18 files changed, 1020 insertions, 165 deletions

diff --git a/drivers/acpi/bus.c b/drivers/acpi/bus.c
index 284bc2e03580..16917dc3ad60 100644
--- a/drivers/acpi/bus.c
+++ b/drivers/acpi/bus.c
@@ -1203,6 +1203,9 @@ static int __init acpi_bus_init_irq(void)
 	case ACPI_IRQ_MODEL_LPIC:
 		message = "LPIC";
 		break;
+	case ACPI_IRQ_MODEL_RINTC:
+		message = "RINTC";
+		break;
 	default:
 		pr_info("Unknown interrupt routing model\n");
 		return -ENODEV;
@@ -1459,6 +1462,7 @@ static int __init acpi_init(void)
 	acpi_hest_init();
 	acpi_ghes_init();
 	acpi_arm_init();
+	acpi_riscv_init();
 	acpi_scan_init();
 	acpi_ec_init();
 	acpi_debugfs_init();
diff --git a/drivers/acpi/pci_link.c b/drivers/acpi/pci_link.c
index aa1038b8aec4..b727db968f33 100644
--- a/drivers/acpi/pci_link.c
+++ b/drivers/acpi/pci_link.c
@@ -748,6 +748,8 @@ static int acpi_pci_link_add(struct acpi_device *device,
 	if (result)
 		kfree(link);
 
