x86: tangier: Add a sysreset driver

This adds a reset driver for tangier processor.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Tested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

arch/x86/cpu/tangier/Makefile

@@ -2,5 +2,5 @@
 #
 # Copyright (c) 2017 Intel Corporation
 
-obj-y += car.o tangier.o sdram.o
+obj-y += car.o tangier.o sdram.o sysreset.o
 obj-$(CONFIG_GENERATE_ACPI_TABLE) += acpi.o

arch/x86/cpu/tangier/sysreset.c

@@ -0,0 +1,48 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2018, Bin Meng <bmeng.cn@gmail.com>
+ *
+ * Reset driver for tangier processor
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <sysreset.h>
+#include <asm/scu.h>
+
+static int tangier_sysreset_request(struct udevice *dev, enum sysreset_t type)
+{
+	int value;
+
+	switch (type) {
+	case SYSRESET_WARM:
+		value = IPCMSG_WARM_RESET;
+		break;
+	case SYSRESET_COLD:
+		value = IPCMSG_COLD_RESET;
+		break;
+	default:
+		return -ENOSYS;
+	}
+
+	scu_ipc_simple_command(value, 0);
+
+	return -EINPROGRESS;
+}
+
+static const struct udevice_id tangier_sysreset_ids[] = {
+	{ .compatible = "intel,reset-tangier" },
+	{ }
+};
+
+static struct sysreset_ops tangier_sysreset_ops = {
+	.request = tangier_sysreset_request,
+};
+
+U_BOOT_DRIVER(tangier_sysreset) = {
+	.name = "tangier-sysreset",
+	.id = UCLASS_SYSRESET,
+	.of_match = tangier_sysreset_ids,
+	.ops = &tangier_sysreset_ops,
+	.flags = DM_FLAG_PRE_RELOC,
+};