On Monday, February 03, 2014 at 09:05:06 AM, Lukasz Majewski wrote:
[...]
To sum up:
- s3c_udc_ep0_zlp - EP0 ZLP packets don't need to invalidate the
cache (since it is zero length transmission)
- s3c_udc_pre_setup - cache invalidation is not needed when I setup
buffer for OUT EP0 transmission.
The above two invalidation calls had been added by me, and are mine mistakes. Those don't contribute to transmission speed up (and shall be regarded as a cosmetic changes)
- setdma_rx - here I invalidate parts of the s3c UDC driver's
internal buffer. This call is not needed anymore since we reuse the buffers passed from gadgets.
And you do correct cache management on those in the UDC driver or in the gadget driver ?
For download, buffers are allocated in gadgets. Then buffer is passed to the UDC driver in a USB request. After receiving data via USB the UDC driver takes care to invalidate cache, hence the gadget can work on the data.
Cache management is performed in the UDC driver.
OK, this is the correct place. I just wanted to make sure about this. Thanks :)
This is the key speed improvement here.
This should be in the commit message really ;-)
I wrongly assumed, that code explains what was the rationale :-). I'm going to prepare more verbose commit message for v2.
Please do, thanks!
Best regards, Marek Vasut