+	acpi_dev_clear_dependencies(device);
+
 	return result < 0 ? result : 1;
 }
 
diff --git a/drivers/acpi/riscv/Makefile b/drivers/acpi/riscv/Makefile
index 86b0925f612d..a96fdf1e2cb8 100644
--- a/drivers/acpi/riscv/Makefile
+++ b/drivers/acpi/riscv/Makefile
@@ -1,4 +1,4 @@
 # SPDX-License-Identifier: GPL-2.0-only
-obj-y					+= rhct.o
+obj-y					+= rhct.o init.o irq.o
 obj-$(CONFIG_ACPI_PROCESSOR_IDLE)	+= cpuidle.o
 obj-$(CONFIG_ACPI_CPPC_LIB)		+= cppc.o
diff --git a/drivers/acpi/riscv/init.c b/drivers/acpi/riscv/init.c
new file mode 100644
index 000000000000..5ef97905a727
--- /dev/null
+++ b/drivers/acpi/riscv/init.c
@@ -0,0 +1,13 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2023-2024, Ventana Micro Systems Inc
+ *	Author: Sunil V L <sunilvl@ventanamicro.com>
+ */
+
+#include <linux/acpi.h>
+#include "init.h"
+
+void __init acpi_riscv_init(void)
+{
+	riscv_acpi_init_gsi_mapping();
+}
diff --git a/drivers/acpi/riscv/init.h b/drivers/acpi/riscv/init.h
new file mode 100644
index 000000000000..0b9a07e4031f
--- /dev/null
+++ b/drivers/acpi/riscv/init.h
@@ -0,0 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+#include <linux/init.h>
+
+void __init riscv_acpi_init_gsi_mapping(void);
diff --git a/drivers/acpi/riscv/irq.c b/drivers/acpi/riscv/irq.c
new file mode 100644
index 000000000000..cced960c2aef
--- /dev/null
+++ b/drivers/acpi/riscv/irq.c
@@ -0,0 +1,335 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2023-2024, Ventana Micro Systems Inc
+ *	Author: Sunil V L <sunilvl@ventanamicro.com>
+ */
+
+#include <linux/acpi.h>
+#include <linux/sort.h>
+#include <linux/irq.h>
+
+#include "init.h"
+
+struct riscv_ext_intc_list {
+	acpi_handle		handle;
+	u32			gsi_base;
+	u32			nr_irqs;
+	u32			nr_idcs;
+	u32			id;
+	u32			type;
+	struct list_head	list;
+};
+
+struct acpi_irq_dep_ctx {
+	int		rc;
+	unsigned int	index;
+	acpi_handle	handle;
+};
+
+LIST_HEAD(ext_intc_list);
+
+static int irqchip_cmp_func(const void *in0, const void *in1)
+{
+	struct acpi_probe_entry *elem0 = (struct acpi_probe_entry *)in0;
+	struct acpi_probe_entry *elem1 = (struct acpi_probe_entry *)in1;
+
+	return (elem0->type > elem1->type) - (elem0->type < elem1->type);
+}
+
+/*
+ * On RISC-V, RINTC structures in MADT should be probed before any other
+ * interrupt controller structures and IMSIC before APLIC. The interrupt
+ * controller subtypes in MADT of ACPI spec for RISC-V are defined in
+ * the incremental order like RINTC(24)->IMSIC(25)->APLIC(26)->PLIC(27).
+ * Hence, simply sorting the subtypes in incremental order will
+ * establish the required order.
+ */
+void arch_sort_irqchip_probe(struct acpi_probe_entry *ap_head, int nr)
+{
+	struct acpi_probe_entry *ape = ap_head;
+
+	if (nr == 1 || !ACPI_COMPARE_NAMESEG(ACPI_SIG_MADT, ape->id))
+		return;
+	sort(ape, nr, sizeof(*ape), irqchip_cmp_func, NULL);
+}
+
+static acpi_status riscv_acpi_update_gsi_handle(u32 gsi_base, acpi_handle handle)
+{
+	struct riscv_ext_intc_list *ext_intc_element;
+	struct list_head *i, *tmp;
+
+	list_for_each_safe(i, tmp, &ext_intc_list) {
+		ext_intc_element = list_entry(i, struct riscv_ext_intc_list, list);
+		if (gsi_base == ext_intc_element->gsi_base) {
+			ext_intc_element->handle = handle;
+			return AE_OK;
+		}
+	}
+
+	return AE_NOT_FOUND;
+}
+
+int riscv_acpi_get_gsi_info(struct fwnode_handle *fwnode, u32 *gsi_base,
+			    u32 *id, u32 *nr_irqs, u32 *nr_idcs)
+{
+	struct riscv_ext_intc_list *ext_intc_element;
+	struct list_head *i;
+
+	list_for_each(i, &ext_intc_list) {
+		ext_intc_element = list_entry(i, struct riscv_ext_intc_list, list);
+		if (ext_intc_element->handle == ACPI_HANDLE_FWNODE(fwnode)) {
+			*gsi_base = ext_intc_element->gsi_base;
+			*id = ext_intc_element->id;
+			*nr_irqs = ext_intc_element->nr_irqs;
+			if (nr_idcs)
+				*nr_idcs = ext_intc_element->nr_idcs;
+
+			return 0;
+		}
+	}
+
+	return -ENODEV;
+}
+
+struct fwnode_handle *riscv_acpi_get_gsi_domain_id(u32 gsi)
+{
+	struct riscv_ext_intc_list *ext_intc_element;
+	struct acpi_device *adev;
+	struct list_head *i;
+
+	list_for_each(i, &ext_intc_list) {
+		ext_intc_element = list_entry(i, struct riscv_ext_intc_list, list);
+		if (gsi >= ext_intc_element->gsi_base &&
+		    gsi < (ext_intc_element->gsi_base + ext_intc_element->nr_irqs)) {
+			adev = acpi_fetch_acpi_dev(ext_intc_element->handle);
+			if (!adev)
+				return NULL;
+
+			return acpi_fwnode_handle(adev);
+		}
+	}
+
+	return NULL;
+}
+
+static int __init riscv_acpi_register_ext_intc(u32 gsi_base, u32 nr_irqs, u32 nr_idcs,
+					       u32 id, u32 type)
+{
+	struct riscv_ext_intc_list *ext_intc_element;
+
+	ext_intc_element = kzalloc(sizeof(*ext_intc_element), GFP_KERNEL);
+	if (!ext_intc_element)
+		return -ENOMEM;
+
+	ext_intc_element->gsi_base = gsi_base;
+	ext_intc_element->nr_irqs = nr_irqs;
+	ext_intc_element->nr_idcs = nr_idcs;
+	ext_intc_element->id = id;
+	list_add_tail(&ext_intc_element->list, &ext_intc_list);
+	return 0;
+}
+
+static acpi_status __init riscv_acpi_create_gsi_map(acpi_handle handle, u32 level,
+						    void *context, void **return_value)
+{
+	acpi_status status;
+	u64 gbase;
+
+	if (!acpi_has_method(handle, "_GSB")) {
+		acpi_handle_err(handle, "_GSB method not found\n");
+		return AE_ERROR;
+	}
+
+	status = acpi_evaluate_integer(handle, "_GSB", NULL, &gbase);
+	if (ACPI_FAILURE(status)) {
+		acpi_handle_err(handle, "failed to evaluate _GSB method\n");
+		return status;
+	}
+
+	status = riscv_acpi_update_gsi_handle((u32)gbase, handle);
+	if (ACPI_FAILURE(status)) {
+		acpi_handle_err(handle, "failed to find the GSI mapping entry\n");
+		return status;
+	}
+
+	return AE_OK;
+}
+
+static int __init riscv_acpi_aplic_parse_madt(union acpi_subtable_headers *header,
