[RFC,v1,20/21] RISC-V: ACPI: Create PLIC platform device

diff --git a/Documentation/riscv/acpi.rst b/Documentation/riscv/acpi.rst
index 9ea9008288ea..007483dfddc1 100644
--- a/Documentation/riscv/acpi.rst
+++ b/Documentation/riscv/acpi.rst
@@ -35,3 +35,9 @@  to this hart.
 
 ``riscv,gsi-base`` - The global system interrupt number where this APLIC’s
 interrupt inputs start.
+
+3) RISC-V Platform Level Interrupt Controller (PLIC)
+-----------
+
+``riscv,gsi-base`` - The global system interrupt number where this PLIC’s
+interrupt inputs start.
diff --git a/arch/riscv/include/asm/acpi.h b/arch/riscv/include/asm/acpi.h
index 6dde3d63dc0e..163b8eefa744 100644
--- a/arch/riscv/include/asm/acpi.h
+++ b/arch/riscv/include/asm/acpi.h
@@ -71,6 +71,7 @@  int acpi_get_cbo_block_size(struct acpi_table_header *table, unsigned int cpu, u
 struct fwnode_handle *acpi_rintc_create_irqchip_fwnode(struct acpi_madt_rintc *rintc);
 struct fwnode_handle *acpi_imsic_create_fwnode(struct acpi_madt_imsic *imsic);
 struct fwnode_handle *acpi_riscv_get_msi_fwnode(struct device *dev);
+int acpi_plic_get_context_id(u8 plic_id, u16 idx);
 #else
 static inline void acpi_init_rintc_map(void) { }
 static inline struct acpi_madt_rintc *acpi_cpu_get_madt_rintc(int cpu)
@@ -95,6 +96,8 @@  static inline struct fwnode_handle *acpi_riscv_get_msi_fwnode(struct device *dev
 {
 	return NULL;
 }
+
+static inline int acpi_plic_get_context_id(u8 plic_id, u16 idx) { return idx; }
 #endif /* CONFIG_ACPI */
 
 #endif /*_ASM_ACPI_H*/
diff --git a/drivers/acpi/riscv/init.c b/drivers/acpi/riscv/init.c
index ee747211174f..cc733ea9ef1d 100644
--- a/drivers/acpi/riscv/init.c
+++ b/drivers/acpi/riscv/init.c
@@ -12,4 +12,5 @@  void __init acpi_riscv_init(void)
 {
 	riscv_acpi_imsic_platform_init();
 	riscv_acpi_aplic_platform_init();
+	riscv_acpi_plic_platform_init();
 }
diff --git a/drivers/acpi/riscv/init.h b/drivers/acpi/riscv/init.h
index 17bcf0baaadb..b4b305d83b3a 100644
--- a/drivers/acpi/riscv/init.h
+++ b/drivers/acpi/riscv/init.h
@@ -3,3 +3,4 @@ 
 
 void __init riscv_acpi_imsic_platform_init(void);
 void __init riscv_acpi_aplic_platform_init(void);
+void __init riscv_acpi_plic_platform_init(void);
diff --git a/drivers/acpi/riscv/irqchip.c b/drivers/acpi/riscv/irqchip.c
index 7fb7befdb303..cb70f0f2294b 100644
--- a/drivers/acpi/riscv/irqchip.c
+++ b/drivers/acpi/riscv/irqchip.c
@@ -25,6 +25,8 @@  static struct fwnode_handle *imsic_acpi_fwnode;
 
 LIST_HEAD(aplic_list);
 
