doc: arch: Convert README.sandbox to reST

Convert plain text documentation to reStructuredText format and add
it to Sphinx TOC tree. No essential content change.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>

2 files changed, 518 insertions, 0 deletions

diff --git a/doc/arch/index.rst b/doc/arch/index.rst
index d24662e..2980b77 100644
--- a/doc/arch/index.rst
+++ b/doc/arch/index.rst
@@ -12,5 +12,6 @@ Architecture-specific doc
    mips
    nds32
    nios2
+   sandbox
    sh
    x86
diff --git a/doc/arch/sandbox.rst b/doc/arch/sandbox.rst
new file mode 100644
index 0000000..5c0caeb
--- /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)
+=======   ========================   ===============================