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>

src/arch/riscv/rom_media.c

@@ -1,7 +1,7 @@
 /*
  * This file is part of the coreboot project.
  *
- * Copyright (C) 2013 The Chromium OS Authors. All rights reserved.
+ * 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
@@ -17,40 +17,59 @@
  * along with this program; if not, write to the Free Software
  * Foundation, Inc.
  */
+#include <boot_device.h>
 #include <cbfs.h>
+#include <console/console.h>
 #include <string.h>
 
-#ifdef LIBPAYLOAD
-# define printk(x...)
-# define init_default_cbfs_media libpayload_init_default_cbfs_media
-  extern int libpayload_init_default_cbfs_media(struct cbfs_media *media);
-#else
-# include <console/console.h>
-#endif
+/* This assumes that the CBFS resides at 0x0, which is true for the default
+ * configuration. */
+static const struct mem_region_device gboot_dev =
+	MEM_REGION_DEV_INIT(NULL, CONFIG_ROM_SIZE);
 
-// Implementation of memory-mapped ROM media source on X86.
+const struct region_device *boot_device_ro(void)
+{
+	return &gboot_dev.rdev;
+}
 
 static int rom_media_open(struct cbfs_media *media) {
 	return 0;
 }
 
 static void *rom_media_map(struct cbfs_media *media, size_t offset, size_t count) {
+	const struct region_device *boot_dev;
 	void *ptr;
-	printk(BIOS_INFO, "%s: media %p, offset %lx, size %ld.\n", __func__, media, offset, count);
 
-	ptr = (void*)offset;
+	printk(BIOS_INFO, "%s: media %p, offset %lx, size %ld.\n", __func__, media, offset, count);
+	boot_dev = media->context;
+
+	ptr = rdev_mmap(boot_dev, offset, count);
+
+	if (ptr == NULL)
+		return (void *)-1;
+
 	return ptr;
 }
 
 static void *rom_media_unmap(struct cbfs_media *media, const void *address) {
+	const struct region_device *boot_dev;
+
+	boot_dev = media->context;
+
+	rdev_munmap(boot_dev, (void *)address);
+
 	return NULL;
 }
 
 static size_t rom_media_read(struct cbfs_media *media, void *dest, size_t offset,
 			   size_t count) {
-	void *ptr = rom_media_map(media, offset, count);
-	memcpy(dest, ptr, count);
-	rom_media_unmap(media, ptr);
+	const struct region_device *boot_dev;
+
+	boot_dev = media->context;
+
+	if (rdev_readat(boot_dev, dest, offset, count) < 0)
+		return 0;
+
 	return count;
 }
 
@@ -59,25 +78,8 @@ static int rom_media_close(struct cbfs_media *media) {
 }
 
 static int init_rom_media_cbfs(struct cbfs_media *media) {
-	/* this assumes that the CBFS resides at 0x0,
-	 * which is true for the default configuration
-	 */
-	int32_t *cbfs_header_ptr = (int32_t*)(uintptr_t)(CONFIG_CBFS_SIZE - 4);
-	uint64_t cbfs_header_offset = CONFIG_CBFS_SIZE + *cbfs_header_ptr;
-	struct cbfs_header *header = (struct cbfs_header*) cbfs_header_offset;
-	if (CBFS_HEADER_MAGIC != ntohl(header->magic)) {
-		printk(BIOS_ERR, "Invalid CBFS master header at %p\n", header);
-		printk(BIOS_ERR, "Expected %08lx and got %08lx\n", (unsigned long) CBFS_HEADER_MAGIC, (unsigned long) ntohl(header->magic));
-		return -1;
-	} else {
-		uint32_t romsize = ntohl(header->romsize);
-		media->context = (void*)(uintptr_t)romsize;
-#if defined(CONFIG_ROM_SIZE)
-		if (CONFIG_ROM_SIZE != romsize)
-			printk(BIOS_INFO, "Warning: rom size unmatch (%d/%d)\n",
-			       CONFIG_ROM_SIZE, romsize);
-#endif
-	}
+	boot_device_init();
+	media->context = (void *)boot_device_ro();
 	media->open = rom_media_open;
 	media->close = rom_media_close;
 	media->map = rom_media_map;