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Date: Mon, 31 Aug 2015 10:28:41 +0800 From: Peter Chen <peter.chen@...escale.com> To: punnaiah choudary kalluri <punnaia@...inx.com> CC: Nathan Sullivan <nathan.sullivan@...com>, sundeep subbaraya <sundeep.lkml@...il.com>, Subbaraya Sundeep Bhatta <sbhatta@...inx.com>, "robh+dt@...nel.org" <robh+dt@...nel.org>, "pawel.moll@....com" <pawel.moll@....com>, Mark Rutland <mark.rutland@....com>, "ijc+devicetree@...lion.org.uk" <ijc+devicetree@...lion.org.uk>, Kumar Gala <galak@...eaurora.org>, Greg Kroah-Hartman <gregkh@...uxfoundation.org>, "devicetree@...r.kernel.org" <devicetree@...r.kernel.org>, "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>, "linux-usb@...r.kernel.org" <linux-usb@...r.kernel.org> Subject: Re: [PATCH 1/2] usb: chipidea: add xilinx zynq platform data On Mon, Aug 31, 2015 at 09:01:51AM +0530, punnaiah choudary kalluri wrote: > On Mon, Aug 31, 2015 at 6:10 AM, Peter Chen <peter.chen@...escale.com> wrote: > > On Fri, Aug 28, 2015 at 09:42:56AM -0500, Nathan Sullivan wrote: > >> On Fri, Aug 28, 2015 at 09:30:12AM +0800, Peter Chen wrote: > >> > On Thu, Aug 27, 2015 at 09:33:07AM -0500, Nathan Sullivan wrote: > >> > > On Thu, Aug 27, 2015 at 01:11:30PM +0530, punnaiah choudary kalluri wrote: > >> > > > Hi, > >> > > > > >> > > > On Thu, Aug 27, 2015 at 10:03 AM, Peter Chen <peter.chen@...escale.com> wrote: > >> > > > > On Thu, Aug 27, 2015 at 10:59:22AM +0530, sundeep subbaraya wrote: > >> > > > >> Hi, > >> > > > >> > >> > > > >> > >> > > > >> On Wed, Aug 26, 2015 at 8:57 PM, Nathan Sullivan <nathan.sullivan@...com> wrote: > >> > > > >> > The Xilinx Zynq udc does not need the CI_HDRC_DISABLE_STREAMING flag, > >> > > > >> > unlike the default platform data. Add platform data specific to the > >> > > > >> > Zynq udc. > >> > > > >> > > >> > > > >> > Based on a patch by the same name from the Xilinx vendor tree. > >> > > > >> > >> > > > >> I am that Xilinx guy who sent this patch :). It is in Xilinx tree as > >> > > > >> temporary fix and > >> > > > >> I did not debug further why UDC works only when streaming is enabled. > >> > > > >> Probably this is right time to post my question here. > >> > > > >> I was expecting like: > >> > > > >> Streaming disabled - both low bandwidth and high bandwidth systems > >> > > > >> should work fine > >> > > > >> Streaming enabled - only for high bandwidth systems > >> > > > >> but this is not the case, Zynq UDC works only when Streaming is enabled. > >> > > > >> Please correct me if I am wrong. > >> > > > > > >> > > > > You are right, stream mode disabled should work at anytime. > >> > > > > It is so strange why zynq UDC only works when stream mode is enabled. > >> > > > > >> > > > I am referring the section 8.5.2 in Synopsys usb 2.0 HS controllervDoc 2.20a, > >> > > > this is what it says about SDIS (streaming mode disable option) > >> > > > > >> > > > Before activating this mode, the user must check if the TX latency > >> > > > buffers per endpoint are able to > >> > > > accommodate at least one entire maximum size packet. The RX buffer > >> > > > size must, at least, double the TX > >> > > > buffer size per endpoint. To optimize the stream disable performance, > >> > > > system bus burst must be set as high > >> > > > as possible. > >> > > > When the stream disable mode is used, the burst size (VUSB_HS_RX_BURST > >> > > > and VUSB_HS_TX_BURST) > >> > > > must be a integer sub-multiple of the latency buffer size > >> > > > (VUSB_HS_RX_DEPTH for RX buffer and > >> > > > VUSB_HS_TX_CHAN for the TX buffer). If this is not respected the > >> > > > controller will not work properly in stream > >> > > > disable mode. > >> > > > The stream disable mode should just be used in situations where the > >> > > > available system bandwidth is low or the > >> > > > system bus access latency is high, in order to avoid underruns and > >> > > > overruns in the latency buffers. This works > >> > > > for all types of endpoints, except for ISO endpoints. > >> > > > Such a system can't ensure the real time support that the ISO > >> > > > endpoints require, so the ISO endpoints are not > >> > > > supported when the SDIS bit is set. > >> > > > > >> > > > Definitely we need to root cause why disable streaming mode is not > >> > > > working for zynq but from controller spec > >> > > > point of view it is possible that controller not work properly in > >> > > > stream disable mode. > >> > > > > >> > > > Regards, > >> > > > Punnaiah > >> > > > > >> > > > >> > > Maybe the burst size isn't set correctly by default? It does say the controller > >> > > won't work correctly with stream disable set and an invalid burst size. Looks > >> > > like TX and RX burst both default to 16, per the Zynq manual. > >> > > > >> > > With the stream disable bit set, the behvior we see on our hardware is > >> > > that priming just stops, with an outstanding transfer in memory marked > >> > > active in the status field by the controller. This happens at random, even > >> > > when doing single transfers at a time like with g_ether set to have a queue > >> > > size of 1. With SDIS clear everything works great. Given that the Zynq is not > >> > > bandwidth constrained, it seems like SDIS clear should be the default. > >> > > > >> > > >> > I suspect the possible reason is the tx buffer for each endpoint is > >> > small (<=512 bytes), so it can't copy one packet (assume max packet size > >> > for bulk) to tx buffer, then the prime can't be finished. > >> > > >> > Would you help to dump the registers HWTXBUF ($BASE + 0x10) and DCCPARAMS > >> > ($BASE + 124)? > >> > > >> > tx buffer size = ((2 ^ HWTXBUF.VUSB_HS_TX_ADD) / DCCPARAMS.DEN) * > >> > (DWORD_PER_BYTES) > >> > > >> > DWORD_PER_BYTES is 4 > >> > > >> > -- > >> > > >> > Best Regards, > >> > Peter Chen > >> > >> HWTXBUF is 0x80060A10, DCCPARAMS is 0xE0003124. > > > > Are you sure you read correct address? Your DCCPARAMS means > > it is host capable, but not device capable. > > HWTXBUF is 0x8060A10 > DCCPARAMS is 0x0000018C > > VUSB_HS_TX_ADD - 0xA > DEN - 0xC > > From the above formula tx buffer size is 341.33 bytes. > > ok, so your platform can't use stream mode disabled. -- Best Regards, Peter Chen -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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