[RFC PATCH v4 10/20] RISC-V: ACPI: Initialize GSI mapping structures

[Sunil V L]

RISC-V has PLIC and APLIC in MADT as well as namespace devices.
Initialize the list of those structures using MADT and namespace devices
to create mapping between the ACPI handle and the GSI ranges. This is
will be used later to add dependencies.

Signed-off-by: Sunil V L <sunilvl@xxxxxxxxxxxxxxxx>
---
 arch/riscv/include/asm/irq.h |  22 +++++
 drivers/acpi/riscv/init.c    |   2 +
 drivers/acpi/riscv/init.h    |   4 +
 drivers/acpi/riscv/irq.c     | 159 +++++++++++++++++++++++++++++++++++
 4 files changed, 187 insertions(+)
 create mode 100644 drivers/acpi/riscv/init.h

diff --git a/arch/riscv/include/asm/irq.h b/arch/riscv/include/asm/irq.h
index 8e10a94430a2..44a0b128c602 100644
--- a/arch/riscv/include/asm/irq.h
+++ b/arch/riscv/include/asm/irq.h
@@ -16,4 +16,26 @@ void riscv_set_intc_hwnode_fn(struct fwnode_handle *(*fn)(void));
 
 struct fwnode_handle *riscv_get_intc_hwnode(void);
 
+#ifdef CONFIG_ACPI
+
+enum riscv_irqchip_type {
+	ACPI_RISCV_IRQCHIP_INTC		= 0x00,
+	ACPI_RISCV_IRQCHIP_IMSIC	= 0x01,
+	ACPI_RISCV_IRQCHIP_PLIC		= 0x02,
+	ACPI_RISCV_IRQCHIP_APLIC	= 0x03,
+};
+
+int riscv_acpi_get_gsi_info(struct fwnode_handle *fwnode, u32 *gsi_base,
+			    u32 *id, u32 *nr_irqs, u32 *nr_idcs);
+struct fwnode_handle *riscv_acpi_get_gsi_domain_id(u32 gsi);
+
+#else
+static inline int riscv_acpi_get_gsi_info(struct fwnode_handle *fwnode, u32 *gsi_base,
+					  u32 *id, u32 *nr_irqs, u32 *nr_idcs)
+{
+	return 0;
+}
+
+#endif /* CONFIG_ACPI */
+
 #endif /* _ASM_RISCV_IRQ_H */
diff --git a/drivers/acpi/riscv/init.c b/drivers/acpi/riscv/init.c
index b5807bbdb171..56780af6ceb3 100644
--- a/drivers/acpi/riscv/init.c
+++ b/drivers/acpi/riscv/init.c
@@ -6,7 +6,9 @@
  */
 
 #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..2a488ec684b9
--- /dev/null
+++ b/drivers/acpi/riscv/init.h
@@ -0,0 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+#include <linux/init.h>
+
+int __init riscv_acpi_init_gsi_mapping(void);
diff --git a/drivers/acpi/riscv/irq.c b/drivers/acpi/riscv/irq.c
index 36e0525b3235..de0f1ba92068 100644
--- a/drivers/acpi/riscv/irq.c
+++ b/drivers/acpi/riscv/irq.c
@@ -7,6 +7,21 @@
 
 #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;
+};
+
+LIST_HEAD(ext_intc_list);
 
 static int irqchip_cmp_func(const void *in0, const void *in1)
 {
@@ -30,3 +45,147 @@ void arch_sort_irqchip_probe(struct acpi_probe_entry *ap_head, int nr)
 		return;
 	sort(ape, nr, sizeof(*ape), irqchip_cmp_func, NULL);
 }
+
+static int 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 0;
+		}
+	}
+
+	return -1;
+}
+
+static acpi_handle riscv_acpi_get_gsi_handle(u32 gsi)
+{
+	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 >= ext_intc_element->gsi_base &&
+		    gsi < (ext_intc_element->gsi_base + ext_intc_element->nr_irqs))
+			return ext_intc_element->handle;
+	}
+
+	return NULL;
+}
+
+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, *tmp;
+
+	list_for_each_safe(i, tmp, &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, *tmp;
+
+	list_for_each_safe(i, tmp, &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 -1;
+
+	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"))
+		return AE_OK;
+
+	status = acpi_evaluate_integer(handle, "_GSB", NULL, &gbase);
+	if (ACPI_FAILURE(status)) {
+		acpi_handle_err(handle, "failed to evaluate _GSB method\n");
+		return AE_OK;
+	}
+
+	riscv_acpi_update_gsi_handle((u32)gbase, handle);
+	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;
+
+	riscv_acpi_register_ext_intc(aplic->gsi_base, aplic->num_sources,
+				     aplic->num_idcs, aplic->id, ACPI_RISCV_IRQCHIP_APLIC);
+	return 0;
+}
+
+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;
+
+	riscv_acpi_register_ext_intc(plic->gsi_base, plic->num_irqs, 0,
+				     plic->id, ACPI_RISCV_IRQCHIP_PLIC);
+	return 0;
+}
+
+int __init riscv_acpi_init_gsi_mapping(void)
+{
+	int count = 0;
+
+	count = acpi_table_parse_madt(ACPI_MADT_TYPE_PLIC, riscv_acpi_plic_parse_madt, 0);
+	if (count <= 0) {
+		acpi_table_parse_madt(ACPI_MADT_TYPE_APLIC, riscv_acpi_aplic_parse_madt, 0);
+		acpi_get_devices("RSCV0002", riscv_acpi_create_gsi_map, NULL, NULL);
+		return 0;
+	}
+
+	acpi_get_devices("RSCV0001", riscv_acpi_create_gsi_map, NULL, NULL);
+	return 0;
+}
-- 
2.40.1