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 X-Spam-Level: X-Spam-Status: No, score=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5EA54C10F13 for ; Fri, 12 Apr 2019 01:23:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3812A21850 for ; Fri, 12 Apr 2019 01:23:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726860AbfDLBX4 (ORCPT ); Thu, 11 Apr 2019 21:23:56 -0400 Received: from szxga04-in.huawei.com ([45.249.212.190]:6168 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726636AbfDLBXz (ORCPT ); Thu, 11 Apr 2019 21:23:55 -0400 Received: from DGGEMS414-HUB.china.huawei.com (unknown [172.30.72.58]) by Forcepoint Email with ESMTP id C91B793732090A697CCC; Fri, 12 Apr 2019 09:23:53 +0800 (CST) Received: from [127.0.0.1] (10.142.63.192) by DGGEMS414-HUB.china.huawei.com (10.3.19.214) with Microsoft SMTP Server id 14.3.408.0; Fri, 12 Apr 2019 09:23:44 +0800 CC: , Linux USB List , "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" , lkml , "Zhuangluan Su" , Kongfei , , butao , , , Li Pengcheng , , YiPing Xu , , Yudongbin , Zang Leigang , Jun Li , Valentin Schneider , Felipe Balbi , Greg Kroah-Hartman , Heikki Krogerus Subject: Re: [PATCH v5 10/13] usb: dwc3: Registering a role switch in the DRD code. To: John Stultz References: <20190329041409.70138-1-chenyu56@huawei.com> <20190329041409.70138-11-chenyu56@huawei.com> From: Chen Yu Message-ID: <7d5ba117-735e-3fb0-97f7-33be328a4ae6@huawei.com> Date: Fri, 12 Apr 2019 09:23:42 +0800 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.5.2 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.142.63.192] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi John, On 2019/4/12 8:48, John Stultz wrote: > On Thu, Mar 28, 2019 at 9:14 PM Yu Chen wrote: >> >> The Type-C drivers use USB role switch API to inform the >> system about the negotiated data role, so registering a role >> switch in the DRD code in order to support platforms with >> USB Type-C connectors. >> > > Hey Yu Chen! > Thanks so much for sending these patches out! I have run into some > troubles on bootup where things aren't working properly at first, that > seem to be due to state initialization races. In chasing those down, > I've found some other quirks I wanted to bring up. > >> --- a/drivers/usb/dwc3/drd.c >> +++ b/drivers/usb/dwc3/drd.c >> @@ -479,6 +479,43 @@ static struct extcon_dev *dwc3_get_extcon(struct dwc3 *dwc) >> return edev; >> } >> >> +static int dwc3_usb_role_switch_set(struct device *dev, enum