| /* |
| * Copyright (c) 2014 The Chromium OS Authors. |
| * |
| * SPDX-License-Identifier: GPL-2.0+ |
| */ |
| |
| Native Execution of U-Boot |
| ========================== |
| |
| The 'sandbox' architecture is designed to allow U-Boot to run under Linux on |
| almost any hardware. To achieve this it builds U-Boot (so far as possible) |
| as a normal C application with a main() and normal C libraries. |
| |
| All of U-Boot's architecture-specific code therefore cannot be built as part |
| of the sandbox U-Boot. The purpose of running U-Boot under Linux is to test |
| all the generic code, not specific to any one architecture. The idea is to |
| create unit tests which we can run to test this upper level code. |
| |
| CONFIG_SANDBOX is defined when building a native board. |
| |
| The board name is 'sandbox' but the vendor name is unset, so there is a |
| single board in board/sandbox. |
| |
| CONFIG_SANDBOX_BIG_ENDIAN should be defined when running on big-endian |
| machines. |
| |
| By default sandbox builds and runs on 64-bit hosts. If you are going to build |
| and run sandbox on a 32-bit host, select CONFIG_SANDBOX_32BIT. |
| |
| Note that standalone/API support is not available at present. |
| |
| |
| Basic Operation |
| --------------- |
| |
| To run sandbox U-Boot use something like: |
| |
| make sandbox_defconfig all |
| ./u-boot |
| |
| Note: |
| If you get errors about 'sdl-config: Command not found' you may need to |
| install libsdl1.2-dev or similar to get SDL support. Alternatively you can |
| build sandbox without SDL (i.e. no display/keyboard support) by removing |
| the CONFIG_SANDBOX_SDL line in include/configs/sandbox.h or using: |
| |
| make sandbox_defconfig all NO_SDL=1 |
| ./u-boot |
| |
| U-Boot will start on your computer, showing a sandbox emulation of the serial |
| console: |
| |
| |
| U-Boot 2014.04 (Mar 20 2014 - 19:06:00) |
| |
| DRAM: 128 MiB |
| Using default environment |
| |
| In: serial |
| Out: lcd |
| Err: lcd |
| => |
| |
| You can issue commands as your would normally. If the command you want is |
| not supported you can add it to include/configs/sandbox.h. |
| |
| To exit, type 'reset' or press Ctrl-C. |
| |
| |
| Console / LCD support |
| --------------------- |
| |
| Assuming that CONFIG_SANDBOX_SDL is defined when building, you can run the |
| sandbox with LCD and keyboard emulation, using something like: |
| |
| ./u-boot -d u-boot.dtb -l |
| |
| This will start U-Boot with a window showing the contents of the LCD. If |
| that window has the focus then you will be able to type commands as you |
| would on the console. You can adjust the display settings in the device |
| tree file - see arch/sandbox/dts/sandbox.dts. |
| |
| |
| Command-line Options |
| -------------------- |
| |
| Various options are available, mostly for test purposes. Use -h to see |
| available options. Some of these are described below. |
| |
| The terminal is normally in what is called 'raw-with-sigs' mode. This means |
| that you can use arrow keys for command editing and history, but if you |
| press Ctrl-C, U-Boot will exit instead of handling this as a keypress. |
| |
| Other options are 'raw' (so Ctrl-C is handled within U-Boot) and 'cooked' |
| (where the terminal is in cooked mode and cursor keys will not work, Ctrl-C |
| will exit). |
| |
| As mentioned above, -l causes the LCD emulation window to be shown. |
| |
| A device tree binary file can be provided with -d. If you edit the source |
| (it is stored at arch/sandbox/dts/sandbox.dts) you must rebuild U-Boot to |
| recreate the binary file. |
| |
| To execute commands directly, use the -c option. You can specify a single |
| command, or multiple commands separated by a semicolon, as is normal in |
| U-Boot. Be careful with quoting as the shall will normally process and |
| swallow quotes. When -c is used, U-Boot exists after the command is complete, |
| but you can force it to go to interactive mode instead with -i. |
| |
| |
| Memory Emulation |
| ---------------- |
| |
| Memory emulation is supported, with the size set by CONFIG_SYS_SDRAM_SIZE. |
| The -m option can be used to read memory from a file on start-up and write |
| it when shutting down. This allows preserving of memory contents across |
| test runs. You can tell U-Boot to remove the memory file after it is read |
| (on start-up) with the --rm_memory option. |
| |
| To access U-Boot's emulated memory within the code, use map_sysmem(). This |
| function is used throughout U-Boot to ensure that emulated memory is used |
| rather than the U-Boot application memory. This provides memory starting |
| at 0 and extending to the size of the emulation. |
| |
| |
| Storing State |
| ------------- |
| |
| With sandbox you can write drivers which emulate the operation of drivers on |
