2 * Copyright (c) 2014 The Chromium OS Authors.
4 * SPDX-License-Identifier: GPL-2.0+
7 Native Execution of U-Boot
8 ==========================
10 The 'sandbox' architecture is designed to allow U-Boot to run under Linux on
11 almost any hardware. To achieve this it builds U-Boot (so far as possible)
12 as a normal C application with a main() and normal C libraries.
14 All of U-Boot's architecture-specific code therefore cannot be built as part
15 of the sandbox U-Boot. The purpose of running U-Boot under Linux is to test
16 all the generic code, not specific to any one architecture. The idea is to
17 create unit tests which we can run to test this upper level code.
19 CONFIG_SANDBOX is defined when building a native board.
21 The board name is 'sandbox' but the vendor name is unset, so there is a
22 single board in board/sandbox.
24 CONFIG_SANDBOX_BIG_ENDIAN should be defined when running on big-endian
27 Note that standalone/API support is not available at present.
33 To run sandbox U-Boot use something like:
35 make sandbox_defconfig all
39 If you get errors about 'sdl-config: Command not found' you may need to
40 install libsdl1.2-dev or similar to get SDL support. Alternatively you can
41 build sandbox without SDL (i.e. no display/keyboard support) by removing
42 the CONFIG_SANDBOX_SDL line in include/configs/sandbox.h or using:
44 make sandbox_defconfig all NO_SDL=1
48 U-Boot will start on your computer, showing a sandbox emulation of the serial
52 U-Boot 2014.04 (Mar 20 2014 - 19:06:00)
55 Using default environment
62 You can issue commands as your would normally. If the command you want is
63 not supported you can add it to include/configs/sandbox.h.
65 To exit, type 'reset' or press Ctrl-C.
71 Assuming that CONFIG_SANDBOX_SDL is defined when building, you can run the
72 sandbox with LCD and keyboard emulation, using something like:
74 ./u-boot -d u-boot.dtb -l
76 This will start U-Boot with a window showing the contents of the LCD. If
77 that window has the focus then you will be able to type commands as you
78 would on the console. You can adjust the display settings in the device
79 tree file - see arch/sandbox/dts/sandbox.dts.
85 Various options are available, mostly for test purposes. Use -h to see
86 available options. Some of these are described below.
88 The terminal is normally in what is called 'raw-with-sigs' mode. This means
89 that you can use arrow keys for command editing and history, but if you
90 press Ctrl-C, U-Boot will exit instead of handling this as a keypress.
92 Other options are 'raw' (so Ctrl-C is handled within U-Boot) and 'cooked'
93 (where the terminal is in cooked mode and cursor keys will not work, Ctrl-C
96 As mentioned above, -l causes the LCD emulation window to be shown.
98 A device tree binary file can be provided with -d. If you edit the source
99 (it is stored at arch/sandbox/dts/sandbox.dts) you must rebuild U-Boot to
100 recreate the binary file.
102 To execute commands directly, use the -c option. You can specify a single
103 command, or multiple commands separated by a semicolon, as is normal in
104 U-Boot. Be careful with quoting as the shall will normally process and
105 swallow quotes. When -c is used, U-Boot exists after the command is complete,
106 but you can force it to go to interactive mode instead with -i.
112 Memory emulation is supported, with the size set by CONFIG_SYS_SDRAM_SIZE.
113 The -m option can be used to read memory from a file on start-up and write
114 it when shutting down. This allows preserving of memory contents across
115 test runs. You can tell U-Boot to remove the memory file after it is read
116 (on start-up) with the --rm_memory option.
118 To access U-Boot's emulated memory within the code, use map_sysmem(). This
119 function is used throughout U-Boot to ensure that emulated memory is used
120 rather than the U-Boot application memory. This provides memory starting
121 at 0 and extending to the size of the emulation.
127 With sandbox you can write drivers which emulate the operation of drivers on
128 real devices. Some of these drivers may want to record state which is
129 preserved across U-Boot runs. This is particularly useful for testing. For
130 example, the contents of a SPI flash chip should not disappear just because
133 State is stored in a device tree file in a simple format which is driver-
134 specific. You then use the -s option to specify the state file. Use -r to
135 make U-Boot read the state on start-up (otherwise it starts empty) and -w
136 to write it on exit (otherwise the stored state is left unchanged and any
137 changes U-Boot made will be lost). You can also use -n to tell U-Boot to
138 ignore any problems with missing state. This is useful when first running
139 since the state file will be empty.
141 The device tree file has one node for each driver - the driver can store
142 whatever properties it likes in there. See 'Writing Sandbox Drivers' below
143 for more details on how to get drivers to read and write their state.
149 Since there is no machine architecture, sandbox U-Boot cannot actually boot
150 a kernel, but it does support the bootm command. Filesystems, memory
151 commands, hashing, FIT images, verified boot and many other features are
154 When 'bootm' runs a kernel, sandbox will exit, as U-Boot does on a real
155 machine. Of course in this case, no kernel is run.
157 It is also possible to tell U-Boot that it has jumped from a temporary
158 previous U-Boot binary, with the -j option. That binary is automatically
159 removed by the U-Boot that gets the -j option. This allows you to write
160 tests which emulate the action of chain-loading U-Boot, typically used in
161 a situation where a second 'updatable' U-Boot is stored on your board. It
162 is very risky to overwrite or upgrade the only U-Boot on a board, since a
163 power or other failure will brick the board and require return to the
164 manufacturer in the case of a consumer device.
