broadwell: Add romstage usbdebug support

This function will enable the EHCI port 1 on haswell/broadwell
PCH to act as USB debug port.  This is hardcoded to port 1.
The EHCI controller must be kept enabled if CONFIG_USBDEBUG
is enabled so this logic is added to the ehci ramstage driver.

BUG=chrome-os-partner:28234
TEST=enable CONFIG_USBDEBUG and build+boot with USB debug output.
Note that libpayload does not support usbdebug yet (I have separate
patches for that) so no payload output is visible.

Change-Id: I704a4786438173b2f3ee2c246636f5a24d8b428c
Signed-off-by: Duncan Laurie <dlaurie@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/199412
Reviewed-by: Aaron Durbin <adurbin@chromium.org>

src/soc/intel/broadwell/Makefile.inc

@@ -62,6 +62,12 @@ ramstage-y += ehci.c
 ramstage-y += xhci.c
 smm-y      += xhci.c
 
+ifeq ($(CONFIG_USBDEBUG),y)
+ramstage-y += usbdebug.c
+romstage-y += usbdebug.c
+smm-y      += usbdebug.c
+endif
+
 INCLUDES += -Isrc/soc/intel/broadwell/
 
 # Run an intermediate step when producing coreboot.rom

src/soc/intel/broadwell/ehci.c

@@ -26,6 +26,7 @@
 #include <usbdebug.h>
 #include <arch/io.h>
 #include <broadwell/ehci.h>
+#include <broadwell/pch.h>
 
 static void usb_ehci_set_subsystem(device_t dev, unsigned vendor, unsigned device)
 {
@@ -70,6 +71,14 @@ static void usb_ehci_set_resources(struct device *dev)
 #endif
 }
 
+static void ehci_enable(struct device *dev)
+{
+	if (CONFIG_USBDEBUG)
+		dev->enabled = 1;
+	else
+		pch_disable_devfn(dev);
+}
+
 static struct pci_operations ehci_ops_pci = {
 	.set_subsystem	= &usb_ehci_set_subsystem,
 };
@@ -79,6 +88,7 @@ static struct device_operations usb_ehci_ops = {
 	.set_resources		= &usb_ehci_set_resources,
 	.enable_resources	= &pci_dev_enable_resources,
 	.ops_pci		= &ehci_ops_pci,
+	.enable			= &ehci_enable,
 };
 
 static const unsigned short pci_device_ids[] = {

src/soc/intel/broadwell/pch.c

@@ -190,6 +190,10 @@ void broadwell_pch_enable_dev(device_t dev)
 	if (PCI_SLOT(dev->path.pci.devfn) == PCH_DEV_SLOT_PCIE)
 		return;
 
+	/* EHCI disable is handled in ramstage driver */
+	if (PCI_SLOT(dev->path.pci.devfn) == PCH_DEV_SLOT_EHCI)
+		return;
+
 	if (!dev->enabled) {
 		printk(BIOS_DEBUG, "%s: Disabling device\n", dev_path(dev));
 

src/soc/intel/broadwell/usbdebug.c

@@ -0,0 +1,51 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * Copyright (C) 2014 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., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include <stdint.h>
+#include <arch/io.h>
+#include <console/console.h>
+#include <usbdebug.h>
+#include <device/pci.h>
+#include <device/pci_def.h>
+#include <broadwell/pci_devs.h>
+
+void set_debug_port(unsigned int port)
+{
+	/* Hardcoded to physical port 1 */
+}
+
+void enable_usbdebug(unsigned int port)
+{
+	u32 tmp32;
+
+	tmp32 = pci_read_config32(PCH_DEV_EHCI, PCI_VENDOR_ID);
+	if (tmp32 == 0xffffffff || tmp32 == 0)
+		return;
+
+	/* Set the EHCI BAR address. */
+	pci_write_config32(PCH_DEV_EHCI, EHCI_BAR_INDEX, CONFIG_EHCI_BAR);
+
+	/* Enable access to the EHCI memory space registers. */
+	pci_write_config8(PCH_DEV_EHCI, PCI_COMMAND, PCI_COMMAND_MEMORY);
+
+	/* Force ownership of the Debug Port to the EHCI controller. */
+	tmp32 = read32(CONFIG_EHCI_BAR + CONFIG_EHCI_DEBUG_OFFSET);
+	tmp32 |= (1 << 30);
+	write32(CONFIG_EHCI_BAR + CONFIG_EHCI_DEBUG_OFFSET, tmp32);
+}