+					      const unsigned long end)
+{
+	struct acpi_madt_aplic *aplic = (struct acpi_madt_aplic *)header;
+
+	return riscv_acpi_register_ext_intc(aplic->gsi_base, aplic->num_sources, aplic->num_idcs,
+					    aplic->id, ACPI_RISCV_IRQCHIP_APLIC);
+}
+
+static int __init riscv_acpi_plic_parse_madt(union acpi_subtable_headers *header,
+					     const unsigned long end)
+{
+	struct acpi_madt_plic *plic = (struct acpi_madt_plic *)header;
+
+	return riscv_acpi_register_ext_intc(plic->gsi_base, plic->num_irqs, 0,
+					    plic->id, ACPI_RISCV_IRQCHIP_PLIC);
+}
+
+void __init riscv_acpi_init_gsi_mapping(void)
+{
+	/* There can be either PLIC or APLIC */
+	if (acpi_table_parse_madt(ACPI_MADT_TYPE_PLIC, riscv_acpi_plic_parse_madt, 0) > 0) {
+		acpi_get_devices("RSCV0001", riscv_acpi_create_gsi_map, NULL, NULL);
+		return;
+	}
+
+	if (acpi_table_parse_madt(ACPI_MADT_TYPE_APLIC, riscv_acpi_aplic_parse_madt, 0) > 0)
+		acpi_get_devices("RSCV0002", riscv_acpi_create_gsi_map, NULL, NULL);
+}
+
+static acpi_handle riscv_acpi_get_gsi_handle(u32 gsi)
+{
+	struct riscv_ext_intc_list *ext_intc_element;
+	struct list_head *i;
+
+	list_for_each(i, &ext_intc_list) {
+		ext_intc_element = list_entry(i, struct riscv_ext_intc_list, list);
+		if (gsi >= ext_intc_element->gsi_base &&
+		    gsi < (ext_intc_element->gsi_base + ext_intc_element->nr_irqs))
+			return ext_intc_element->handle;
+	}
+
+	return NULL;
+}
+
+static acpi_status riscv_acpi_irq_get_parent(struct acpi_resource *ares, void *context)
+{
+	struct acpi_irq_dep_ctx *ctx = context;
+	struct acpi_resource_irq *irq;
+	struct acpi_resource_extended_irq *eirq;
+
+	switch (ares->type) {
+	case ACPI_RESOURCE_TYPE_IRQ:
+		irq = &ares->data.irq;
+		if (ctx->index >= irq->interrupt_count) {
+			ctx->index -= irq->interrupt_count;
+			return AE_OK;
+		}
+		ctx->handle = riscv_acpi_get_gsi_handle(irq->interrupts[ctx->index]);
+		return AE_CTRL_TERMINATE;
+	case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
+		eirq = &ares->data.extended_irq;
+		if (eirq->producer_consumer == ACPI_PRODUCER)
+			return AE_OK;
+
+		if (ctx->index >= eirq->interrupt_count) {
+			ctx->index -= eirq->interrupt_count;
+			return AE_OK;
+		}
+
+		/* Support GSIs only */
+		if (eirq->resource_source.string_length)
+			return AE_OK;
+
+		ctx->handle = riscv_acpi_get_gsi_handle(eirq->interrupts[ctx->index]);
+		return AE_CTRL_TERMINATE;
+	}
+
+	return AE_OK;
+}
+
+static int riscv_acpi_irq_get_dep(acpi_handle handle, unsigned int index, acpi_handle *gsi_handle)
+{
+	struct acpi_irq_dep_ctx ctx = {-EINVAL, index, NULL};
+
+	if (!gsi_handle)
+		return 0;
+
+	acpi_walk_resources(handle, METHOD_NAME__CRS, riscv_acpi_irq_get_parent, &ctx);
+	*gsi_handle = ctx.handle;
+	if (*gsi_handle)
+		return 1;
+
+	return 0;
+}
+
+static u32 riscv_acpi_add_prt_dep(acpi_handle handle)
+{
+	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
+	struct acpi_pci_routing_table *entry;
+	struct acpi_handle_list dep_devices;
+	acpi_handle gsi_handle;
+	acpi_handle link_handle;
+	acpi_status status;
+	u32 count = 0;
+
+	status = acpi_get_irq_routing_table(handle, &buffer);
+	if (ACPI_FAILURE(status)) {
+		acpi_handle_err(handle, "failed to get IRQ routing table\n");
+		kfree(buffer.pointer);
+		return 0;
+	}
+
+	entry = buffer.pointer;
+	while (entry && (entry->length > 0)) {
+		if (entry->source[0]) {
+			acpi_get_handle(handle, entry->source, &link_handle);
+			dep_devices.count = 1;
+			dep_devices.handles = kcalloc(1, sizeof(*dep_devices.handles), GFP_KERNEL);
+			if (!dep_devices.handles) {
+				acpi_handle_err(handle, "failed to allocate memory\n");
+				continue;
+			}
+
+			dep_devices.handles[0] = link_handle;
+			count += acpi_scan_add_dep(handle, &dep_devices);
+		} else {
+			gsi_handle = riscv_acpi_get_gsi_handle(entry->source_index);
+			dep_devices.count = 1;
+			dep_devices.handles = kcalloc(1, sizeof(*dep_devices.handles), GFP_KERNEL);
+			if (!dep_devices.handles) {
+				acpi_handle_err(handle, "failed to allocate memory\n");
+				continue;
+			}
+
+			dep_devices.handles[0] = gsi_handle;
+			count += acpi_scan_add_dep(handle, &dep_devices);
+		}
+
+		entry = (struct acpi_pci_routing_table *)
+			((unsigned long)entry + entry->length);
+	}
+
+	kfree(buffer.pointer);
+	return count;
+}
+
+static u32 riscv_acpi_add_irq_dep(acpi_handle handle)
+{
+	struct acpi_handle_list dep_devices;
+	acpi_handle gsi_handle;
+	u32 count = 0;
+	int i;
+
+	for (i = 0;
+	     riscv_acpi_irq_get_dep(handle, i, &gsi_handle);
+	     i++) {
+		dep_devices.count = 1;
+		dep_devices.handles = kcalloc(1, sizeof(*dep_devices.handles), GFP_KERNEL);
+		if (!dep_devices.handles) {
+			acpi_handle_err(handle, "failed to allocate memory\n");
+			continue;
+		}
+
+		dep_devices.handles[0] = gsi_handle;
+		count += acpi_scan_add_dep(handle, &dep_devices);
+	}
+
+	return count;
+}
+
+u32 arch_acpi_add_auto_dep(acpi_handle handle)
+{
+	if (acpi_has_method(handle, "_PRT"))
+		return riscv_acpi_add_prt_dep(handle);
+
+	return riscv_acpi_add_irq_dep(handle);
+}
diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index 22ae7829a915..eba282c86edd 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -861,6 +861,9 @@ static const char * const acpi_honor_dep_ids[] = {
 	"INTC1095", /* IVSC (ADL) driver must be loaded to allow i2c access to camera sensors */
 	"INTC100A", /* IVSC (RPL) driver must be loaded to allow i2c access to camera sensors */
 	"INTC10CF", /* IVSC (MTL) driver must be loaded to allow i2c access to camera sensors */
+	"RSCV0001", /* RISC-V PLIC */
+	"RSCV0002", /* RISC-V APLIC */
+	"PNP0C0F",  /* PCI Link Device */
 	NULL
 };
 
