[PATCH v2 12/16] xen/riscv: introduce intc_init() and helpers

[Oleksii Kurochko <oleksii.kurochko@xxxxxxxxx>]

Introduce intc_init() to initialize the interrupt controller using the
registered hardware ops.
Also add intc_route_irq_to_xen() to route IRQs to Xen, with support for
setting IRQ type and priority via new internal helpers intc_set_irq_type()
and intc_set_irq_priority().

Call intc_init() to do basic initialization steps for APLIC and IMSIC.

Co-developed-by: Romain Caritey <Romain.Caritey@xxxxxxxxxxxxx>
Signed-off-by: Oleksii Kurochko <oleksii.kurochko@xxxxxxxxx>
---
Changes in V2:
 - This patch was part of "xen/riscv: Introduce intc_hw_operations abstraction"
   and splitted to have ability to merge patch "xen/riscv: initialize interrupt
   controller" to the current patch (where intc_init() call is actually
   introduced).
 - Add checks of that callbacks aren't set to NULL in intc_set_irq_priority()
   and intc_set_irq_type().
 - add num_irqs member to struct intc_info as it is used now in
   intc_route_irq_to_xen().
 - Add ASSERT(spin_is_locked(&desc->lock)) to intc_set_irq_priority() in
   the case this function will be called outside intc_route_irq_to_xen().
---
 xen/arch/riscv/include/asm/intc.h |  4 +++
 xen/arch/riscv/intc.c             | 45 +++++++++++++++++++++++++++++++
 xen/arch/riscv/setup.c            |  2 ++
 3 files changed, 51 insertions(+)

diff --git a/xen/arch/riscv/include/asm/intc.h 
b/xen/arch/riscv/include/asm/intc.h
index 2d55d74a2e..45a41147a6 100644
--- a/xen/arch/riscv/include/asm/intc.h
+++ b/xen/arch/riscv/include/asm/intc.h
@@ -44,4 +44,8 @@ void intc_preinit(void);
 
 void register_intc_ops(struct intc_hw_operations *ops);
 
+void intc_init(void);
+
+void intc_route_irq_to_xen(struct irq_desc *desc, unsigned int priority);
+
 #endif /* ASM__RISCV__INTERRUPT_CONTOLLER_H */
diff --git a/xen/arch/riscv/intc.c b/xen/arch/riscv/intc.c
index 122e7b32b5..15f358601d 100644
--- a/xen/arch/riscv/intc.c
+++ b/xen/arch/riscv/intc.c
@@ -1,9 +1,12 @@
 /* SPDX-License-Identifier: GPL-2.0-only */
 
 #include <xen/acpi.h>
+#include <xen/bug.h>
 #include <xen/device_tree.h>
 #include <xen/init.h>
+#include <xen/irq.h>
 #include <xen/lib.h>
+#include <xen/spinlock.h>
 
 #include <asm/intc.h>
 
@@ -21,3 +24,45 @@ void __init intc_preinit(void)
     else
         panic("ACPI interrupt controller preinit() isn't implemented\n");
 }
+
+void __init intc_init(void)
+{
+    ASSERT(intc_hw_ops);
+
+    if ( intc_hw_ops->init() )
+        panic("Failed to initialize the interrupt controller drivers\n");
+}
+
+/* desc->irq needs to be disabled before calling this function */
+static void intc_set_irq_type(struct irq_desc *desc, unsigned int type)
+{
+    ASSERT(desc->status & IRQ_DISABLED);
+    ASSERT(spin_is_locked(&desc->lock));
+    ASSERT(type != IRQ_TYPE_INVALID);
+    ASSERT(intc_hw_ops);
+
+    if ( intc_hw_ops->set_irq_type )
+        intc_hw_ops->set_irq_type(desc, type);
+}
+
+static void intc_set_irq_priority(struct irq_desc *desc, unsigned int priority)
+{
+    ASSERT(spin_is_locked(&desc->lock));
+    ASSERT(intc_hw_ops);
+
+    if ( intc_hw_ops->set_irq_priority )
+        intc_hw_ops->set_irq_priority(desc, priority);
+}
+
+void intc_route_irq_to_xen(struct irq_desc *desc, unsigned int priority)
+{
+    ASSERT(desc->status & IRQ_DISABLED);
+    ASSERT(spin_is_locked(&desc->lock));
+    /* Can't route interrupts that don't exist */
+    ASSERT(intc_hw_ops && desc->irq < intc_hw_ops->info->num_irqs);
+
+    desc->handler = intc_hw_ops->host_irq_type;
+
+    intc_set_irq_type(desc, desc->arch.type);
+    intc_set_irq_priority(desc, priority);
+}
diff --git a/xen/arch/riscv/setup.c b/xen/arch/riscv/setup.c
index 82f8839eff..4f92266224 100644
--- a/xen/arch/riscv/setup.c
+++ b/xen/arch/riscv/setup.c
@@ -136,6 +136,8 @@ void __init noreturn start_xen(unsigned long bootcpu_id,
 
     intc_preinit();
 
+    intc_init();
+
     printk("All set up\n");
 
     machine_halt();
-- 
2.49.0