[RFC PATCH v1 13/21] irqchip/riscv-imsic-early: Add ACPI support

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

Add support to probe the IMSIC early driver on ACPI
based RISC-V platforms.

Signed-off-by: Sunil V L <sunilvl@ventanamicro.com>
---
 arch/riscv/include/asm/acpi.h           |  6 +++
 drivers/acpi/riscv/irqchip.c            | 57 +++++++++++++++++++++++++
 drivers/irqchip/irq-riscv-imsic-early.c | 28 ++++++++++++
 drivers/irqchip/irq-riscv-imsic-state.c | 33 +++++++++++---
 4 files changed, 119 insertions(+), 5 deletions(-)

diff --git a/arch/riscv/include/asm/acpi.h b/arch/riscv/include/asm/acpi.h
index 0ac2df2dd194..6dde3d63dc0e 100644
--- a/arch/riscv/include/asm/acpi.h
+++ b/arch/riscv/include/asm/acpi.h
@@ -69,6 +69,8 @@ static inline int acpi_numa_get_nid(unsigned int cpu) { return NUMA_NO_NODE; }
 int acpi_get_cbo_block_size(struct acpi_table_header *table, unsigned int cpu, u32 *cbom_size,
 			    u32 *cboz_size, u32 *cbop_size);
 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);
 #else
 static inline void acpi_init_rintc_map(void) { }
 static inline struct acpi_madt_rintc *acpi_cpu_get_madt_rintc(int cpu)
@@ -89,6 +91,10 @@ static inline int acpi_get_cbo_block_size(struct acpi_table_header *table,
 	return -EINVAL;
 }
 
+static inline struct fwnode_handle *acpi_riscv_get_msi_fwnode(struct device *dev)
+{
+	return NULL;
+}
 #endif /* CONFIG_ACPI */
 
 #endif /*_ASM_ACPI_H*/
diff --git a/drivers/acpi/riscv/irqchip.c b/drivers/acpi/riscv/irqchip.c
index 36f066a2cad5..6e15d45cb229 100644
--- a/drivers/acpi/riscv/irqchip.c
+++ b/drivers/acpi/riscv/irqchip.c
@@ -18,6 +18,8 @@ struct riscv_irqchip_list {
 
 LIST_HEAD(rintc_list);
 
+static struct fwnode_handle *imsic_acpi_fwnode;
+
 struct fwnode_handle *acpi_rintc_create_irqchip_fwnode(struct acpi_madt_rintc *rintc)
 {
 	struct property_entry props[6] = {};
@@ -44,3 +46,58 @@ struct fwnode_handle *acpi_rintc_create_irqchip_fwnode(struct acpi_madt_rintc *r
 
 	return fwnode;
 }
+
+static struct fwnode_handle *acpi_imsic_get_rintc_fwnode(u32 idx)
+{
+	struct riscv_irqchip_list *rintc_element;
+	struct fwnode_handle *fwnode;
+	struct list_head *i, *tmp;
+	unsigned int j = 0;
+
+	list_for_each_safe(i, tmp, &rintc_list) {
+		rintc_element = list_entry(i, struct riscv_irqchip_list, list);
+		fwnode = rintc_element->fwnode;
+
+		if (j == idx)
+			return fwnode;
+
+		j++;
+	}
+
+	return NULL;
+}
+
+struct fwnode_handle *acpi_imsic_create_fwnode(struct acpi_madt_imsic *imsic)
+{
+	struct property_entry props[8] = {};
+	struct software_node_ref_args *refs;
+	struct fwnode_handle *parent_fwnode;
+	unsigned int nr_rintc, i;
+
+	props[0] = PROPERTY_ENTRY_U32("riscv,guest-index-bits", imsic->guest_index_bits);
+	props[1] = PROPERTY_ENTRY_U32("riscv,hart-index-bits", imsic->hart_index_bits);
+	props[2] = PROPERTY_ENTRY_U32("riscv,group-index-bits", imsic->group_index_bits);
+	props[3] = PROPERTY_ENTRY_U32("riscv,group-index-shift", imsic->group_index_shift);
+	props[4] = PROPERTY_ENTRY_U32("riscv,num-ids", imsic->num_ids);
+	props[5] = PROPERTY_ENTRY_U32("riscv,num-guest-ids", imsic->num_guest_ids);
+
+	nr_rintc = list_count_nodes(&rintc_list);
+	refs = kcalloc(nr_rintc, sizeof(*refs), GFP_KERNEL);
+	if (!refs)
+		return NULL;
+
+	for (i = 0; i < nr_rintc; i++) {
+		parent_fwnode = acpi_imsic_get_rintc_fwnode(i);
+		refs[i] = SOFTWARE_NODE_REFERENCE(to_software_node(parent_fwnode), RV_IRQ_EXT);
+	}
+	props[6] = PROPERTY_ENTRY_REF_ARRAY_LEN("interrupts-extended", refs, nr_rintc);
+
+	imsic_acpi_fwnode = fwnode_create_software_node_early(props, NULL);
+
+	return imsic_acpi_fwnode;
+}
+
+struct fwnode_handle *acpi_riscv_get_msi_fwnode(struct device *dev)
+{
+	return imsic_acpi_fwnode;
+}
diff --git a/drivers/irqchip/irq-riscv-imsic-early.c b/drivers/irqchip/irq-riscv-imsic-early.c
index 1de89ce1ec2f..93f4d748ca6d 100644
--- a/drivers/irqchip/irq-riscv-imsic-early.c
+++ b/drivers/irqchip/irq-riscv-imsic-early.c
@@ -12,6 +12,7 @@
 #include <linux/irqchip.h>
 #include <linux/irqchip/chained_irq.h>
 #include <linux/module.h>
+#include <linux/pci.h>
 #include <linux/spinlock.h>
 #include <linux/smp.h>
 
