irqchip/gic-v3: Make distributor priorities variables

In subsequent patches the GICv3 driver will choose the regular interrupt
priority at boot time.

In preparation for using dynamic priorities, place the priorities in
variables and update the code to pass these as parameters. Users of
GICD_INT_DEF_PRI_X4 are modified to replicate the priority byte using
REPEAT_BYTE_U32().

There should be no functional change as a result of this patch.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Alexandru Elisei <alexandru.elisei@arm.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will@kernel.org>
Reviewed-by: Marc Zyngier <maz@kernel.org>
Tested-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20240617111841.2529370-4-mark.rutland@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>

drivers/irqchip/irq-gic-common.c

@@ -7,6 +7,7 @@
 #include <linux/io.h>
 #include <linux/irq.h>
 #include <linux/irqchip/arm-gic.h>
+#include <linux/kernel.h>
 
 #include "irq-gic-common.h"
 
@@ -87,7 +88,7 @@ int gic_configure_irq(unsigned int irq, unsigned int type,
 	return ret;
 }
 
-void gic_dist_config(void __iomem *base, int gic_irqs)
+void gic_dist_config(void __iomem *base, int gic_irqs, u8 priority)
 {
 	unsigned int i;
 
@@ -102,7 +103,8 @@ void gic_dist_config(void __iomem *base, int gic_irqs)
 	 * Set priority on all global interrupts.
 	 */
 	for (i = 32; i < gic_irqs; i += 4)
-		writel_relaxed(GICD_INT_DEF_PRI_X4, base + GIC_DIST_PRI + i);
+		writel_relaxed(REPEAT_BYTE_U32(priority),
+			       base + GIC_DIST_PRI + i);
 
 	/*
 	 * Deactivate and disable all SPIs. Leave the PPI and SGIs
@@ -116,7 +118,7 @@ void gic_dist_config(void __iomem *base, int gic_irqs)
 	}
 }
 
-void gic_cpu_config(void __iomem *base, int nr)
+void gic_cpu_config(void __iomem *base, int nr, u8 priority)
 {
 	int i;
 
@@ -135,6 +137,6 @@ void gic_cpu_config(void __iomem *base, int nr)
 	 * Set priority on PPI and SGI interrupts
 	 */
 	for (i = 0; i < nr; i += 4)
-		writel_relaxed(GICD_INT_DEF_PRI_X4,
+		writel_relaxed(REPEAT_BYTE_U32(priority),
 					base + GIC_DIST_PRI + i * 4 / 4);
 }

drivers/irqchip/irq-gic-common.h

@@ -21,8 +21,8 @@ struct gic_quirk {
 
 int gic_configure_irq(unsigned int irq, unsigned int type,
                        void __iomem *base);
-void gic_dist_config(void __iomem *base, int gic_irqs);
-void gic_cpu_config(void __iomem *base, int nr);
+void gic_dist_config(void __iomem *base, int gic_irqs, u8 priority);
+void gic_cpu_config(void __iomem *base, int nr, u8 priority);
 void gic_enable_quirks(u32 iidr, const struct gic_quirk *quirks,
 		void *data);
 void gic_enable_of_quirks(const struct device_node *np,

drivers/irqchip/irq-gic-v3-its.c

@@ -59,7 +59,7 @@ static u32 lpi_id_bits;
 #define LPI_PROPBASE_SZ		ALIGN(BIT(LPI_NRBITS), SZ_64K)
 #define LPI_PENDBASE_SZ		ALIGN(BIT(LPI_NRBITS) / 8, SZ_64K)
 
-#define LPI_PROP_DEFAULT_PRIO	GICD_INT_DEF_PRI
+static u8 __ro_after_init lpi_prop_prio;
 
 /*
  * Collection structure - just an ID, and a redistributor address to
@@ -1926,7 +1926,7 @@ static int its_vlpi_unmap(struct irq_data *d)
 	/* and restore the physical one */
 	irqd_clr_forwarded_to_vcpu(d);
 	its_send_mapti(its_dev, d->hwirq, event);
-	lpi_update_config(d, 0xff, (LPI_PROP_DEFAULT_PRIO |
+	lpi_update_config(d, 0xff, (lpi_prop_prio |
 				    LPI_PROP_ENABLED |
 				    LPI_PROP_GROUP1));
 
@@ -2181,8 +2181,8 @@ static void its_lpi_free(unsigned long *bitmap, u32 base, u32 nr_ids)
 
 static void gic_reset_prop_table(void *va)
 {
-	/* Priority 0xa0, Group-1, disabled */
-	memset(va, LPI_PROP_DEFAULT_PRIO | LPI_PROP_GROUP1, LPI_PROPBASE_SZ);
+	/* Regular IRQ priority, Group-1, disabled */
+	memset(va, lpi_prop_prio | LPI_PROP_GROUP1, LPI_PROPBASE_SZ);
 