170 U-Boot sandbox supports these emulations:
175 - Host filesystem (access files on the host from within U-Boot)
177 - Keyboard (Chrome OS)
180 - Serial (for console only)
181 - Sound (incomplete - see sandbox_sdl_sound_init() for details)
184 - TPM (Trusted Platform Module)
186 A wide range of commands is implemented. Filesystems which use a block
187 device are supported.
189 Also sandbox supports driver model (CONFIG_DM) and associated commands.
192 Linux RAW Networking Bridge
193 ---------------------------
195 The sandbox_eth_raw driver bridges traffic between the bottom of the network
196 stack and the RAW sockets API in Linux. This allows much of the U-Boot network
197 functionality to be tested in sandbox against real network traffic.
199 For Ethernet network adapters, the bridge utilizes the RAW AF_PACKET API. This
200 is needed to get access to the lowest level of the network stack in Linux. This
201 means that all of the Ethernet frame is included. This allows the U-Boot network
202 stack to be fully used. In other words, nothing about the Linux network stack is
203 involved in forming the packets that end up on the wire. To receive the
204 responses to packets sent from U-Boot the network interface has to be set to
205 promiscuous mode so that the network card won't filter out packets not destined
206 for its configured (on Linux) MAC address.
208 The RAW sockets Ethernet API requires elevated privileges in Linux. You can
209 either run as root, or you can add the capability needed like so:
211 sudo /sbin/setcap "CAP_NET_RAW+ep" /path/to/u-boot
213 The default device tree for sandbox includes an entry for eth0 on the sandbox
214 host machine whose alias is "eth1". The following are a few examples of network
215 operations being tested on the eth0 interface.
217 sudo /path/to/u-boot -D
240 set serverip WWW.XXX.YYY.ZZZ
243 The bridge also support (to a lesser extent) the localhost inderface, 'lo'.
245 The 'lo' interface cannot use the RAW AF_PACKET API because the lo interface
246 doesn't support Ethernet-level traffic. It is a higher-level interface that is
247 expected only to be used at the AF_INET level of the API. As such, the most raw
248 we can get on that interface is the RAW AF_INET API on UDP. This allows us to
249 set the IP_HDRINCL option to include everything except the Ethernet header in
250 the packets we send and receive.
252 Because only UDP is supported, ICMP traffic will not work, so expect that ping
253 commands will time out.
255 The default device tree for sandbox includes an entry for lo on the sandbox
256 host machine whose alias is "eth5". The following is an example of a network
257 operation being tested on the lo interface.
269 Sandbox supports SPI and SPI flash emulation.
271 This is controlled by the spi_sf argument, the format of which is:
276 cs - SPI chip select number
277 device - SPI device emulation name
278 file - File on disk containing the data
282 dd if=/dev/zero of=spi.bin bs=1M count=4
283 ./u-boot --spi_sf 0:0:M25P16:spi.bin
285 With this setup you can issue SPI flash commands as normal:
288 SF: Detected M25P16 with page size 64 KiB, total 2 MiB
290 SF: 65536 bytes @ 0x0 Read: OK
293 Since this is a full SPI emulation (rather than just flash), you can
294 also use low-level SPI commands:
299 This is issuing a READ_ID command and getting back 20 (ST Micro) part
302 Drivers are connected to a particular bus/cs using sandbox's state
303 structure (see the 'spi' member). A set of operations must be provided
307 Configuration settings for the curious are:
309 CONFIG_SANDBOX_SPI_MAX_BUS
310 The maximum number of SPI buses supported by the driver (default 1).
312 CONFIG_SANDBOX_SPI_MAX_CS
313 The maximum number of chip selects supported by the driver
317 The idle value on the SPI bus
320 Writing Sandbox Drivers
321 -----------------------
323 Generally you should put your driver in a file containing the word 'sandbox'
324 and put it in the same directory as other drivers of its type. You can then
325 implement the same hooks as the other drivers.
327 To access U-Boot's emulated memory, use map_sysmem() as mentioned above.
329 If your driver needs to store configuration or state (such as SPI flash
330 contents or emulated chip registers), you can use the device tree as
331 described above. Define handlers for this with the SANDBOX_STATE_IO macro.
332 See arch/sandbox/include/asm/state.h for documentation. In short you provide
333 a node name, compatible string and functions to read and write the state.
334 Since writing the state can expand the device tree, you may need to use
335 state_setprop() which does this automatically and avoids running out of
336 space. See existing code for examples.
342 U-Boot sandbox can be used to run various tests, mostly in the test/
343 directory. These include:
346 - Unit tests for command parsing and handling
348 - Unit tests for U-Boot's compression algorithms, useful for
349 security checking. It supports gzip, bzip2, lzma and lzo.
352 ./test/py/test.py --bd sandbox --build -k ut_dm -v
354 - Unit tests for images:
355 test/image/test-imagetools.sh - multi-file images
356 test/image/test-fit.py - FIT images
358 - test/trace/test-trace.sh tests the tracing system (see README.trace)
360 - See test/vboot/vboot_test.sh for this
362 If you change or enhance any of the above subsystems, you shold write or
363 expand a test and include it with your patch series submission. Test
364 coverage in U-Boot is limited, as we need to work to improve it.
366 Note that many of these tests are implemented as commands which you can
367 run natively on your board if desired (and enabled).
369 It would be useful to have a central script to run all of these.
372 Simon Glass <sjg@chromium.org>