@@ -2013,6 +2016,49 @@ void acpi_scan_hotplug_enabled(struct acpi_hotplug_profile *hotplug, bool val)
 	mutex_unlock(&acpi_scan_lock);
 }
 
+int acpi_scan_add_dep(acpi_handle handle, struct acpi_handle_list *dep_devices)
+{
+	u32 count;
+	int i;
+
+	for (count = 0, i = 0; i < dep_devices->count; i++) {
+		struct acpi_device_info *info;
+		struct acpi_dep_data *dep;
+		bool skip, honor_dep;
+		acpi_status status;
+
+		status = acpi_get_object_info(dep_devices->handles[i], &info);
+		if (ACPI_FAILURE(status)) {
+			acpi_handle_debug(handle, "Error reading _DEP device info\n");
+			continue;
+		}
+
+		skip = acpi_info_matches_ids(info, acpi_ignore_dep_ids);
+		honor_dep = acpi_info_matches_ids(info, acpi_honor_dep_ids);
+		kfree(info);
+
+		if (skip)
+			continue;
+
+		dep = kzalloc(sizeof(*dep), GFP_KERNEL);
+		if (!dep)
+			continue;
+
+		count++;
+
+		dep->supplier = dep_devices->handles[i];
+		dep->consumer = handle;
+		dep->honor_dep = honor_dep;
+
+		mutex_lock(&acpi_dep_list_lock);
+		list_add_tail(&dep->node, &acpi_dep_list);
+		mutex_unlock(&acpi_dep_list_lock);
+	}
+
+	acpi_handle_list_free(dep_devices);
+	return count;
+}
+
 static void acpi_scan_init_hotplug(struct acpi_device *adev)
 {
 	struct acpi_hardware_id *hwid;
@@ -2032,11 +2078,21 @@ static void acpi_scan_init_hotplug(struct acpi_device *adev)
 	}
 }
 
+u32 __weak arch_acpi_add_auto_dep(acpi_handle handle) { return 0; }
+
 static u32 acpi_scan_check_dep(acpi_handle handle)
 {
 	struct acpi_handle_list dep_devices;
-	u32 count;
-	int i;
+	u32 count = 0;
+
+	/*
+	 * Some architectures like RISC-V need to add dependencies for
+	 * all devices which use GSI to the interrupt controller so that
+	 * interrupt controller is probed before any of those devices.
+	 * Instead of mandating _DEP on all the devices, detect the
+	 * dependency and add automatically.
+	 */
+	count += arch_acpi_add_auto_dep(handle);
 