 	/* Make sure the GIC will observe the written configuration */
 	gic_flush_dcache_to_poc(va, LPI_PROPBASE_SZ);
@@ -5650,7 +5650,7 @@ int __init its_lpi_memreserve_init(void)
 }
 
 int __init its_init(struct fwnode_handle *handle, struct rdists *rdists,
-		    struct irq_domain *parent_domain)
+		    struct irq_domain *parent_domain, u8 irq_prio)
 {
 	struct device_node *of_node;
 	struct its_node *its;
@@ -5660,6 +5660,7 @@ int __init its_init(struct fwnode_handle *handle, struct rdists *rdists,
 
 	gic_rdists = rdists;
 
+	lpi_prop_prio = irq_prio;
 	its_parent = parent_domain;
 	of_node = to_of_node(handle);
 	if (of_node)

drivers/irqchip/irq-gic-v3.c

@@ -12,6 +12,7 @@
 #include <linux/delay.h>
 #include <linux/interrupt.h>
 #include <linux/irqdomain.h>
+#include <linux/kernel.h>
 #include <linux/kstrtox.h>
 #include <linux/of.h>
 #include <linux/of_address.h>
@@ -36,7 +37,8 @@
 
 #include "irq-gic-common.h"
 
-#define GICD_INT_NMI_PRI	(GICD_INT_DEF_PRI & ~0x80)
+static u8 dist_prio_irq __ro_after_init = GICD_INT_DEF_PRI;
+static u8 dist_prio_nmi __ro_after_init = GICD_INT_DEF_PRI & ~0x80;
 
 #define FLAGS_WORKAROUND_GICR_WAKER_MSM8996	(1ULL << 0)
 #define FLAGS_WORKAROUND_CAVIUM_ERRATUM_38539	(1ULL << 1)
@@ -556,7 +558,7 @@ static int gic_irq_nmi_setup(struct irq_data *d)
 		desc->handle_irq = handle_fasteoi_nmi;
 	}
 
-	gic_irq_set_prio(d, GICD_INT_NMI_PRI);
+	gic_irq_set_prio(d, dist_prio_nmi);
 
 	return 0;
 }
@@ -591,7 +593,7 @@ static void gic_irq_nmi_teardown(struct irq_data *d)
 		desc->handle_irq = handle_fasteoi_irq;
 	}
 
-	gic_irq_set_prio(d, GICD_INT_DEF_PRI);
+	gic_irq_set_prio(d, dist_prio_irq);
 }
 
 static bool gic_arm64_erratum_2941627_needed(struct irq_data *d)
@@ -753,7 +755,7 @@ static bool gic_rpr_is_nmi_prio(void)
 	if (!gic_supports_nmi())
 		return false;
 
-	return unlikely(gic_read_rpr() == GICD_INT_RPR_PRI(GICD_INT_NMI_PRI));
+	return unlikely(gic_read_rpr() == GICD_INT_RPR_PRI(dist_prio_nmi));
 }
 
 static bool gic_irqnr_is_special(u32 irqnr)
@@ -937,10 +939,11 @@ static void __init gic_dist_init(void)
 		writel_relaxed(0, base + GICD_ICFGRnE + i / 4);
 
 	for (i = 0; i < GIC_ESPI_NR; i += 4)
-		writel_relaxed(GICD_INT_DEF_PRI_X4, base + GICD_IPRIORITYRnE + i);
+		writel_relaxed(REPEAT_BYTE_U32(dist_prio_irq),
+			       base + GICD_IPRIORITYRnE + i);
 
 	/* Now do the common stuff */
-	gic_dist_config(base, GIC_LINE_NR);
+	gic_dist_config(base, GIC_LINE_NR, dist_prio_irq);
 
 	val = GICD_CTLR_ARE_NS | GICD_CTLR_ENABLE_G1A | GICD_CTLR_ENABLE_G1;
 	if (gic_data.rdists.gicd_typer2 & GICD_TYPER2_nASSGIcap) {
@@ -1282,7 +1285,7 @@ static void gic_cpu_init(void)
 	for (i = 0; i < gic_data.ppi_nr + SGI_NR; i += 32)
 		writel_relaxed(~0, rbase + GICR_IGROUPR0 + i / 8);
 
-	gic_cpu_config(rbase, gic_data.ppi_nr + SGI_NR);
+	gic_cpu_config(rbase, gic_data.ppi_nr + SGI_NR, dist_prio_irq);
 	gic_redist_wait_for_rwp();
 