@@ -256,3 +257,30 @@ static int __init imsic_early_dt_init(struct device_node *node,
 	return 0;
 }
 IRQCHIP_DECLARE(riscv_imsic, "riscv,imsics", imsic_early_dt_init);
+
+#ifdef CONFIG_ACPI
+static int __init imsic_early_acpi_init(union acpi_subtable_headers *header,
+					const unsigned long end)
+{
+	struct fwnode_handle *fwnode;
+	int rc;
+
+	/*
+	 * There should be only one IMSIC node.
+	 */
+	fwnode = acpi_imsic_create_fwnode((struct acpi_madt_imsic *)header);
+	if (!fwnode) {
+		pr_err("unable to create IMSIC FW node\n");
+		return -ENOMEM;
+	}
+
+	rc = imsic_early_probe(fwnode);
+	if (!rc)
+		pci_msi_register_fwnode_provider(&acpi_riscv_get_msi_fwnode);
+
+	return rc;
+}
+
+IRQCHIP_ACPI_DECLARE(riscv_imsic, ACPI_MADT_TYPE_IMSIC,
+		     NULL, 1, imsic_early_acpi_init);
+#endif
diff --git a/drivers/irqchip/irq-riscv-imsic-state.c b/drivers/irqchip/irq-riscv-imsic-state.c
index 412b5b919dcc..d0e09e51e8ae 100644
--- a/drivers/irqchip/irq-riscv-imsic-state.c
+++ b/drivers/irqchip/irq-riscv-imsic-state.c
@@ -225,15 +225,38 @@ static int __init imsic_get_parent_hartid(struct fwnode_handle *fwnode,
 	return riscv_get_intc_hartid(parent.fwnode, hartid);
 }
 
+static int __init imsic_acpi_get_mmio_resource(struct fwnode_handle *fwnode,
+					       u32 index, struct resource *res)
+{
+	int rc;
+	struct fwnode_reference_args parent;
+	u64 base;
+	u32 size;
+
+	rc = fwnode_property_get_reference_args(fwnode,
+						"interrupts-extended", NULL,
+						0, index, &parent);
+	if (rc)
+		return rc;
+
+	rc = fwnode_property_read_u64_array(parent.fwnode, "riscv,imsic-addr",
+					    &base, 1);
+	rc = fwnode_property_read_u32_array(parent.fwnode, "riscv,imsic-size",
+					    &size, 1);
+	if (!rc) {
+		res->start = base;
+		res->end = res->start + size - 1;
+	}
+
+	return 0;
+}
+
 static int __init imsic_get_mmio_resource(struct fwnode_handle *fwnode,
 					  u32 index, struct resource *res)
 {
-	/*
-	 * Currently, only OF fwnode is support so extend this function
-	 * for other types of fwnode for ACPI support.
-	 */
 	if (!is_of_node(fwnode))
-		return -EINVAL;
+		return imsic_acpi_get_mmio_resource(fwnode, index, res);
+
 	return of_address_to_resource(to_of_node(fwnode), index, res);
 }
 
-- 
2.39.2