 	/*
 	 * Check for _HID here to avoid deferring the enumeration of:
@@ -2045,48 +2101,14 @@ static u32 acpi_scan_check_dep(acpi_handle handle)
 	 * Still, checking for _HID catches more then just these cases ...
 	 */
 	if (!acpi_has_method(handle, "_DEP") || !acpi_has_method(handle, "_HID"))
-		return 0;
+		return count;
 
 	if (!acpi_evaluate_reference(handle, "_DEP", NULL, &dep_devices)) {
 		acpi_handle_debug(handle, "Failed to evaluate _DEP.\n");
-		return 0;
-	}
-
-	for (count = 0, i = 0; i < dep_devices.count; i++) {
-		struct acpi_device_info *info;
-		struct acpi_dep_data *dep;
-		bool skip, honor_dep;
-		acpi_status status;
-
-		status = acpi_get_object_info(dep_devices.handles[i], &info);
-		if (ACPI_FAILURE(status)) {
-			acpi_handle_debug(handle, "Error reading _DEP device info\n");
-			continue;
-		}
-
-		skip = acpi_info_matches_ids(info, acpi_ignore_dep_ids);
-		honor_dep = acpi_info_matches_ids(info, acpi_honor_dep_ids);
-		kfree(info);
-
-		if (skip)
-			continue;
-
-		dep = kzalloc(sizeof(*dep), GFP_KERNEL);
-		if (!dep)
-			continue;
-
-		count++;
-
-		dep->supplier = dep_devices.handles[i];
-		dep->consumer = handle;
-		dep->honor_dep = honor_dep;
-
-		mutex_lock(&acpi_dep_list_lock);
-		list_add_tail(&dep->node , &acpi_dep_list);
-		mutex_unlock(&acpi_dep_list_lock);
+		return count;
 	}
 
-	acpi_handle_list_free(&dep_devices);
+	count += acpi_scan_add_dep(handle, &dep_devices);
 	return count;
 }
 
@@ -2757,6 +2779,8 @@ static int __init acpi_match_madt(union acpi_subtable_headers *header,
 	return 0;
 }
 
+void __weak arch_sort_irqchip_probe(struct acpi_probe_entry *ap_head, int nr) { }
+
 int __init __acpi_probe_device_table(struct acpi_probe_entry *ap_head, int nr)
 {
 	int count = 0;
@@ -2765,6 +2789,7 @@ int __init __acpi_probe_device_table(struct acpi_probe_entry *ap_head, int nr)
 		return 0;
 
 	mutex_lock(&acpi_probe_mutex);
+	arch_sort_irqchip_probe(ap_head, nr);
 	for (ape = ap_head; nr; ape++, nr--) {
 		if (ACPI_COMPARE_NAMESEG(ACPI_SIG_MADT, ape->id)) {
 			acpi_probe_count = 0;
diff --git a/drivers/irqchip/irq-riscv-aplic-direct.c b/drivers/irqchip/irq-riscv-aplic-direct.c
index 4a3ffe856d6c..7cd6b646774b 100644
--- a/drivers/irqchip/irq-riscv-aplic-direct.c
+++ b/drivers/irqchip/irq-riscv-aplic-direct.c
@@ -4,6 +4,7 @@
  * Copyright (C) 2022 Ventana Micro Systems Inc.
  */
 
+#include <linux/acpi.h>
 #include <linux/bitfield.h>
 #include <linux/bitops.h>
 #include <linux/cpu.h>
@@ -189,17 +190,22 @@ static int aplic_direct_starting_cpu(unsigned int cpu)
 }
 
 static int aplic_direct_parse_parent_hwirq(struct device *dev, u32 index,
-					   u32 *parent_hwirq, unsigned long *parent_hartid)
+					   u32 *parent_hwirq, unsigned long *parent_hartid,
+					   struct aplic_priv *priv)
 {
 	struct of_phandle_args parent;
+	unsigned long hartid;
 	int rc;
 
-	/*
-	 * Currently, only OF fwnode is supported so extend this
-	 * function for ACPI support.
-	 */
-	if (!is_of_node(dev->fwnode))
-		return -EINVAL;
+	if (!is_of_node(dev->fwnode)) {
+		hartid = acpi_rintc_ext_parent_to_hartid(priv->acpi_aplic_id, index);
+		if (hartid == INVALID_HARTID)
+			return -ENODEV;
+
+		*parent_hartid = hartid;
+		*parent_hwirq = RV_IRQ_EXT;
+		return 0;
+	}
 
 	rc = of_irq_parse_one(to_of_node(dev->fwnode), index, &parent);
 	if (rc)
@@ -237,7 +243,7 @@ int aplic_direct_setup(struct device *dev, void __iomem *regs)
 	/* Setup per-CPU IDC and target CPU mask */
 	current_cpu = get_cpu();
 	for (i = 0; i < priv->nr_idcs; i++) {
-		rc = aplic_direct_parse_parent_hwirq(dev, i, &hwirq, &hartid);
+		rc = aplic_direct_parse_parent_hwirq(dev, i, &hwirq, &hartid, priv);
 		if (rc) {
 			dev_warn(dev, "parent irq for IDC%d not found\n", i);
 			continue;
diff --git a/drivers/irqchip/irq-riscv-aplic-main.c b/drivers/irqchip/irq-riscv-aplic-main.c
index 981fad6fb8f7..900e72541db9 100644
--- a/drivers/irqchip/irq-riscv-aplic-main.c
+++ b/drivers/irqchip/irq-riscv-aplic-main.c
@@ -4,8 +4,10 @@
  * Copyright (C) 2022 Ventana Micro Systems Inc.
  */
 
