From mboxrd@z Thu Jan 1 00:00:00 1970 From: Simon Glass Date: Sat, 1 Apr 2017 17:40:25 -0600 Subject: [U-Boot] [PATCH v5 02/19] usb: dwc2: Use separate input and output buffers In-Reply-To: <2ae9f6f1-421f-4aa8-a568-f70b3ba66408@denx.de> References: <20170401180556.2416-1-sjg@chromium.org> <20170401180556.2416-3-sjg@chromium.org> <2ae9f6f1-421f-4aa8-a568-f70b3ba66408@denx.de> Message-ID: List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de Hi Marek, On 1 April 2017 at 14:15, Marek Vasut wrote: > On 04/01/2017 08:05 PM, Simon Glass wrote: >> On Raspberry Pi 2 and 3 a problem was noticed when enabling driver model >> for USB: the cache invalidate after an incoming transfer does not seem to >> work correctly. >> >> This may be a problem with the underlying caching implementation on armv7 >> and armv8 but this seems very unlikely. As a work-around, use separate >> buffers for input and output. This ensures that the input buffer will not >> hold dirty cache data. > > What do you think of this patch: > [U-Boot] usb: dwc2: invalidate the dcache before starting the DMA Yes that matches what I did as a hack. I didn't realise that the DMA would go through the cache. Thanks for the pointer. Regards, Simon