[PATCHv3 3/6] irqchip/irq-pruss-intc: Add support for shared and invalid interrupts

[Grzegorz Jaszczyk <grzegorz.jaszczyk@linaro.org>]

From: Suman Anna <s-anna@ti.com>

The PRUSS INTC has a fixed number of output interrupt lines that are
connected to a number of processors or other PRUSS instances or other
devices (like DMA) on the SoC. The output interrupt lines 2 through 9
are usually connected to the main Arm host processor and are referred
to as host interrupts 0 through 7 from ARM/MPU perspective.

All of these 8 host interrupts are not always exclusively connected
to the Arm interrupt controller. Some SoCs have some interrupt lines
not connected to the Arm interrupt controller at all, while a few others
have the interrupt lines connected to multiple processors in which they
need to be partitioned as per SoC integration needs. For example, AM437x
and 66AK2G SoCs have 2 PRUSS instances each and have the host interrupt 5
connected to the other PRUSS, while AM335x has host interrupt 0 shared
between MPU and TSC_ADC and host interrupts 6 & 7 shared between MPU and
a DMA controller.

Add support to the PRUSS INTC driver to allow both these shared and
invalid interrupts by not returning a failure if any of these interrupts
are skipped from the corresponding INTC DT node.

Signed-off-by: Suman Anna <s-anna@ti.com>
Signed-off-by: Grzegorz Jaszczyk <grzegorz.jaszczyk@linaro.org>
---
v2->v3:
- Extra checks for (intc->irqs[i]) in error/remove path was moved from
  "irqchip/irq-pruss-intc: Add a PRUSS irqchip driver for PRUSS
  interrupts" to this patch
v1->v2:
- https://patchwork.kernel.org/patch/11069757/
---
 drivers/irqchip/irq-pruss-intc.c | 73 +++++++++++++++++++++++++++++++++++++---
 1 file changed, 68 insertions(+), 5 deletions(-)

diff --git a/drivers/irqchip/irq-pruss-intc.c b/drivers/irqchip/irq-pruss-intc.c
index fb3dda3..49c936f 100644
--- a/drivers/irqchip/irq-pruss-intc.c
+++ b/drivers/irqchip/irq-pruss-intc.c
@@ -65,11 +65,15 @@
  * @irqs: kernel irq numbers corresponding to PRUSS host interrupts
  * @base: base virtual address of INTC register space
  * @domain: irq domain for this interrupt controller
+ * @shared_intr: bit-map denoting if the MPU host interrupt is shared
+ * @invalid_intr: bit-map denoting if host interrupt is not connected to MPU
  */
 struct pruss_intc {
 	unsigned int irqs[MAX_NUM_HOST_IRQS];
 	void __iomem *base;
 	struct irq_domain *domain;
+	u16 shared_intr;
+	u16 invalid_intr;
 };
 
 static inline u32 pruss_intc_read_reg(struct pruss_intc *intc, unsigned int reg)
@@ -222,7 +226,8 @@ static int pruss_intc_probe(struct platform_device *pdev)
 		"host_intr4", "host_intr5", "host_intr6", "host_intr7", };
 	struct device *dev = &pdev->dev;
 	struct pruss_intc *intc;
-	int i, irq;
+	int i, irq, count;
+	u8 temp_intr[MAX_NUM_HOST_IRQS] = { 0 };
 
 	intc = devm_kzalloc(dev, sizeof(*intc), GFP_KERNEL);
 	if (!intc)
@@ -235,6 +240,52 @@ static int pruss_intc_probe(struct platform_device *pdev)
 		return PTR_ERR(intc->base);
 	}
 
+	count = of_property_read_variable_u8_array(dev->of_node,
+						   "ti,irqs-reserved",
+						   temp_intr, 0,
+						   MAX_NUM_HOST_IRQS);
+	/*
+	 * The irqs-reserved is used only for some SoC's therefore not having
+	 * this property is still valid
+	 */
+	if (count == -EINVAL)
+		count = 0;
+	if (count < 0)
+		return count;
+
+	for (i = 0; i < count; i++) {
+		if (temp_intr[i] >= MAX_NUM_HOST_IRQS) {
+			dev_warn(dev, "ignoring invalid reserved irq %d\n",
+				 temp_intr[i]);
+			continue;
+		}
+
+		intc->invalid_intr |= BIT(temp_intr[i]);
+	}
+
+	count = of_property_read_variable_u8_array(dev->of_node,
+						   "ti,irqs-shared",
+						   temp_intr, 0,
+						   MAX_NUM_HOST_IRQS);
+	/*
+	 * The irqs-shared is used only for some SoC's therefore not having
+	 * this property is still valid
+	 */
+	if (count == -EINVAL)
+		count = 0;
+	if (count < 0)
+		return count;
+
+	for (i = 0; i < count; i++) {
+		if (temp_intr[i] >= MAX_NUM_HOST_IRQS) {
+			dev_warn(dev, "ignoring invalid shared irq %d\n",
+				 temp_intr[i]);
+			continue;
+		}
+
+		intc->shared_intr |= BIT(temp_intr[i]);
+	}
+
 	pruss_intc_init(intc);
 
 	/* always 64 events */
@@ -244,8 +295,14 @@ static int pruss_intc_probe(struct platform_device *pdev)
 		return -ENOMEM;
 
 	for (i = 0; i < MAX_NUM_HOST_IRQS; i++) {
+		if (intc->invalid_intr & BIT(i))
+			continue;
+
 		irq = platform_get_irq_byname(pdev, irq_names[i]);
 		if (irq <= 0) {
+			if (intc->shared_intr & BIT(i))
+				continue;
+
 			dev_err(dev, "platform_get_irq_byname failed for %s : %d\n",
 				irq_names[i], irq);
 			goto fail_irq;
@@ -259,8 +316,11 @@ static int pruss_intc_probe(struct platform_device *pdev)
 	return 0;
 
 fail_irq:
-	while (--i >= 0)
-		irq_set_chained_handler_and_data(intc->irqs[i], NULL, NULL);
+	while (--i >= 0) {
+		if (intc->irqs[i])
+			irq_set_chained_handler_and_data(intc->irqs[i], NULL,
+							 NULL);
+	}
 
 	irq_domain_remove(intc->domain);
 
@@ -273,8 +333,11 @@ static int pruss_intc_remove(struct platform_device *pdev)
 	unsigned int hwirq;
 	int i;
 
-	for (i = 0; i < MAX_NUM_HOST_IRQS; i++)
-		irq_set_chained_handler_and_data(intc->irqs[i], NULL, NULL);
+	for (i = 0; i < MAX_NUM_HOST_IRQS; i++) {
+		if (intc->irqs[i])
+			irq_set_chained_handler_and_data(intc->irqs[i], NULL,
+							 NULL);
+	}
 
 	for (hwirq = 0; hwirq < MAX_PRU_SYS_EVENTS; hwirq++)
 		irq_dispose_mapping(irq_find_mapping(intc->domain, hwirq));
-- 
2.7.4