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 :-)