[PATCH v3 3/9] ALSA: hda: Introduce snd_hdac_stream_wait_drsm()

[Amadeusz Sławiński]

On 10/27/2022 12:21 PM, Takashi Iwai wrote:
> On Thu, 27 Oct 2022 10:23:25 +0200,
> Cezary Rojewski wrote:
>> --- a/sound/hda/hdac_stream.c
>> +++ b/sound/hda/hdac_stream.c
>> @@ -821,6 +821,27 @@ void snd_hdac_stream_drsm_enable(struct hdac_bus *bus,
>>   }
>>   EXPORT_SYMBOL_GPL(snd_hdac_stream_drsm_enable);
>>   
>> +/*
>> + * snd_hdac_stream_wait_drsm - wait for HW to clear RSM for a stream
>> + * @azx_dev: HD-audio core stream to await RSM for
>> + *
>> + * Returns 0 on success and -ETIMEDOUT upon a timeout.
>> + */
>> +int snd_hdac_stream_wait_drsm(struct hdac_stream *azx_dev)
>> +{
>> +	struct hdac_bus *bus = azx_dev->bus;
>> +	u32 mask, reg;
>> +	int ret;
>> +
>> +	mask = 1 << azx_dev->index;
>> +
>> +	ret = readb_poll_timeout(bus->drsmcap + AZX_REG_DRSM_CTL, reg, !(reg & mask), 250, 2000);
> 
> Remember that HD-audio bus doesn't always allow readb().  Tegra
> requires the aligned access, for example.
> 

The readb_poll_timeout macro was updated to take care of that,
https://lore.kernel.org/all/20221007084856.1638302-1-amadeuszx.slawinski@linux.intel.com/
so it should be fine?