skylake: fix serial port with new code base

Many Kconfig options changed in coreboot.org since
skylake was first started. Fix Kconfig option name
changes, and also provide a common option, UART_DEBUG
that can be selected to select all the necessary
options.

Note: It's still a requirement to manually unset the
      8250IO option because that's unconditionally set.

BUG=chrome-os-partner:43419
BUG=chrome-os-partner:43463
BRANCH=None
TEST=Built glados. Booted into kernel. Kernel reboots somewhere.

Original-Change-Id: I9e6549ea0f1d6b9ffe64a73856ec87b5bc7b7091
Original-Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Original-Reviewed-on: https://chromium-review.googlesource.com/289951
Original-Reviewed-by: Duncan Laurie <dlaurie@chromium.org>

Change-Id: I0e6b492d7279cc35d4fb3ac17fd727177adce39d
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: http://review.coreboot.org/11172
Tested-by: build bot (Jenkins)
Reviewed-by: Patrick Georgi <pgeorgi@google.com>

src/soc/intel/skylake/uart_debug.c

@@ -0,0 +1,41 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * Copyright 2015 Google Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc.
+ */
+
+#include <stddef.h>
+#include <console/uart.h>
+#include <soc/iomap.h>
+#include <soc/serialio.h>
+
+unsigned int uart_platform_refclk(void)
+{
+	/*
+	 * Set M and N divisor inputs and enable clock.
+	 * Main reference frequency to UART is:
+	 *  120MHz * M / N = 120MHz * 48 / 3125 = 1843200Hz
+	 * The different order below is to handle integer math overflow.
+	 */
+	return 120 * MHz / SIO_REG_PPR_CLOCK_N_DIV * SIO_REG_PPR_CLOCK_M_DIV;
+}
+
+uintptr_t uart_platform_base(int idx)
+{
+	/* Same base address for all debug port usage. In reality UART2
+	 * is currently only supported. */
+	return UART_DEBUG_BASE_ADDRESS;
+}