amd/stoneyridge: Convert MP init to mp_init_with_smm

Change the Stoney Ridge SOC to a more modern method for setting up
the multiple cores.

Add a new cpu.c file for most of the processor initiliazation.  Build
mp_ops with the necessary callbacks.  Note also that this patch removes
cpu_bus_scan.  Rather than manually find CPUs and add them to the
devicetree, allow this to be done automatically in the generic
mp_init.c file.

SMM information is left blank in mp_ops to avoid having mp_init.c
install a handler at this time.  A later patch will add TSEG SMM
capabilities for the APU.

This patch also contains a hack to mask the behavior of AGESA which
configures the MTRRs and Tom2ForceMemTypeWB coming out of AmdInitPost.
The hack immediately changes all WB variable MTRRs, on the BSP, to UC
so that all writes to memory space will make it to the DRAM.

BUG=b:66200075

Change-Id: Ie54295cb00c6835947456e8818a289b7eb260914
Signed-off-by: Marshall Dawson <marshalldawson3rd@gmail.com>
Reviewed-on: https://review.coreboot.org/21498
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>

src/soc/amd/stoneyridge/cpu.c

@@ -0,0 +1,54 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * Copyright (C) 2015-2016 Intel Corp.
+ * Copyright (C) 2017 Advanced Micro Devices, 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.
+ */
+
+#include <cpu/x86/mp.h>
+#include <cpu/x86/mtrr.h>
+#include <device/device.h>
+#include <soc/pci_devs.h>
+#include <soc/cpu.h>
+#include <soc/northbridge.h>
+#include <console/console.h>
+
+/*
+ * Do essential initialization tasks before APs can be fired up -
+ *
+ *  1. Prevent race condition in MTRR solution. Enable MTRRs on the BSP. This
+ *  creates the MTRR solution that the APs will use. Otherwise APs will try to
+ *  apply the incomplete solution as the BSP is calculating it.
+ */
+static void pre_mp_init(void)
+{
+	x86_setup_mtrrs_with_detect();
+	x86_mtrr_check();
+}
+
+static int get_cpu_count(void)
+{
+	device_t nb = dev_find_slot(0, HT_DEVFN);
+	return (pci_read_config16(nb, D18F0_CPU_CNT) & CPU_CNT_MASK) + 1;
+}
+
+static const struct mp_ops mp_ops = {
+	.pre_mp_init = pre_mp_init,
+	.get_cpu_count = get_cpu_count,
+};
+
+void stoney_init_cpus(struct device *dev)
+{
+	/* Clear for take-off */
+	if (mp_init_with_smm(dev->link_list, &mp_ops) < 0)
+		printk(BIOS_ERR, "MP initialization failure.\n");
+}