Make the device tree available in the rom stage

We thought about two ways to do this change. The way we decided to try
was to
1. drop all ops from devices in romstage
2. constify all devices in romstage (make them read-only) so we can
   compile static.c into romstage
3. the device tree "devices" can be used to read configuration from
   the device tree (and nothing else, really)
4. the device tree devices are accessed through struct device * in
   romstage only. device_t stays the typedef to int in romstage
5. Use the same static.c file in ramstage and romstage

We declare structs as follows:
ROMSTAGE_CONST struct bus dev_root_links[];
ROMSTAGE_CONST is const in romstage and empty in ramstage; This
forces all of the device tree into the text area.

So a struct looks like this:
static ROMSTAGE_CONST struct device _dev21 = {
 #ifndef __PRE_RAM__
        .ops = 0,
 #endif
        .bus = &_dev7_links[0],
        .path = {.type=DEVICE_PATH_PCI,{.pci={ .devfn = PCI_DEVFN(0x1c,3)}}},
        .enabled = 0,
        .on_mainboard = 1,
        .subsystem_vendor = 0x1ae0,
        .subsystem_device = 0xc000,
        .link_list = NULL,
        .sibling = &_dev22,
 #ifndef __PRE_RAM__
        .chip_ops = &southbridge_intel_bd82x6x_ops,
 #endif
        .chip_info = &southbridge_intel_bd82x6x_info_10,
        .next=&_dev22
};

Change-Id: I722454d8d3c40baf7df989f5a6891f6ba7db5727
Signed-off-by: Ronald G. Minnich <rminnich@chromium.org>
Signed-off-by: Stefan Reinauer <reinauer@google.com>
Reviewed-on: http://review.coreboot.org/1398
Tested-by: build bot (Jenkins)
Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>

2 files changed, 82 insertions, 0 deletions

diff --git a/src/devices/Makefile.inc b/src/devices/Makefile.inc
index 9ffc0bb921..9a2f71e683 100644
--- a/src/devices/Makefile.inc
+++ b/src/devices/Makefile.inc
@@ -11,6 +11,8 @@ ramstage-y += pnp_device.c
 ramstage-y += pci_ops.c
 ramstage-y += smbus_ops.c
 
+romstage-y+= device_romstage.c
+
 subdirs-y += oprom
 
 ifeq ($(CONFIG_PCI_ROM_RUN),y)
diff --git a/src/devices/device_romstage.c b/src/devices/device_romstage.c
new file mode 100644
index 0000000000..475f94aeaf
--- /dev/null
+++ b/src/devices/device_romstage.c
@@ -0,0 +1,80 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * Copyright (C) 2003-2004 Linux Networx
+ * (Written by Eric Biederman <ebiederman@lnxi.com> for Linux Networx)
+ * Copyright (C) 2003 Greg Watson <jarrah@users.sourceforge.net>
+ * Copyright (C) 2004 Li-Ta Lo <ollie@lanl.gov>
+ * Copyright (C) 2005-2006 Tyan
+ * (Written by Yinghai Lu <yhlu@tyan.com> for Tyan)
+ *
+ * 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 <device/device.h>
+#include <device/path.h>
+#include <device/pci.h>
+#include <device/resource.h>
+
+/** Linked list of ALL devices */
+ROMSTAGE_CONST struct device * ROMSTAGE_CONST all_devices = &dev_root;
+
+/**
+ * Given a PCI bus and a devfn number, find the device structure.
+ *
+ * @param bus The bus number.
+ * @param devfn A device/function number.
+ * @return Pointer to the device structure (if found), 0 otherwise.
+ */
+ROMSTAGE_CONST struct device *dev_find_slot(unsigned int bus,
+						unsigned int devfn)
+{
+	ROMSTAGE_CONST struct device *dev, *result;
+
+	result = 0;
+	for (dev = all_devices; dev; dev = dev->next) {
+		if ((dev->path.type == DEVICE_PATH_PCI) &&
+		    (dev->bus->secondary == bus) &&
+		    (dev->path.pci.devfn == devfn)) {
+			result = dev;
+			break;
+		}
+	}
+	return result;
+}
+
+/**
+ * Given an SMBus bus and a device number, find the device structure.
+ *
+ * @param bus The bus number.
+ * @param addr A device number.
+ * @return Pointer to the device structure (if found), 0 otherwise.
+ */
+ROMSTAGE_CONST struct device *dev_find_slot_on_smbus(unsigned int bus,
+							unsigned int addr)
+{
+	ROMSTAGE_CONST struct device *dev, *result;
+
+	result = 0;
+	for (dev = all_devices; dev; dev = dev->next) {
+		if ((dev->path.type == DEVICE_PATH_I2C) &&
+		    (dev->bus->secondary == bus) &&
+		    (dev->path.i2c.device == addr)) {
+			result = dev;
+			break;
+		}
+	}
+	return result;
+}
+