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Subject: Re: [alsa-devel] [RFC PATCH 4/5] ASoC: SOF: Intel: hda: add SoundWire
 stream config/free callbacks
To:     Vinod Koul <vkoul@kernel.org>
Cc:     Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>,
        alsa-devel@alsa-project.org, linux-kernel@vger.kernel.org,
        tiwai@suse.de, broonie@kernel.org, gregkh@linuxfoundation.org,
        jank@cadence.com, srinivas.kandagatla@linaro.org,
        slawomir.blauciak@intel.com,
        Bard liao <yung-chuan.liao@linux.intel.com>,
        Rander Wang <rander.wang@linux.intel.com>,
        Ranjani Sridharan <ranjani.sridharan@linux.intel.com>,
        Liam Girdwood <lgirdwood@gmail.com>,
        Jaroslav Kysela <perex@perex.cz>,
        Takashi Iwai <tiwai@suse.com>,
        Zhu Yingjiang <yingjiang.zhu@linux.intel.com>,
        YueHaibing <yuehaibing@huawei.com>,
        Kai Vehmanen <kai.vehmanen@linux.intel.com>,
        Arnd Bergmann <arnd@arndb.de>
References: <20190821201720.17768-1-pierre-louis.bossart@linux.intel.com>
 <20190821201720.17768-5-pierre-louis.bossart@linux.intel.com>
 <20190822071835.GA30262@ubuntu>
 <f73796d6-fcfa-97c8-69ae-0a183edbbd97@linux.intel.com>
 <20190904073549.GL2672@vkoul-mobl>
 <4de9613c-2da4-8d39-6f99-3039811673b8@linux.intel.com>
 <20190904165522.GC2672@vkoul-mobl>
From:   Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Message-ID: <b37f7be2-27b4-4ba5-e07a-8993d8c171f2@linux.intel.com>
Date:   Wed, 4 Sep 2019 12:49:24 -0500
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On 9/4/19 11:55 AM, Vinod Koul wrote:
> On 04-09-19, 08:31, Pierre-Louis Bossart wrote:
>> On 9/4/19 2:35 AM, Vinod Koul wrote:
>>> On 22-08-19, 08:53, Pierre-Louis Bossart wrote:
>>>> Thanks for the review Guennadi
>>>>
>>>>>> +static int sdw_config_stream(void *arg, void *s, void *dai,
>>>>>> +			     void *params, int link_id, int alh_stream_id)
>>>>>
>>>>> I realise, that these function prototypes aren't being introduced by these
>>>>> patches, but just wondering whether such overly generic prototype is really
>>>>> a good idea here, whether some of those "void *" pointers could be given
>>>>> real types. The first one could be "struct device *" etc.
>>>>
>>>> In this case the 'arg' parameter is actually a private 'struct snd_sof_dev',
>>>> as shown below [1]. We probably want to keep this relatively opaque, this is
>>>> a context that doesn't need to be exposed to the SoundWire code.
>>>
>>> This does look bit ugly.
>>>
>>>> The dai and params are indeed cases where we could use stronger types, they
>>>> are snd_soc_dai and hw_params respectively. I don't recall why the existing
>>>> code is this way, Vinod and Sanyog may have the history of this.
>>>
>>> Yes we wanted to decouple the sdw and audio bits that is the reason why
>>> none of the audio types are used here, but I think it should be revisited
>>> and perhaps made as:
>>>
>>> sdw_config_stream(struct device *sdw, struct sdw_callback_ctx *ctx)
>>>
>>> where the callback context contains all the other args. That would make
>>> it look lot neater too and of course use real structs if possible
>>
>> the suggested sdw_callbback_ctx is really intel-specific at the moment, e.g.
>> the notion of link_id and alh_stream_id are due to the hardware, it's not
>> generic at all. And in the latest code we also pass the dai->id.
> 
> s/sdw_callback_ctx/intel_sdw_callback_ctx
> 
> Yes this code is intel specific and this would be intel specific too

ok, I'll fold all the fields in a structure then. That's a nice cleanup, 
thanks Guennadi and Vinod for the reviews.