+LIST_HEAD(plic_list);
+
 struct fwnode_handle *acpi_rintc_create_irqchip_fwnode(struct acpi_madt_rintc *rintc)
 {
 	struct property_entry props[6] = {};
@@ -307,3 +309,199 @@  void __init riscv_acpi_aplic_platform_init(void)
 		acpi_set_gsi_to_irq_fallback(aplic_gsi_to_irq);
 	}
 }
+
+static int acpi_plic_get_nr_contexts(u8 plic_id)
+{
+	struct riscv_irqchip_list *rintc_element;
+	struct fwnode_handle *fwnode;
+	struct list_head *i, *tmp;
+	u32 id;
+	int rc, nr_contexts = 0;
+
+	list_for_each_safe(i, tmp, &rintc_list) {
+		rintc_element = list_entry(i, struct riscv_irqchip_list, list);
+		fwnode = rintc_element->fwnode;
+		rc = fwnode_property_read_u32_array(fwnode, "riscv,ext-intc-id", &id, 1);
+		if (rc)
+			continue;
+
+		if (APLIC_PLIC_ID(id) == plic_id)
+			nr_contexts++;
+	}
+
+	return nr_contexts * 2;
+}
+
+int acpi_plic_get_context_id(u8 plic_id, u16 idx)
+{
+	struct riscv_irqchip_list *rintc_element;
+	struct fwnode_handle *fwnode;
+	struct list_head *i, *tmp;
+	u32 id;
+	int rc, nr_contexts = -1;
+
+	list_for_each_safe(i, tmp, &rintc_list) {
+		rintc_element = list_entry(i, struct riscv_irqchip_list, list);
+		fwnode = rintc_element->fwnode;
+		rc = fwnode_property_read_u32_array(fwnode, "riscv,ext-intc-id", &id, 1);
+		if (rc)
+			continue;
+
+		if (APLIC_PLIC_ID(id) == plic_id)
+			nr_contexts++;
+		if (nr_contexts == idx)
+			return IDC_CONTEXT_ID(id);
+	}
+
+	return -1;
+}
+
+static struct fwnode_handle *acpi_plic_create_fwnode(struct acpi_madt_plic *plic)
+{
+	struct fwnode_handle *fwnode, *parent_fwnode;
+	struct riscv_irqchip_list *plic_element;
+	struct software_node_ref_args *refs;
+	struct property_entry props[8] = {};
+	int nr_contexts;
+
+	props[0] = PROPERTY_ENTRY_U32("riscv,gsi-base", plic->gsi_base);
+	props[1] = PROPERTY_ENTRY_U32("riscv,ndev", plic->num_irqs);
+	props[2] = PROPERTY_ENTRY_U32("riscv,max_prio", plic->max_prio);
+	props[3] = PROPERTY_ENTRY_U8("riscv,plic-id", plic->id);
+	props[4] = PROPERTY_ENTRY_U64("riscv,plic-base", plic->base_addr);
+	props[5] = PROPERTY_ENTRY_U32("riscv,plic-size", plic->size);
+
+	nr_contexts = acpi_plic_get_nr_contexts(plic->id);
+	if (nr_contexts) {
+		refs = kcalloc(nr_contexts, sizeof(*refs), GFP_KERNEL);
+		for (int i = 0; i < nr_contexts / 2; i++) {
+			int context_id = acpi_plic_get_context_id(plic->id, i);
+
+			parent_fwnode = acpi_ext_intc_get_rintc_fwnode(plic->id, context_id);
+			refs[2 * i] = SOFTWARE_NODE_REFERENCE(to_software_node(parent_fwnode), 0);
+			refs[2 * i + 1] = SOFTWARE_NODE_REFERENCE(to_software_node(parent_fwnode),
+								  RV_IRQ_EXT);
+		}
+		props[6] = PROPERTY_ENTRY_REF_ARRAY_LEN("interrupts-extended", refs, nr_contexts);
+	}
+
+	fwnode = fwnode_create_software_node_early(props, NULL);
+
+	if (fwnode) {
+		plic_element = kzalloc(sizeof(*plic_element), GFP_KERNEL);
+		if (!plic_element) {
+			fwnode_remove_software_node(fwnode);
+			return NULL;
+		}
+
+		plic_element->fwnode = fwnode;
+		list_add_tail(&plic_element->list, &plic_list);
+	}
+
+	return fwnode;
+}
+
+static struct fwnode_handle *plic_get_gsi_domain_id(u32 gsi)
+{
+	struct riscv_irqchip_list *plic_element;
+	struct fwnode_handle *fwnode;
+	struct list_head *i, *tmp;
+	u32 gsi_base;
+	u32 nr_irqs;
+	int rc;
+
+	list_for_each_safe(i, tmp, &plic_list) {
+		plic_element = list_entry(i, struct riscv_irqchip_list, list);
+		fwnode = plic_element->fwnode;
+		rc = fwnode_property_read_u32_array(fwnode, "riscv,gsi-base", &gsi_base, 1);
+		if (!rc) {
+			rc = fwnode_property_read_u32_array(fwnode, "riscv,ndev", &nr_irqs, 1);
+			if (!rc && (gsi >= gsi_base && gsi < gsi_base + nr_irqs))
+				return fwnode;
+		}
+	}
+
+	return NULL;
+}
+
+static u32 plic_gsi_to_irq(u32 gsi)
+{
+	return acpi_register_gsi(NULL, gsi, ACPI_LEVEL_SENSITIVE, ACPI_ACTIVE_HIGH);
+}
+
+static int __init plic_create_platform_device(struct fwnode_handle *fwnode)
+{
+	struct platform_device *pdev;
+	u32 plic_size;
+	u8  plic_id;
+	struct resource *res;
+	u64 plic_base;
+	int ret;
+
+	if (!fwnode)
+		return -ENODEV;
+
+	ret = fwnode_property_read_u64_array(fwnode, "riscv,plic-base", &plic_base, 1);
+	if (ret)
+		return -ENODEV;
+
+	ret = fwnode_property_read_u32_array(fwnode, "riscv,plic-size", &plic_size, 1);
+	if (ret)
+		return -ENODEV;
+
+	ret = fwnode_property_read_u8_array(fwnode, "riscv,plic-id", &plic_id, 1);
+	if (ret)
+		return -ENODEV;
+
+	pdev = platform_device_alloc("riscv-plic", plic_id);
+	if (!pdev)
+		return -ENOMEM;
+
+	res = kcalloc(1, sizeof(*res), GFP_KERNEL);
+	if (!res) {
+		ret = -ENOMEM;
+		goto dev_put;
+	}
+
+	res->start = plic_base;
+	res->end = res->start + plic_size - 1;
+	res->flags = IORESOURCE_MEM;
+	ret = platform_device_add_resources(pdev, res, 1);
+	/*
+	 * Resources are duplicated in platform_device_add_resources,
+	 * free their allocated memory
+	 */
+	kfree(res);
+
+	pdev->dev.fwnode = fwnode;
+	ret = platform_device_add(pdev);
+	if (ret)
+		goto dev_put;
+
+	return 0;
+
+dev_put:
+	platform_device_put(pdev);
+	return ret;
+}
+
+static int __init plic_parse_madt(union acpi_subtable_headers *header,
+				  const unsigned long end)
+{
+	struct acpi_madt_plic *plic = (struct acpi_madt_plic *)header;
+	struct fwnode_handle *fwnode;
+
+	fwnode = acpi_plic_create_fwnode(plic);
+	if (fwnode)
+		plic_create_platform_device(fwnode);
+
+	return 0;
+}
+
+void __init riscv_acpi_plic_platform_init(void)
+{
+	if (acpi_table_parse_madt(ACPI_MADT_TYPE_PLIC, plic_parse_madt, 0) > 0) {
+		acpi_set_irq_model(ACPI_IRQ_MODEL_PLIC, plic_get_gsi_domain_id);
+		acpi_set_gsi_to_irq_fallback(plic_gsi_to_irq);
+	}
+}