irqchip/xilinx: Add support for parent intc

The MIPS based xilfpga platform has the following IRQ structure

Peripherals --> xilinx_intcontroller -> mips_cpu_int controller

Add support for the driver to chain the irq handler

Signed-off-by: Zubair Lutfullah Kakakhel <Zubair.Kakakhel@imgtec.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

diff --git a/drivers/irqchip/irq-xilinx-intc.c b/drivers/irqchip/irq-xilinx-intc.c
index 34ec609ea89839d4029d10731c3bcd1d409a4562..971c141d575dabbcfe3f3b9c7ff3508ae75cd513 100644 (file)
--- a/drivers/irqchip/irq-xilinx-intc.c
+++ b/drivers/irqchip/irq-xilinx-intc.c
@@ -12,10 +12,12 @@
 #include <linux/irqdomain.h>
 #include <linux/irq.h>
 #include <linux/irqchip.h>
+#include <linux/irqchip/chained_irq.h>
 #include <linux/of_address.h>
 #include <linux/io.h>
 #include <linux/jump_label.h>
 #include <linux/bug.h>
+#include <linux/of_irq.h>
 
 /* No one else should require these constants, so define them locally here. */
 #define ISR 0x00                       /* Interrupt Status Register */
@@ -133,11 +135,26 @@ static const struct irq_domain_ops xintc_irq_domain_ops = {
        .map = xintc_map,
 };
 
+static void xil_intc_irq_handler(struct irq_desc *desc)
+{
+       struct irq_chip *chip = irq_desc_get_chip(desc);
+       u32 pending;
+
+       chained_irq_enter(chip, desc);
+       do {
+               pending = xintc_get_irq();
+               if (pending == -1U)
+                       break;
+               generic_handle_irq(pending);
+       } while (true);
+       chained_irq_exit(chip, desc);
+}
+
 static int __init xilinx_intc_of_init(struct device_node *intc,
                                             struct device_node *parent)
 {
        u32 nr_irq;
-       int ret;
+       int ret, irq;
        struct xintc_irq_chip *irqc;
 
        if (xintc_irqc) {
@@ -196,7 +213,20 @@ static int __init xilinx_intc_of_init(struct device_node *intc,
                goto err_alloc;
        }
 
-       irq_set_default_host(irqc->root_domain);
+       if (parent) {
+               irq = irq_of_parse_and_map(intc, 0);
+               if (irq) {
+                       irq_set_chained_handler_and_data(irq,
+                                                        xil_intc_irq_handler,
+                                                        irqc);
+               } else {
+                       pr_err("irq-xilinx: interrupts property not in DT\n");
+                       ret = -EINVAL;
+                       goto err_alloc;
+               }
+       } else {
+               irq_set_default_host(irqc->root_domain);
+       }
 
        return 0;