xen/riscv: introduce register_intc_ops() and intc_hw_ops

Introduce the intc_hw_operations structure to encapsulate interrupt
controller-specific data and operations. This structure includes:
- A pointer to interrupt controller information (`intc_info`)
- Callbacks to initialize the controller and set IRQ type/priority
- A reference to an interupt controller descriptor (`host_irq_type`)
- number of interrupt controller irqs.

Add function register_intc_ops() to mentioned above structure.

Co-developed-by: Romain Caritey <Romain.Caritey@microchip.com>
Signed-off-by: Oleksii Kurochko <oleksii.kurochko@gmail.com>
Acked-by: Jan Beulich <jbeulich@suse.com>

xen/arch/riscv/include/asm/intc.h

@@ -14,11 +14,30 @@ enum intc_version {
     INTC_APLIC,
 };
 
+struct irq_desc;
+
 struct intc_info {
     enum intc_version hw_version;
     const struct dt_device_node *node;
 };
 
+struct intc_hw_operations {
+    /* Hold intc hw information */
+    const struct intc_info *info;
+    /* Initialize the intc and the boot CPU */
+    int (*init)(void);
+
+    /* hw_irq_controller to enable/disable/eoi host irq */
+    const struct hw_interrupt_type *host_irq_type;
+
+    /* Set IRQ type */
+    void (*set_irq_type)(struct irq_desc *desc, unsigned int type);
+    /* Set IRQ priority */
+    void (*set_irq_priority)(struct irq_desc *desc, unsigned int priority);
+};
+
 void intc_preinit(void);
 
+void register_intc_ops(const struct intc_hw_operations *ops);
+
 #endif /* ASM__RISCV__INTERRUPT_CONTOLLER_H */

xen/arch/riscv/intc.c

@@ -5,6 +5,15 @@
 #include <xen/init.h>
 #include <xen/lib.h>
 
+#include <asm/intc.h>
+
+static const struct intc_hw_operations *__ro_after_init intc_hw_ops;
+
+void __init register_intc_ops(const struct intc_hw_operations *ops)
+{
+    intc_hw_ops = ops;
+}
+
 void __init intc_preinit(void)
 {
     if ( acpi_disabled )