From: Peter Chen <hzpeterchen@gmail.com>
To: Roger Quadros <rogerq@ti.com>
Cc: Jun Li <jun.li@nxp.com>,
"stern@rowland.harvard.edu" <stern@rowland.harvard.edu>,
"balbi@kernel.org" <balbi@kernel.org>,
"gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>,
"peter.chen@freescale.com" <peter.chen@freescale.com>,
"dan.j.williams@intel.com" <dan.j.williams@intel.com>,
"jun.li@freescale.com" <jun.li@freescale.com>,
"mathias.nyman@linux.intel.com" <mathias.nyman@linux.intel.com>,
"tony@atomide.com" <tony@atomide.com>,
"Joao.Pinto@synopsys.com" <Joao.Pinto@synopsys.com>,
"abrestic@chromium.org" <abrestic@chromium.org>,
"r.baldyga@samsung.com" <r.baldyga@samsung.com>,
"linux-usb@vger.kernel.org" <linux-usb@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-omap@vger.kernel.org" <linux-omap@vger.kernel.org>
Subject: Re: [PATCH v6 07/12] usb: otg: add OTG/dual-role core
Date: Thu, 28 Apr 2016 09:54:09 +0800 [thread overview]
Message-ID: <20160428015409.GA12199@shlinux2.ap.freescale.net> (raw)
In-Reply-To: <57209BA0.6040508@ti.com>
On Wed, Apr 27, 2016 at 01:59:44PM +0300, Roger Quadros wrote:
> Hi,
>
> On 27/04/16 06:15, Peter Chen wrote:
> > On Tue, Apr 26, 2016 at 04:21:07PM +0800, Peter Chen wrote:
> >> On Tue, Apr 26, 2016 at 07:00:22AM +0000, Jun Li wrote:
> >>> Hi
> >>>
> >>>> -----Original Message-----
> >>>> From: Peter Chen [mailto:hzpeterchen@gmail.com]
> >>>> Sent: Tuesday, April 26, 2016 2:28 PM
> >>>> To: Jun Li <jun.li@nxp.com>
> >>>> Cc: Roger Quadros <rogerq@ti.com>; stern@rowland.harvard.edu;
> >>>> balbi@kernel.org; gregkh@linuxfoundation.org; peter.chen@freescale.com;
> >>>> dan.j.williams@intel.com; jun.li@freescale.com;
> >>>> mathias.nyman@linux.intel.com; tony@atomide.com; Joao.Pinto@synopsys.com;
> >>>> abrestic@chromium.org; r.baldyga@samsung.com; linux-usb@vger.kernel.org;
> >>>> linux-kernel@vger.kernel.org; linux-omap@vger.kernel.org
> >>>> Subject: Re: [PATCH v6 07/12] usb: otg: add OTG/dual-role core
> >>>>
> >>>> On Tue, Apr 26, 2016 at 05:11:36AM +0000, Jun Li wrote:
> >>>>> Hi
> >>>>>
> >>>>>> -----Original Message-----
> >>>>>> From: Peter Chen [mailto:hzpeterchen@gmail.com]
> >>>>>> Sent: Tuesday, April 26, 2016 11:47 AM
> >>>>>> To: Jun Li <jun.li@nxp.com>
> >>>>>> Cc: Roger Quadros <rogerq@ti.com>; stern@rowland.harvard.edu;
> >>>>>> balbi@kernel.org; gregkh@linuxfoundation.org;
> >>>>>> peter.chen@freescale.com; dan.j.williams@intel.com;
> >>>>>> jun.li@freescale.com; mathias.nyman@linux.intel.com;
> >>>>>> tony@atomide.com; Joao.Pinto@synopsys.com; abrestic@chromium.org;
> >>>>>> r.baldyga@samsung.com; linux-usb@vger.kernel.org;
> >>>>>> linux-kernel@vger.kernel.org; linux-omap@vger.kernel.org
> >>>>>> Subject: Re: [PATCH v6 07/12] usb: otg: add OTG/dual-role core
> >>>>>>
> >>>>>> On Tue, Apr 26, 2016 at 02:07:56AM +0000, Jun Li wrote:
> >>>>>>>> +struct usb_otg *usb_otg_register(struct device *dev,
> >>>>>>>> + struct usb_otg_config *config) {
> >>>>>>>> + struct usb_otg *otg;
> >>>>>>>> + struct otg_wait_data *wait;