| real devices. Some of these drivers may want to record state which is |
| preserved across U-Boot runs. This is particularly useful for testing. For |
| example, the contents of a SPI flash chip should not disappear just because |
| U-Boot exits. |
| |
| State is stored in a device tree file in a simple format which is driver- |
| specific. You then use the -s option to specify the state file. Use -r to |
| make U-Boot read the state on start-up (otherwise it starts empty) and -w |
| to write it on exit (otherwise the stored state is left unchanged and any |
| changes U-Boot made will be lost). You can also use -n to tell U-Boot to |
| ignore any problems with missing state. This is useful when first running |
| since the state file will be empty. |
| |
| The device tree file has one node for each driver - the driver can store |
| whatever properties it likes in there. See 'Writing Sandbox Drivers' below |
| for more details on how to get drivers to read and write their state. |
| |
| |
| Running and Booting |
| ------------------- |
| |
| Since there is no machine architecture, sandbox U-Boot cannot actually boot |
| a kernel, but it does support the bootm command. Filesystems, memory |
| commands, hashing, FIT images, verified boot and many other features are |
| supported. |
| |
| When 'bootm' runs a kernel, sandbox will exit, as U-Boot does on a real |
| machine. Of course in this case, no kernel is run. |
| |
| It is also possible to tell U-Boot that it has jumped from a temporary |
| previous U-Boot binary, with the -j option. That binary is automatically |
| removed by the U-Boot that gets the -j option. This allows you to write |
| tests which emulate the action of chain-loading U-Boot, typically used in |
| a situation where a second 'updatable' U-Boot is stored on your board. It |
| is very risky to overwrite or upgrade the only U-Boot on a board, since a |
| power or other failure will brick the board and require return to the |
| manufacturer in the case of a consumer device. |
| |
| |
| Supported Drivers |
| ----------------- |
| |
| U-Boot sandbox supports these emulations: |
| |
| - Block devices |
| - Chrome OS EC |
| - GPIO |
| - Host filesystem (access files on the host from within U-Boot) |
| - I2C |
| - Keyboard (Chrome OS) |
| - LCD |
| - Network |
| - Serial (for console only) |
| - Sound (incomplete - see sandbox_sdl_sound_init() for details) |
| - SPI |
| - SPI flash |
| - TPM (Trusted Platform Module) |
| |
| A wide range of commands is implemented. Filesystems which use a block |
| device are supported. |
| |
| Also sandbox supports driver model (CONFIG_DM) and associated commands. |
| |
| |
| Linux RAW Networking Bridge |
| --------------------------- |
| |
| The sandbox_eth_raw driver bridges traffic between the bottom of the network |
| stack and the RAW sockets API in Linux. This allows much of the U-Boot network |
| functionality to be tested in sandbox against real network traffic. |
| |
| For Ethernet network adapters, the bridge utilizes the RAW AF_PACKET API. This |
| is needed to get access to the lowest level of the network stack in Linux. This |
| means that all of the Ethernet frame is included. This allows the U-Boot network |
| stack to be fully used. In other words, nothing about the Linux network stack is |
| involved in forming the packets that end up on the wire. To receive the |
| responses to packets sent from U-Boot the network interface has to be set to |
| promiscuous mode so that the network card won't filter out packets not destined |
| for its configured (on Linux) MAC address. |
| |
| The RAW sockets Ethernet API requires elevated privileges in Linux. You can |
| either run as root, or you can add the capability needed like so: |
| |
| sudo /sbin/setcap "CAP_NET_RAW+ep" /path/to/u-boot |
| |
| The default device tree for sandbox includes an entry for eth0 on the sandbox |
| host machine whose alias is "eth1". The following are a few examples of network |
| operations being tested on the eth0 interface. |
| |
| sudo /path/to/u-boot -D |
| |
| DHCP |
| .... |
| |
| set autoload no |
| set ethact eth1 |
| dhcp |
| |
| PING |
| .... |
| |
| set autoload no |
| set ethact eth1 |
| dhcp |
| ping $gatewayip |
| |
| TFTP |
| .... |
| |
| set autoload no |
| set ethact eth1 |
| dhcp |
| set serverip WWW.XXX.YYY.ZZZ |
| tftpboot u-boot.bin |
| |
| The bridge also support (to a lesser extent) the localhost inderface, 'lo'. |
| |
| The 'lo' interface cannot use the RAW AF_PACKET API because the lo interface |
| doesn't support Ethernet-level traffic. It is a higher-level interface that is |
| expected only to be used at the AF_INET level of the API. As such, the most raw |
| we can get on that interface is the RAW AF_INET API on UDP. This allows us to |
