ARC: IRQ: Do not use hwirq as virq and vice versa

This came up when reviewing code to address missing IRQ affinity
setting in AXS103 platform and/or implementing hierarchical IRQ domains

- smp_ipi_irq_setup() callers pass hwirq but in turn calls
  request_percpu_irq() which expects a linux virq. So invoke
  irq_find_mapping() to do the conversion
  (also explicitify this in code by renaming the args appropriately)

- idu_of_init()/idu_cascade_isr() were similarly using linux virq where
  hwirq is expected, so do the conversion using irqd_to_hwirq() helper
Signed-off-by: Yuriy Kolerov <yuriy.kolerov@synopsys.com>
[vgupta: made changelog a bit concise a bit]
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>

arch/arc/include/asm/smp.h

@@ -37,9 +37,9 @@ extern const char *arc_platform_smp_cpuinfo(void);
  * API expected BY platform smp code (FROM arch smp code)
  *
  * smp_ipi_irq_setup:
- *	Takes @cpu and @irq to which the arch-common ISR is hooked up
+ *	Takes @cpu and @hwirq to which the arch-common ISR is hooked up
  */
-extern int smp_ipi_irq_setup(int cpu, int irq);
+extern int smp_ipi_irq_setup(int cpu, irq_hw_number_t hwirq);
 
 /*
  * struct plat_smp_ops	- SMP callbacks provided by platform to ARC SMP

arch/arc/kernel/mcip.c

@@ -207,16 +207,15 @@ static struct irq_chip idu_irq_chip = {
 
 };
 
-static int idu_first_irq;
+static irq_hw_number_t idu_first_hwirq;
 
 static void idu_cascade_isr(struct irq_desc *desc)
 {
-	struct irq_domain *domain = irq_desc_get_handler_data(desc);
-	unsigned int core_irq = irq_desc_get_irq(desc);
-	unsigned int idu_irq;
+	struct irq_domain *idu_domain = irq_desc_get_handler_data(desc);
+	irq_hw_number_t core_hwirq = irqd_to_hwirq(irq_desc_get_irq_data(desc));
+	irq_hw_number_t idu_hwirq = core_hwirq - idu_first_hwirq;
 
-	idu_irq = core_irq - idu_first_irq;
-	generic_handle_irq(irq_find_mapping(domain, idu_irq));
+	generic_handle_irq(irq_find_mapping(idu_domain, idu_hwirq));
 }
 
 static int idu_irq_map(struct irq_domain *d, unsigned int virq, irq_hw_number_t hwirq)
@@ -282,7 +281,7 @@ idu_of_init(struct device_node *intc, struct device_node *parent)
 	struct irq_domain *domain;
 	/* Read IDU BCR to confirm nr_irqs */
 	int nr_irqs = of_irq_count(intc);
-	int i, irq;
+	int i, virq;
 	struct mcip_bcr mp;
 
 	READ_BCR(ARC_REG_MCIP_BCR, mp);
@@ -303,11 +302,11 @@ idu_of_init(struct device_node *intc, struct device_node *parent)
 		 * however we need it to get the parent virq and set IDU handler
 		 * as first level isr
 		 */
-		irq = irq_of_parse_and_map(intc, i);
+		virq = irq_of_parse_and_map(intc, i);
 		if (!i)
-			idu_first_irq = irq;
+			idu_first_hwirq = irqd_to_hwirq(irq_get_irq_data(virq));
 
-		irq_set_chained_handler_and_data(irq, idu_cascade_isr, domain);
+		irq_set_chained_handler_and_data(virq, idu_cascade_isr, domain);
 	}
 
 	__mcip_cmd(CMD_IDU_ENABLE, 0);

arch/arc/kernel/smp.c

@@ -22,6 +22,7 @@
 #include <linux/atomic.h>
 #include <linux/cpumask.h>
 #include <linux/reboot.h>
+#include <linux/irqdomain.h>
 #include <asm/processor.h>
 #include <asm/setup.h>
 #include <asm/mach_desc.h>
@@ -353,20 +354,24 @@ irqreturn_t do_IPI(int irq, void *dev_id)
  */
 static DEFINE_PER_CPU(int, ipi_dev);
 
-int smp_ipi_irq_setup(int cpu, int irq)
+int smp_ipi_irq_setup(int cpu, irq_hw_number_t hwirq)
 {
 	int *dev = per_cpu_ptr(&ipi_dev, cpu);
+	unsigned int virq = irq_find_mapping(NULL, hwirq);
+
+	if (!virq)
+		panic("Cannot find virq for root domain and hwirq=%lu", hwirq);
 
 	/* Boot cpu calls request, all call enable */
 	if (!cpu) {
 		int rc;
 
-		rc = request_percpu_irq(irq, do_IPI, "IPI Interrupt", dev);
+		rc = request_percpu_irq(virq, do_IPI, "IPI Interrupt", dev);
 		if (rc)
-			panic("Percpu IRQ request failed for %d\n", irq);
+			panic("Percpu IRQ request failed for %u\n", virq);
 	}
 
-	enable_percpu_irq(irq, 0);
+	enable_percpu_irq(virq, 0);
 
 	return 0;
 }