- Add missing `volatile` to DMA descriptor, as memory is also accessed by the
DMA without knowledge of the compiler
- Dropped `__attribute__((packed))` from DMA descriptor
- The DMA descriptor fields need to be aligned on word boundries to
properly function
- The compiler can now more efficiently access the fields (safes ~300 B ROM)
- Moved the DMA descriptor struct and the flags to `periph_cpu.h`
- This allows Doxygen documentation being build for it
- Those types and fields are needed for a future PTP implementation
- Renamed DMA descriptor flags
- They now reflect to which field in the DMA descriptor they refer to, so
that confusion is avoided
- Added documentation to the DMA descriptor and the corresponding flags
The available GPIO ports may also differ within a family. Therefore, the vendor definitions GPIO* are used instad of CPU_FAM_STM definitions to determine which ports are available for a certain MCU.
The STM32 line of microcontrollers comes with a bootloader in the ROM.
It provides the option to flash the device firmware in DFU mode (USB)
or via UART or SPI.
To enter the bootloader we have to jump to a specific address in memory,
but before reset the CPU to make sure the system is in a known state.
This enables us to use the usb_board_reset module on all STM32 platforms.
This commit adds two new functions to the DMA peripheral code for the
stm32. The setup function allows for a one-time setup of peripheral
config. The prepare function does the per-transfer setup. This allows
for a single setup call during the peripheral lock step and a
per-transfer call to the prepare function.
`usbdev_stm32.h` will pull in `usb.h` which causes an error if
`USB_H_USER_IS_RIOT_INTERNAL` is not set.
Turns out this include is not needed, so just drop it.
