Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752216AbbKKSeI (ORCPT ); Wed, 11 Nov 2015 13:34:08 -0500 Received: from mail-pa0-f44.google.com ([209.85.220.44]:36617 "EHLO mail-pa0-f44.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750827AbbKKSeF (ORCPT ); Wed, 11 Nov 2015 13:34:05 -0500 From: Douglas Anderson To: John Youn , balbi@ti.com Cc: Yunzhi Li , =?UTF-8?q?Heiko=20St=C3=BCbner?= , linux-rockchip@lists.infradead.org, Julius Werner , gregory.herrero@intel.com, yousaf.kaukab@intel.com, dinguyen@opensource.altera.com, Douglas Anderson , johnyoun@synopsys.com, gregkh@linuxfoundation.org, linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [REPOST PATCH] usb: dwc2: host: Support immediate retries for split transactions Date: Wed, 11 Nov 2015 10:33:52 -0800 Message-Id: <1447266833-32096-1-git-send-email-dianders@chromium.org> X-Mailer: git-send-email 2.6.0.rc2.230.g3dd15c0 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2735 Lines: 78 In some cases, like when you've got a "Microsoft Wireless Keyboard 2000" connected to dwc2 with a hub, expected that we'll get some transfer errors sometimes. The controller is expected to try at least 3 times before giving up. See figure "Figure A-67. Normal HS CSPLIT 3 Strikes Smash" in the USB spec. The dwc2 controller has a way to support this by using the "EC_MC" field. The Raspberry Pi driver has logic for setting this right. See fiq_fsm_queue_split_transaction() in their "dwc_otg_hcd.c". Let's use the same logic. After making this change, we no longer get dropped characters from the above mentioned keyboard. Other devices on the same bus as the keyboard also behave more properly. Thanks for Julius Werner for the expert analysis and suggestions. Signed-off-by: Douglas Anderson --- Repost without the WIP in tags (sorry for that). drivers/usb/dwc2/core.c | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-) diff --git a/drivers/usb/dwc2/core.c b/drivers/usb/dwc2/core.c index ef73e498e98f..dcb4cd1d3b34 100644 --- a/drivers/usb/dwc2/core.c +++ b/drivers/usb/dwc2/core.c @@ -1707,6 +1707,7 @@ void dwc2_hc_start_transfer(struct dwc2_hsotg *hsotg, u32 hcchar; u32 hctsiz = 0; u16 num_packets; + u32 ec_mc; if (dbg_hc(chan)) dev_vdbg(hsotg->dev, "%s()\n", __func__); @@ -1743,6 +1744,13 @@ void dwc2_hc_start_transfer(struct dwc2_hsotg *hsotg, hctsiz |= chan->xfer_len << TSIZ_XFERSIZE_SHIFT & TSIZ_XFERSIZE_MASK; + + /* For split set ec_mc for immediate retries */ + if (chan->ep_type == USB_ENDPOINT_XFER_INT || + chan->ep_type == USB_ENDPOINT_XFER_ISOC) + ec_mc = 3; + else + ec_mc = 1; } else { if (dbg_hc(chan)) dev_vdbg(hsotg->dev, "no split\n"); @@ -1805,6 +1813,9 @@ void dwc2_hc_start_transfer(struct dwc2_hsotg *hsotg, hctsiz |= chan->xfer_len << TSIZ_XFERSIZE_SHIFT & TSIZ_XFERSIZE_MASK; + + /* The ec_mc gets the multi_count for non-split */ + ec_mc = chan->multi_count; } chan->start_pkt_count = num_packets; @@ -1855,8 +1866,7 @@ void dwc2_hc_start_transfer(struct dwc2_hsotg *hsotg, hcchar = dwc2_readl(hsotg->regs + HCCHAR(chan->hc_num)); hcchar &= ~HCCHAR_MULTICNT_MASK; - hcchar |= chan->multi_count << HCCHAR_MULTICNT_SHIFT & - HCCHAR_MULTICNT_MASK; + hcchar |= (ec_mc << HCCHAR_MULTICNT_SHIFT) & HCCHAR_MULTICNT_MASK; dwc2_hc_set_even_odd_frame(hsotg, chan, &hcchar); if (hcchar & HCCHAR_CHDIS) -- 2.6.0.rc2.230.g3dd15c0 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/