RE: [PATCH v9 02/14] ASoC: Intel: catpt: Implement IPC protocol

["Rojewski, Cezary" <cezary.rojewski@intel.com>]

On 2020-09-28 3:44 PM, Andy Shevchenko wrote:
> On Sat, Sep 26, 2020 at 10:58:58AM +0200, Cezary Rojewski wrote:
>> Implement IRQ handlers for immediate and delayed replies and
>> notifications. Communication is synchronous and allows for serialization
>> of maximum one message at a time.
>>
>> DSP may respond with ADSP_PENDING status for a request - known as
>> delayed reply - and when situation occurs, framework keeps the lock and
>> awaits upcoming response through IPCD channel which is handled in
>> bottom-half. Immediate replies spawn no BH at all as their processing is
>> very short.

...

>> +static int catpt_dsp_do_send_msg(struct catpt_dev *cdev,
>> +				 struct catpt_ipc_msg request,
>> +				 struct catpt_ipc_msg *reply, int timeout)
>> +{
>> +	struct catpt_ipc *ipc = &cdev->ipc;
>> +	unsigned long flags;
>> +	int ret;
>> +
>> +	if (!ipc->ready)
>> +		return -EPERM;
>> +	if (request.size > ipc->config.outbox_size ||
>> +	    (reply && reply->size > ipc->config.outbox_size))
>> +		return -EINVAL;
>> +
>> +	spin_lock_irqsave(&ipc->lock, flags);
>> +	catpt_ipc_msg_init(ipc, reply);
>> +	catpt_dsp_send_tx(cdev, &request);
>> +	spin_unlock_irqrestore(&ipc->lock, flags);
>> +
>> +	ret = catpt_wait_msg_completion(cdev, timeout);
>> +	if (ret) {
>> +		dev_crit(cdev->dev, "communication severed: %d, rebooting dsp..\n",
>> +			 ret);
>> +		ipc->ready = false;
>> +		/* TODO: attempt recovery */
>> +		return ret;
>> +	}
> 
>> +	ret = ipc->rx.rsp.status;
>> +	if (reply) {
>> +		reply->header = ipc->rx.header;
>> +		if (!ret && reply->data)
>> +			memcpy(reply->data, ipc->rx.data, reply->size);
>> +	}
>> +
>> +	return ret;
> 
> One more looking into this... What about
> 
> 	if (reply)
> 		reply->header = ipc->rx.header;
> 
> 	ret = ipc->rx.rsp.status; // or even directly if (status) return status.
> 	if (ret)
> 		return ret;
> 
> 	if (reply->data)
> 		memcpy(reply->data, ipc->rx.data, reply->size);
> 
> 	return 0;
> 
> It may be verbose but I think readability is better here.
> 
>> +}
> 

In your example, last 'if' will cause exception if reply==NULL.

Got your point, although that's just few lines which already involve
'if' with { } spacing. After removing size-checks you suggested this
code is quite thin already.

>> +	CATPT_CHANNEL_CONFIG_5_POINT_0	= 7, /* L, C, R, Ls & Rs */
>> +	CATPT_CHANNEL_CONFIG_5_POINT_1	= 8, /* L, C, R, Ls, Rs & LFE */
>> +	CATPT_CHANNEL_CONFIG_DUAL_MONO	= 9, /* One channel replicated in two */
>> +	CATPT_CHANNEL_CONFIG_INVALID	= 10,
> 
> Hmm... I think I got the point why DUAL_MONO was at the end of the switch-case.
> 

Well, well. Indeed we found where Willy is..

>> +enum catpt_module_id {
>> +	CATPT_MODID_BASE_FW = 0x0,
>> +	CATPT_MODID_MP3 = 0x1,
>> +	CATPT_MODID_AAC_5_1 = 0x2,
>> +	CATPT_MODID_AAC_2_0 = 0x3,
>> +	CATPT_MODID_SRC = 0x4,
>> +	CATPT_MODID_WAVES = 0x5,
>> +	CATPT_MODID_DOLBY = 0x6,
>> +	CATPT_MODID_BOOST = 0x7,
>> +	CATPT_MODID_LPAL = 0x8,
>> +	CATPT_MODID_DTS = 0x9,
>> +	CATPT_MODID_PCM_CAPTURE = 0xA,
>> +	CATPT_MODID_PCM_SYSTEM = 0xB,
>> +	CATPT_MODID_PCM_REFERENCE = 0xC,
>> +	CATPT_MODID_PCM = 0xD, /* offload */
>> +	CATPT_MODID_BLUETOOTH_RENDER = 0xE,
>> +	CATPT_MODID_BLUETOOTH_CAPTURE = 0xF,
>> +	CATPT_MODID_LAST = CATPT_MODID_BLUETOOTH_CAPTURE,
>> +};
> 
> if you indent the values to be on the same column it will increase readability.
> 

Sure, can indent for readability reasons.

>> +enum catpt_mclk_frequency {
>> +	CATPT_MCLK_OFF = 0,
>> +	CATPT_MCLK_FREQ_6_MHZ = 1,
>> +	CATPT_MCLK_FREQ_21_MHZ = 2,
>> +	CATPT_MCLK_FREQ_24_MHZ = 3,
>> +};
> 
> Looks like a 3 MHz as base frequency with multiplicators 0, 2, 7, 8.
> 

Naming based on FW enum type equivalent.

>> +#define CATPT_STREAM_MSG(msg_type) \
>> +{ \
>> +	.stream_msg_type = CATPT_STRM_##msg_type, \
>> +	.global_msg_type = CATPT_GLB_STREAM_MESSAGE }
>> +#define CATPT_STAGE_MSG(msg_type) \
>> +{ \
>> +	.stage_action = CATPT_STG_##msg_type, \
>> +	.stream_msg_type = CATPT_STRM_STAGE_MESSAGE, \
>> +	.global_msg_type = CATPT_GLB_STREAM_MESSAGE }
> 
> Hmm... This split is interesting. I would rather move } to a new line.
> 

As basically everything in my code, style is based on existing example -
usually stuff from ASoC core - here, it's include/sound/soc.h. It's full
of such definitions so because catpt belongs to ASoC subsystem, I've
used the exact same style. No problem changing if that's your preference.

>> @@ -15,7 +15,6 @@
>>   #define CATPT_SHIM_REGS_SIZE	4096
>>   #define CATPT_DMA_REGS_SIZE	1024
>>   #define CATPT_DMA_COUNT		2
> 
>> -#define CATPT_SSP_COUNT		2
> 
> Why is this?
> 

Declaration of struct catpt_spec in patch 01/14 requires this while the
actual, logical (I'm not sure that's the right word here but I bet you
know what I mean) definition - one based on enum catpt_ssp_iface - is
available only here (02/14), with all other messages structs. I'd rather
modify the location of this constant than play with declaration of
struct catpt_spec between the patches.

Czarek