[PATCH v6 14/44] x86/boot: introduce boot module interator

["Daniel P. Smith" <dpsmith@xxxxxxxxxxxxxxxxxxxx>]

Provide an iterator to go through boot module array searching based on type.

Signed-off-by: Daniel P. Smith <dpsmith@xxxxxxxxxxxxxxxxxxxx>
---
Changes since v5:
- documented help next_boot_module_index
- switch to unsigned int for next_boot_module_index
- changes identified that BOOTMOD_XEN was not supported, so added support
---
 xen/arch/x86/include/asm/bootinfo.h | 29 ++++++++++++++++++++++++++++-
 1 file changed, 28 insertions(+), 1 deletion(-)

diff --git a/xen/arch/x86/include/asm/bootinfo.h 
b/xen/arch/x86/include/asm/bootinfo.h
index 5862054b8cef..3010e6f4af9c 100644
--- a/xen/arch/x86/include/asm/bootinfo.h
+++ b/xen/arch/x86/include/asm/bootinfo.h
@@ -62,8 +62,35 @@ struct boot_info {
     struct boot_module mods[MAX_NR_BOOTMODS + 1];
 };
 
-#endif /* __XEN_X86_BOOTINFO_H__ */
+/*
+ * next_boot_module_index:
+ *     Finds the next boot module of type t, starting at array index start.
+ *
+ * Returns:
+ *      Success - index in boot_module array
+ *      Failure - a value greater than MAX_NR_BOOTMODS
+ */
+static inline unsigned int __init next_boot_module_index(
+    const struct boot_info *bi, enum bootmod_type t, unsigned int start)
+{
+    unsigned int i;
+
+    if ( t == BOOTMOD_XEN )
+        return MAX_NR_BOOTMODS;
 
+    for ( i = start; i < bi->nr_modules; i++ )
+    {
+        if ( bi->mods[i].type == t )
+            return i;
+    }
+
+    return MAX_NR_BOOTMODS + 1;
+}
+
+#define first_boot_module_index(bi, t)              \
+    next_boot_module_index(bi, t, 0)
+
+#endif /* __XEN_X86_BOOTINFO_H__ */
 /*
  * Local variables:
  * mode: C
-- 
2.30.2