Subject: [PATCH 08/11] irqchip/gic: Configure SGIs as standard interrupts

From: Marc Zyngier <[email-masked]>
Date: Tue, 19 May 2020 17:17:52 +0100

Change the way we deal with GIC SGIs by turning them into proper
IRQs, and calling into the arch code to register the interrupt range
instead of a callback.

Signed-off-by: Marc Zyngier <[email-masked]>
---
 drivers/irqchip/irq-gic.c | 113 +++++++++++++++++++++++++-------------
 1 file changed, 74 insertions(+), 39 deletions(-)

diff --git a/drivers/irqchip/irq-gic.c b/drivers/irqchip/irq-gic.c
index e289810e794c..8d146ac28c74 100644
--- a/drivers/irqchip/irq-gic.c
+++ b/drivers/irqchip/irq-gic.c
@@ -47,6 +47,8 @@
 
 #include "irq-gic-common.h"
 
+#define GIC_IRQ_TYPE_SGI	0x561
+
 #ifdef CONFIG_ARM64
 #include <asm/cpufeature.h>
 
@@ -335,31 +337,22 @@ static void __exception_irq_entry gic_handle_irq(struct pt_regs *regs)
 		irqstat = readl_relaxed(cpu_base + GIC_CPU_INTACK);
 		irqnr = irqstat & GICC_IAR_INT_ID_MASK;
 
-		if (likely(irqnr > 15 && irqnr < 1020)) {
-			if (static_branch_likely(&supports_deactivate_key))
-				writel_relaxed(irqstat, cpu_base + GIC_CPU_EOI);
-			isb();
-			handle_domain_irq(gic->domain, irqnr, regs);
-			continue;
-		}
-		if (irqnr < 16) {
+		if (unlikely(irqnr >= 1020))
+			break;
+
+		if (static_branch_likely(&supports_deactivate_key))
 			writel_relaxed(irqstat, cpu_base + GIC_CPU_EOI);
-			if (static_branch_likely(&supports_deactivate_key))
-				writel_relaxed(irqstat, cpu_base + GIC_CPU_DEACTIVATE);
-#ifdef CONFIG_SMP
-			/*
-			 * Ensure any shared data written by the CPU sending
-			 * the IPI is read after we've read the ACK register
-			 * on the GIC.
-			 *
-			 * Pairs with the write barrier in gic_raise_softirq
-			 */
+		isb();
+
+		/*
+		 * Ensure any shared data written by the CPU sending the IPI
+		 * is read after we've read the ACK register on the GIC.
+		 *
+		 * Pairs with the write barrier in gic_ipi_send_mask
+		 */
+		if (irqnr <= 15)
 			smp_rmb();
-			handle_IPI(irqnr, regs);
-#endif
-			continue;
-		}
-		break;
+		handle_domain_irq(gic->domain, irqnr, regs);
 	} while (1);
 }
 
@@ -801,14 +794,14 @@ static int gic_set_affinity(struct irq_data *d, const struct cpumask *mask_val,
 	return IRQ_SET_MASK_OK_DONE;
 }
 
-static void gic_raise_softirq(const struct cpumask *mask, unsigned int irq)
+static void gic_ipi_send_mask(struct irq_data *d, const struct cpumask *mask)
 {
 	int cpu;
 	unsigned long flags, map = 0;
 
 	if (unlikely(nr_cpu_ids == 1)) {
 		/* Only one CPU? let's do a self-IPI... */
-		writel_relaxed(2 << 24 | irq,
+		writel_relaxed(2 << 24 | d->hwirq,
 			       gic_data_dist_base(&gic_data[0]) + GIC_DIST_SOFTINT);
 		return;
 	}
@@ -826,7 +819,7 @@ static void gic_raise_softirq(const struct cpumask *mask, unsigned int irq)
 	dmb(ishst);
 
