irqchip/riscv-intc: Add ACPI support for AIA

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@ventanamicro.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
Tested-by: Björn Töpel <bjorn@rivosinc.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://patch.msgid.link/20240812005929.113499-14-sunilvl@ventanamicro.comSigned-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

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_rintc_index_to_hartid(u32 index);
+unsigned long acpi_rintc_ext_parent_to_hartid(unsigned int plic_id, unsigned int ctxt_idx);
+unsigned int acpi_rintc_get_plic_nr_contexts(unsigned int plic_id);
+unsigned int acpi_rintc_get_plic_context(unsigned int plic_id, unsigned int ctxt_idx);
+int __init acpi_rintc_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_rintc_index_to_hartid(u32 index)
+{
+	return INVALID_HARTID;
+}
+
+static inline unsigned long acpi_rintc_ext_parent_to_hartid(unsigned int plic_id,
+							    unsigned int ctxt_idx)
+{
+	return INVALID_HARTID;
+}
+
+static inline unsigned int acpi_rintc_get_plic_nr_contexts(unsigned int plic_id)
+{
+	return INVALID_CONTEXT;
+}
+
+static inline unsigned int acpi_rintc_get_plic_context(unsigned int plic_id, unsigned int ctxt_idx)
+{
+	return INVALID_CONTEXT;
+}
+
+static inline int __init acpi_rintc_get_imsic_mmio_info(u32 index, struct resource *res)
+{
+	return 0;
+}
+
 #endif /* CONFIG_ACPI */
 
 #endif /* _ASM_RISCV_IRQ_H */

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_rintc_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_rintc_ext_parent_to_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_rintc_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_rintc_index_to_hartid(u32 index)
+{
+	return index >= nr_rintc ? INVALID_HARTID : rintc_acpi_data[index]->hart_id;
+}
+
+int acpi_rintc_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;
 }