coreboot: introduce boot_device

The boot_device is a region_device that represents the
device from which coreboot retrieves and boots its stages.
The existing cbfs implementations use the boot_device as
the intermediary for accessing the CBFS region. Also,
there's currently only support for a read-only view of
the boot_device. i.e. one cannot write to the boot_device
using this view. However, a writable boot_device could
be added in the future.

Change-Id: Ic0da796ab161b8025c90631be3423ba6473ad31c
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: http://review.coreboot.org/10216
Tested-by: build bot (Jenkins)
Tested-by: Raptor Engineering Automated Test Stand <noreply@raptorengineeringinc.com>
Reviewed-by: Patrick Georgi <pgeorgi@google.com>

1 files changed, 31 insertions, 0 deletions

diff --git a/src/arch/x86/lib/mmap_boot.c b/src/arch/x86/lib/mmap_boot.c
new file mode 100644
index 0000000000..eb7b23e2b1
--- /dev/null
+++ b/src/arch/x86/lib/mmap_boot.c
@@ -0,0 +1,31 @@
+/*
+ * 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 <boot_device.h>
+
+/* The ROM is memory mapped just below 4GiB. Form a pointer for the base. */
+#define rom_base ((void *)(uintptr_t)(-(int32_t)CONFIG_ROM_SIZE))
+
+static const struct mem_region_device boot_dev =
+	MEM_REGION_DEV_INIT(rom_base, CONFIG_ROM_SIZE);
+
+const struct region_device *boot_device_ro(void)
+{
+	return &boot_dev.rdev;
+}