[PATCH v2] xen/common: Move gic_preinit() to common code

[Oleksii Kurochko <oleksii.kurochko@xxxxxxxxx>]

Introduce ic_preinit() in the common codebase, as it is not
architecture-specific and can be reused by both PPC and RISC-V.
This function identifies the node with the interrupt-controller property
in the device tree and calls device_init() to handle architecture-specific
initialization of the interrupt controller.

Additionally, rename gic_acpi_preinit() to ic_acpi_preinit() as it is used
by ic_preinit(), while keeping it defined in architecture-specific as this
part is architecture-specific. In case if CONFIG_ACPI=n a stub for
ic_acpi_preinit() is provided. To declaration/defintion of ic_acpi_preint()
is added `inline` to deal with the compilation issue:
  error: 'ic_acpi_preinit' defined but not used [-Werror=unused-function]

Make minor adjustments compared to the original ARM implementation of
gic_dt_preinit():
 - Remove the local rc variable in gic_dt_preinit() since it is only used once.
 - Change the prefix from gic to ic to clarify that the function is not
   specific to ARM’s GIC, making it suitable for other architectures as well.

Signed-off-by: Oleksii Kurochko <oleksii.kurochko@xxxxxxxxx>
---
Changes in v2:
 - Revert changes connected to moving of gic_acpi_preinit() to common code as
   it isn't really architecture indepent part.
 - Update the commit message.
 - Move stub of ic_acpi_preinit() to <asm-generic/device.h> for the case when
   CONFIG_ACPI=n.
---
 xen/arch/arm/gic.c               | 45 +------------------------------
 xen/arch/arm/setup.c             |  3 ++-
 xen/common/device.c              | 46 ++++++++++++++++++++++++++++++++
 xen/include/asm-generic/device.h | 10 +++++++
 4 files changed, 59 insertions(+), 45 deletions(-)

diff --git a/xen/arch/arm/gic.c b/xen/arch/arm/gic.c
index 3eaf670fd7..b4a1e769df 100644
--- a/xen/arch/arm/gic.c
+++ b/xen/arch/arm/gic.c
@@ -214,38 +214,8 @@ int gic_map_hwdom_extra_mappings(struct domain *d)
     return 0;
 }
 
-static void __init gic_dt_preinit(void)
-{
-    int rc;
-    struct dt_device_node *node;
-    uint8_t num_gics = 0;
-
-    dt_for_each_device_node( dt_host, node )
-    {
-        if ( !dt_get_property(node, "interrupt-controller", NULL) )
-            continue;
-
-        if ( !dt_get_parent(node) )
-            continue;
-
-        rc = device_init(node, DEVICE_INTERRUPT_CONTROLLER, NULL);
-        if ( !rc )
-        {
-            /* NOTE: Only one GIC is supported */
-            num_gics = 1;
-            break;
-        }
-    }
-    if ( !num_gics )
-        panic("Unable to find compatible GIC in the device tree\n");
-
-    /* Set the GIC as the primary interrupt controller */
-    dt_interrupt_controller = node;
-    dt_device_set_used_by(node, DOMID_XEN);
-}
-
 #ifdef CONFIG_ACPI
-static void __init gic_acpi_preinit(void)
+void __init ic_acpi_preinit(void)
 {
     struct acpi_subtable_header *header;
     struct acpi_madt_generic_distributor *dist;
@@ -259,21 +229,8 @@ static void __init gic_acpi_preinit(void)
     if ( acpi_device_init(DEVICE_INTERRUPT_CONTROLLER, NULL, dist->version) )
         panic("Unable to find compatible GIC in the ACPI table\n");
 }
-#else
-static void __init gic_acpi_preinit(void) { }
 #endif
 
-/* Find the interrupt controller and set up the callback to translate
- * device tree or ACPI IRQ.
- */
-void __init gic_preinit(void)
-{
-    if ( acpi_disabled )
-        gic_dt_preinit();
-    else
-        gic_acpi_preinit();
-}
-
 /* Set up the GIC */
 void __init gic_init(void)
 {
diff --git a/xen/arch/arm/setup.c b/xen/arch/arm/setup.c
index 71ebaa77ca..1ea7db0bd4 100644
--- a/xen/arch/arm/setup.c
+++ b/xen/arch/arm/setup.c
@@ -38,6 +38,7 @@
 #include <asm/page.h>
 #include <asm/static-evtchn.h>
 #include <asm/current.h>
+#include <asm/device.h>
 #include <asm/setup.h>
 #include <asm/gic.h>
 #include <asm/cpuerrata.h>
@@ -359,7 +360,7 @@ void asmlinkage __init start_xen(unsigned long fdt_paddr)
 
     preinit_xen_time();
 
-    gic_preinit();
+    ic_preinit();
 
     arm_uart_init();
     console_init_preirq();
diff --git a/xen/common/device.c b/xen/common/device.c
index 33e0d58f2f..f440d8be88 100644
--- a/xen/common/device.c
+++ b/xen/common/device.c
@@ -4,10 +4,14 @@
  *   xen/arch/arm/device.c
  */
 
+#include <xen/acpi.h>
 #include <xen/bug.h>
 #include <xen/device_tree.h>
 #include <xen/errno.h>
 #include <xen/init.h>
+#include <xen/kernel.h>
+#include <xen/lib.h>
+#include <xen/types.h>
 
 #include <asm/device.h>
 
@@ -56,6 +60,40 @@ enum device_class device_get_class(const struct 
dt_device_node *dev)
     return DEVICE_UNKNOWN;
 }
 
+static void __init ic_dt_preinit(void)
+{
+    struct dt_device_node *node;
+    uint8_t num_gics = 0;
+
+    dt_for_each_device_node( dt_host, node )
+    {
+        if ( !dt_get_property(node, "interrupt-controller", NULL) )
+            continue;
+
+        if ( !dt_get_parent(node) )
+            continue;
+
+        if ( !device_init(node, DEVICE_INTERRUPT_CONTROLLER, NULL) )
+        {
+            /* NOTE: Only one GIC is supported */
+            num_gics = 1;
+            break;
+        }
+    }
+
+    if ( !num_gics )
+        panic("Unable to find compatible interrupt contoller"
+              "in the device tree\n");
+
+    /* Set the interrupt controller as the primary interrupt controller */
+    dt_interrupt_controller = node;
+    dt_device_set_used_by(node, DOMID_XEN);
+}
+
+#else /* !CONFIG_HAS_DEVICE_TREE */
+
+static void __init ic_dt_preinit(void) { }
+
 #endif
 
 #ifdef CONFIG_ACPI
@@ -80,3 +118,11 @@ int __init acpi_device_init(enum device_class class, const 
void *data, int class
 }
 
 #endif
+
+void __init ic_preinit(void)
+{
+    if ( acpi_disabled )
+        ic_dt_preinit();
+    else
+        ic_acpi_preinit();
+}
diff --git a/xen/include/asm-generic/device.h b/xen/include/asm-generic/device.h
index 1acd1ba1d8..0ce2bb3cdf 100644
--- a/xen/include/asm-generic/device.h
+++ b/xen/include/asm-generic/device.h
@@ -127,6 +127,16 @@ __section(".adev.info") = {                                
         \
 
 #endif /* CONFIG_ACPI */
 
+void ic_preinit(void);
+
+#ifdef CONFIG_ACPI
+void ic_acpi_preinit(void);
+#else
+#include <xen/init.h>
+
+static inline void __init ic_acpi_preinit(void) { }
+#endif
+
 #endif /* __ASM_GENERIC_DEVICE_H__ */
 
 /*
-- 
2.47.0