xtensa: add support for the 'xtfpga' evaluation board

The 'xtfpga' board is actually a set of FPGA evaluation boards that
can be configured to run an Xtensa processor.

 - Avnet Xilinx LX60
 - Avnet Xilinx LX110
 - Avnet Xilinx LX200
 - Xilinx ML605
 - Xilinx KC705

These boards share the same components (open-ethernet, ns16550 serial,
lcd display, flash, etc.).

Signed-off-by: Chris Zankel <chris@zankel.net>
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Tom Rini <trini@konsulko.com>

drivers/sysreset/sysreset_xtfpga.c

@@ -0,0 +1,37 @@
+/*
+ * Cadence Tensilica xtfpga system reset driver.
+ *
+ * (C) Copyright 2016 Cadence Design Systems Inc.
+ *
+ * SPDX-License-Identifier:     GPL-2.0+
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <errno.h>
+#include <sysreset.h>
+#include <asm/io.h>
+
+static int xtfpga_reset_request(struct udevice *dev, enum sysreset_t type)
+{
+	switch (type) {
+	case SYSRESET_COLD:
+		writel(CONFIG_SYS_FPGAREG_RESET_CODE,
+		       CONFIG_SYS_FPGAREG_RESET);
+		break;
+	default:
+		return -EPROTONOSUPPORT;
+	}
+
+	return -EINPROGRESS;
+}
+
+static struct sysreset_ops xtfpga_sysreset_ops = {
+	.request	= xtfpga_reset_request,
+};
+
+U_BOOT_DRIVER(xtfpga_sysreset) = {
+	.name	= "xtfpga_sysreset",
+	.id	= UCLASS_SYSRESET,
+	.ops	= &xtfpga_sysreset_ops,
+};