[PATCH v6 04/10] irqchip/gic-v2: Parse and export virtual GIC information

[Julien Grall <julien.grall@arm.com>]

For now, the firmware tables are parsed 2 times: once in the GIC
drivers, the other timer when initializing the vGIC. It means code
duplication and make more tedious to add the support for another
firmware table (like ACPI).

Introduce a new structure and set of helpers to get/set the virtual GIC
information. Also fill up the structure for GICv2.

Signed-off-by: Julien Grall <julien.grall@arm.com>

---
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: Marc Zyngier <marc.zyngier@arm.com>

    Changes in v6:
        - Move the code to get the maintenance interrupt later. It will
        avoid to call acpi_unregister_gsi when the function fails.

    Changes in v4:
        - Change the flow to call gic_set_kvm_info when all the
        information are present.
        - Rework comments in arm-gic-common.h
        - Replace WARN_ON with BUG_ON in gic_set_kvm_info

    Changes in v2:
        - Use 0 rather than a negative value to know when the maintenance IRQ
        is not present.
        - Use resource for vcpu and vctrl
---
 drivers/irqchip/irq-gic-common.c       | 13 ++++++
 drivers/irqchip/irq-gic-common.h       |  3 ++
 drivers/irqchip/irq-gic.c              | 76 +++++++++++++++++++++++++++++++++-
 include/linux/irqchip/arm-gic-common.h | 33 +++++++++++++++
 4 files changed, 124 insertions(+), 1 deletion(-)
 create mode 100644 include/linux/irqchip/arm-gic-common.h

diff --git a/drivers/irqchip/irq-gic-common.c b/drivers/irqchip/irq-gic-common.c
index f174ce0..2e9443b 100644
--- a/drivers/irqchip/irq-gic-common.c
+++ b/drivers/irqchip/irq-gic-common.c
@@ -21,6 +21,19 @@
 
 #include "irq-gic-common.h"
 
+static const struct gic_kvm_info *gic_kvm_info;
+
+const struct gic_kvm_info *gic_get_kvm_info(void)
+{
+	return gic_kvm_info;
+}
+
+void gic_set_kvm_info(const struct gic_kvm_info *info)
+{
+	BUG_ON(gic_kvm_info != NULL);
+	gic_kvm_info = info;
+}
+
 void gic_enable_quirks(u32 iidr, const struct gic_quirk *quirks,
 		void *data)
 {
diff --git a/drivers/irqchip/irq-gic-common.h b/drivers/irqchip/irq-gic-common.h
index fff697d..205e5fd 100644
--- a/drivers/irqchip/irq-gic-common.h
+++ b/drivers/irqchip/irq-gic-common.h
@@ -19,6 +19,7 @@
 
 #include <linux/of.h>
 #include <linux/irqdomain.h>
+#include <linux/irqchip/arm-gic-common.h>
 
 struct gic_quirk {
 	const char *desc;
@@ -35,4 +36,6 @@ void gic_cpu_config(void __iomem *base, void (*sync_access)(void));
 void gic_enable_quirks(u32 iidr, const struct gic_quirk *quirks,
 		void *data);
 
+void gic_set_kvm_info(const struct gic_kvm_info *info);
+
 #endif /* _IRQ_GIC_COMMON_H */
diff --git a/drivers/irqchip/irq-gic.c b/drivers/irqchip/irq-gic.c
index 7a73786..3f1d9fd 100644
--- a/drivers/irqchip/irq-gic.c
+++ b/drivers/irqchip/irq-gic.c
@@ -102,6 +102,8 @@ static struct static_key supports_deactivate = STATIC_KEY_INIT_TRUE;
 
 static struct gic_chip_data gic_data[CONFIG_ARM_GIC_MAX_NR] __read_mostly;
 
+static struct gic_kvm_info gic_v2_kvm_info;
+
 #ifdef CONFIG_GIC_NON_BANKED
 static void __iomem *gic_get_percpu_base(union gic_base *base)
 {
@@ -1189,6 +1191,29 @@ static bool gic_check_eoimode(struct device_node *node, void __iomem **base)
 	return true;
 }
 
+static void __init gic_of_setup_kvm_info(struct device_node *node)
+{
+	int ret;
+	struct resource *vctrl_res = &gic_v2_kvm_info.vctrl;
+	struct resource *vcpu_res = &gic_v2_kvm_info.vcpu;
+
+	gic_v2_kvm_info.type = GIC_V2;
+
+	gic_v2_kvm_info.maint_irq = irq_of_parse_and_map(node, 0);
+	if (!gic_v2_kvm_info.maint_irq)
+		return;
+
+	ret = of_address_to_resource(node, 2, vctrl_res);
+	if (ret)
+		return;
+
+	ret = of_address_to_resource(node, 3, vcpu_res);
+	if (ret)
+		return;
+
+	gic_set_kvm_info(&gic_v2_kvm_info);
+}
+
 int __init
 gic_of_init(struct device_node *node, struct device_node *parent)
 {
@@ -1218,8 +1243,10 @@ gic_of_init(struct device_node *node, struct device_node *parent)
 
