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From:   Jianmin Lv <lvjianmin@loongson.cn>
To:     Thomas Gleixner <tglx@linutronix.de>, Marc Zyngier <maz@kernel.org>
Cc:     linux-kernel@vger.kernel.org, Hanjun Guo <guohanjun@huawei.com>,
        Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
        Xuefeng Li <lixuefeng@loongson.cn>,
        Huacai Chen <chenhuacai@gmail.com>,
        Jiaxun Yang <jiaxun.yang@flygoat.com>,
        Huacai Chen <chenhuacai@loongson.cn>,
        Jianmin Lv <lvjianmin@loongson.cn>
Subject: [PATCH RFC V3 01/11] APCI: irq: Add support for multiple GSI domains
Date:   Sat, 11 Jun 2022 19:03:43 +0800
Message-Id: <1654945427-30763-2-git-send-email-lvjianmin@loongson.cn>
In-Reply-To: <1654945427-30763-1-git-send-email-lvjianmin@loongson.cn>
References: <1654945427-30763-1-git-send-email-lvjianmin@loongson.cn>
Precedence: bulk

In an unfortunate departure from the ACPI spec, the LoongArch
architecture split its GSI space across multiple interrupt
controllers.

In order to be able to reuse sthe core code and prevent
architectures from reinventing an already square wheel, offer
the arch code the ability to register a dispatcher function
that will return the domain fwnode for a given GSI.

The ARM GIC drivers are updated to support this (with a single
domain, as intended).

Signed-off-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Jianmin Lv <lvjianmin@loongson.cn>
Cc: Hanjun Guo <guohanjun@huawei.com>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
---
 drivers/acpi/irq.c           | 40 +++++++++++++++++++++++-----------------
 drivers/irqchip/irq-gic-v3.c | 18 ++++++++++++------
 drivers/irqchip/irq-gic.c    | 18 ++++++++++++------
 include/linux/acpi.h         |  2 +-
 4 files changed, 48 insertions(+), 30 deletions(-)

diff --git a/drivers/acpi/irq.c b/drivers/acpi/irq.c
index c68e694..b7460ab 100644
--- a/drivers/acpi/irq.c
+++ b/drivers/acpi/irq.c
@@ -12,7 +12,7 @@
 
 enum acpi_irq_model_id acpi_irq_model;
 
-static struct fwnode_handle *acpi_gsi_domain_id;
+static struct fwnode_handle *(*acpi_get_gsi_domain_id)(u32 gsi);
 
 /**
  * acpi_gsi_to_irq() - Retrieve the linux irq number for a given GSI
@@ -26,10 +26,7 @@
  */
 int acpi_gsi_to_irq(u32 gsi, unsigned int *irq)
 {
-	struct irq_domain *d = irq_find_matching_fwnode(acpi_gsi_domain_id,
-							DOMAIN_BUS_ANY);
-
-	*irq = irq_find_mapping(d, gsi);
+	*irq = acpi_register_gsi(NULL, gsi, -1, -1);
 	/*
 	 * *irq == 0 means no mapping, that should
 	 * be reported as a failure
@@ -53,12 +50,12 @@ int acpi_register_gsi(struct device *dev, u32 gsi, int trigger,
 {
 	struct irq_fwspec fwspec;
 
-	if (WARN_ON(!acpi_gsi_domain_id)) {
+	fwspec.fwnode = acpi_get_gsi_domain_id(gsi);
+	if (WARN_ON(!fwspec.fwnode)) {
 		pr_warn("GSI: No registered irqchip, giving up\n");
 		return -EINVAL;
 	}
 
-	fwspec.fwnode = acpi_gsi_domain_id;
 	fwspec.param[0] = gsi;
 	fwspec.param[1] = acpi_dev_get_irq_type(trigger, polarity);
 	fwspec.param_count = 2;
@@ -73,13 +70,14 @@ int acpi_register_gsi(struct device *dev, u32 gsi, int trigger,
  */
 void acpi_unregister_gsi(u32 gsi)
 {
-	struct irq_domain *d = irq_find_matching_fwnode(acpi_gsi_domain_id,
-							DOMAIN_BUS_ANY);
+	struct irq_domain *d;
 	int irq;
 
 	if (WARN_ON(acpi_irq_model == ACPI_IRQ_MODEL_GIC && gsi < 16))
 		return;
 
