Unverified Commit 7430dea4 authored by Pierre-Louis Bossart's avatar Pierre-Louis Bossart Committed by Mark Brown
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ASoC: SOF: Intel: hda-mlink: fix sublink refcounting 



In hindsight it was a very bad idea to use the same refcount for
Extended and 'legacy' HDaudio multi-links. The existing solution only
powers-up the first sublink, which causes SoundWire and SSP tests to
fail when more than one DAI is used concurrently. Solving this problem
requires per-sublink refcounting, as suggested in this patch.

The existing refcounting remains for 'legacy' HdAudio links, mainly to
avoid changing the obscure programming sequence in
snd_hdac_ext_bus_link_put().

Signed-off-by: default avatarPierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: default avatarRanjani Sridharan <ranjani.sridharan@linux.intel.com>
Reviewed-by: default avatarBard Liao <yung-chuan.liao@linux.intel.com>
Link: https://lore.kernel.org/r/20230512174611.84372-2-pierre-louis.bossart@linux.intel.com


Signed-off-by: default avatarMark Brown <broonie@kernel.org>
parent f63550e2

sound/soc/sof/intel/hda-mlink.c

+19 −5
Original line number Diff line number Diff line
@@ -19,6 +19,9 @@ 


#if IS_ENABLED(CONFIG_SND_SOC_SOF_HDA_MLINK)



/* worst-case number of sublinks is used for sublink refcount array allocation only */

#define HDAML_MAX_SUBLINKS (AZX_ML_LCTL_CPA_SHIFT - AZX_ML_LCTL_SPA_SHIFT)



/**

 * struct hdac_ext2_link - HDAudio extended+alternate link

 *
@@ -33,6 +36,7 @@ 
 * @leptr:		extended link pointer

 * @eml_lock:		mutual exclusion to access shared registers e.g. CPA/SPA bits

 * in LCTL register

 * @sublink_ref_count:	array of refcounts, required to power-manage sublinks independently

 * @base_ptr:		pointer to shim/ip/shim_vs space

 * @instance_offset:	offset between each of @slcount instances managed by link

 * @shim_offset:	offset to SHIM register base
@@ -53,6 +57,7 @@ struct hdac_ext2_link { 
	u32 leptr;



	struct mutex eml_lock; /* prevent concurrent access to e.g. CPA/SPA */

	int sublink_ref_count[HDAML_MAX_SUBLINKS];



	/* internal values computed from LCAP contents */

	void __iomem *base_ptr;
@@ -641,8 +646,13 @@ static int hdac_bus_eml_power_up_base(struct hdac_bus *bus, bool alt, int elid, 
	if (eml_lock)

		mutex_lock(&h2link->eml_lock);



	if (!alt) {

		if (++hlink->ref_count > 1)

			goto skip_init;

	} else {

		if (++h2link->sublink_ref_count[sublink] > 1)

			goto skip_init;

	}



	ret = hdaml_link_init(hlink->ml_addr + AZX_REG_ML_LCTL, sublink);
@@ -684,9 +694,13 @@ static int hdac_bus_eml_power_down_base(struct hdac_bus *bus, bool alt, int elid 
	if (eml_lock)

		mutex_lock(&h2link->eml_lock);



	if (!alt) {

		if (--hlink->ref_count > 0)

			goto skip_shutdown;



	} else {

		if (--h2link->sublink_ref_count[sublink] > 0)

			goto skip_shutdown;

	}

	ret = hdaml_link_shutdown(hlink->ml_addr + AZX_REG_ML_LCTL, sublink);



skip_shutdown: