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>
diff --git a/arch/x86/cpu/apollolake/Makefile b/arch/x86/cpu/apollolake/Makefile
index fdda748..3a8c2f6 100644
--- a/arch/x86/cpu/apollolake/Makefile
+++ b/arch/x86/cpu/apollolake/Makefile
@@ -2,5 +2,7 @@
#
# Copyright 2019 Google LLC
+obj-$(CONFIG_SPL_BUILD) += systemagent.o
+
obj-y += pmc.o
obj-y += uart.o
diff --git a/arch/x86/cpu/apollolake/systemagent.c b/arch/x86/cpu/apollolake/systemagent.c
new file mode 100644
index 0000000..b6bc2ba
--- /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);
+}