 	/* this always happens on GIC0 */
-	writel_relaxed(map << 16 | irq, gic_data_dist_base(&gic_data[0]) + GIC_DIST_SOFTINT);
+	writel_relaxed(map << 16 | d->hwirq, gic_data_dist_base(&gic_data[0]) + GIC_DIST_SOFTINT);
 
 	gic_unlock_irqrestore(flags);
 }
@@ -839,14 +832,40 @@ static int gic_starting_cpu(unsigned int cpu)
 
 static __init void gic_smp_init(void)
 {
-	set_smp_cross_call(gic_raise_softirq);
+	struct irq_fwspec sgi_fwspec = {
+		.fwnode		= gic_data[0].domain->fwnode,
+	};
+	int base_sgi;
+
 	cpuhp_setup_state_nocalls(CPUHP_AP_IRQ_GIC_STARTING,
 				  "irqchip/arm/gic:starting",
 				  gic_starting_cpu, NULL);
+
+	if (is_of_node(gic_data[0].domain->fwnode)) {
+		/* DT */
+		sgi_fwspec.param_count = 3;
+		sgi_fwspec.param[0] = GIC_IRQ_TYPE_SGI;
+		sgi_fwspec.param[1] = 0;
+		sgi_fwspec.param[2] = IRQ_TYPE_EDGE_RISING;
+	} else {
+		/* ACPI */
+		sgi_fwspec.param_count = 2;
+		sgi_fwspec.param[0] = 0;
+		sgi_fwspec.param[1] = IRQ_TYPE_EDGE_RISING;
+	}
+
+	base_sgi = __irq_domain_alloc_irqs(gic_data[0].domain, -1, 8,
+					   NUMA_NO_NODE, &sgi_fwspec,
+					   false, NULL);
+	if (WARN_ON(base_sgi <= 0))
+		return;
+
+	set_smp_ipi_range(base_sgi, 8);
 }
 #else
 #define gic_smp_init()		do { } while(0)
 #define gic_set_affinity	NULL
+#define gic_ipi_send_mask	NULL
 #endif
 
 #ifdef CONFIG_BL_SWITCHER
@@ -993,16 +1012,26 @@ static int gic_irq_domain_map(struct irq_domain *d, unsigned int irq,
 {
 	struct gic_chip_data *gic = d->host_data;
 
-	if (hw < 32) {
+	switch (hw) {
+	case 0 ... 15:
+		irq_set_percpu_devid(irq);
+		irq_domain_set_info(d, irq, hw, &gic->chip, d->host_data,
+				    handle_percpu_devid_fasteoi_ipi,
+				    NULL, NULL);
+		irq_set_status_flags(irq, IRQ_NOAUTOEN);
+		break;
+	case 16 ... 31:
 		irq_set_percpu_devid(irq);
 		irq_domain_set_info(d, irq, hw, &gic->chip, d->host_data,
 				    handle_percpu_devid_irq, NULL, NULL);
 		irq_set_status_flags(irq, IRQ_NOAUTOEN);
-	} else {
+		break;
+	default:
 		irq_domain_set_info(d, irq, hw, &gic->chip, d->host_data,
 				    handle_fasteoi_irq, NULL, NULL);
 		irq_set_probe(irq);
 		irqd_set_single_target(irq_desc_get_irq_data(irq_to_desc(irq)));
+		break;
 	}
 	return 0;
 }
@@ -1020,15 +1049,19 @@ static int gic_irq_domain_translate(struct irq_domain *d,
 		if (fwspec->param_count < 3)
 			return -EINVAL;
 
-		/* Get the interrupt number and add 16 to skip over SGIs */
-		*hwirq = fwspec->param[1] + 16;
-
-		/*
-		 * For SPIs, we need to add 16 more to get the GIC irq
-		 * ID number
-		 */
-		if (!fwspec->param[0])
-			*hwirq += 16;
+		switch (fwspec->param[0]) {
+		case 0:			/* SPI */
+			*hwirq = fwspec->param[1] + 32;
+			break;
+		case 1:			/* PPI */
+			*hwirq = fwspec->param[1] + 16;
+			break;
+		case GIC_IRQ_TYPE_SGI:	/* SGI, can't be set via DT */
+			*hwirq = fwspec->param[1];
+			break;
+		default:
+			return -EINVAL;
+		}
 
 		*type = fwspec->param[2] & IRQ_TYPE_SENSE_MASK;
 
@@ -1097,8 +1130,10 @@ static void gic_init_chip(struct gic_chip_data *gic, struct device *dev,
 		gic->chip.irq_set_vcpu_affinity = gic_irq_set_vcpu_affinity;
 	}
 
-	if (gic == &gic_data[0])
+	if (gic == &gic_data[0]) {
 		gic->chip.irq_set_affinity = gic_set_affinity;
+		gic->chip.ipi_send_mask = gic_ipi_send_mask;
+	}
 }
 
 static int gic_init_bases(struct gic_chip_data *gic,
-- 
2.26.2

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