+#include <linux/acpi.h>
 #include <linux/bitfield.h>
 #include <linux/irqchip/riscv-aplic.h>
+#include <linux/irqchip/riscv-imsic.h>
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/of_irq.h>
@@ -125,39 +127,50 @@ static void aplic_init_hw_irqs(struct aplic_priv *priv)
 	writel(0, priv->regs + APLIC_DOMAINCFG);
 }
 
+#ifdef CONFIG_ACPI
+static const struct acpi_device_id aplic_acpi_match[] = {
+	{ "RSCV0002", 0 },
+	{}
+};
+MODULE_DEVICE_TABLE(acpi, aplic_acpi_match);
+
+#endif
+
 int aplic_setup_priv(struct aplic_priv *priv, struct device *dev, void __iomem *regs)
 {
 	struct device_node *np = to_of_node(dev->fwnode);
 	struct of_phandle_args parent;
 	int rc;
 
-	/*
-	 * Currently, only OF fwnode is supported so extend this
-	 * function for ACPI support.
-	 */
-	if (!np)
-		return -EINVAL;
-
 	/* Save device pointer and register base */
 	priv->dev = dev;
 	priv->regs = regs;
 
-	/* Find out number of interrupt sources */
-	rc = of_property_read_u32(np, "riscv,num-sources", &priv->nr_irqs);
-	if (rc) {
-		dev_err(dev, "failed to get number of interrupt sources\n");
-		return rc;
-	}
-
-	/*
-	 * Find out number of IDCs based on parent interrupts
-	 *
-	 * If "msi-parent" property is present then we ignore the
-	 * APLIC IDCs which forces the APLIC driver to use MSI mode.
-	 */
-	if (!of_property_present(np, "msi-parent")) {
-		while (!of_irq_parse_one(np, priv->nr_idcs, &parent))
-			priv->nr_idcs++;
+	if (np) {
+		/* Find out number of interrupt sources */
+		rc = of_property_read_u32(np, "riscv,num-sources", &priv->nr_irqs);
+		if (rc) {
+			dev_err(dev, "failed to get number of interrupt sources\n");
+			return rc;
+		}
+
+		/*
+		 * Find out number of IDCs based on parent interrupts
+		 *
+		 * If "msi-parent" property is present then we ignore the
+		 * APLIC IDCs which forces the APLIC driver to use MSI mode.
+		 */
+		if (!of_property_present(np, "msi-parent")) {
+			while (!of_irq_parse_one(np, priv->nr_idcs, &parent))
+				priv->nr_idcs++;
+		}
+	} else {
+		rc = riscv_acpi_get_gsi_info(dev->fwnode, &priv->gsi_base, &priv->acpi_aplic_id,
+					     &priv->nr_irqs, &priv->nr_idcs);
+		if (rc) {
+			dev_err(dev, "failed to find GSI mapping\n");
+			return rc;
+		}
 	}
 
 	/* Setup initial state APLIC interrupts */
@@ -184,7 +197,11 @@ static int aplic_probe(struct platform_device *pdev)
 	 * If msi-parent property is present then setup APLIC MSI
 	 * mode otherwise setup APLIC direct mode.
 	 */
-	msi_mode = of_property_present(to_of_node(dev->fwnode), "msi-parent");
+	if (is_of_node(dev->fwnode))
+		msi_mode = of_property_present(to_of_node(dev->fwnode), "msi-parent");
+	else
+		msi_mode = imsic_acpi_get_fwnode(NULL) ? 1 : 0;
+
 	if (msi_mode)
 		rc = aplic_msi_setup(dev, regs);
 	else
@@ -192,6 +209,11 @@ static int aplic_probe(struct platform_device *pdev)
 	if (rc)
 		dev_err(dev, "failed to setup APLIC in %s mode\n", msi_mode ? "MSI" : "direct");
 
+#ifdef CONFIG_ACPI
+	if (!acpi_disabled)
+		acpi_dev_clear_dependencies(ACPI_COMPANION(dev));
+#endif
+
 	return rc;
 }
 
