arch/x86: Implement common CF9 reset

It's very common across many x86 silicon vendors, so place it in
`arch/x86/`.

Change-Id: I06c27afa31e5eecfdb7093c02f703bdaabf0594c
Signed-off-by: Nico Huber <nico.h@gmx.de>
Reviewed-on: https://review.coreboot.org/29054
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>

1 files changed, 65 insertions, 0 deletions

diff --git a/src/arch/x86/cf9_reset.c b/src/arch/x86/cf9_reset.c
new file mode 100644
index 0000000000..c28e4488a6
--- /dev/null
+++ b/src/arch/x86/cf9_reset.c
@@ -0,0 +1,65 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * Copyright 2017 Google, Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <arch/io.h>
+#include <arch/cache.h>
+#include <cf9_reset.h>
+#include <console/console.h>
+#include <halt.h>
+#include <reset.h>
+
+/*
+ * A system reset in terms of the CF9 register asserts the INIT#
+ * signal to reset the CPU along the PLTRST# signal to reset other
+ * board components. It is usually the hardest reset type that
+ * does not power cycle the board. Thus, it could be called a
+ * "warm reset".
+ */
+void do_system_reset(void)
+{
+	dcache_clean_all();
+	outb(SYS_RST, RST_CNT);
+	outb(RST_CPU | SYS_RST, RST_CNT);
+}
+
+/*
+ * A full reset in terms of the CF9 register triggers a power cycle
+ * (i.e. S0 -> S5 -> S0 transition). Thus, it could be called a
+ * "cold reset".
+ * Note: Not all x86 implementations comply with this defitinion,
+ *       some may require additional configuration to power cycle.
+ */
+void do_full_reset(void)
+{
+	dcache_clean_all();
+	outb(FULL_RST | SYS_RST, RST_CNT);
+	outb(FULL_RST | RST_CPU | SYS_RST, RST_CNT);
+}
+
+void system_reset(void)
+{
+	printk(BIOS_INFO, "%s() called!\n", __func__);
+	cf9_reset_prepare();
+	do_system_reset();
+	halt();
+}
+
+void full_reset(void)
+{
+	printk(BIOS_INFO, "%s() called!\n", __func__);
+	cf9_reset_prepare();
+	do_full_reset();
+	halt();
+}