src/base/loader/dtb_file.cc

   1 /*
   2  * Copyright (c) 2013 The Regents of The University of Michigan
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions are
   7  * met: redistributions of source code must retain the above copyright
   8  * notice, this list of conditions and the following disclaimer;
   9  * redistributions in binary form must reproduce the above copyright
  10  * notice, this list of conditions and the following disclaimer in the
  11  * documentation and/or other materials provided with the distribution;
  12  * neither the name of the copyright holders nor the names of its
  13  * contributors may be used to endorse or promote products derived from
  14  * this software without specific prior written permission.
  15  *
  16  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  17  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  18  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  19  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  20  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  21  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  22  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  23  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  24  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  26  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27  */
  28
  29 #include "base/loader/dtb_file.hh"
  30
  31 #include <sys/mman.h>
  32 #include <unistd.h>
  33
  34 #include <cassert>
  35
  36 #include "fdt.h"
  37 #include "libfdt.h"
  38 #include "sim/byteswap.hh"
  39
  40 namespace Loader
  41 {
  42
  43 DtbFile::DtbFile(const std::string &filename) :
  44     ImageFile(ImageFileDataPtr(new ImageFileData(filename)))
  45 {
  46     panic_if(fdt_magic((const void *)imageData->data()) != FDT_MAGIC,
  47             "File %s doesn't seem to be a DTB.\n", filename);
  48     fileDataMmapped = true;
  49     fileData = const_cast<uint8_t *>(imageData->data());
  50     length = imageData->len();
  51 }
  52
  53 DtbFile::~DtbFile()
  54 {
  55     // Make sure to clean up memory properly depending
  56     // on how buffer was allocated.
  57     if (!fileDataMmapped)
  58         delete [] fileData;
  59 }
  60
  61 bool
  62 DtbFile::addBootCmdLine(const char *_args, size_t len)
  63 {
  64     const char *root_path = "/";
  65     const char *node_name = "chosen";
  66     const char *full_path_node_name = "/chosen";
  67     const char *property_name = "bootargs";
  68
  69     // Make a new buffer that has extra space to add nodes/properties
  70     int newLen = 2 * length;
  71     uint8_t *fdt_buf_w_space = new uint8_t[newLen];
  72     // Copy and unpack flattened device tree into new buffer
  73     int ret = fdt_open_into((void *)fileData, (void *)fdt_buf_w_space, newLen);
  74     if (ret < 0) {
  75         warn("Error resizing buffer of flattened device tree, "
  76              "errno: %d\n", ret);
  77         delete [] fdt_buf_w_space;
  78         return false;
  79     }
  80
  81     // First try finding the /chosen node in the dtb
  82     int offset = fdt_path_offset((void *)fdt_buf_w_space, full_path_node_name);
  83     if (offset < 0) {
  84         // try adding the node by walking dtb tree to proper insertion point
  85         offset = fdt_path_offset((void *)fdt_buf_w_space, root_path);
  86         offset = fdt_add_subnode((void *)fdt_buf_w_space, offset, node_name);
  87         // if we successfully add the subnode, get the offset
  88         if (offset >= 0)
  89           offset = fdt_path_offset((void *)fdt_buf_w_space,
  90                                    full_path_node_name);
  91
  92         if (offset < 0) {
  93             warn("Error finding or adding \"chosen\" subnode to flattened "
  94                  "device tree, errno: %d\n", offset);
  95             delete [] fdt_buf_w_space;
  96             return false;
  97         }
  98     }
  99
 100     // Set the bootargs property in the /chosen node
 101     ret = fdt_setprop((void *)fdt_buf_w_space, offset, property_name,
 102                       (const void *)_args, len+1);
 103     if (ret < 0) {
 104         warn("Error setting \"bootargs\" property to flattened device tree, "
 105              "errno: %d\n", ret);
 106         delete [] fdt_buf_w_space;
 107         return false;
 108     }
 109
 110     // Repack the dtb for kernel use
 111     ret = fdt_pack((void *)fdt_buf_w_space);
 112     if (ret < 0) {
 113         warn("Error re-packing flattened device tree structure, "
 114              "errno: %d\n", ret);
 115         delete [] fdt_buf_w_space;
 116         return false;
 117     }
 118
 119     // clean up old buffer and set to new fdt blob
 120     if (!fileDataMmapped)
 121         delete [] fileData;
 122     fileData = fdt_buf_w_space;
 123     fileDataMmapped = false;
 124     length = newLen;
 125
 126     return true;
 127 }
 128
 129 Addr
 130 DtbFile::findReleaseAddr()
 131 {
 132     void *fd = (void *)fileData;
 133
 134     int offset = fdt_path_offset(fd, "/cpus/cpu@0");
 135     int len;
 136
 137     const void *temp = fdt_getprop(fd, offset, "cpu-release-addr", &len);
 138     Addr rel_addr = 0;
 139
 140     if (len > 3)
 141         rel_addr = betoh(*static_cast<const uint32_t *>(temp));
 142     if (len == 8) {
 143         rel_addr = (rel_addr << 32) |
 144             betoh(*(static_cast<const uint32_t *>(temp) + 1));
 145     }
 146
 147     return rel_addr;
 148 }
 149
 150 MemoryImage
 151 DtbFile::buildImage() const
 152 {
 153     if (fileDataMmapped)
 154         return {{ "data", imageData }};
 155     else
 156         return {{ "data", 0, fileData, length }};
 157 }
 158
 159 } // namespace Loader