This cleans up the semihosting code and adds the following new features:
- hostfs support (like sandbox) - support for being used as a SPL boot device - serial device support
The main device affected by these changes is vexpress64, so I'd appreciate if Linus (or anyone else) could try booting.
These changes are motivated by bringup for ls1046a. When forcing JTAG boot, this device disables most communication peripherals, including serial and ethernet devices. This appears to be fixed in later generation devices, but we are stuck with it for now. Semihosting provides an easy way to run a few console commands.
Future work could include modifying one of the reset handlers to catch semihosting calls not handled by a debugger. This would allow using the same U-Boot when booting from JTAG and when booting normally. Additionally, we could use puts in more places. DM serial is especially slow with semihisting because all we have is putc.
The patches in this series are organized as follows: 0-3: rST conversions and other documentation updates 4-8: Semihosting cleanups 9-13: Filesystem support (including SPL boot device) 14-15: Serial support 16: Documentation update 17: JTAG boot support for LS1046A
Patch 17 depends on [1].
[1] https://lore.kernel.org/u-boot/20220222183840.1355337-2-sean.anderson@seco.c...
Sean Anderson (17): doc: Convert semihosting readme to rST nxp: ls1046ardb: Convert README to rST doc: ls1046ardb: Expand boot mode section arm: smh: Add semihosting entry to MAINTAINERS arm: smh: Export semihosting functions arm: smh: Use numeric modes for smh_open arm: smh: Return errno on error arm: smh: Document functions in header arm: smh: Add some file manipulation commands spl: Add semihosting boot method fs: Add semihosting filesystem cmd: fdt: Use start/size for chosen instead of start/end arm: smh: Remove smhload command arm: smh: Add some functions for working with the host console serial: Add semihosting driver doc: smh: Update semihosting documentation ls1046ardb: Add support for JTAG boot
MAINTAINERS | 4 + arch/arm/Kconfig | 25 ++- arch/arm/cpu/armv8/fsl-layerscape/spl.c | 2 + arch/arm/include/asm/spl.h | 1 + arch/arm/lib/semihosting.c | 209 ++++++++++-------------- board/freescale/ls1046ardb/MAINTAINERS | 1 + board/freescale/ls1046ardb/README | 76 --------- cmd/fdt.c | 6 +- common/spl/Makefile | 1 + common/spl/spl_semihosting.c | 71 ++++++++ configs/vexpress_aemv8a_semi_defconfig | 2 +- disk/part.c | 4 +- doc/README.semihosting | 38 ----- doc/board/nxp/index.rst | 1 + doc/board/nxp/ls1046ardb.rst | 182 +++++++++++++++++++++ doc/usage/index.rst | 1 + doc/usage/semihosting.rst | 51 ++++++ drivers/serial/Kconfig | 22 +++ drivers/serial/Makefile | 1 + drivers/serial/serial.c | 2 + drivers/serial/serial_semihosting.c | 108 ++++++++++++ fs/Makefile | 1 + fs/fs.c | 20 +++ fs/semihostingfs.c | 115 +++++++++++++ include/configs/ls1046ardb.h | 2 + include/fs.h | 1 + include/semihosting.h | 108 ++++++++++++ include/semihostingfs.h | 21 +++ 28 files changed, 832 insertions(+), 244 deletions(-) delete mode 100644 board/freescale/ls1046ardb/README create mode 100644 common/spl/spl_semihosting.c delete mode 100644 doc/README.semihosting create mode 100644 doc/board/nxp/ls1046ardb.rst create mode 100644 doc/usage/semihosting.rst create mode 100644 drivers/serial/serial_semihosting.c create mode 100644 fs/semihostingfs.c create mode 100644 include/semihosting.h create mode 100644 include/semihostingfs.h