Re: [PATCH v3 1/2] crypto: engine - support for parallel requests

[Iuliana Prodan]

On 2/13/2020 8:18 AM, Herbert Xu wrote:
> On Fri, Feb 07, 2020 at 02:36:13PM +0200, Iuliana Prodan wrote:
>>
>> +start_request:
>> +	/* If hardware is busy, do not send any request */
>> +	if (engine->can_enqueue_more) {
>> +		if (!engine->can_enqueue_more(engine))
>> +			goto out;
> 
> Instead of a driver callback I'd rather the driver called into
> the engine telling it to stop/start, similar to how net drivers
> work.
> 

Given your suggestion, I’m thinking of implementing do_one_request, in 
the driver, to return -IN_PROGRESS if the hw can enqueue more and -EBUSY 
if otherwise (solution 1). But, this implies to update all the drivers 
that use crypto-engine (something I wouldn’t mind doing, but I don’t 
have the hw to test it).

My current proposal keeps the backward compatibility of crypto-engine, 
so no need to change the other drivers. If they want to use multiple 
requests or batch requests, they can implement can_enqueue_more, 
respective do_batch_requests (solution 2).

Please, let me know how do you want me to proceed?  Solution 1 or 
solution 2, or… maybe I’ve missed something?

Thanks,
Iulia