irqchip/irq-pruss-intc: Add logic for handling reserved interrupts

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 logic to the PRUSS INTC driver to ignore both these shared and
invalid interrupts.

Co-developed-by: Grzegorz Jaszczyk <grzegorz.jaszczyk@linaro.org>
Signed-off-by: Suman Anna <s-anna@ti.com>
Signed-off-by: Grzegorz Jaszczyk <grzegorz.jaszczyk@linaro.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>

diff --git a/drivers/irqchip/irq-pruss-intc.c b/drivers/irqchip/irq-pruss-intc.c
index c8bdef4..e7ba358 100644 (file)
--- a/drivers/irqchip/irq-pruss-intc.c
+++ b/drivers/irqchip/irq-pruss-intc.c
@@ -484,7 +484,7 @@ static int pruss_intc_probe(struct platform_device *pdev)
        struct pruss_intc *intc;
        struct pruss_host_irq_data *host_data;
        int i, irq, ret;
-       u8 max_system_events;
+       u8 max_system_events, irqs_reserved = 0;
 
        data = of_device_get_match_data(dev);
        if (!data)
@@ -504,6 +504,16 @@ static int pruss_intc_probe(struct platform_device *pdev)
        if (IS_ERR(intc->base))
                return PTR_ERR(intc->base);
 
+       ret = of_property_read_u8(dev->of_node, "ti,irqs-reserved",
+                                 &irqs_reserved);
+
+       /*
+        * The irqs-reserved is used only for some SoC's therefore not having
+        * this property is still valid
+        */
+       if (ret < 0 && ret != -EINVAL)
+               return ret;
+
        pruss_intc_init(intc);
 
        mutex_init(&intc->lock);
@@ -514,6 +524,9 @@ static int pruss_intc_probe(struct platform_device *pdev)
                return -ENOMEM;
 
        for (i = 0; i < MAX_NUM_HOST_IRQS; i++) {
+               if (irqs_reserved & BIT(i))
+                       continue;
+
                irq = platform_get_irq_byname(pdev, irq_names[i]);
                if (irq <= 0) {
                        ret = (irq == 0) ? -EINVAL : irq;
@@ -538,8 +551,11 @@ 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);
 
@@ -553,8 +569,11 @@ 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_system_events; hwirq++)
                irq_dispose_mapping(irq_find_mapping(intc->domain, hwirq));