[U-Boot] [PATCH 1/2] usb: ci_udc: allow multiple buffer allocs per ep

[Marek Vasut]

On Tuesday, May 06, 2014 at 01:48:11 AM, Stephen Warren wrote:
> From: Stephen Warren <swarren at nvidia.com>
> 
> Modify ci_ep_alloc_request() to return a dynamically allocated request
> object, rather than a singleton that's part of the endpoint. This
> requires moving various state from the endpoint structure to the request
> structure, since we need one copy per request.
> 
> The "fast bounce buffer" b_fast is removed by this change rather than
> moved to the request object. Instead, we enhance the bounce buffer logic
> in ci_bounce()/ci_debounce() to keep the bounce buffer around between
> request submissions. This avoids the need to allocate an arbitrarily-
> sized bounce buffer up-front, yet avoids incurring the allocation
> overhead each time a request is submitted.
> 
> A future enhancement would be to actually submit multiple requests to HW
> at once. The Linux driver shows that this is possible. That might improve
> throughput (depending on the USB protocol in use), since USB could be
> performing a transfer to one HW buffer in parallel with whatever SW
> actions U-Boot performs on another buffer. However, I have not made this
> change as part of this patch, in order to keep SW changes related to
> buffer management separate from any change in the way the HW is
> programmed.

Applied, thanks

Best regards,
Marek Vasut