risc-v/qemu-rv: Add LED Driver for QEMU RISC-V 32-bit and 64-bit

[rushabhvg]

Summary

• This PR adds the LED Driver for QEMU RISC-V 32-bit and 64-bit (User LEDs and Auto LEDs)
• QEMU RISC-V LED Driver will be used by the Rust Blinky App for Google Summer of Code
• Blinking the LED is probably the most common Embedded Demo, and now it's supported by QEMU RISC-V
• We added NuttX Configs rv-virt:leds and rv-virt:leds64 to support User LEDs for 32-bit and 64-bit RISC-V
• Turning on/off a Simulated User LED will print a log message: "LED 1 set to 1"
• The code is derived from NuttX PinePhone LED Driver

Modified Files in boards:

• Kconfig: Added ARCH_HAVE_LEDS for QEMU RISC-V

Modified Files in boards/risc-v/qemu-rv/rv-virt:

• include/board.h: Added LED Definitions
• src/qemu_rv_appinit.c: Init User LEDs at startup
• src/Makefile: Added source files for User LEDs and Auto LEDs
• src/CMakeLists.txt: Added source files for User LEDs and Auto LEDs

New Files in boards/risc-v/qemu-rv/rv-virt:

• src/qemu_rv_autoleds.c: QEMU RISC-V driver for Auto LEDs
• src/qemu_rv_userleds.c: QEMU RISC-V driver for User LEDs
• configs/leds/defconfig: NuttX Config for 32-bit RISC-V with User LEDs (rv-virt:leds)
• configs/leds64/defconfig: NuttX Config for 64-bit RISC-V with User LEDs (rv-virt:leds64)

Updated Documentation:

• platforms/risc-v/qemu-rv/boards/rv-virt/index.rst: Added rv-virt:leds and rv-virt:leds64

Impact

• With this PR, NuttX for QEMU RISC-V (32-bit and 64-bit) will be able to control the Simulated User LEDs (for rv-virt:leds and rv-virt:leds64 only)
• Auto LED Driver will be called by all QEMU RISC-V Boards at Startup, even when CONFIG_USERLED is disabled. We provided Empty Stub Functions for the Auto LED Driver, to minimise the impact on all QEMU RISC-V Boards.

Testing

We tested Rust Blinky App and the leds Example App on rv-virt:leds and rv-virt:leds64:

• rv-virt:leds Log
• rv-virt:leds64 Log

$ tools/configure.sh rv-virt:leds / leds64
...
nsh> uname -a
NuttX 0.0.0 e0ad35542b0 Jul 24 2024 08:27:18 risc-v rv-virt

nsh> hello_rust
Hello, Rust!!
Opening /dev/userleds
Set LED 1 to 1
board_userled: LED 1 set to 1
board_userled: LED 2 set to 0
board_userled: LED 3 set to 0
Sleeping...
Set LED 1 to 0
board_userled: LED 1 set to 0
board_userled: LED 2 set to 0
board_userled: LED 3 set to 0

nsh> leds
board_userled: LED 1 set to 1
board_userled: LED 2 set to 0
board_userled: LED 3 set to 0
...
nsh> ostest
ostest_main: Exiting with status 0

Regression Testing

For Regression Testing, we tested QEMU RISC-V Flat Build and Kernel Build, 32-bit and 64-bit:

• rv-virt:nsh Log
• rv-virt:nsh64 Log
• rv-virt:knsh32 Log
• rv-virt:knsh64 Log

$ tools/configure.sh rv-virt:nsh / nsh64 / knsh32 / knsh64
...
nsh> uname -a
NuttX 0.0.0 e0ad35542b0 Jul 24 2024 08:27:18 risc-v rv-virt
nsh> ostest
ostest_main: Exiting with status 0

[lupyuen]

Thanks again Rushabh for your awesome contribution to NuttX Kernel in Google Summer of Code! :-)

[lupyuen]

@rushabhvg Could you please Rebase To The Latest Master? It should fix the "imx9-sdimage.img" Issue for NuttX Continuous Integration thanks!

[rushabhvg]

@lupyuen Yes, I have rebased to latest master and re-pushed the code. Thanks!

[lupyuen]

@rushabhvg Oops sorry we have a problem with the 2 defconfig files, it's missing the newline at the end of the files. Could you fix the newlines, then run tools/refresh.sh to verify? Remember to squash the commits thanks!

$ ./tools/refresh.sh --silent rv-virt:leds64
  Normalize rv-virt:leds64
75c75
< CONFIG_USERLED_LOWER=y
\ No newline at end of file
---
> CONFIG_USERLED_LOWER=y
Saving the new configuration file

$ ./tools/refresh.sh --silent rv-virt:leds
  Normalize rv-virt:leds
71c71
< CONFIG_USERLED_LOWER=y
\ No newline at end of file
---
> CONFIG_USERLED_LOWER=y
Saving the new configuration file

UPDATE: Sorry the rv-virt/smp and rv-virt/smp64 builds are also failing. I'll update you when I figure out what's wrong thanks!

[lupyuen]

The defconfig newlines are fixed and CMakeLists.txt has been updated. The build is now OK for rv-virt:smp and smp64. Thanks!

[rushabhvg]

Thank you @lupyuen for the last minute fixes!