irqchip/ti-sci-inta: Fix processing of masked irqs

The ti_sci_inta_irq_handler() does not take into account INTA IRQs state
(masked/unmasked) as it uses INTA_STATUS_CLEAR_j register to get INTA IRQs
status, which provides raw status value.
This causes hard IRQ handlers to be called or threaded handlers to be
scheduled many times even if corresponding INTA IRQ is masked.
Above, first of all, affects the LEVEL interrupts processing and causes
unexpected behavior up the system stack or crash.

Fix it by using the Interrupt Masked Status INTA_STATUSM_j register which
provides masked INTA IRQs status.

Fixes: 9f1463b86c13 ("irqchip/ti-sci-inta: Add support for Interrupt Aggregator driver")
Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Lokesh Vutla <lokeshvutla@ti.com>
Link: https://lore.kernel.org/r/20200408191532.31252-1-grygorii.strashko@ti.com
Cc: stable@vger.kernel.org

diff --git a/drivers/irqchip/irq-ti-sci-inta.c b/drivers/irqchip/irq-ti-sci-inta.c
index 8f6e6b0..7e3ebf6 100644 (file)
--- a/drivers/irqchip/irq-ti-sci-inta.c
+++ b/drivers/irqchip/irq-ti-sci-inta.c
@@ -37,6 +37,7 @@
 #define VINT_ENABLE_SET_OFFSET 0x0
 #define VINT_ENABLE_CLR_OFFSET 0x8
 #define VINT_STATUS_OFFSET     0x18
+#define VINT_STATUS_MASKED_OFFSET      0x20
 
 /**
  * struct ti_sci_inta_event_desc - Description of an event coming to
@@ -116,7 +117,7 @@ static void ti_sci_inta_irq_handler(struct irq_desc *desc)
        chained_irq_enter(irq_desc_get_chip(desc), desc);
 
        val = readq_relaxed(inta->base + vint_desc->vint_id * 0x1000 +
-                           VINT_STATUS_OFFSET);
+                           VINT_STATUS_MASKED_OFFSET);
 
        for_each_set_bit(bit, &val, MAX_EVENTS_PER_VINT) {
                virq = irq_find_mapping(domain, vint_desc->events[bit].hwirq);