 	/* initialise system registers */
@@ -2066,7 +2069,7 @@ static int __init gic_init_bases(phys_addr_t dist_phys_base,
 	gic_cpu_pm_init();
 
 	if (gic_dist_supports_lpis()) {
-		its_init(handle, &gic_data.rdists, gic_data.domain);
+		its_init(handle, &gic_data.rdists, gic_data.domain, dist_prio_irq);
 		its_cpu_init();
 		its_lpi_memreserve_init();
 	} else {

drivers/irqchip/irq-gic.c

@@ -479,7 +479,7 @@ static void gic_dist_init(struct gic_chip_data *gic)
 	for (i = 32; i < gic_irqs; i += 4)
 		writel_relaxed(cpumask, base + GIC_DIST_TARGET + i * 4 / 4);
 
-	gic_dist_config(base, gic_irqs);
+	gic_dist_config(base, gic_irqs, GICD_INT_DEF_PRI);
 
 	writel_relaxed(GICD_ENABLE, base + GIC_DIST_CTRL);
 }
@@ -516,7 +516,7 @@ static int gic_cpu_init(struct gic_chip_data *gic)
 				gic_cpu_map[i] &= ~cpu_mask;
 	}
 
-	gic_cpu_config(dist_base, 32);
+	gic_cpu_config(dist_base, 32, GICD_INT_DEF_PRI);
 
 	writel_relaxed(GICC_INT_PRI_THRESHOLD, base + GIC_CPU_PRIMASK);
 	gic_cpu_if_up(gic);
@@ -608,7 +608,7 @@ void gic_dist_restore(struct gic_chip_data *gic)
 			dist_base + GIC_DIST_CONFIG + i * 4);
 
 	for (i = 0; i < DIV_ROUND_UP(gic_irqs, 4); i++)
-		writel_relaxed(GICD_INT_DEF_PRI_X4,
+		writel_relaxed(REPEAT_BYTE_U32(GICD_INT_DEF_PRI),
 			dist_base + GIC_DIST_PRI + i * 4);
 
 	for (i = 0; i < DIV_ROUND_UP(gic_irqs, 4); i++)
@@ -697,7 +697,7 @@ void gic_cpu_restore(struct gic_chip_data *gic)
 		writel_relaxed(ptr[i], dist_base + GIC_DIST_CONFIG + i * 4);
 
 	for (i = 0; i < DIV_ROUND_UP(32, 4); i++)
-		writel_relaxed(GICD_INT_DEF_PRI_X4,
+		writel_relaxed(REPEAT_BYTE_U32(GICD_INT_DEF_PRI),
 					dist_base + GIC_DIST_PRI + i * 4);
 
 	writel_relaxed(GICC_INT_PRI_THRESHOLD, cpu_base + GIC_CPU_PRIMASK);

drivers/irqchip/irq-hip04.c

@@ -260,7 +260,7 @@ static void __init hip04_irq_dist_init(struct hip04_irq_data *intc)
 	for (i = 32; i < nr_irqs; i += 2)
 		writel_relaxed(cpumask, base + GIC_DIST_TARGET + ((i * 2) & ~3));
 
-	gic_dist_config(base, nr_irqs);
+	gic_dist_config(base, nr_irqs, GICD_INT_DEF_PRI);
 
 	writel_relaxed(1, base + GIC_DIST_CTRL);
 }
@@ -287,7 +287,7 @@ static void hip04_irq_cpu_init(struct hip04_irq_data *intc)
 		if (i != cpu)
 			hip04_cpu_map[i] &= ~cpu_mask;
 
-	gic_cpu_config(dist_base, 32);
+	gic_cpu_config(dist_base, 32, GICD_INT_DEF_PRI);
 
 	writel_relaxed(0xf0, base + GIC_CPU_PRIMASK);
 	writel_relaxed(1, base + GIC_CPU_CTRL);

include/linux/irqchip/arm-gic-common.h

@@ -10,10 +10,6 @@
 #include <linux/irqchip/arm-vgic-info.h>
 
 #define GICD_INT_DEF_PRI		0xa0
-#define GICD_INT_DEF_PRI_X4		((GICD_INT_DEF_PRI << 24) |\
-					(GICD_INT_DEF_PRI << 16) |\
-					(GICD_INT_DEF_PRI << 8) |\
-					GICD_INT_DEF_PRI)
 
 struct irq_domain;
 struct fwnode_handle;

include/linux/irqchip/arm-gic-v3.h

@@ -638,7 +638,7 @@ struct fwnode_handle;
 int __init its_lpi_memreserve_init(void);
 int its_cpu_init(void);
 int its_init(struct fwnode_handle *handle, struct rdists *rdists,
-	     struct irq_domain *domain);
+	     struct irq_domain *domain, u8 irq_prio);
 int mbi_init(struct fwnode_handle *fwnode, struct irq_domain *parent);
 
 static inline bool gic_enable_sre(void)