[GitHub] [mynewt-mcumgr] sw opened a new issue #122: Zephyr port: unnecessary flash alignment check

[GitBox <gi...@apache.org>]

sw opened a new issue #122:
URL: https://github.com/apache/mynewt-mcumgr/issues/122


   This relates to https://github.com/apache/mynewt-newtmgr/issues/185
   
   There is a performance problem when using mcumgr CLI to upload firmware images to a Zephyr system. There is an overhead of up to 4x in the data transmitted on the serial port.
   
   On the one hand, this is due to sub-optimal frame handling in mcumgr CLI as reported in https://github.com/apache/mynewt-newtmgr/issues/185
   
   But I suspect the MCU side could also be improved.
   
   `img_mgmt_impl_upload_inspect` rounds the data length down to a multiple of the flash write block size:
   https://github.com/apache/mynewt-mcumgr/blob/798f7fe28bb32335ba25d1c180808cd88d73a83c/cmd/img_mgmt/port/zephyr/src/zephyr_img_mgmt.c#L571-L576
   
   But then, buffered write is used in `img_mgmt_impl_write_image_data`:
   https://github.com/apache/mynewt-mcumgr/blob/798f7fe28bb32335ba25d1c180808cd88d73a83c/cmd/img_mgmt/port/zephyr/src/zephyr_img_mgmt.c#L307
   
   According to the documentation of `flash_img_buffered_write`, this function will store non-complete blocks in RAM until it is called with `flush == true`. So a length that is *not* a multiple of the flash write block size should not pose  a problem.
   
   My suggestion would be to remove the length truncation in `img_mgmt_impl_upload_inspect`.
   Or is there some special case that this would break?


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