@@ -204,6 +226,7 @@ static struct platform_driver aplic_driver = {
 	.driver = {
 		.name		= "riscv-aplic",
 		.of_match_table	= aplic_match,
+		.acpi_match_table = ACPI_PTR(aplic_acpi_match),
 	},
 	.probe = aplic_probe,
 };
diff --git a/drivers/irqchip/irq-riscv-aplic-main.h b/drivers/irqchip/irq-riscv-aplic-main.h
index 4393927d8c80..b0ad8cde69b1 100644
--- a/drivers/irqchip/irq-riscv-aplic-main.h
+++ b/drivers/irqchip/irq-riscv-aplic-main.h
@@ -28,6 +28,7 @@ struct aplic_priv {
 	u32			gsi_base;
 	u32			nr_irqs;
 	u32			nr_idcs;
+	u32			acpi_aplic_id;
 	void __iomem		*regs;
 	struct aplic_msicfg	msicfg;
 };
diff --git a/drivers/irqchip/irq-riscv-aplic-msi.c b/drivers/irqchip/irq-riscv-aplic-msi.c
index d7773f76e5d0..945bff28265c 100644
--- a/drivers/irqchip/irq-riscv-aplic-msi.c
+++ b/drivers/irqchip/irq-riscv-aplic-msi.c
@@ -175,6 +175,7 @@ static const struct msi_domain_template aplic_msi_template = {
 int aplic_msi_setup(struct device *dev, void __iomem *regs)
 {
 	const struct imsic_global_config *imsic_global;
+	struct irq_domain *msi_domain;
 	struct aplic_priv *priv;
 	struct aplic_msicfg *mc;
 	phys_addr_t pa;
@@ -257,8 +258,14 @@ int aplic_msi_setup(struct device *dev, void __iomem *regs)
 		 * IMSIC and the IMSIC MSI domains are created later through
 		 * the platform driver probing so we set it explicitly here.
 		 */
-		if (is_of_node(dev->fwnode))
+		if (is_of_node(dev->fwnode)) {
 			of_msi_configure(dev, to_of_node(dev->fwnode));
+		} else {
+			msi_domain = irq_find_matching_fwnode(imsic_acpi_get_fwnode(dev),
+							      DOMAIN_BUS_PLATFORM_MSI);
+			if (msi_domain)
+				dev_set_msi_domain(dev, msi_domain);
+		}
 	}
 
 	if (!msi_create_device_irq_domain(dev, MSI_DEFAULT_DOMAIN, &aplic_msi_template,
diff --git a/drivers/irqchip/irq-riscv-imsic-early.c b/drivers/irqchip/irq-riscv-imsic-early.c
index 4fbb37074d29..c5c2e6929a2f 100644
--- a/drivers/irqchip/irq-riscv-imsic-early.c
+++ b/drivers/irqchip/irq-riscv-imsic-early.c
@@ -5,13 +5,16 @@
  */
 
 #define pr_fmt(fmt) "riscv-imsic: " fmt
+#include <linux/acpi.h>
 #include <linux/cpu.h>
 #include <linux/interrupt.h>
 #include <linux/io.h>
 #include <linux/irq.h>
 #include <linux/irqchip.h>
 #include <linux/irqchip/chained_irq.h>
+#include <linux/irqchip/riscv-imsic.h>
 #include <linux/module.h>
+#include <linux/pci.h>
 #include <linux/spinlock.h>
 #include <linux/smp.h>
 
@@ -182,7 +185,7 @@ static int __init imsic_early_dt_init(struct device_node *node, struct device_no
 	int rc;
 
 	/* Setup IMSIC state */
-	rc = imsic_setup_state(fwnode);
+	rc = imsic_setup_state(fwnode, NULL);
 	if (rc) {
 		pr_err("%pfwP: failed to setup state (error %d)\n", fwnode, rc);
 		return rc;
@@ -199,3 +202,62 @@ static int __init imsic_early_dt_init(struct device_node *node, struct device_no
 }
 
