[PATCH v5 03/10] MIPS: smp: Provide platform IPI virq & domain hooks

[Jiaxun Yang <jiaxun.yang@flygoat.com>]

Provide platform virq & domain hooks to allow platform
interrupt controllers or SMP code to override IPI interrupt
allocation.

This is required by ipi-mux, the API is aligned with RISC-V
and Arm.

Tested-by: Serge Semin <fancer.lancer@gmail.com>
Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
---
 arch/mips/include/asm/ipi.h | 17 ++++++++++
 arch/mips/kernel/smp.c      | 78 +++++++++++++++++++++++++--------------------
 2 files changed, 61 insertions(+), 34 deletions(-)

diff --git a/arch/mips/include/asm/ipi.h b/arch/mips/include/asm/ipi.h
index 88b507339f51..7cac0f4ccf37 100644
--- a/arch/mips/include/asm/ipi.h
+++ b/arch/mips/include/asm/ipi.h
@@ -2,6 +2,7 @@
 
 #include <linux/cpumask.h>
 #include <linux/interrupt.h>
+#include <linux/irqdomain.h>
 
 #ifndef __ASM_IPI_H
 #define __ASM_IPI_H
@@ -32,6 +33,9 @@ int mips_smp_ipi_free(const struct cpumask *mask);
 
 void mips_smp_ipi_enable(void);
 void mips_smp_ipi_disable(void);
+extern bool mips_smp_ipi_have_virq_range(void);
+void mips_smp_ipi_set_irqdomain(struct irq_domain *d);
+extern void mips_smp_ipi_set_virq_range(int virq, int nr);
 #else
 static inline void mips_smp_ipi_enable(void)
 {
@@ -41,5 +45,18 @@ static inline void mips_smp_ipi_disable(void)
 {
 }
 #endif /* CONFIG_GENERIC_IRQ_IPI */
+#else
+static inline void mips_smp_ipi_set_virq_range(int virq, int nr)
+{
+}
+
+static inline void mips_smp_ipi_set_irqdomain(struct irq_domain *d)
+{
+}
+
+static inline bool mips_smp_ipi_have_virq_range(void)
+{
+	return false;
+}
 #endif /* CONFIG_SMP */
 #endif
diff --git a/arch/mips/kernel/smp.c b/arch/mips/kernel/smp.c
index 9918bf341ffd..d3c7486fee3d 100644
--- a/arch/mips/kernel/smp.c
+++ b/arch/mips/kernel/smp.c
@@ -189,6 +189,7 @@ irq_handler_t ipi_handlers[IPI_MAX] __read_mostly = {
 static DEFINE_PER_CPU_READ_MOSTLY(int, ipi_dummy_dev);
 static int ipi_virqs[IPI_MAX] __ro_after_init;
 static struct irq_desc *ipi_desc[IPI_MAX] __read_mostly;
+static struct irq_domain *ipidomain;
 
 void mips_smp_send_ipi_single(int cpu, enum ipi_message_type op)
 {
@@ -255,11 +256,12 @@ static void smp_ipi_init_one(unsigned int virq, const char *name,
 int mips_smp_ipi_allocate(const struct cpumask *mask)
 {
 	int virq, i;
-	struct irq_domain *ipidomain;
 	struct device_node *node;
 
-	node = of_irq_find_parent(of_root);
-	ipidomain = irq_find_matching_host(node, DOMAIN_BUS_IPI);
+	if (!ipidomain) {
+		node = of_irq_find_parent(of_root);
+		ipidomain = irq_find_matching_host(node, DOMAIN_BUS_IPI);
+	}
 
 	/*
 	 * Some platforms have half DT setup. So if we found irq node but
@@ -291,43 +293,15 @@ int mips_smp_ipi_allocate(const struct cpumask *mask)
 		ipi_virqs[i] = virq;
 	}
 
-	if (irq_domain_is_ipi_per_cpu(ipidomain)) {
-		int cpu;
-
-		for_each_cpu(cpu, mask) {
-			for (i = 0; i < IPI_MAX; i++) {
-				smp_ipi_init_one(ipi_virqs[i] + cpu, ipi_names[i],
-						 ipi_handlers[i]);
-			}
-		}
-	} else {
-		for (i = 0; i < IPI_MAX; i++) {
-			smp_ipi_init_one(ipi_virqs[i], ipi_names[i],
-					 ipi_handlers[i]);
-		}
-	}
-
 	return 0;
 }
 
 int mips_smp_ipi_free(const struct cpumask *mask)
 {
 	int i;
-	struct irq_domain *ipidomain;
-	struct device_node *node;
-
-	node = of_irq_find_parent(of_root);
-	ipidomain = irq_find_matching_host(node, DOMAIN_BUS_IPI);
-
-	/*
-	 * Some platforms have half DT setup. So if we found irq node but
-	 * didn't find an ipidomain, try to search for one that is not in the
-	 * DT.
-	 */
-	if (node && !ipidomain)
-		ipidomain = irq_find_matching_host(NULL, DOMAIN_BUS_IPI);
 
-	BUG_ON(!ipidomain);
+	if (!ipidomain)
+		return -ENODEV;
 
 	if (irq_domain_is_ipi_per_cpu(ipidomain)) {
 		int cpu;
@@ -344,6 +318,25 @@ int mips_smp_ipi_free(const struct cpumask *mask)
 	return 0;
 }
 
+void mips_smp_ipi_set_virq_range(int virq, int nr)
+{
+	int i;
+
+	WARN_ON(nr < IPI_MAX);
+
+	for (i = 0; i < IPI_MAX; i++)
+		ipi_virqs[i] = virq + i;
+}
+
+void mips_smp_ipi_set_irqdomain(struct irq_domain *d)
+{
+	ipidomain = d;
+}
+
+bool mips_smp_ipi_have_virq_range(void)
+{
+	return ipi_virqs[0];
+}
 
 static int __init mips_smp_ipi_init(void)
 {
@@ -352,7 +345,24 @@ static int __init mips_smp_ipi_init(void)
 	if (num_possible_cpus() == 1)
 		return 0;
 
-	mips_smp_ipi_allocate(cpu_possible_mask);
+	if (!mips_smp_ipi_have_virq_range())
+		mips_smp_ipi_allocate(cpu_possible_mask);
+
+	if (ipidomain && irq_domain_is_ipi_per_cpu(ipidomain)) {
+		int cpu;
+
+		for_each_possible_cpu(cpu) {
+			for (i = 0; i < IPI_MAX; i++) {
+				smp_ipi_init_one(ipi_virqs[i] + cpu, ipi_names[i],
+						 ipi_handlers[i]);
+			}
+		}
+	} else {
+		for (i = 0; i < IPI_MAX; i++) {
+			smp_ipi_init_one(ipi_virqs[i], ipi_names[i],
+					 ipi_handlers[i]);
+		}
+	}
 
 	for (i = 0; i < IPI_MAX; i++) {
 		ipi_desc[i] = irq_to_desc(ipi_virqs[i]);

-- 
2.46.0