 	__gic_init_bases(gic_cnt, -1, dist_base, cpu_base, percpu_offset,
 			 &node->fwnode);
-	if (!gic_cnt)
+	if (!gic_cnt) {
 		gic_init_physaddr(node);
+		gic_of_setup_kvm_info(node);
+	}
 
 	if (parent) {
 		irq = irq_of_parse_and_map(node, 0);
@@ -1248,6 +1275,10 @@ IRQCHIP_DECLARE(pl390, "arm,pl390", gic_of_init);
 static struct
 {
 	phys_addr_t cpu_phys_base;
+	u32 maint_irq;
+	int maint_irq_mode;
+	phys_addr_t vctrl_base;
+	phys_addr_t vcpu_base;
 } acpi_data __initdata;
 
 static int __init
@@ -1272,6 +1303,12 @@ gic_acpi_parse_madt_cpu(struct acpi_subtable_header *header,
 		return -EINVAL;
 
 	acpi_data.cpu_phys_base = gic_cpu_base;
+	acpi_data.maint_irq = processor->vgic_interrupt;
+	acpi_data.maint_irq_mode = (processor->flags & ACPI_MADT_VGIC_IRQ_MODE) ?
+				    ACPI_EDGE_SENSITIVE : ACPI_LEVEL_SENSITIVE;
+	acpi_data.vctrl_base = processor->gich_base_address;
+	acpi_data.vcpu_base = processor->gicv_base_address;
+
 	cpu_base_assigned = 1;
 	return 0;
 }
@@ -1302,6 +1339,41 @@ static bool __init gic_validate_dist(struct acpi_subtable_header *header,
 
 #define ACPI_GICV2_DIST_MEM_SIZE	(SZ_4K)
 #define ACPI_GIC_CPU_IF_MEM_SIZE	(SZ_8K)
+#define ACPI_GICV2_VCTRL_MEM_SIZE	(SZ_4K)
+#define ACPI_GICV2_VCPU_MEM_SIZE	(SZ_8K)
+
+static void __init gic_acpi_setup_kvm_info(void)
+{
+	int irq;
+	struct resource *vctrl_res = &gic_v2_kvm_info.vctrl;
+	struct resource *vcpu_res = &gic_v2_kvm_info.vcpu;
+
+	gic_v2_kvm_info.type = GIC_V2;
+
+	if (!acpi_data.vctrl_base)
+		return;
+
+	vctrl_res->flags = IORESOURCE_MEM;
+	vctrl_res->start = acpi_data.vctrl_base;
+	vctrl_res->end = vctrl_res->start + ACPI_GICV2_VCTRL_MEM_SIZE - 1;
+
+	if (!acpi_data.vcpu_base)
+		return;
+
+	vcpu_res->flags = IORESOURCE_MEM;
+	vcpu_res->start = acpi_data.vcpu_base;
+	vcpu_res->end = vcpu_res->start + ACPI_GICV2_VCPU_MEM_SIZE - 1;
+
+	irq = acpi_register_gsi(NULL, acpi_data.maint_irq,
+				acpi_data.maint_irq_mode,
+				ACPI_ACTIVE_HIGH);
+	if (irq <= 0)
+		return;
+
+	gic_v2_kvm_info.maint_irq = irq;
+
+	gic_set_kvm_info(&gic_v2_kvm_info);
+}
 
 static int __init gic_v2_acpi_init(struct acpi_subtable_header *header,
 				   const unsigned long end)
@@ -1359,6 +1431,8 @@ static int __init gic_v2_acpi_init(struct acpi_subtable_header *header,
 	if (IS_ENABLED(CONFIG_ARM_GIC_V2M))
 		gicv2m_init(NULL, gic_data[0].domain);
 
+	gic_acpi_setup_kvm_info();
+
 	return 0;
 }
 IRQCHIP_ACPI_DECLARE(gic_v2, ACPI_MADT_TYPE_GENERIC_DISTRIBUTOR,
diff --git a/include/linux/irqchip/arm-gic-common.h b/include/linux/irqchip/arm-gic-common.h
new file mode 100644
index 0000000..ef34f6f
--- /dev/null
+++ b/include/linux/irqchip/arm-gic-common.h
@@ -0,0 +1,33 @@
+/*
+ * include/linux/irqchip/arm-gic-common.h
+ *
+ * Copyright (C) 2016 ARM Limited, All Rights Reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#ifndef __LINUX_IRQCHIP_ARM_GIC_COMMON_H
+#define __LINUX_IRQCHIP_ARM_GIC_COMMON_H
+
+#include <linux/types.h>
+#include <linux/ioport.h>
+
+enum gic_type {
+	GIC_V2,
+};
+
+struct gic_kvm_info {
+	/* GIC type */
+	enum gic_type	type;
+	/* Virtual CPU interface */
+	struct resource vcpu;
+	/* Interrupt number */
+	unsigned int	maint_irq;
+	/* Virtual control interface */
+	struct resource vctrl;
+};
+
+const struct gic_kvm_info *gic_get_kvm_info(void);
+
+#endif /* __LINUX_IRQCHIP_ARM_GIC_COMMON_H */
-- 
1.9.1