From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 19218ECAAD4 for ; Sat, 3 Sep 2022 07:43:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232324AbiICHn2 (ORCPT ); Sat, 3 Sep 2022 03:43:28 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51834 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229580AbiICHn0 (ORCPT ); Sat, 3 Sep 2022 03:43:26 -0400 X-Greylist: delayed 545 seconds by postgrey-1.37 at lindbergh.monkeyblade.net; Sat, 03 Sep 2022 00:43:24 PDT Received: from mail-m118112.qiye.163.com (mail-m118112.qiye.163.com [115.236.118.112]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6624898376; Sat, 3 Sep 2022 00:43:24 -0700 (PDT) Received: from [172.16.12.102] (unknown [58.22.7.114]) by mail-m118112.qiye.163.com (Hmail) with ESMTPA id 8D36D360184; Sat, 3 Sep 2022 15:34:16 +0800 (CST) Subject: Re: [PATCH] usb: dwc3: core: leave default DMA if the controller does not support 64-bit DMA To: Sven Peter , William Wu , Felipe Balbi , Greg Kroah-Hartman Cc: linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, Fabio Aiuto , frank.wang@rock-chips.com, jianwei.zheng@rock-chips.com References: <20220901083446.3799754-1-william.wu@rock-chips.com> <8fc4eb4b-25c4-4d4c-8203-1e5c314436b3@www.fastmail.com> From: wuliangfeng Message-ID: <5d1c1338-b820-e10b-76eb-daee9abda7c2@rock-chips.com> Date: Sat, 3 Sep 2022 23:33:09 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <8fc4eb4b-25c4-4d4c-8203-1e5c314436b3@www.fastmail.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit X-HM-Spam-Status: e1kfGhgUHx5ZQUpXWQgPGg8OCBgUHx5ZQUlOS1dZFg8aDwILHllBWSg2Ly tZV1koWUFJSktLSjdXWS1ZQUlXWQ8JGhUIEh9ZQVkZGB5LVkNOGR9JQx5CSUIfSFUTARMWGhIXJB QOD1lXWRgSC1lBWU5DVUlJVUxVSkpPWVdZFhoPEhUdFFlBWU9LSFVKSktMSkhVSktLWQY+ X-HM-Sender-Digest: e1kMHhlZQR0aFwgeV1kSHx4VD1lBWUc6MBw6LRw*SD0pGDk0LiEVNgIw HRlPCzpVSlVKTU1JSkJLT05MSUhNVTMWGhIXVQwOFx07CRQYEFYYExILCFUYFBZFWVdZEgtZQVlO Q1VJSVVMVUpKT1lXWQgBWUFPSEhJNwY+ X-HM-Tid: 0a830245901a2ec0kusn8d36d360184 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2022/9/2 上午1:38, Sven Peter wrote: > > > On Thu, Sep 1, 2022, at 10:34, William Wu wrote: >> On some DWC3 controllers (e.g. Rockchip SoCs), the DWC3 core >> doesn't support 64-bit DMA address width. In this case, this >> driver should use the default 32-bit mask. Otherwise, the DWC3 >> controller will break if it runs on above 4GB physical memory >> environment. >> >> This patch reads the DWC_USB3_AWIDTH bits of GHWPARAMS0 which >> used for the DMA address width, and only configure 64-bit DMA >> mask if the DWC_USB3_AWIDTH is 64. >> >> Fixes: 45d39448b4d0 ("usb: dwc3: support 64 bit DMA in platform driver") >> Signed-off-by: William Wu > > Reviewed-by: Sven Peter > >> --- >> drivers/usb/dwc3/core.c | 13 +++++++------ >> 1 file changed, 7 insertions(+), 6 deletions(-) >> >> diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c >> index c5c238ab3083..2fcbd05b2af1 100644 >> --- a/drivers/usb/dwc3/core.c >> +++ b/drivers/usb/dwc3/core.c >> @@ -1751,12 +1751,6 @@ static int dwc3_probe(struct platform_device *pdev) >> >> dwc3_get_properties(dwc); >> >> - if (!dwc->sysdev_is_parent) { >> - ret = dma_set_mask_and_coherent(dwc->sysdev, DMA_BIT_MASK(64)); >> - if (ret) >> - return ret; >> - } >> - >> dwc->reset = devm_reset_control_array_get_optional_shared(dev); >> if (IS_ERR(dwc->reset)) >> return PTR_ERR(dwc->reset); >> @@ -1823,6 +1817,13 @@ static int dwc3_probe(struct platform_device >> *pdev) >> dwc3_cache_hwparams(dwc); >> device_init_wakeup(&pdev->dev, of_property_read_bool(dev->of_node, >> "wakeup-source")); >> >> + if (!dwc->sysdev_is_parent && >> + DWC3_GHWPARAMS0_AWIDTH(dwc->hwparams.hwparams0) == 64) { >> + ret = dma_set_mask_and_coherent(dwc->sysdev, DMA_BIT_MASK(64)); >> + if (ret) >> + goto disable_clks; >> + } > > I guess you could also create the mask from DWC3_GHWPARAMS0_AWIDTH(dwc->hwparams.hwparams0) > directly instead of hardcoding it to 64bit here. Probably doesn't matter though unless > there are some weird systems where dwc3 can only do 48bit DMA but there's actually memory > above that. > > Refer to the DWC3 databook "Table 4-1 Basic Config Parameters", it describe that "If your system address bus width for example is 40bits, select 64 and tie the address bits[63:40] of the DWC3_usb3 to 0", so it seems that "DWC3_GHWPARAMS0_AWIDTH(dwc->hwparams.hwparams0) == 64" can cover 40-bit DMA or 48-bit DMA.