Pebble Smartwatch QEMU Implementation
This is a derivative of QEMU v2.1.1 that has been modified to include an implementation of the STM32F2xx microcontroller. This is based off of a QEMU fork that is targeting the STM32F103: https://github.com/beckus/qemu_stm32. This repo contains both beckus' STM32F1xx implementation and Pebble's STM32F2xx additions.
DANGER DANGER: It is very much a work-in-progress! Only some of the peripherals are working at the moment. Please contribute!
QEMU requires that development packages for glib20 and pixman are installed.
Mac OS X
Commands for a typical build:
./configure --disable-werror --enable-debug --target-list="arm-softmmu" \ --extra-cflags=-DSTM32_UART_NO_BAUD_DELAY make
Summary set of configure options that are useful when developing (tested only on OS X 10.9.5):
./configure --enable-tcg-interpreter --extra-ldflags=-g \ --with-coroutine=gthread --enable-debug-tcg --enable-cocoa \ --enable-debug --disable-werror --target-list="arm-softmmu" \ --extra-cflags=-DDEBUG_CLKTREE --extra-cflags=-DDEBUG_STM32_RCC \ --extra-cflags=-DDEBUG_STM32_UART --extra-cflags=-DSTM32_UART_NO_BAUD_DELAY \ --extra-cflags=-DDEBUG_GIC
####Configure options which control the STM32 implementation:
--extra-cflags=-DDEBUG_CLKTREE Print out clock tree debug statements. --extra-cflags=-DDEBUG_STM32_RCC Print RCC debug statements. --extra-cflags=-DDEBUG_STM32_UART Print UART debug statements. --extra-cflags=-DSTM32_UART_NO_BAUD_DELAY Disable the BAUD rate timing simulation (i.e. the UART will transmit or receive as fast as possible, rather than using a realistic delay). --extra-cflags=-DSTM32_UART_ENABLE_OVERRUN Enable setting of the overrun flag if a character is received before the last one is processed. If this is not set, the UART will not receive the next character until the previous one is read by software. Although less realisitic, it is safer NOT to use this, in case the VM is running slow.
####Other QEMU configure options which are useful for troubleshooting: --extra-cflags=-DDEBUG_GIC Extra logging around which interrupts are asserted
####qemu-system-arm options which are useful for troubleshooting: -d ? To see available log levels
-d cpu,in_asm Enable logging to view the CPU state during execution and the ARM instructions which are being executed. I believe --enable-debug must be used for this to work.
Useful make commands when rebuilding:
make defconfig make clean
./waf build qemu_image_spito generate
./waf build qemu_image_microto generate
Under the covers of the images
QEMU's -pflash argument is used to specify a file to use as the micro flash. An image can be created by concatenating the boot and main firmware files, like so:
truncate -s 64k tintin_boot.bin cat tintin_boot.bin tintin_fw.bin > micro_flash.bin truncate -s 512k micro_flash.bin
There is a convenience script
pebble.sh that runs QEMU. It depends on the existence of (symlinked) images
More details about running QEMU
The generated executable is arm-softmmu/qemu-system-arm .
qemu-system-arm -rtc base=localtime -machine pebble-bb2 -cpu cortex-m3 -s \ -pflash qemu_micro_flash.bin -mtdblock qemu_spi_flash.bin
-S to the commandline will have QEMU wait in the monitor at start;
the _c_ontinue command is necessary to start the virtual CPU.
Read original the documentation in qemu-doc.html or on http://wiki.qemu.org
This emulator consists largely of new hardware device models; it includes only minor changes to existing QEMU functionality.
The changes can be reviewed by running
git diff --diff-filter=M v1.5.0-backports.
To list the added files, use
git diff --name-only --diff-filter=A v1.5.0-backports.
The following points clarify the QEMU license:
QEMU as a whole is released under the GNU General Public License
Parts of QEMU have specific licenses which are compatible with the GNU General Public License. Hence each source file contains its own licensing information.
Many hardware device emulation sources are released under the BSD license.
The Tiny Code Generator (TCG) is released under the BSD license (see license headers in files).
QEMU is a trademark of Fabrice Bellard.