+	d = irq_find_matching_fwnode(acpi_get_gsi_domain_id(gsi),
+				     DOMAIN_BUS_ANY);
 	irq = irq_find_mapping(d, gsi);
 	irq_dispose_mapping(irq);
 }
@@ -97,7 +95,8 @@ void acpi_unregister_gsi(u32 gsi)
  * The referenced device fwhandle or NULL on failure
  */
 static struct fwnode_handle *
-acpi_get_irq_source_fwhandle(const struct acpi_resource_source *source)
+acpi_get_irq_source_fwhandle(const struct acpi_resource_source *source,
+			     u32 gsi)
 {
 	struct fwnode_handle *result;
 	struct acpi_device *device;
@@ -105,7 +104,7 @@ void acpi_unregister_gsi(u32 gsi)
 	acpi_status status;
 
 	if (!source->string_length)
-		return acpi_gsi_domain_id;
+		return acpi_get_gsi_domain_id(gsi);
 
 	status = acpi_get_handle(NULL, source->string_ptr, &handle);
 	if (WARN_ON(ACPI_FAILURE(status)))
@@ -194,7 +193,7 @@ static acpi_status acpi_irq_parse_one_cb(struct acpi_resource *ares,
 			ctx->index -= irq->interrupt_count;
 			return AE_OK;
 		}
-		fwnode = acpi_gsi_domain_id;
+		fwnode = acpi_get_gsi_domain_id(irq->interrupts[ctx->index]);
 		acpi_irq_parse_one_match(fwnode, irq->interrupts[ctx->index],
 					 irq->triggering, irq->polarity,
 					 irq->shareable, ctx);
@@ -207,7 +206,8 @@ static acpi_status acpi_irq_parse_one_cb(struct acpi_resource *ares,
 			ctx->index -= eirq->interrupt_count;
 			return AE_OK;
 		}
-		fwnode = acpi_get_irq_source_fwhandle(&eirq->resource_source);
+		fwnode = acpi_get_irq_source_fwhandle(&eirq->resource_source,
+						      eirq->interrupts[ctx->index]);
 		acpi_irq_parse_one_match(fwnode, eirq->interrupts[ctx->index],
 					 eirq->triggering, eirq->polarity,
 					 eirq->shareable, ctx);
@@ -291,10 +291,10 @@ int acpi_irq_get(acpi_handle handle, unsigned int index, struct resource *res)
  *          GSI interrupts
  */
 void __init acpi_set_irq_model(enum acpi_irq_model_id model,
-			       struct fwnode_handle *fwnode)
+			       struct fwnode_handle *(*fn)(u32))
 {
 	acpi_irq_model = model;
-	acpi_gsi_domain_id = fwnode;
+	acpi_get_gsi_domain_id = fn;
 }
 
 /**
@@ -312,8 +312,14 @@ struct irq_domain *acpi_irq_create_hierarchy(unsigned int flags,
 					     const struct irq_domain_ops *ops,
 					     void *host_data)
 {
-	struct irq_domain *d = irq_find_matching_fwnode(acpi_gsi_domain_id,
-							DOMAIN_BUS_ANY);
+	struct irq_domain *d;
+
+	/* This only works for the GIC model... */
+	if (acpi_irq_model != ACPI_IRQ_MODEL_GIC)
+		return NULL;
+
+	d = irq_find_matching_fwnode(acpi_get_gsi_domain_id(0),
+				     DOMAIN_BUS_ANY);
 
 	if (!d)
 		return NULL;
diff --git a/drivers/irqchip/irq-gic-v3.c b/drivers/irqchip/irq-gic-v3.c
index 5e935d9..eb8c73a 100644
--- a/drivers/irqchip/irq-gic-v3.c
+++ b/drivers/irqchip/irq-gic-v3.c
@@ -2282,11 +2282,17 @@ static void __init gic_acpi_setup_kvm_info(void)
 	vgic_set_kvm_info(&gic_v3_kvm_info);
 }
 
+static struct fwnode_handle *gsi_domain_handle;
+
+static struct fwnode_handle *gic_v3_get_gsi_domain_id(u32 gsi)
+{
+	return gsi_domain_handle;
+}
+
 static int __init
 gic_acpi_init(union acpi_subtable_headers *header, const unsigned long end)
 {
 	struct acpi_madt_generic_distributor *dist;
-	struct fwnode_handle *domain_handle;
 	size_t size;
 	int i, err;
 
