On Tue, 19 Dec 2023 18:36:04 +0100, Geoffrey D. Bennett wrote: > > Hi Takashi, > > 11 patches to improve error handling and add firmware upgrade support > to the scarlett2 driver. The notes below incorporate your feedback & > include answers to your questions in response to my previous RFC v2 > email. > > Patch 1 adds GitHub links for the repo where I share this code before > submission here, and for issue reporting. > > Patches 2-5 add missing error/bounds checks. > > Patch 6 adds a missing lock. > > Patches 7-11 add support for firmware upgrades. > > The usage of the hwdep interface is as per my previous proposal: > > - ioctl pversion to check the protocol version > - ioctl select_flash_segment SCARLETT2_SEGMENT_ID_SETTINGS > - ioctl erase_flash_segment > - ioctl get_erase_progress (optional) > - ioctl select_flash_segment SCARLETT2_SEGMENT_ID_FIRMWARE > - ioctl erase_flash_segment > - ioctl get_erase_progress (optional) > - write() the firmware > - ioctl reboot > > Notes on the hwdep interface: > > - Conflicting mixer operations are denied with EBUSY. > > - The hwdep interface is marked as exclusive so there can't be > conflicting hwdep operations. > > - Invalid sequences of operations (e.g. erase before select, write > before erase) return an error. > > - The erase operation is asynchronous, and the progress can optionally > be monitored by calling get_erase_progress. > > - If the erase progress is not monitored then subsequent hwdep > operations will wait until the erase is complete. > > - The write operation is synchronous, but <1KB can be written per > call, and it returns very quickly. On the user-side it looks like > this with error checking omitted: > > while (offset < len) > offset += snd_hwdep_write(hwdep, buf + offset, len - offset); > > - By using a subset of the firmware-upgrade steps, other useful > high-level operations can be performed: reset-to-factory-defaults, > reset-to-factory-firmware, or just reboot. > > - I considered combining the select and erase operations, but that > would prevent a future read-flash operation if that ever become > possible. > > - I considered separate one-shot ioctls for reset-to-factory, etc., > but that prevents providing progress feedback. > > - In case the purpose of the other firmware segments is discovered in > the future, this implementation would be able to support > erase/write/read of them with minimal changes. > > Here is a user-space implementation of all of the above: > https://github.com/geoffreybennett/scarlett2 > > This has been tested by me on every supported Scarlett 2nd, 3rd, 4th > Gen and Clarett+ device, and tested by a handful of others on their > Scarlett 4th Gen devices. > > Thanks, > Geoffrey. > > Geoffrey D. Bennett (11): > ALSA: scarlett2: Update maintainer info > ALSA: scarlett2: Add missing error check to scarlett2_config_save() > ALSA: scarlett2: Add missing error check to scarlett2_usb_set_config() > ALSA: scarlett2: Add missing error checks to *_ctl_get() > ALSA: scarlett2: Add clamp() in scarlett2_mixer_ctl_put() > ALSA: scarlett2: Add missing mutex lock around get meter levels > ALSA: scarlett2: Add #defines for firmware upgrade > ALSA: scarlett2: Retrieve useful flash segment numbers > ALSA: scarlett2: Add skeleton hwdep/ioctl interface > ALSA: scarlett2: Add ioctl commands to erase flash segments > ALSA: scarlett2: Add support for uploading new firmware Now all patches have been merged to topic/scarlett2 branch (merged to for-next branch for 6.8). thanks, Takashi
