x86: Add I/O APIC register access routines

I/O APIC registers are addressed indirectly. Add io_apic_read() and
io_apic_write() routines to help register access. Two macros for I/O
APIC ID and version register offset are also added.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Acked-by: Simon Glass <sjg@chromium.org>

1 files changed, 21 insertions, 0 deletions

diff --git a/arch/x86/cpu/ioapic.c b/arch/x86/cpu/ioapic.c
new file mode 100644
index 00000000000..112a9c63b44
--- /dev/null
+++ b/arch/x86/cpu/ioapic.c
@@ -0,0 +1,21 @@
+/*
+ * Copyright (C) 2015, Bin Meng <bmeng.cn@gmail.com>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <common.h>
+#include <asm/io.h>
+#include <asm/ioapic.h>
+
+u32 io_apic_read(u32 reg)
+{
+	writel(reg, IO_APIC_INDEX);
+	return readl(IO_APIC_DATA);
+}
+
+void io_apic_write(u32 reg, u32 val)
+{
+	writel(reg, IO_APIC_INDEX);
+	writel(val, IO_APIC_DATA);
+}