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diff --git a/doc/arch/sandbox.rst b/doc/arch/sandbox.rst new file mode 100644 index 0000000000..5c0caebcbf --- /dev/null +++ b/doc/arch/sandbox.rst @@ -0,0 +1,517 @@ +.. SPDX-License-Identifier: GPL-2.0+ */ +.. Copyright (c) 2014 The Chromium OS Authors. +.. sectionauthor:: Simon Glass <sjg@chromium.org> + +Sandbox +======= + +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. + +There are two versions of the sandbox: One using 32-bit-wide integers, and one +using 64-bit-wide integers. The 32-bit version can be build and run on either +32 or 64-bit hosts by either selecting or deselecting CONFIG_SANDBOX_32BIT; by +default, the sandbox it built for a 32-bit host. The sandbox using 64-bit-wide +integers can only be built on 64-bit hosts. + +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 shell will normally process and +swallow quotes. When -c is used, U-Boot exits 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 are implemented. Filesystems which use a block +device are supported. + +Also sandbox supports driver model (CONFIG_DM) and associated commands. + + +Sandbox Variants +---------------- + +There are unfortunately quite a few variants at present: + +sandbox: + should be used for most tests +sandbox64: + special build that forces a 64-bit host +sandbox_flattree: + builds with dev_read\_...() functions defined as inline. + We need this build so that we can test those inline functions, and we + cannot build with both the inline functions and the non-inline functions + since they are named the same. +sandbox_noblk: + builds without CONFIG_BLK, which means the legacy block + drivers are used. We cannot use both the legacy and driver-model block + drivers since they implement the same functions +sandbox_spl: + builds sandbox with SPL support, so you can run spl/u-boot-spl + and it will start up and then load ./u-boot. It is also possible to + run ./u-boot directly. + +Of these sandbox_noblk can be removed once CONFIG_BLK is used everwhere, and +sandbox_spl can probably be removed since it is a superset of sandbox. + +Most of the config options should be identical between these variants. + + +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. + +.. code-block:: none + + sudo /path/to/u-boot -D + + DHCP + .... + + setenv autoload no + setenv ethrotate no + setenv ethact eth1 + dhcp + + PING + .... + + setenv autoload no + setenv ethrotate no + setenv ethact eth1 + dhcp + ping $gatewayip + + TFTP + .... + + setenv autoload no + setenv ethrotate no + setenv ethact eth1 + dhcp + setenv serverip WWW.XXX.YYY.ZZZ + tftpboot u-boot.bin + +The bridge also supports (to a lesser extent) the localhost interface, '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. + +.. code-block:: none + + TFTP + .... + + setenv ethrotate no + setenv 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 + +or utilize the device described in test/py/make_test_disk.py:: + + #!/usr/bin/python + import make_test_disk + make_test_disk.makeDisk() + +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. + + +Debugging the init sequence +--------------------------- + +If you get a failure in the initcall sequence, like this:: + + initcall sequence 0000560775957c80 failed at call 0000000000048134 (err=-96) + +Then you use can use grep to see which init call failed, e.g.:: + + $ grep 0000000000048134 u-boot.map + stdio_add_devices + +Of course another option is to run it with a debugger such as gdb:: + + $ gdb u-boot + ... + (gdb) br initcall.h:41 + Breakpoint 1 at 0x4db9d: initcall.h:41. (2 locations) + +Note that two locations are reported, since this function is used in both +board_init_f() and board_init_r(). + +.. code-block:: none + + (gdb) r + Starting program: /tmp/b/sandbox/u-boot + [Thread debugging using libthread_db enabled] + Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1". + + U-Boot 2018.09-00264-ge0c2ba9814-dirty (Sep 22 2018 - 12:21:46 -0600) + + DRAM: 128 MiB + MMC: + + Breakpoint 1, initcall_run_list (init_sequence=0x5555559619e0 <init_sequence_f>) + at /scratch/sglass/cosarm/src/third_party/u-boot/files/include/initcall.h:41 + 41 printf("initcall sequence %p failed at call %p (err=%d)\n", + (gdb) print *init_fnc_ptr + $1 = (const init_fnc_t) 0x55555559c114 <stdio_add_devices> + (gdb) + + +This approach can be used on normal boards as well as sandbox. + + +SDL_CONFIG +---------- + +If sdl-config is on a different path from the default, set the SDL_CONFIG +environment variable to the correct pathname before building U-Boot. + + +Using valgrind / memcheck +------------------------- + +It is possible to run U-Boot under valgrind to check memory allocations:: + + valgrind u-boot + +If you are running sandbox SPL or TPL, then valgrind will not by default +notice when U-Boot jumps from TPL to SPL, or from SPL to U-Boot proper. To +fix this, use:: + + valgrind --trace-children=yes u-boot + + +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). + +To run all tests use "make check". + + +Memory Map +---------- + +Sandbox has its own emulated memory starting at 0. Here are some of the things +that are mapped into that memory: + +======= ======================== =============================== +Addr Config Usage +======= ======================== =============================== + 0 CONFIG_SYS_FDT_LOAD_ADDR Device tree + e000 CONFIG_BLOBLIST_ADDR Blob list + 10000 CONFIG_MALLOC_F_ADDR Early memory allocation + f0000 CONFIG_PRE_CON_BUF_ADDR Pre-console buffer + 100000 CONFIG_TRACE_EARLY_ADDR Early trace buffer (if enabled) +======= ======================== =============================== |