ASoC: SOF: Intel: hda-mlink: introduce helpers for 'extended links' PM
authorPierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Tue, 4 Apr 2023 10:41:17 +0000 (13:41 +0300)
committerMark Brown <broonie@kernel.org>
Thu, 6 Apr 2023 15:45:40 +0000 (16:45 +0100)
commitfc7dab8ec0b4a451dd5737aa4f06a0e8bd6efa32
tree44fa547fa0863e4772c48da746b40161c96cd403
parent4c2d4e446d5673db2c653a6e53ca9be908582c4e
ASoC: SOF: Intel: hda-mlink: introduce helpers for 'extended links' PM

Add helpers to program SPA/CPA bits, using a mutex to access the
shared LCTL register if required.

All links are managed with the same LCTLx.SPA bits. However there are
quite a few implementation details to be aware of:

Legacy HDaudio multi-links are powered-up when exiting reset, which
requires the ref_count to be manually set to one when initializing the
link.

Alternate links for SoundWire/DMIC/SSP need to be explicitly
powered-up before accessing the SHIM/IP/Vendor-Specific SHIM space for
each sublink. DMIC/SSP/SoundWire are all different cases with a
different device/dai/hlink relationship.

SoundWire will handle power management with the auxiliary device
resume/suspend routine. The ref_count is not necessary in this case.

The DMIC/SSP will by contrast handle the power management from DAI
.startup and .shutdown callbacks.

The SSP has a 1:1 mapping between sublink and DAI, but it's
bidirectional so the ref_count will help avoid turning off the sublink
when one of the two directions is still in use.

The DMIC has a single link but two DAIs for data generated at
different sampling frequencies, again the ref_count will make sure the
two DAIs can be used concurrently.

And last the SoundWire Intel require power-up/down and bank switch to
be handled with a lock already taken, so the 'eml_lock' is made
optional with the _unlocked versions of the helpers.

Note that the _check_power_active() implementation is similar to
previous helpers in sound/hda/ext, with sleep duration and timeout
aligned with hardware recommendations. If desired, this helper could
be modified in a second step with .e.g. readl_poll_timeout()

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Rander Wang <rander.wang@intel.com>
Reviewed-by: Péter Ujfalusi <peter.ujfalusi@linux.intel.com>
Reviewed-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>
Signed-off-by: Peter Ujfalusi <peter.ujfalusi@linux.intel.com>
Reviewed-by: Takashi Iwai <tiwai@suse.de>
Link: https://lore.kernel.org/r/20230404104127.5629-9-peter.ujfalusi@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>
include/sound/hda-mlink.h
sound/soc/sof/intel/hda-mlink.c