[PATCH 3/3] irqchip: xilinx: Add support to remove the Xilinx INTC driver module.

[Anirudha Sarangi <anirudha.sarangi@xilinx.com>]

The existing Xilinx INTC driver does not have mechanism to remove the
driver when it is being used as a module. For example, if the Xilinx
INTC IP is part of a removable fpga partition and a user intends to
replace the removable partition with a new one, the existing
implementation will not support the same.
The enhancement is done by adding a new remove API and making other
necessary changes.

Signed-off-by: Anirudha Sarangi <anirudha.sarangi@xilinx.com>
---
 drivers/irqchip/irq-xilinx-intc.c | 49 +++++++++++++++++++++++++++++--
 1 file changed, 47 insertions(+), 2 deletions(-)

diff --git a/drivers/irqchip/irq-xilinx-intc.c b/drivers/irqchip/irq-xilinx-intc.c
index 642733a6cbdf..2c5b76efabf6 100644
--- a/drivers/irqchip/irq-xilinx-intc.c
+++ b/drivers/irqchip/irq-xilinx-intc.c
@@ -39,6 +39,7 @@ struct xintc_irq_chip {
 	struct		irq_domain *root_domain;
 	u32		intr_mask;
 	u32		nr_irq;
+	int		irq;
 };
 
 static struct xintc_irq_chip *primary_intc;
@@ -234,6 +235,8 @@ static int xilinx_intc_of_init(struct device_node *intc,
 
 	if (parent) {
 		irq = irq_of_parse_and_map(intc, 0);
+		irqc->irq = irq;
+		intc->data = irqc;
 		if (irq) {
 			irq_set_chained_handler_and_data(irq,
 							 xil_intc_irq_handler,
@@ -257,5 +260,47 @@ static int xilinx_intc_of_init(struct device_node *intc,
 
 }
 
-IRQCHIP_DECLARE(xilinx_intc_xps, "xlnx,xps-intc-1.00.a", xilinx_intc_of_init);
-IRQCHIP_DECLARE(xilinx_intc_opb, "xlnx,opb-intc-1.00.c", xilinx_intc_of_init);
+static int xilinx_intc_of_remove(struct device_node *intc,
+				 struct device_node *parent)
+{
+	int irq;
+	struct xintc_irq_chip *irqc;
+
+	if (!parent)
+		return 0;
+
+	irqc = intc->data;
+	irq = irqc->irq;
+	irq_set_chained_handler_and_data(irq, NULL, NULL);
+	if (irqc->domain) {
+		irq_dispose_mapping(irq);
+		irq_domain_remove(irqc->domain);
+	}
+	/*
+	 * Disable all external interrupts until they are
+	 * explicity requested.
+	 */
+	xintc_write(irqc, IER, 0);
+	/* Acknowledge any pending interrupts just in case. */
+	xintc_write(irqc, IAR, 0xffffffff);
+	/* Turn off the Master Enable. */
+	xintc_write(irqc, MER, 0x0);
+
+	iounmap(irqc->base);
+	kfree(irqc);
+
+	return 0;
+}
+
+static struct irqc_init_remove_funps intc_funps = {
+		.irqchip_initp = xilinx_intc_of_init,
+		.irqchip_removep = xilinx_intc_of_remove,
+};
+
+IRQCHIP_PLATFORM_DRIVER_BEGIN(xilinx_intc_xps)
+IRQCHIP_MATCH("xlnx,xps-intc-1.00.a", &intc_funps)
+IRQCHIP_PLATFORM_DRIVER_END(xilinx_intc_xps)
+
+IRQCHIP_PLATFORM_DRIVER_BEGIN(xilinx_intc_opb)
+IRQCHIP_MATCH("xlnx,opb-intc-1.00.c", &intc_funps)
+IRQCHIP_PLATFORM_DRIVER_END(xilinx_intc_opb)
-- 
2.17.1