x86: apl: Add systemagent driver

This driver handles communication with the systemagent which needs to be
told when U-Boot has completed its init.

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

1 files changed, 23 insertions, 0 deletions

diff --git a/arch/x86/cpu/apollolake/systemagent.c b/arch/x86/cpu/apollolake/systemagent.c
new file mode 100644
index 00000000000..b6bc2ba14f1
--- /dev/null
+++ b/arch/x86/cpu/apollolake/systemagent.c
@@ -0,0 +1,23 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2017 Intel Corporation.
+ * Take from coreboot project file of the same name
+ */
+
+#include <common.h>
+#include <asm/intel_regs.h>
+#include <asm/io.h>
+#include <asm/arch/systemagent.h>
+
+void enable_bios_reset_cpl(void)
+{
+	/*
+	 * Set bits 0+1 of BIOS_RESET_CPL to indicate to the CPU
+	 * that BIOS has initialised memory and power management
+	 *
+	 * The FSP-S does not do this. If we leave this as zero then I believe
+	 * the power-aware interrupts don't work in Linux, and CPU 0 always gets
+	 * the interrupt.
+	 */
+	setbits_8(MCHBAR_REG(BIOS_RESET_CPL), 3);
+}