usb: class: dfu: Add a worker thread to flash data from usb to flash
The bulk of implementation in the current DFU arch is done in the ISR.
This works well when the Flash device is memory mapped as these writes
get done comparatively quickly. However, in case of platforms where
the flash device is sitting on the SPI Bus, this was observed to
cause an exception. This exception may be because there are multiple
function calls consuming larger processing time inside the ISR. The
ISR stack may also end up going deeper and risk stack corruption on
devices with low RAM. To resolve this, we deferred flash write to a
worker thread. Also, some handshaking was added to have synchronization
with the host in accordance with the Host-Device DFU protocol.
Signed-off-by: Savinay Dharmappa <savinay.dharmappa@intel.com>
1 file changed
