[PATCH v2 06/16] xen/riscv: introduce init_IRQ()

[Oleksii Kurochko <oleksii.kurochko@xxxxxxxxx>]

Implement init_IRQ() to initalize various IRQs.

Currently, this function initializes the irq_desc[] array,
which stores IRQ descriptors containing various information
about each IRQ, such as the type of hardware handling, whether
the IRQ is disabled, etc.
The initialization is basic at this point and includes setting
IRQ_TYPE_INVALID as the IRQ type, assigning the IRQ number ( which
is just a consequent index of irq_desc[] array ) to
desc->irq, and setting desc->action to NULL.

Additionally, the function init_irq_data() is introduced to
initialize the IRQ descriptors for all IRQs in the system.

Reuse defines of IRQ_TYPE_* from asm-generic/irq-dt.h.

Signed-off-by: Oleksii Kurochko <oleksii.kurochko@xxxxxxxxx>
---
Changes in v2:
 - Move an introduction of IRQ_TYPE_* defines to the separate patch.
 - Reuse asm-generic/irq-dt.h.
 - Use 'unsigned int' for local irq variable inside init_irq_data().
---
 xen/arch/riscv/Makefile             |  1 +
 xen/arch/riscv/include/asm/Makefile |  1 +
 xen/arch/riscv/include/asm/irq.h    |  7 +++++
 xen/arch/riscv/irq.c                | 45 +++++++++++++++++++++++++++++
 xen/arch/riscv/setup.c              |  3 ++
 xen/arch/riscv/stubs.c              |  5 ----
 6 files changed, 57 insertions(+), 5 deletions(-)
 create mode 100644 xen/arch/riscv/irq.c

diff --git a/xen/arch/riscv/Makefile b/xen/arch/riscv/Makefile
index f42cf3dfa6..a1c145c506 100644
--- a/xen/arch/riscv/Makefile
+++ b/xen/arch/riscv/Makefile
@@ -3,6 +3,7 @@ obj-y += cpufeature.o
 obj-$(CONFIG_EARLY_PRINTK) += early_printk.o
 obj-y += entry.o
 obj-y += intc.o
+obj-y += irq.o
 obj-y += mm.o
 obj-y += pt.o
 obj-$(CONFIG_RISCV_64) += riscv64/
diff --git a/xen/arch/riscv/include/asm/Makefile 
b/xen/arch/riscv/include/asm/Makefile
index c989a7f89b..bfdf186c68 100644
--- a/xen/arch/riscv/include/asm/Makefile
+++ b/xen/arch/riscv/include/asm/Makefile
@@ -5,6 +5,7 @@ generic-y += div64.h
 generic-y += hardirq.h
 generic-y += hypercall.h
 generic-y += iocap.h
+generic-y += irq-dt.h
 generic-y += paging.h
 generic-y += percpu.h
 generic-y += perfc_defn.h
diff --git a/xen/arch/riscv/include/asm/irq.h b/xen/arch/riscv/include/asm/irq.h
index 2a48da2651..f609df466e 100644
--- a/xen/arch/riscv/include/asm/irq.h
+++ b/xen/arch/riscv/include/asm/irq.h
@@ -3,6 +3,11 @@
 #define ASM__RISCV__IRQ_H
 
 #include <xen/bug.h>
+#include <xen/device_tree.h>
+
+#include <asm/irq-dt.h>
+
+#define NR_IRQS 1024
 
 /* TODO */
 #define nr_irqs 0U
@@ -25,6 +30,8 @@ static inline void arch_move_irqs(struct vcpu *v)
     BUG_ON("unimplemented");
 }
 
+void init_IRQ(void);
+
 #endif /* ASM__RISCV__IRQ_H */
 
 /*
diff --git a/xen/arch/riscv/irq.c b/xen/arch/riscv/irq.c
new file mode 100644
index 0000000000..26a8556b2c
--- /dev/null
+++ b/xen/arch/riscv/irq.c
@@ -0,0 +1,45 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+/*
+ * RISC-V Trap handlers
+ *
+ * Copyright (c) 2024 Vates
+ */
+
+#include <xen/bug.h>
+#include <xen/init.h>
+#include <xen/irq.h>
+
+static irq_desc_t irq_desc[NR_IRQS];
+
+int arch_init_one_irq_desc(struct irq_desc *desc)
+{
+    desc->arch.type = IRQ_TYPE_INVALID;
+
+    return 0;
+}
+
+static int __init init_irq_data(void)
+{
+    unsigned int irq;
+
+    for ( irq = 0; irq < NR_IRQS; irq++ )
+    {
+        struct irq_desc *desc = irq_to_desc(irq);
+        int rc = init_one_irq_desc(desc);
+
+        if ( rc )
+            return rc;
+
+        desc->irq = irq;
+        desc->action  = NULL;
+    }
+
+    return 0;
+}
+
+void __init init_IRQ(void)
+{
+    if ( init_irq_data() < 0 )
+        panic("initialization of IRQ data failed\n");
+}
diff --git a/xen/arch/riscv/setup.c b/xen/arch/riscv/setup.c
index 2a564512d7..82f8839eff 100644
--- a/xen/arch/riscv/setup.c
+++ b/xen/arch/riscv/setup.c
@@ -6,6 +6,7 @@
 #include <xen/compile.h>
 #include <xen/device_tree.h>
 #include <xen/init.h>
+#include <xen/irq.h>
 #include <xen/mm.h>
 #include <xen/shutdown.h>
 #include <xen/smp.h>
@@ -127,6 +128,8 @@ void __init noreturn start_xen(unsigned long bootcpu_id,
         panic("Booting using ACPI isn't supported\n");
     }
 
+    init_IRQ();
+
     riscv_fill_hwcap();
 
     preinit_xen_time();
diff --git a/xen/arch/riscv/stubs.c b/xen/arch/riscv/stubs.c
index fdcf91054e..e396b67cd3 100644
--- a/xen/arch/riscv/stubs.c
+++ b/xen/arch/riscv/stubs.c
@@ -107,11 +107,6 @@ void irq_ack_none(struct irq_desc *desc)
     BUG_ON("unimplemented");
 }
 
-int arch_init_one_irq_desc(struct irq_desc *desc)
-{
-    BUG_ON("unimplemented");
-}
-
 void smp_send_state_dump(unsigned int cpu)
 {
     BUG_ON("unimplemented");
-- 
2.49.0