usb_role role) >> +{ >> + struct dwc3 *dwc = dev_get_drvdata(dev); >> + u32 mode; >> + >> + switch (role) { >> + case USB_ROLE_HOST: >> + mode = DWC3_GCTL_PRTCAP_HOST; >> + break; >> + case USB_ROLE_DEVICE: >> + mode = DWC3_GCTL_PRTCAP_DEVICE; >> + break; >> + default: >> + if (dwc->role_switch_default_mode == USB_DR_MODE_HOST) >> + mode = DWC3_GCTL_PRTCAP_HOST; >> + else >> + mode = DWC3_GCTL_PRTCAP_DEVICE; >> + break; >> + } >> + >> + dwc3_set_mode(dwc, mode); >> + return 0; >> +} >> + >> +static enum usb_role dwc3_usb_role_switch_get(struct device *dev) >> +{ >> + struct dwc3 *dwc = dev_get_drvdata(dev); >> + unsigned long flags; >> + enum usb_role role; >> + >> + spin_lock_irqsave(&dwc->lock, flags); >> + role = dwc->current_otg_role; >> + spin_unlock_irqrestore(&dwc->lock, flags); >> + >> + return role; >> +} >> + > > So the two functions above are a bit asymmetric. The > dwc3_usb_role_switch_set() can put the device into host or device > mode, which eventually sets the current_dr_role value. However on the > dwc3_usb_role_switch_get() we return the current_otg_role value. > current_otg_role isn't set unless current_dr_role is > DWC3_GCTL_PRTCAP_OTG, which doesn't seem to happen here. > > I suspect in dwc3_usb_role_switch_get() we should return > current_dr_role, unless current_dr_role==DWC3_GCTL_PRTCAP_OTG, in > which case we'd want to return current_otg_role. > > Does that make sense? > Yes, you are right! The dwc3_usb_role_switch_get() should return current_dr_role . Actually if we register the dwc3_role_switch, the current_dr_role would not be DWC3_GCTL_PRTCAP_OTG. > Nothing really actually use this dwc3_usb_role_switch_get() yet, so > this was easy to overlook, and I only caught it as I was trying to > debug some of the initialization races. > > thanks > -john > > . > From mboxrd@z Thu Jan 1 00:00:00 1970 From: Chen Yu Subject: Re: [PATCH v5 10/13] usb: dwc3: Registering a role switch in the DRD code. Date: Fri, 12 Apr 2019 09:23:42 +0800 Message-ID: <7d5ba117-735e-3fb0-97f7-33be328a4ae6@huawei.com> References: <20190329041409.70138-1-chenyu56@huawei.com> <20190329041409.70138-11-chenyu56@huawei.com> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org To: John Stultz Cc: liuyu712@hisilicon.com, Linux USB List , "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" , lkml , Zhuangluan Su , Kongfei , wanghu17@hisilicon.com, butao , chenyao11@huawei.com, fangshengzhou@hisilicon.com, Li Pengcheng , songxiaowei@hisilicon.com, YiPing Xu , xuyoujun4@huawei.com, Yudongbin , Zang Leigang , Jun Li , Valentin Schneider , Felipe Balbi , Greg Kroah-Hartman , Heikki List-Id: devicetree@vger.kernel.org Hi John, On 2019/4/12 8:48, John Stultz wrote: > On Thu, Mar 28, 2019 at 9:14 PM Yu Chen wrote: >> >> The Type-C drivers use USB role switch API to inform the >> system about the negotiated data role, so registering a role >> switch in the DRD code in order to support platforms with >> USB Type-C connectors. >> > > Hey Yu Chen! > Thanks so much for sending these patches out! I have run into some > troubles on bootup where things aren't working properly at first, that > seem to be due to state initialization races. In chasing those down, > I've found some other quirks I wanted to bring up. > >> --- a/drivers/usb/dwc3/drd.c >> +++ b/drivers/usb/dwc3/drd.c >> @@ -479,6 +479,43 @@ static struct extcon_dev *dwc3_get_extcon(struct dwc3 *dwc) >> return edev; >> } >> >> +static int dwc3_usb_role_switch_set(struct device *dev, enum usb_role role) >> +{ >> + struct dwc3 *dwc = dev_get_drvdata(dev); >> + u32 mode; >> + >> + switch (role) { >> + case USB_ROLE_HOST: >> + mode = DWC3_GCTL_PRTCAP_HOST; >> + break; >> + case USB_ROLE_DEVICE: >> + mode = DWC3_GCTL_PRTCAP_DEVICE; >> + break; >> + default: >> + if (dwc->role_switch_default_mode == USB_DR_MODE_HOST) >> + mode = DWC3_GCTL_PRTCAP_HOST; >> + else >> + mode = DWC3_GCTL_PRTCAP_DEVICE; >> + break; >> + } >> + >> + dwc3_set_mode(dwc, mode); >> + return 0; >> +} >> + >> +static enum usb_role dwc3_usb_role_switch_get(struct device *dev) >> +{ >> + struct dwc3 *dwc = dev_get_drvdata(dev); >> + unsigned long flags; >> + enum usb_role role; >> + >> + spin_lock_irqsave(&dwc->lock, flags); >> + role = dwc->current_otg_role; >> + spin_unlock_irqrestore(&dwc->lock, flags); >> + >> + return role; >> +} >> + > > So the two functions above are a bit asymmetric. The > dwc3_usb_role_switch_set() can put the device into host or device > mode, which eventually sets the current_dr_role value. However on the > dwc3_usb_role_switch_get() we return the current_otg_role value. > current_otg_role isn't set unless current_dr_role is > DWC3_GCTL_PRTCAP_OTG, which doesn't seem to happen here. > > I suspect in dwc3_usb_role_switch_get() we should return > current_dr_role, unless current_dr_role==DWC3_GCTL_PRTCAP_OTG, in > which case we'd want to return current_otg_role. > > Does that make sense? > Yes, you are right! The dwc3_usb_role_switch_get() should return current_dr_role . Actually if we register the dwc3_role_switch, the current_dr_role would not be DWC3_GCTL_PRTCAP_OTG. > Nothing really actually use this dwc3_usb_role_switch_get() yet, so > this was easy to overlook, and I only caught it as I was trying to > debug some of the initialization races. > > thanks > -john > > . > From mboxrd@z Thu Jan 1 00:00:00 1970 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: base64 Subject: [v5,10/13] usb: dwc3: Registering a role switch in the DRD code. From: Yu Chen Message-Id: <7d5ba117-735e-3fb0-97f7-33be328a4ae6@huawei.com> Date: Fri, 12 Apr 2019 09:23:42 +0800 To: John Stultz Cc: liuyu712@hisilicon.com, Linux USB List , "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" , lkml , Zhuangluan Su , Kongfei , wanghu17@hisilicon.com, butao , chenyao11@huawei.com, fangshengzhou@hisilicon.com, Li Pengcheng , songxiaowei@hisilicon.com, YiPing Xu , xuyoujun4@huawei.com, Yudongbin , Zang Leigang , Jun Li , Valentin Schneider , Felipe Balbi , Greg Kroah-Hartman , Heikki Krogerus List-ID: SGkgSm9obiwKCk9uIDIwMTkvNC8xMiA4OjQ4LCBKb2huIFN0dWx0eiB3cm90ZToKPiBPbiBUaHUs IE1hciAyOCwgMjAxOSBhdCA5OjE0IFBNIFl1IENoZW4gPGNoZW55dTU2QGh1YXdlaS5jb20+IHdy b3RlOgo+Pgo+PiBUaGUgVHlwZS1DIGRyaXZlcnMgdXNlIFVTQiByb2xlIHN3aXRjaCBBUEkgdG8g aW5mb3JtIHRoZQo+PiBzeXN0ZW0gYWJvdXQgdGhlIG5lZ290aWF0ZWQgZGF0YSByb2xlLCBzbyBy ZWdpc3RlcmluZyBhIHJvbGUKPj4gc3dpdGNoIGluIHRoZSBEUkQgY29kZSBpbiBvcmRlciB0byBz dXBwb3J0IHBsYXRmb3JtcyB3aXRoCj4+IFVTQiBUeXBlLUMgY29ubmVjdG9ycy4KPj4KPiAKPiBI ZXkgWXUgQ2hlbiEKPiAgIFRoYW5rcyBzbyBtdWNoIGZvciBzZW5kaW5nIHRoZXNlIHBhdGNoZXMg b3V0ISAgSSBoYXZlIHJ1biBpbnRvIHNvbWUKPiB0cm91YmxlcyBvbiBib290dXAgd2hlcmUgdGhp bmdzIGFyZW4ndCB3b3JraW5nIHByb3Blcmx5IGF0IGZpcnN0LCB0aGF0Cj4gc2VlbSB0byBiZSBk dWUgdG8gc3RhdGUgaW5pdGlhbGl6YXRpb24gcmFjZXMuICBJbiBjaGFzaW5nIHRob3NlIGRvd24s Cj4gSSd2ZSBmb3VuZCBzb21lIG90aGVyIHF1aXJrcyBJIHdhbnRlZCB0byBicmluZyB1cC4KPiAK Pj4gLS0tIGEvZHJpdmVycy91c2IvZHdjMy9kcmQuYwo+PiArKysgYi9kcml2ZXJzL3VzYi9kd2Mz L2RyZC5jCj4+IEBAIC00NzksNiArNDc5LDQzIEBAIHN0YXRpYyBzdHJ1Y3QgZXh0Y29uX2RldiAq ZHdjM19nZXRfZXh0Y29uKHN0cnVjdCBkd2MzICpkd2MpCj4+ICAgICAgICAgcmV0dXJuIGVkZXY7 Cj4+ICB9Cj4+Cj4+ICtzdGF0aWMgaW50IGR3YzNfdXNiX3JvbGVfc3dpdGNoX3NldChzdHJ1Y3Qg ZGV2aWNlICpkZXYsIGVudW0gdXNiX3JvbGUgcm9sZSkKPj4gK3sKPj4gKyAgICAgICBzdHJ1Y3Qg ZHdjMyAqZHdjID0gZGV2X2dldF9kcnZkYXRhKGRldik7Cj4+ICsgICAgICAgdTMyIG1vZGU7Cj4+ ICsKPj4gKyAgICAgICBzd2l0Y2ggKHJvbGUpIHsKPj4gKyAgICAgICBjYXNlIFVTQl9ST0xFX0hP U1Q6Cj4+ICsgICAgICAgICAgICAgICBtb2RlID0gRFdDM19HQ1RMX1BSVENBUF9IT1NUOwo+PiAr