[Patch V6 4/6] irqchip: xilinx: Add support for parent intc

From: Zubair Lutfullah Kakakhel
Date: Mon Oct 31 2016 - 08:17:29 EST


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@xxxxxxxxxx>

---
V5 -> V6
Use chained_irq_enter and chained_irq_exit
Add error check for irq_of_parse_and_map
Rebase to v4.9-rc3

V4 -> V5
Rebased to v4.9-rc1
Missing curly braces

V3 -> V4
Clean up if/else when a parent is found
Pass irqchip structure to handler as data

V2 -> V3
Reused existing parent node instead of finding again.
Cleanup up handler based on review

V1 -> V2

No change
---
drivers/irqchip/irq-xilinx-intc.c | 36 ++++++++++++++++++++++++++++++++++--
1 file changed, 34 insertions(+), 2 deletions(-)

diff --git a/drivers/irqchip/irq-xilinx-intc.c b/drivers/irqchip/irq-xilinx-intc.c
index 1f37089..ea15446 100644
--- a/drivers/irqchip/irq-xilinx-intc.c
+++ b/drivers/irqchip/irq-xilinx-intc.c
@@ -12,9 +12,11 @@
#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/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 */
@@ -154,11 +156,26 @@ static int xintc_map(struct irq_domain *d, unsigned int irq, irq_hw_number_t hw)
.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) {
@@ -220,7 +237,22 @@ static int __init xilinx_intc_of_init(struct device_node *intc,
goto err_alloc;
}

- irq_set_default_host(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(root_domain);
+ }

return 0;

--
1.9.1