[PATCH v6 13/17] irqchip/riscv-intc: Add ACPI support for AIA

[Sunil V L <sunilvl@xxxxxxxxxxxxxxxx>]

The RINTC subtype structure in MADT also has information about other
interrupt controllers. Save this information and provide interfaces to
retrieve them when required by corresponding drivers.

Signed-off-by: Sunil V L <sunilvl@xxxxxxxxxxxxxxxx>
---
 arch/riscv/include/asm/irq.h     | 33 ++++++++++++
 drivers/irqchip/irq-riscv-intc.c | 90 ++++++++++++++++++++++++++++++++
 2 files changed, 123 insertions(+)

diff --git a/arch/riscv/include/asm/irq.h b/arch/riscv/include/asm/irq.h
index 44a0b128c602..51d86f0b80d2 100644
--- a/arch/riscv/include/asm/irq.h
+++ b/arch/riscv/include/asm/irq.h
@@ -12,6 +12,8 @@
 
 #include <asm-generic/irq.h>
 
+#define INVALID_CONTEXT UINT_MAX
+
 void riscv_set_intc_hwnode_fn(struct fwnode_handle *(*fn)(void));
 
 struct fwnode_handle *riscv_get_intc_hwnode(void);
@@ -28,6 +30,11 @@ enum riscv_irqchip_type {
 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);
+unsigned long acpi_get_intc_index_hartid(u32 index);
+unsigned long acpi_get_ext_intc_parent_hartid(unsigned int plic_id, unsigned int ctxt_idx);
+unsigned int acpi_get_plic_nr_contexts(unsigned int plic_id);
+unsigned int acpi_get_plic_context(unsigned int plic_id, unsigned int ctxt_idx);
+int __init acpi_get_imsic_mmio_info(u32 index, struct resource *res);
 
 #else
 static inline int riscv_acpi_get_gsi_info(struct fwnode_handle *fwnode, u32 *gsi_base,
@@ -36,6 +43,32 @@ static inline int riscv_acpi_get_gsi_info(struct fwnode_handle *fwnode, u32 *gsi
 	return 0;
 }
 
+static inline unsigned long acpi_get_intc_index_hartid(u32 index)
+{
+	return INVALID_HARTID;
+}
+
+static inline unsigned long acpi_get_ext_intc_parent_hartid(unsigned int plic_id,
+							    unsigned int ctxt_idx)
+{
+	return INVALID_HARTID;
+}
+
+static inline unsigned int acpi_get_plic_nr_contexts(unsigned int plic_id)
+{
+	return INVALID_CONTEXT;
+}
+
+static inline unsigned int acpi_get_plic_context(unsigned int plic_id, unsigned int ctxt_idx)
+{
+	return INVALID_CONTEXT;
+}
+
+static inline int __init acpi_get_imsic_mmio_info(u32 index, struct resource *res)
+{
+	return 0;
+}
+
 #endif /* CONFIG_ACPI */
 
 #endif /* _ASM_RISCV_IRQ_H */
diff --git a/drivers/irqchip/irq-riscv-intc.c b/drivers/irqchip/irq-riscv-intc.c
index 4f3a12383a1e..3c6494f1cb02 100644
--- a/drivers/irqchip/irq-riscv-intc.c
+++ b/drivers/irqchip/irq-riscv-intc.c
@@ -250,6 +250,85 @@ IRQCHIP_DECLARE(andes, "andestech,cpu-intc", riscv_intc_init);
 
 #ifdef CONFIG_ACPI
 
+struct rintc_data {
+	union {
+		u32		ext_intc_id;
+		struct {
+			u32	context_id	: 16,
+				reserved	:  8,
+				aplic_plic_id	:  8;
+		};
+	};
+	unsigned long		hart_id;
+	u64			imsic_addr;
+	u32			imsic_size;
+};
+
+static u32 nr_rintc;
+static struct rintc_data *rintc_acpi_data[NR_CPUS];
+
+#define for_each_matching_plic(_plic_id)				\
+	unsigned int _plic;						\
+									\
+	for (_plic = 0; _plic < nr_rintc; _plic++)			\
+		if (rintc_acpi_data[_plic]->aplic_plic_id != _plic_id)	\
+			continue;					\
+		else
+
+unsigned int acpi_get_plic_nr_contexts(unsigned int plic_id)
+{
+	unsigned int nctx = 0;
+
+	for_each_matching_plic(plic_id)
+		nctx++;
+
+	return nctx;
+}
+
+static struct rintc_data *get_plic_context(unsigned int plic_id, unsigned int ctxt_idx)
+{
+	unsigned int ctxt = 0;
+
+	for_each_matching_plic(plic_id) {
+		if (ctxt == ctxt_idx)
+			return rintc_acpi_data[_plic];
+
+		ctxt++;
+	}
+
+	return NULL;
+}
+
+unsigned long acpi_get_ext_intc_parent_hartid(unsigned int plic_id, unsigned int ctxt_idx)
+{
+	struct rintc_data *data = get_plic_context(plic_id, ctxt_idx);
+
+	return data ? data->hart_id : INVALID_HARTID;
+}
+
+unsigned int acpi_get_plic_context(unsigned int plic_id, unsigned int ctxt_idx)
+{
+	struct rintc_data *data = get_plic_context(plic_id, ctxt_idx);
+
+	return data ? data->context_id : INVALID_CONTEXT;
+}
+
+unsigned long acpi_get_intc_index_hartid(u32 index)
+{
+	return index >= nr_rintc ? INVALID_HARTID : rintc_acpi_data[index]->hart_id;
+}
+
+int acpi_get_imsic_mmio_info(u32 index, struct resource *res)
+{
+	if (index >= nr_rintc)
+		return -1;
+
+	res->start = rintc_acpi_data[index]->imsic_addr;
+	res->end = res->start + rintc_acpi_data[index]->imsic_size - 1;
+	res->flags = IORESOURCE_MEM;
+	return 0;
+}
+
 static int __init riscv_intc_acpi_init(union acpi_subtable_headers *header,
 				       const unsigned long end)
 {
@@ -258,6 +337,15 @@ static int __init riscv_intc_acpi_init(union acpi_subtable_headers *header,
 	int rc;
 
 	rintc = (struct acpi_madt_rintc *)header;
+	rintc_acpi_data[nr_rintc] = kzalloc(sizeof(*rintc_acpi_data[0]), GFP_KERNEL);
+	if (!rintc_acpi_data[nr_rintc])
+		return -ENOMEM;
+
+	rintc_acpi_data[nr_rintc]->ext_intc_id = rintc->ext_intc_id;
+	rintc_acpi_data[nr_rintc]->hart_id = rintc->hart_id;
+	rintc_acpi_data[nr_rintc]->imsic_addr = rintc->imsic_addr;
+	rintc_acpi_data[nr_rintc]->imsic_size = rintc->imsic_size;
+	nr_rintc++;
 
 	/*
 	 * The ACPI MADT will have one INTC for each CPU (or HART)
@@ -277,6 +365,8 @@ static int __init riscv_intc_acpi_init(union acpi_subtable_headers *header,
 	rc = riscv_intc_init_common(fn, &riscv_intc_chip);
 	if (rc)
 		irq_domain_free_fwnode(fn);
+	else
+		acpi_set_irq_model(ACPI_IRQ_MODEL_RINTC, riscv_acpi_get_gsi_domain_id);
 
 	return rc;
 }
-- 
2.40.1