On 11/30/23 04:15, Richard Fitzgerald wrote: > On 29/11/23 16:39, Pierre-Louis Bossart wrote: >> >>>>>>>> + .name_prefix = "cs35l56-8" >>>>>>> >>>>>>> Can these prefixes be "AMPn" to match the CS35L41, CS35L51 and >>>>>>> CS35L56-hda driver? This prefix is used to find the matching >>>>>>> firmware >>>>>>> files and our naming convention for these has been cs35lxx-xxxx-ampn >>>>>>> >>>>>>> Is there anything that depends on the prefixes being "cs35l56-n" ? >>>>>> >>>>>> IIRC this name_prefix is just used for the codec_conf and hence for >>>>>> control names/UCM. At some point userspace/driver need to know if >>>>>> amp5 >>>>>> is left or right. >>>>>> >>>>>> We can certainly align on conventions but the values set in this ACPI >>>>>> match table will not be used for firmware download - different scope. >>>>>> >>>>> >>>>> They are used for our firmware download. Each amp can have its own >>>>> unique firmware file. The ALSA prefix is used to identify which >>>>> firmware >>>>> file to load to which amp. >>>> >>>> The prefix will only be used when the card is created, specifically for >>>> control names. >>>> The firmware should be selected and downloaded when the device shows up >>>> on the bus. >>>> Card creation and device enumeration/initialization happen on different >>>> timelines, if the machine driver is "blacklisted" or unbound I am not >>>> sure what happens. >>>> >>>> There is a dependency between machine driver probe and codec firmware >>>> download that I am not able to follow, can you please elaborate? >>>> >>> >>> The codec driver has to choose which firmware to load from under >>> /lib/firmware. It does this using a combination of SSID (to identify the >>> target product), the ALSA prefix string (to identify which amp) and >>> in some systems a GPIO on the motherboard to select between different >>> models of speaker when they have multiple suppliers. This results in a >>> firmware name like: >>> >>> cs35l56-<silicon rev>-dsp1-misc-<SSID>[-<SPEAKER MODEL>]-<ALSA PREFIX> >>> >>> You can see this if you look in the linux-firmware repo under cirrus/ >>> for cs35l41 firmware files (though the ALSA PREFIX section in those >>> cases is not "AMPn" because they are not SDCA parts with rotation, >>> they have a fixed left/right assignment.) >>> >>> We have to be careful of the length of the prefix. The 44 characters of >>> an ALSA control name get eaten up very quickly when we start creating >>> fully-qualified names for controls published by the firmware. So "AMPn" >>> was nice because it was descriptive enough but only uses 5 characters >>> of the 44. >>> >>> Having said that, I've calculated that we have enough characters (just) >>> to use a prefix of "cs35l56-n". If there's a reason why that is >>> necessary/desirable for SOF or SoundWire then we could do that. But we'd >>> intended to use "AMPn" prefixes. >>> >>> We just need to decide whether to go with "AMPn". Or switch to using >>> "cs35l56-n" for the ALSA prefix (the therefore the qualifier at the end >>> of the firmware filename). >> >> Yes we have similar issues with control names in topology, the limit is >> hit very quickly. >> >> I think you missed my point though that the ALSA prefix is only set when >> the card is created, which can be sometime after the firmware needs to >> be downloaded. I guess you could pick the firmware in the component >> probe, which happens during the card creation, but that could be >> sub-optimal. Given the download times you want the download to proceed >> as early as possible. > > We kick off a background task from our component_probe() to do the > firmware download. We need the ALSA prefix, and also the wm_adsp library > that actually handles the DSP is ASoC code so it needs a probed > component. Doing it in a background work means it doesn't block probe(). > And the download to multiple amps can proceed in parallel - obviously > that's constrained by bus bandwidth but we are seeing that they > interleave. ah ok, that makes sense. In practice the delta between codec enumeration and component probe is probably negligible, and in a multi-amplifier setup the download times are much larger. So to circle back to the initial feedback, do you mind submitting a patch with the exact naming you'd want for the prefix?
