[RFC PATCH v1 17/21] ACPI: RISC-V: Create APLIC platform device

[Sunil V L <sunilvl@ventanamicro.com>]

Since APLIC needs to be a platform device, probe the
MADT and create platform devices for each APLIC in the
system. Use software node framework for the fwnode
which allows to create properties and hence the
actual irqchip driver doesn't need to do anything
different for ACPI vs DT.

Signed-off-by: Sunil V L <sunilvl@ventanamicro.com>
---
 Documentation/riscv/acpi.rst |   6 ++
 drivers/acpi/riscv/init.c    |   1 +
 drivers/acpi/riscv/init.h    |   1 +
 drivers/acpi/riscv/irqchip.c | 183 +++++++++++++++++++++++++++++++++++
 4 files changed, 191 insertions(+)

diff --git a/Documentation/riscv/acpi.rst b/Documentation/riscv/acpi.rst
index e2406546bc16..9ea9008288ea 100644
--- a/Documentation/riscv/acpi.rst
+++ b/Documentation/riscv/acpi.rst
@@ -29,3 +29,9 @@ properties are created using the data in MADT table.
 
 ``riscv,ext-intc-id`` - The unique ID of the external interrupts connected
 to this hart.
+
+2) RISC-V Advanced Platform Level Interrupt Controller (APLIC)
+-----------
+
+``riscv,gsi-base`` - The global system interrupt number where this APLIC’s
+interrupt inputs start.
diff --git a/drivers/acpi/riscv/init.c b/drivers/acpi/riscv/init.c
index be61c08ea385..ee747211174f 100644
--- a/drivers/acpi/riscv/init.c
+++ b/drivers/acpi/riscv/init.c
@@ -11,4 +11,5 @@
 void __init acpi_riscv_init(void)
 {
 	riscv_acpi_imsic_platform_init();
+	riscv_acpi_aplic_platform_init();
 }
diff --git a/drivers/acpi/riscv/init.h b/drivers/acpi/riscv/init.h
index a2f72bb294d3..17bcf0baaadb 100644
--- a/drivers/acpi/riscv/init.h
+++ b/drivers/acpi/riscv/init.h
@@ -2,3 +2,4 @@
 #include <linux/init.h>
 
 void __init riscv_acpi_imsic_platform_init(void);
+void __init riscv_acpi_aplic_platform_init(void);
diff --git a/drivers/acpi/riscv/irqchip.c b/drivers/acpi/riscv/irqchip.c
index ca96bf109cf7..7fb7befdb303 100644
--- a/drivers/acpi/riscv/irqchip.c
+++ b/drivers/acpi/riscv/irqchip.c
@@ -23,6 +23,8 @@ LIST_HEAD(rintc_list);
 
 static struct fwnode_handle *imsic_acpi_fwnode;
 
