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
MAINTAINERS | 7 +-
include/uapi/sound/scarlett2.h | 54 ++
sound/usb/mixer_scarlett2.c | 914 ++++++++++++++++++++++++++++++---
3 files changed, 901 insertions(+), 74 deletions(-)
create mode 100644 include/uapi/sound/scarlett2.h
--
2.43.0
