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>

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

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);
+}

arch/x86/include/asm/arch-apollolake/systemagent.h

@@ -0,0 +1,37 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2017 Intel Corporation.
+ * Take from coreboot project file of the same name
+ */
+
+#ifndef _ASM_ARCH_SYSTEMAGENT_H
+#define _ASM_ARCH_SYSTEMAGENT_H
+
+/* Device 0:0.0 PCI configuration space */
+#define MCHBAR		0x48
+
+/* RAPL Package Power Limit register under MCHBAR */
+#define PUNIT_THERMAL_DEVICE_IRQ		0x700C
+#define PUINT_THERMAL_DEVICE_IRQ_VEC_NUMBER	0x18
+#define PUINT_THERMAL_DEVICE_IRQ_LOCK		0x80000000
+#define BIOS_RESET_CPL		0x7078
+#define   PCODE_INIT_DONE	BIT(8)
+#define MCHBAR_RAPL_PPL		0x70A8
+#define CORE_DISABLE_MASK	0x7168
+#define CAPID0_A		0xE4
+#define   VTD_DISABLE		BIT(23)
+#define DEFVTBAR		0x6c80
+#define GFXVTBAR		0x6c88
+#define   VTBAR_ENABLED		0x01
+#define VTBAR_MASK		GENMASK_ULL(39, 12)
+#define VTBAR_SIZE		0x1000
+
+/**
+ * enable_bios_reset_cpl() - Tell the system agent that memory/power are ready
+ *
+ * This should be called when U-Boot has set up the memory and power
+ * management.
+ */
+void enable_bios_reset_cpl(void);
+
+#endif