@@ -2317,18 +2323,18 @@ static void __init gic_acpi_setup_kvm_info(void)
 	if (err)
 		goto out_redist_unmap;
 
-	domain_handle = irq_domain_alloc_fwnode(&dist->base_address);
-	if (!domain_handle) {
+	gsi_domain_handle = irq_domain_alloc_fwnode(&dist->base_address);
+	if (!gsi_domain_handle) {
 		err = -ENOMEM;
 		goto out_redist_unmap;
 	}
 
 	err = gic_init_bases(acpi_data.dist_base, acpi_data.redist_regs,
-			     acpi_data.nr_redist_regions, 0, domain_handle);
+			     acpi_data.nr_redist_regions, 0, gsi_domain_handle);
 	if (err)
 		goto out_fwhandle_free;
 
-	acpi_set_irq_model(ACPI_IRQ_MODEL_GIC, domain_handle);
+	acpi_set_irq_model(ACPI_IRQ_MODEL_GIC, gic_v3_get_gsi_domain_id);
 
 	if (static_branch_likely(&supports_deactivate_key))
 		gic_acpi_setup_kvm_info();
@@ -2336,7 +2342,7 @@ static void __init gic_acpi_setup_kvm_info(void)
 	return 0;
 
 out_fwhandle_free:
-	irq_domain_free_fwnode(domain_handle);
+	irq_domain_free_fwnode(gsi_domain_handle);
 out_redist_unmap:
 	for (i = 0; i < acpi_data.nr_redist_regions; i++)
 		if (acpi_data.redist_regs[i].redist_base)
diff --git a/drivers/irqchip/irq-gic.c b/drivers/irqchip/irq-gic.c
index b8bb46c..c5ffe94 100644
--- a/drivers/irqchip/irq-gic.c
+++ b/drivers/irqchip/irq-gic.c
@@ -1668,11 +1668,17 @@ static void __init gic_acpi_setup_kvm_info(void)
 	vgic_set_kvm_info(&gic_v2_kvm_info);
 }
 
+static struct fwnode_handle *gsi_domain_handle;
+
+static struct fwnode_handle *gic_v2_get_gsi_domain_id(u32 gsi)
+{
+	return gsi_domain_handle;
+}
+
 static int __init gic_v2_acpi_init(union acpi_subtable_headers *header,
 				   const unsigned long end)
 {
 	struct acpi_madt_generic_distributor *dist;
-	struct fwnode_handle *domain_handle;
 	struct gic_chip_data *gic = &gic_data[0];
 	int count, ret;
 
@@ -1710,22 +1716,22 @@ static int __init gic_v2_acpi_init(union acpi_subtable_headers *header,
 	/*
 	 * Initialize GIC instance zero (no multi-GIC support).
 	 */
-	domain_handle = irq_domain_alloc_fwnode(&dist->base_address);
-	if (!domain_handle) {
+	gsi_domain_handle = irq_domain_alloc_fwnode(&dist->base_address);
+	if (!gsi_domain_handle) {
 		pr_err("Unable to allocate domain handle\n");
 		gic_teardown(gic);
 		return -ENOMEM;
 	}
 
-	ret = __gic_init_bases(gic, domain_handle);
+	ret = __gic_init_bases(gic, gsi_domain_handle);
 	if (ret) {
 		pr_err("Failed to initialise GIC\n");
-		irq_domain_free_fwnode(domain_handle);
+		irq_domain_free_fwnode(gsi_domain_handle);
 		gic_teardown(gic);
 		return ret;
 	}
 
-	acpi_set_irq_model(ACPI_IRQ_MODEL_GIC, domain_handle);
+	acpi_set_irq_model(ACPI_IRQ_MODEL_GIC, gic_v2_get_gsi_domain_id);
 
 	if (IS_ENABLED(CONFIG_ARM_GIC_V2M))
 		gicv2m_init(NULL, gic_data[0].domain);
diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index 6274758..895b962 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -356,7 +356,7 @@ static inline bool acpi_sci_irq_valid(void)
 int acpi_isa_irq_to_gsi (unsigned isa_irq, u32 *gsi);
 
 void acpi_set_irq_model(enum acpi_irq_model_id model,
-			struct fwnode_handle *fwnode);
+			struct fwnode_handle *(*)(u32));
 
 struct irq_domain *acpi_irq_create_hierarchy(unsigned int flags,
 					     unsigned int size,
-- 
1.8.3.1