 IRQCHIP_DECLARE(riscv_imsic, "riscv,imsics", imsic_early_dt_init);
+
+#ifdef CONFIG_ACPI
+
+static struct fwnode_handle *imsic_acpi_fwnode;
+
+struct fwnode_handle *imsic_acpi_get_fwnode(struct device *dev)
+{
+	return imsic_acpi_fwnode;
+}
+
+static int __init imsic_early_acpi_init(union acpi_subtable_headers *header,
+					const unsigned long end)
+{
+	struct acpi_madt_imsic *imsic = (struct acpi_madt_imsic *)header;
+	int rc;
+
+	imsic_acpi_fwnode = irq_domain_alloc_named_fwnode("imsic");
+	if (!imsic_acpi_fwnode) {
+		pr_err("unable to allocate IMSIC FW node\n");
+		return -ENOMEM;
+	}
+
+	/* Setup IMSIC state */
+	rc = imsic_setup_state(imsic_acpi_fwnode, imsic);
+	if (rc) {
+		pr_err("%pfwP: failed to setup state (error %d)\n", imsic_acpi_fwnode, rc);
+		return rc;
+	}
+
+	/* Do early setup of IMSIC state and IPIs */
+	rc = imsic_early_probe(imsic_acpi_fwnode);
+	if (rc) {
+		irq_domain_free_fwnode(imsic_acpi_fwnode);
+		imsic_acpi_fwnode = NULL;
+		return rc;
+	}
+
+	rc = imsic_platform_acpi_probe(imsic_acpi_fwnode);
+
+#ifdef CONFIG_PCI
+	if (!rc)
+		pci_msi_register_fwnode_provider(&imsic_acpi_get_fwnode);
+#endif
+
+	if (rc)
+		pr_err("%pfwP: failed to register IMSIC for MSI functionality (error %d)\n",
+		       imsic_acpi_fwnode, rc);
+
+	/*
+	 * Even if imsic_platform_acpi_probe() fails, the IPI part of IMSIC can
+	 * continue to work. So, no need to return failure. This is similar to
+	 * DT where IPI works but MSI probe fails for some reason.
+	 */
+	return 0;
+}
+
+IRQCHIP_ACPI_DECLARE(riscv_imsic, ACPI_MADT_TYPE_IMSIC, NULL,
+		     1, imsic_early_acpi_init);
+#endif
diff --git a/drivers/irqchip/irq-riscv-imsic-platform.c b/drivers/irqchip/irq-riscv-imsic-platform.c
index 11723a763c10..64905e6f52d7 100644
--- a/drivers/irqchip/irq-riscv-imsic-platform.c
+++ b/drivers/irqchip/irq-riscv-imsic-platform.c
@@ -5,6 +5,7 @@
  */
 
 #define pr_fmt(fmt) "riscv-imsic: " fmt
+#include <linux/acpi.h>
 #include <linux/bitmap.h>
 #include <linux/cpu.h>
 #include <linux/interrupt.h>
@@ -348,18 +349,37 @@ int imsic_irqdomain_init(void)
 	return 0;
 }
 
-static int imsic_platform_probe(struct platform_device *pdev)
+static int imsic_platform_probe_common(struct fwnode_handle *fwnode)
 {
-	struct device *dev = &pdev->dev;
-
-	if (imsic && imsic->fwnode != dev->fwnode) {
-		dev_err(dev, "fwnode mismatch\n");
+	if (imsic && imsic->fwnode != fwnode) {
+		pr_err("%pfwP: fwnode mismatch\n", fwnode);
 		return -ENODEV;
 	}
 
 	return imsic_irqdomain_init();
 }
 
+static int imsic_platform_dt_probe(struct platform_device *pdev)
+{
+	return imsic_platform_probe_common(pdev->dev.fwnode);
+}
+
+#ifdef CONFIG_ACPI
+
+/*
+ *  On ACPI based systems, PCI enumeration happens early during boot in
+ *  acpi_scan_init(). PCI enumeration expects MSI domain setup before
+ *  it calls pci_set_msi_domain(). Hence, unlike in DT where
+ *  imsic-platform drive probe happens late during boot, ACPI based
+ *  systems need to setup the MSI domain early.
+ */
+int imsic_platform_acpi_probe(struct fwnode_handle *fwnode)
+{
+	return imsic_platform_probe_common(fwnode);
+}
+
+#endif
+
 static const struct of_device_id imsic_platform_match[] = {
 	{ .compatible = "riscv,imsics" },
 	{}
@@ -370,6 +390,6 @@ static struct platform_driver imsic_platform_driver = {
 		.name		= "riscv-imsic",
 		.of_match_table	= imsic_platform_match,
 	},
-	.probe = imsic_platform_probe,
+	.probe = imsic_platform_dt_probe,
 };
 builtin_platform_driver(imsic_platform_driver);
diff --git a/drivers/irqchip/irq-riscv-imsic-state.c b/drivers/irqchip/irq-riscv-imsic-state.c
index 5479f872e62b..b97e6cd89ed7 100644
--- a/drivers/irqchip/irq-riscv-imsic-state.c
+++ b/drivers/irqchip/irq-riscv-imsic-state.c
@@ -5,6 +5,7 @@
  */
 
 #define pr_fmt(fmt) "riscv-imsic: " fmt
+#include <linux/acpi.h>
 #include <linux/cpu.h>
 #include <linux/bitmap.h>
 #include <linux/interrupt.h>
@@ -510,18 +511,90 @@ static int __init imsic_matrix_init(void)
 	return 0;
 }
 
+static int __init imsic_populate_global_dt(struct fwnode_handle *fwnode,
+					   struct imsic_global_config *global,
+					   u32 *nr_parent_irqs)
+{
+	int rc;
+
+	/* Find number of guest index bits in MSI address */
+	rc = of_property_read_u32(to_of_node(fwnode), "riscv,guest-index-bits",
+