qemu-armv7r

This board configuration will use QEMU to emulate generic ARM v7-R series hardware platform and provides support for these devices:

ARM Generic Timer
PL011 UART controller
VirtIO Device

Note

The upstream QEMU does not support ARM Cortex-R virtual machine. This board uses the OpenVela QEMU fork which adds ARM Cortex-R support. You can find the source code and prebuilt binaries at: https://github.com/open-vela/platform_external_qemu/commits/trunk/

Prerequisites

Download and extract the prebuilt QEMU from OpenVela. For Linux x86_64, download from: https://github.com/open-vela/prebuilts_qemu_linux-x86_64

The QEMU binary path will be referred to as <QEMU_PATH> in the following sections:

# Example path structure after extraction:
# <QEMU_PATH>/bin/qemu-system-arm
# <QEMU_PATH>/share/qemu/

Note

The -L option is required because the QEMU shared resources are not installed to system directories. It specifies the directory for the QEMU BIOS and device tree files.

Getting Started

NSH (Flat Build)

Configuring NuttX and compile:

$ ./tools/configure.sh -l qemu-armv7r:nsh
$ make -j`nproc`

Running with qemu:

$ <QEMU_PATH>/bin/qemu-system-arm \
  -L <QEMU_PATH>/share/qemu \
  -M virt -semihosting -nographic -cpu cortex-r5f \
  -kernel ./nuttx

PNSH (Protected Build)

This is a configuration for testing the BUILD_PROTECTED configuration with MPU support:

$ cd nuttx
$ ./tools/configure.sh qemu-armv7r:pnsh
$ make -j`nproc`

Running with qemu (note: both nuttx and nuttx_user must be loaded):

$ <QEMU_PATH>/bin/qemu-system-arm \
  -L <QEMU_PATH>/share/qemu \
  -M virt -semihosting -nographic -cpu cortex-r5f \
  -device loader,file=./nuttx_user \
  -device loader,file=./nuttx

Debugging with QEMU

The nuttx ELF image can be debugged with QEMU.

To debug the nuttx (ELF) with symbols, make sure the following change have been applied to defconfig:
```
+CONFIG_DEBUG_SYMBOLS=y
```

Run QEMU at shell terminal 1 (for NSH flat build):

$ <QEMU_PATH>/bin/qemu-system-arm \
  -L <QEMU_PATH>/share/qemu \
  -M virt -semihosting -nographic -cpu cortex-r5f \
  -kernel ./nuttx -S -s

Or for PNSH protected build:

$ <QEMU_PATH>/bin/qemu-system-arm \
  -L <QEMU_PATH>/share/qemu \
  -M virt -semihosting -nographic -cpu cortex-r5f \
  -device loader,file=./nuttx_user \
  -device loader,file=./nuttx -S -s

Run gdb with TUI, connect to QEMU, load nuttx and continue (at shell terminal 2):

$ arm-none-eabi-gdb -tui --eval-command='target remote localhost:1234' nuttx
(gdb) c
Continuing.
^C
Program received signal SIGINT, Interrupt.
(gdb)

For PNSH protected build, you need to load the user space symbols as well:

$ arm-none-eabi-gdb -tui --eval-command='target remote localhost:1234' nuttx
(gdb) add-symbol-file nuttx_user
(gdb) c