[PATCH 08/13] irqchip: i8259: Add plat-poll support

[Jiaxun Yang]

For some platforms (e.g. Loongson-3), platfrom interrupt controller
supports polling interrupt vector from i8259 automaticly and generating
sepreated interrupt.

Thus we add plat-poll OF property for these platforms and setup sepreated
chained interrupt handler.

Signed-off-by: Jiaxun Yang <jiaxun.y...@flygoat.com>
---
 drivers/irqchip/irq-i8259.c | 47 ++++++++++++++++++++++++++++++++-----
 1 file changed, 41 insertions(+), 6 deletions(-)

diff --git a/drivers/irqchip/irq-i8259.c b/drivers/irqchip/irq-i8259.c
index d000870d9b6b..e7a9895f3b2d 100644
--- a/drivers/irqchip/irq-i8259.c
+++ b/drivers/irqchip/irq-i8259.c
@@ -40,6 +40,12 @@ static void mask_and_ack_8259A(struct irq_data *d);
 static void init_8259A(int auto_eoi);
 static int (*i8259_poll)(void) = i8259_irq;
 
+struct plat_poll_priv {
+       struct irq_domain *domain;
+       int hwirq;
+};
+static struct plat_poll_priv plat_poll_priv[16];
+
 static struct irq_chip i8259A_chip = {
        .name                   = "XT-PIC",
        .irq_mask               = disable_8259A_irq,
@@ -346,22 +352,51 @@ static void i8259_irq_dispatch(struct irq_desc *desc)
        generic_handle_irq(irq);
 }
 
+static void plat_poll_irq_dispatch(struct irq_desc *desc)
+{
+       struct plat_poll_priv *priv = irq_desc_get_handler_data(desc);
+       unsigned int irq;
+
+       irq = irq_linear_revmap(priv->domain, priv->hwirq);
+       generic_handle_irq(irq);
+}
+
 int __init i8259_of_init(struct device_node *node, struct device_node *parent)
 {
        struct irq_domain *domain;
-       unsigned int parent_irq;
 
        domain = __init_i8259_irqs(node);
 
-       parent_irq = irq_of_parse_and_map(node, 0);
-       if (!parent_irq) {
-               pr_err("Failed to map i8259 parent IRQ\n");
-               irq_domain_remove(domain);
-               return -ENODEV;
+       if (of_find_property(node, "plat-poll", NULL)) {
+               int i;
+
+               for (i = 0; i < 16; i++) {
+                       int parent_irq = irq_of_parse_and_map(node, i);
+
+                       if (!parent_irq) {
+                               pr_err("Failed to map %d plat-poll i8259 parent 
IRQ\n", i);
+                               irq_domain_remove(domain);
+                               return -ENODEV;
+                       }
+                       plat_poll_priv[i].domain = domain;
+                       plat_poll_priv[i].hwirq = i;
+                       irq_set_chained_handler_and_data(parent_irq,
+                               plat_poll_irq_dispatch,
+                               &plat_poll_priv[i]);
+               }
+       } else {
+               unsigned int parent_irq;
+
+               parent_irq = irq_of_parse_and_map(node, 0);
+               if (!parent_irq) {
+                       pr_err("Failed to map i8259 parent IRQ\n");
+                       irq_domain_remove(domain);
+                       return -ENODEV;
        }
 
        irq_set_chained_handler_and_data(parent_irq, i8259_irq_dispatch,
                                         domain);
+       }
        return 0;
 }
 IRQCHIP_DECLARE(i8259, "intel,i8259", i8259_of_init);
-- 
2.22.0