked they never wake up.
Since smp-cmp support is deprecated and everybody who was using it
should be switching to smp-cps which brings up the secondary CPUs
without bootloader assistance, I've gone for the simple fix which can be
easily removed once smp-cmp is removed, rather than a fully generic fix.
In __gic_init() the local GIC_VPE_TIMER_MAP register is read to find the
boot-time routing of the local timer interrupt, and a chained handler is
added to that CPU pin as well as the normal one.
Fixes: e9de688dac65 ("irqchip: mips-gic: Support local interrupts")
Signed-off-by: James Hogan <james.hogan@xxxxxxxxxx>
Cc: Andrew Bresticker <abrestic@xxxxxxxxxxxx>
Cc: Qais Yousef <qais.yousef@xxxxxxxxxx>
Cc: Paul Burton <paul.burton@xxxxxxxxxx>
Cc: Jason Cooper <jason@xxxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: linux-mips@xxxxxxxxxxxxxx
---
drivers/irqchip/irq-mips-gic.c | 27 +++++++++++++++++++++++++++
1 file changed, 27 insertions(+)
diff --git a/drivers/irqchip/irq-mips-gic.c b/drivers/irqchip/irq-mips-gic.c
index 2b0468e3df6a..56b96c63dc4b 100644
--- a/drivers/irqchip/irq-mips-gic.c
+++ b/drivers/irqchip/irq-mips-gic.c
@@ -37,6 +37,7 @@ static struct irq_domain *gic_irq_domain;
static int gic_shared_intrs;
static int gic_vpes;
static unsigned int gic_cpu_pin;
+static unsigned int timer_cpu_pin;
static struct irq_chip gic_level_irq_controller, gic_edge_irq_controller;
static void __gic_irq_dispatch(void);
@@ -616,6 +617,8 @@ static int gic_local_irq_domain_map(struct irq_domain *d, unsigned int virq,
gic_write(GIC_REG(VPE_OTHER, GIC_VPE_COMPARE_MAP), val);
break;
case GIC_LOCAL_INT_TIMER:
+ /* CONFIG_MIPS_CMP workaround (see __gic_init) */
+ val = GIC_MAP_TO_PIN_MSK | timer_cpu_pin;
gic_write(GIC_REG(VPE_OTHER, GIC_VPE_TIMER_MAP), val);
break;
case GIC_LOCAL_INT_PERFCTR:
@@ -713,12 +716,36 @@ static void __init __gic_init(unsigned long gic_base_addr,
if (cpu_has_veic) {
/* Always use vector 1 in EIC mode */
gic_cpu_pin = 0;
+ timer_cpu_pin = gic_cpu_pin;
set_vi_handler(gic_cpu_pin + GIC_PIN_TO_VEC_OFFSET,
__gic_irq_dispatch);
} else {
gic_cpu_pin = cpu_vec - GIC_CPU_PIN_OFFSET;
irq_set_chained_handler(MIPS_CPU_IRQ_BASE + cpu_vec,
gic_irq_dispatch);
+ /*
+ * With the CMP implementation of SMP (deprecated), other CPUs
+ * are started by the bootloader and put into a timer based
+ * waiting poll loop. We must not re-route those CPU's local
+ * timer interrupts as the wait instruction will never finish,
+ * so just handle whatever CPU interrupt it is routed to by
+ * default.
+ *
+ * This workaround should be removed when CMP support is
+ * dropped.
+ */
+ if (IS_ENABLED(CONFIG_MIPS_CMP) &&
+ gic_local_irq_is_routable(GIC_LOCAL_INT_TIMER)) {
+ timer_cpu_pin = gic_read(GIC_REG(VPE_LOCAL,
+ GIC_VPE_TIMER_MAP)) &
+ GIC_MAP_MSK;
+ irq_set_chained_handler(MIPS_CPU_IRQ_BASE +
+ GIC_CPU_PIN_OFFSET +
+ timer_cpu_pin,
+ gic_irq_dispatch);
+ } else {
+ timer_cpu_pin = gic_cpu_pin;
+ }
}
gic_irq_domain = irq_domain_add_simple(node, GIC_NUM_LOCAL_INTRS +
--
2.0.5
