Re: [RFC PATCH 4/5] ASoC: SOF: Intel: hda: add SoundWire stream config/free callbacks

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



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.

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.


+{
+	struct snd_sof_dev *sdev = arg;
+	struct snd_soc_dai *d = dai;
[1]

+	struct sof_ipc_dai_config config;
+	struct sof_ipc_reply reply;
+	int ret;
+	u32 size = sizeof(config);
+
+	memset(&config, 0, size);
+	config.hdr.size = size;
+	config.hdr.cmd = SOF_IPC_GLB_DAI_MSG | SOF_IPC_DAI_CONFIG;
+	config.type = SOF_DAI_INTEL_ALH;
+	config.dai_index = (link_id << 8) | (d->id);
+	config.alh.stream_id = alh_stream_id;

Entirely up to you, in such cases I usually do something like

+	struct sof_ipc_dai_config config = {
+		.type = SOF_DAI_INTEL_ALH,
+		.hre = {
+			.size = sizeof(config),
+			.cmd = SOF_IPC_GLB_DAI_MSG | SOF_IPC_DAI_CONFIG,
+			...

which then also avoids a memset(). But that's mostly a matter of personal
preference, since this is on stack, the compiler would probably internally
anyway translate the above initialisation to a memset() with all the
following assignments.

I have no preference, so in this case I will go with consistency with existing code, which uses the suggested style for all IPCs.


+
+	/* send message to DSP */
+	ret = sof_ipc_tx_message(sdev->ipc,
+				 config.hdr.cmd, &config, size, &reply,
+				 sizeof(reply));
+	if (ret < 0) {
+		dev_err(sdev->dev,
+			"error: failed to set DAI hw_params for link %d dai->id %d ALH %d\n",

Are readers really expected to understand what "dai->id" means? Wouldn't
"DAI ID" be friendlier, although I understand you - who might not know
what "x->y" stands for?.. ;-)

I was trying to avoid a confusion here, we have config->dai_index which are shared concepts between topology and firmware, and dai->id which is shared between topology and machine driver (which refers to the dai in the dai_link which has its own .id). In topology files we have the three indices and of course after a couple of weeks I can't recall which one maps to what. I am afraid DAI ID might be confused with dai_index. If there are suggestions on this I am all ears, all I care about is avoiding ambiguity and having to ask Ranjani what index this really is :-)
_______________________________________________
Alsa-devel mailing list
Alsa-devel@xxxxxxxxxxxxxxxx
https://mailman.alsa-project.org/mailman/listinfo/alsa-devel



[Index of Archives]     [ALSA User]     [Linux Audio Users]     [Pulse Audio]     [Kernel Archive]     [Asterisk PBX]     [Photo Sharing]     [Linux Sound]     [Video 4 Linux]     [Gimp]     [Yosemite News]

  Powered by Linux