From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932319AbcA0KNc (ORCPT ); Wed, 27 Jan 2016 05:13:32 -0500 Received: from regular2.263xmail.com ([211.157.152.4]:52507 "EHLO regular2.263xmail.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754411AbcA0KN1 (ORCPT ); Wed, 27 Jan 2016 05:13:27 -0500 X-263anti-spam: KSV:0; X-MAIL-GRAY: 0 X-MAIL-DELIVERY: 1 X-KSVirus-check: 0 X-ABS-CHECKED: 4 X-ADDR-CHECKED: 0 X-RL-SENDER: kever.yang@rock-chips.com X-FST-TO: linux-kernel@vger.kernel.org X-SENDER-IP: 58.22.7.114 X-LOGIN-NAME: kever.yang@rock-chips.com X-UNIQUE-TAG: <87e1fcd30ada59242cfb091ed3b71378> X-ATTACHMENT-NUM: 0 X-DNS-TYPE: 0 Message-ID: <56A89838.3040202@rock-chips.com> Date: Wed, 27 Jan 2016 18:13:12 +0800 From: Kever Yang User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.4.0 MIME-Version: 1.0 To: Douglas Anderson , John Youn , balbi@ti.com CC: william.wu@rock-chips.com, huangtao@rock-chips.com, heiko@sntech.de, linux-rockchip@lists.infradead.org, Julius Werner , gregory.herrero@intel.com, yousaf.kaukab@intel.com, dinguyen@opensource.altera.com, stern@rowland.harvard.edu, ming.lei@canonical.com, johnyoun@synopsys.com, gregkh@linuxfoundation.org, linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v5 03/21] usb: dwc2: host: Set host_rx_fifo_size to 528 for rk3066 References: <1453486736-15358-1-git-send-email-dianders@chromium.org> <1453486736-15358-4-git-send-email-dianders@chromium.org> In-Reply-To: <1453486736-15358-4-git-send-email-dianders@chromium.org> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Doug, On 01/23/2016 02:18 AM, Douglas Anderson wrote: > As documented in dwc2_calculate_dynamic_fifo(), host_rx_fifo_size should > really be: > 2 * ((Largest Packet size / 4) + 1 + 1) + n > with n = number of host channel. > > We have 9 host channels, so > 2 * ((1024/4) + 2) + 9 = 516 + 9 = 525 > > We've got 960 / 972 total_fifo_size on rk3288 (and presumably on > rk3066) and 525 + 128 + 256 = 909 so we're still under on both ports > even when we increment by 5. > > Since we have space, Kever Yang suggests bumping by 8. He says this > will meet INCR16 access and next fifo type can start with a aligned > address. I have double check this feature, the INCR16 is actually a burst 16 on to the bus, the aligned problem only happen on the DRAM access, and it's OK for internal RAM access via internal DMA. Bump to 8 looks much better when we check the FIFO setting if we have enough memory, right? :) rk3066/rk3188/rk3288 have the same hw config for dwc2 controller, so this patch should works on those files. Reviewed-by: Kever Yang > > ...so let's bump up by 8. In the future, it would be nice if > dwc2_calculate_dynamic_fifo() could handle the "too small" FIFO case and > come up with something more dynamically. When we do that we can figure > out how to allocate the extra 48 / 60 bytes of FIFO that we're currently > wasting. > > NOTE: no known bugs are fixed by this patch, but it seems like a simple > fix and ought to fix someone. > > Signed-off-by: Douglas Anderson > --- > Changes in v5: None > Changes in v4: > - Set host_rx_fifo_size to 528 for rk3066 new for v4. > > Changes in v3: None > Changes in v2: None > > drivers/usb/dwc2/platform.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/usb/dwc2/platform.c b/drivers/usb/dwc2/platform.c > index 5008a467ce06..b6d7666e715c 100644 > --- a/drivers/usb/dwc2/platform.c > +++ b/drivers/usb/dwc2/platform.c > @@ -126,7 +126,7 @@ static const struct dwc2_core_params params_rk3066 = { > .speed = -1, > .enable_dynamic_fifo = 1, > .en_multiple_tx_fifo = -1, > - .host_rx_fifo_size = 520, /* 520 DWORDs */ > + .host_rx_fifo_size = 528, /* 528 DWORDs */ > .host_nperio_tx_fifo_size = 128, /* 128 DWORDs */ > .host_perio_tx_fifo_size = 256, /* 256 DWORDs */ > .max_transfer_size = -1,