| set the IP_HDRINCL option to include everything except the Ethernet header in |
| the packets we send and receive. |
| |
| Because only UDP is supported, ICMP traffic will not work, so expect that ping |
| commands will time out. |
| |
| The default device tree for sandbox includes an entry for lo on the sandbox |
| host machine whose alias is "eth5". The following is an example of a network |
| operation being tested on the lo interface. |
| |
| TFTP |
| .... |
| |
| set ethact eth5 |
| tftpboot u-boot.bin |
| |
| |
| SPI Emulation |
| ------------- |
| |
| Sandbox supports SPI and SPI flash emulation. |
| |
| This is controlled by the spi_sf argument, the format of which is: |
| |
| bus:cs:device:file |
| |
| bus - SPI bus number |
| cs - SPI chip select number |
| device - SPI device emulation name |
| file - File on disk containing the data |
| |
| For example: |
| |
| dd if=/dev/zero of=spi.bin bs=1M count=4 |
| ./u-boot --spi_sf 0:0:M25P16:spi.bin |
| |
| With this setup you can issue SPI flash commands as normal: |
| |
| =>sf probe |
| SF: Detected M25P16 with page size 64 KiB, total 2 MiB |
| =>sf read 0 0 10000 |
| SF: 65536 bytes @ 0x0 Read: OK |
| => |
| |
| Since this is a full SPI emulation (rather than just flash), you can |
| also use low-level SPI commands: |
| |
| =>sspi 0:0 32 9f |
| FF202015 |
| |
| This is issuing a READ_ID command and getting back 20 (ST Micro) part |
| 0x2015 (the M25P16). |
| |
| Drivers are connected to a particular bus/cs using sandbox's state |
| structure (see the 'spi' member). A set of operations must be provided |
| for each driver. |
| |
| |
| Configuration settings for the curious are: |
| |
| CONFIG_SANDBOX_SPI_MAX_BUS |
| The maximum number of SPI buses supported by the driver (default 1). |
| |
| CONFIG_SANDBOX_SPI_MAX_CS |
| The maximum number of chip selects supported by the driver |
| (default 10). |
| |
| CONFIG_SPI_IDLE_VAL |
| The idle value on the SPI bus |
| |
| |
| Block Device Emulation |
| ---------------------- |
| |
| U-Boot can use raw disk images for block device emulation. To e.g. list |
| the contents of the root directory on the second partion of the image |
| "disk.raw", you can use the following commands: |
| |
| =>host bind 0 ./disk.raw |
| =>ls host 0:2 |
| |
| A disk image can be created using the following commands: |
| |
| $> truncate -s 1200M ./disk.raw |
| $> echo -e "label: gpt\n,64M,U\n,,L" | /usr/sbin/sgdisk ./disk.raw |
| $> lodev=`sudo losetup -P -f --show ./disk.raw` |
| $> sudo mkfs.vfat -n EFI -v ${lodev}p1 |
| $> sudo mkfs.ext4 -L ROOT -v ${lodev}p2 |
| |
| |
| Writing Sandbox Drivers |
| ----------------------- |
| |
| Generally you should put your driver in a file containing the word 'sandbox' |
| and put it in the same directory as other drivers of its type. You can then |
| implement the same hooks as the other drivers. |
| |
| To access U-Boot's emulated memory, use map_sysmem() as mentioned above. |
| |
| If your driver needs to store configuration or state (such as SPI flash |
| contents or emulated chip registers), you can use the device tree as |
| described above. Define handlers for this with the SANDBOX_STATE_IO macro. |
| See arch/sandbox/include/asm/state.h for documentation. In short you provide |
| a node name, compatible string and functions to read and write the state. |
| Since writing the state can expand the device tree, you may need to use |
| state_setprop() which does this automatically and avoids running out of |
| space. See existing code for examples. |
| |
| |
| Testing |
| ------- |
| |
| U-Boot sandbox can be used to run various tests, mostly in the test/ |
| directory. These include: |
| |
| command_ut |
| - Unit tests for command parsing and handling |
| compression |
| - Unit tests for U-Boot's compression algorithms, useful for |
| security checking. It supports gzip, bzip2, lzma and lzo. |
| driver model |
| - Run this pytest |
| ./test/py/test.py --bd sandbox --build -k ut_dm -v |
| image |
| - Unit tests for images: |
| test/image/test-imagetools.sh - multi-file images |
| test/image/test-fit.py - FIT images |
| tracing |
| - test/trace/test-trace.sh tests the tracing system (see README.trace) |
| verified boot |
| - See test/vboot/vboot_test.sh for this |
| |
| If you change or enhance any of the above subsystems, you shold write or |
| expand a test and include it with your patch series submission. Test |
| coverage in U-Boot is limited, as we need to work to improve it. |
| |
| Note that many of these tests are implemented as commands which you can |
| run natively on your board if desired (and enabled). |
| |
| It would be useful to have a central script to run all of these. |
| |
| -- |
| Simon Glass <sjg@chromium.org> |
| Updated 22-Mar-14 |