ICAgICAgICAgICAgICAgYnJlYWs7Cj4+ICsgICAgICAgY2FzZSBVU0JfUk9MRV9ERVZJQ0U6Cj4+ ICsgICAgICAgICAgICAgICBtb2RlID0gRFdDM19HQ1RMX1BSVENBUF9ERVZJQ0U7Cj4+ICsgICAg ICAgICAgICAgICBicmVhazsKPj4gKyAgICAgICBkZWZhdWx0Ogo+PiArICAgICAgICAgICAgICAg aWYgKGR3Yy0+cm9sZV9zd2l0Y2hfZGVmYXVsdF9tb2RlID09IFVTQl9EUl9NT0RFX0hPU1QpCj4+ ICsgICAgICAgICAgICAgICAgICAgICAgIG1vZGUgPSBEV0MzX0dDVExfUFJUQ0FQX0hPU1Q7Cj4+ ICsgICAgICAgICAgICAgICBlbHNlCj4+ICsgICAgICAgICAgICAgICAgICAgICAgIG1vZGUgPSBE V0MzX0dDVExfUFJUQ0FQX0RFVklDRTsKPj4gKyAgICAgICAgICAgICAgIGJyZWFrOwo+PiArICAg ICAgIH0KPj4gKwo+PiArICAgICAgIGR3YzNfc2V0X21vZGUoZHdjLCBtb2RlKTsKPj4gKyAgICAg ICByZXR1cm4gMDsKPj4gK30KPj4gKwo+PiArc3RhdGljIGVudW0gdXNiX3JvbGUgZHdjM191c2Jf cm9sZV9zd2l0Y2hfZ2V0KHN0cnVjdCBkZXZpY2UgKmRldikKPj4gK3sKPj4gKyAgICAgICBzdHJ1 Y3QgZHdjMyAqZHdjID0gZGV2X2dldF9kcnZkYXRhKGRldik7Cj4+ICsgICAgICAgdW5zaWduZWQg bG9uZyBmbGFnczsKPj4gKyAgICAgICBlbnVtIHVzYl9yb2xlIHJvbGU7Cj4+ICsKPj4gKyAgICAg ICBzcGluX2xvY2tfaXJxc2F2ZSgmZHdjLT5sb2NrLCBmbGFncyk7Cj4+ICsgICAgICAgcm9sZSA9 IGR3Yy0+Y3VycmVudF9vdGdfcm9sZTsKPj4gKyAgICAgICBzcGluX3VubG9ja19pcnFyZXN0b3Jl KCZkd2MtPmxvY2ssIGZsYWdzKTsKPj4gKwo+PiArICAgICAgIHJldHVybiByb2xlOwo+PiArfQo+ PiArCj4gCj4gU28gdGhlIHR3byBmdW5jdGlvbnMgYWJvdmUgYXJlIGEgYml0IGFzeW1tZXRyaWMu ICBUaGUKPiBkd2MzX3VzYl9yb2xlX3N3aXRjaF9zZXQoKSBjYW4gcHV0IHRoZSBkZXZpY2UgaW50 byBob3N0IG9yIGRldmljZQo+IG1vZGUsIHdoaWNoIGV2ZW50dWFsbHkgc2V0cyB0aGUgY3VycmVu dF9kcl9yb2xlIHZhbHVlLiAgSG93ZXZlciBvbiB0aGUKPiBkd2MzX3VzYl9yb2xlX3N3aXRjaF9n ZXQoKSB3ZSByZXR1cm4gdGhlIGN1cnJlbnRfb3RnX3JvbGUgdmFsdWUuCj4gY3VycmVudF9vdGdf cm9sZSBpc24ndCBzZXQgdW5sZXNzIGN1cnJlbnRfZHJfcm9sZSBpcwo+IERXQzNfR0NUTF9QUlRD QVBfT1RHLCB3aGljaCBkb2Vzbid0IHNlZW0gdG8gaGFwcGVuIGhlcmUuCj4gCj4gSSBzdXNwZWN0 IGluIGR3YzNfdXNiX3JvbGVfc3dpdGNoX2dldCgpIHdlIHNob3VsZCByZXR1cm4KPiBjdXJyZW50 X2RyX3JvbGUsIHVubGVzcyBjdXJyZW50X2RyX3JvbGU9PURXQzNfR0NUTF9QUlRDQVBfT1RHLCBp bgo+IHdoaWNoIGNhc2Ugd2UnZCB3YW50IHRvIHJldHVybiBjdXJyZW50X290Z19yb2xlLgo+IAo+ IERvZXMgdGhhdCBtYWtlIHNlbnNlPwo+IApZZXMsIHlvdSBhcmUgcmlnaHQhIFRoZSBkd2MzX3Vz Yl9yb2xlX3N3aXRjaF9nZXQoKSBzaG91bGQgcmV0dXJuIGN1cnJlbnRfZHJfcm9sZQouIEFjdHVh bGx5IGlmIHdlIHJlZ2lzdGVyIHRoZSBkd2MzX3JvbGVfc3dpdGNoLCB0aGUgY3VycmVudF9kcl9y b2xlIHdvdWxkIG5vdCBiZSBEV0MzX0dDVExfUFJUQ0FQX09URy4KPiBOb3RoaW5nIHJlYWxseSBh Y3R1YWxseSB1c2UgdGhpcyBkd2MzX3VzYl9yb2xlX3N3aXRjaF9nZXQoKSB5ZXQsIHNvCj4gdGhp cyB3YXMgZWFzeSB0byBvdmVybG9vaywgYW5kIEkgb25seSBjYXVnaHQgaXQgYXMgSSB3YXMgdHJ5 aW5nIHRvCj4gZGVidWcgc29tZSBvZiB0aGUgaW5pdGlhbGl6YXRpb24gcmFjZXMuCj4gCj4gdGhh bmtzCj4gLWpvaG4KPiAKPiAuCj4K