+LIST_HEAD(aplic_list);
+
 struct fwnode_handle *acpi_rintc_create_irqchip_fwnode(struct acpi_madt_rintc *rintc)
 {
 	struct property_entry props[6] = {};
@@ -124,3 +126,184 @@ void __init riscv_acpi_imsic_platform_init(void)
 	if (ret)
 		platform_device_put(pdev);
 }
+
+/*
+ * The ext_intc_id format is as follows:
+ * Bits [31:24] APLIC/PLIC ID
+ * Bits [15:0] APLIC IDC ID / PLIC S-Mode Context ID for this hart
+ */
+#define APLIC_PLIC_ID(x) ((x) >> 24)
+#define IDC_CONTEXT_ID(x) ((x) & 0x0000ffff)
+
+static struct fwnode_handle *acpi_ext_intc_get_rintc_fwnode(u8 aplic_plic_id, u16 index)
+{
+	struct riscv_irqchip_list *rintc_element;
+	struct fwnode_handle *fwnode;
+	struct list_head *i, *tmp;
+	u32 id;
+	int rc;
+
+	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) == aplic_plic_id) && (IDC_CONTEXT_ID(id) == index))
+			return fwnode;
+	}
+
+	return NULL;
+}
+
+static struct fwnode_handle *acpi_aplic_create_fwnode(struct acpi_madt_aplic *aplic)
+{
+	struct fwnode_handle *fwnode, *parent_fwnode;
+	struct riscv_irqchip_list *aplic_element;
+	struct software_node_ref_args *refs;
+	struct property_entry props[8] = {};
+	unsigned int i;
+
+	props[0] = PROPERTY_ENTRY_U32("riscv,gsi-base", aplic->gsi_base);
+	props[1] = PROPERTY_ENTRY_U32("riscv,num-sources", aplic->num_sources);
+	props[2] = PROPERTY_ENTRY_U32("riscv,num-idcs", aplic->num_idcs);
+	props[3] = PROPERTY_ENTRY_U32("riscv,aplic-id", aplic->id);
+	props[4] = PROPERTY_ENTRY_U64("riscv,aplic-base", aplic->base_addr);
+	props[5] = PROPERTY_ENTRY_U32("riscv,aplic-size", aplic->size);
+	if (aplic->num_idcs) {
+		refs = kcalloc(aplic->num_idcs, sizeof(*refs), GFP_KERNEL);
+		if (!refs)
+			return NULL;
+
+		for (i = 0; i < aplic->num_idcs; i++) {
+			parent_fwnode = acpi_ext_intc_get_rintc_fwnode(aplic->id, i);
+			refs[i] = SOFTWARE_NODE_REFERENCE(to_software_node(parent_fwnode),
+							  RV_IRQ_EXT);
+		}
+		props[6] = PROPERTY_ENTRY_REF_ARRAY_LEN("interrupts-extended",
+							refs, aplic->num_idcs);
+	} else {
+		props[6] = PROPERTY_ENTRY_BOOL("msi-parent");
+	}
+
+	fwnode = fwnode_create_software_node_early(props, NULL);
+
+	if (fwnode) {
+		aplic_element = kzalloc(sizeof(*aplic_element), GFP_KERNEL);
+		if (!aplic_element) {
+			fwnode_remove_software_node(fwnode);
+			return NULL;
+		}
+
+		aplic_element->fwnode = fwnode;
+		list_add_tail(&aplic_element->list, &aplic_list);
+	}
+
+	return fwnode;
+}
+
+static struct fwnode_handle *aplic_get_gsi_domain_id(u32 gsi)
+{
+	struct riscv_irqchip_list *aplic_element;
+	struct fwnode_handle *fwnode;
+	struct list_head *i, *tmp;
+	u32 gsi_base;
+	u32 nr_irqs;
+	int rc;
+
+	list_for_each_safe(i, tmp, &aplic_list) {
+		aplic_element = list_entry(i, struct riscv_irqchip_list, list);
+		fwnode = aplic_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,num-sources",
+							    &nr_irqs, 1);
+			if (!rc && (gsi >= gsi_base && gsi < gsi_base + nr_irqs))
+				return fwnode;
+		}
+	}
+
+	return NULL;
+}
+
+static u32 __init aplic_gsi_to_irq(u32 gsi)
+{
+	return acpi_register_gsi(NULL, gsi, ACPI_LEVEL_SENSITIVE, ACPI_ACTIVE_HIGH);
+}
+
+static int __init aplic_create_platform_device(struct fwnode_handle *fwnode)
+{
+	struct platform_device *pdev;
+	u32 aplic_size, aplic_id;
+	struct resource *res;
+	u64 aplic_base;
+	int ret;
+
+	if (!fwnode)
+		return -ENODEV;
+
+	ret = fwnode_property_read_u64_array(fwnode, "riscv,aplic-base", &aplic_base, 1);
+	if (ret)
+		return -ENODEV;
+
+	ret = fwnode_property_read_u32_array(fwnode, "riscv,aplic-size", &aplic_size, 1);
+	if (ret)
+		return -ENODEV;
+
+	ret = fwnode_property_read_u32_array(fwnode, "riscv,aplic-id", &aplic_id, 1);
+	if (ret)
+		return -ENODEV;
+
+	pdev = platform_device_alloc("riscv-aplic", aplic_id);
+	if (!pdev)
+		return -ENOMEM;
+
+	res = kcalloc(1, sizeof(*res), GFP_KERNEL);
+	if (!res) {
+		ret = -ENOMEM;
+		goto dev_put;
+	}
+
+	res->start = aplic_base;
+	res->end = res->start + aplic_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 aplic_parse_madt(union acpi_subtable_headers *header,
+				   const unsigned long end)
+{
+	struct acpi_madt_aplic *aplic = (struct acpi_madt_aplic *)header;
+	struct fwnode_handle *fwnode;
+
+	fwnode = acpi_aplic_create_fwnode(aplic);
+	if (fwnode)
+		aplic_create_platform_device(fwnode);
+
+	return 0;
+}
+
+void __init riscv_acpi_aplic_platform_init(void)
+{
+	if (acpi_table_parse_madt(ACPI_MADT_TYPE_APLIC, aplic_parse_madt, 0) > 0) {
+		acpi_set_irq_model(ACPI_IRQ_MODEL_APLIC, aplic_get_gsi_domain_id);
+		acpi_set_gsi_to_irq_fallback(aplic_gsi_to_irq);
+	}
+}
-- 
2.39.2