> >>>>>>>> + int ret = 0;
> >>>>>>>> +
> >>>>>>>> + if (!dev || !config || !config->fsm_ops)
> >>>>>>>> + return ERR_PTR(-EINVAL);
> >>>>>>>> +
> >>>>>>>> + /* already in list? */
> >>>>>>>> + mutex_lock(&otg_list_mutex);
> >>>>>>>> + if (usb_otg_get_data(dev)) {
> >>>>>>>> + dev_err(dev, "otg: %s: device already in otg list\n",
> >>>>>>>> + __func__);
> >>>>>>>> + ret = -EINVAL;
> >>>>>>>> + goto unlock;
> >>>>>>>> + }
> >>>>>>>> +
> >>>>>>>> + /* allocate and add to list */
> >>>>>>>> + otg = kzalloc(sizeof(*otg), GFP_KERNEL);
> >>>>>>>> + if (!otg) {
> >>>>>>>> + ret = -ENOMEM;
> >>>>>>>> + goto unlock;
> >>>>>>>> + }
> >>>>>>>> +
> >>>>>>>> + otg->dev = dev;
> >>>>>>>> + otg->caps = config->otg_caps;
> >>>>>>>> +
> >>>>>>>> + if ((otg->caps->hnp_support || otg->caps->srp_support ||
> >>>>>>>> + otg->caps->adp_support) && !config->otg_work)
> >>>>>>>> + dev_info(dev, "otg: limiting to dual-role\n");
> >>>>>>>
> >>>>>>> dev_err, this should be an error.
> >>>>>>
> >>>>>> The condition may be wrong, but it is an information to show that
> >>>>>> current OTG is dual-role.
> >>>>>
> >>>>> This should not happen in any correct design, I even doubt if we
> >>>>> should try to continue by "downgrade" it to be duel role, currently
> >>>>> the only example user is dual role, so doing like this can't be tested
> >>>>> by real case, this downgrade is not so easy like we image, at least
> >>>>> for chipidea otg driver, simply replace a queue worker may not work,
> >>>>> as we have much more difference between the 2 configs.
> >>>>>
> >>>>
> >>>> Would you show more why chipidea can't work just replace the work item,
> >>>> and see if anything we still can improve for this framework?
> >>>
> >>> In real OTG, we need enable AVV irq,
> >>
> >> Enable and Handling AVV is platform stuff. In this framework, we are
> >> focus on how otg device manages host and gadget together, and the state
> >> machine when the related otg event occurs.
> >>
> >>> but for duel role, nobody care/handle,
> >>> there are much more resource required for OTG: timers, hnp polling,
> >>> otg test device handling...
> >>
> >> They are common things for fully OTG fsm, you can move them
> >> to common code (In fact, hnp polling handling is already common code).
> >>
> >>>
> >>> with current design, chipidea driver can support real OTG with its own
> >>> queue worker, or DRD with Roger's drd work item if config is correct.
> >>>
> >>> But improve something to work on a *wrong* config will make it complicated
> >>> and does not make much sense IMO.
> >>>
> >>
> >> What does above "config" you mean?
> >>
> >> If the configure is fully OTG, you can choose different state machine,
> >> eg otg_statemachine, if you find it is hard for chipidea to use this
> >> framework, just list the reason, and see if we can improve.
> >>
> >
> > Roger, after discussing with Jun off line, we think usb_otg_register
> > should return -ENOTSUPP if platform is OTG capabilities (HNP || SRP ||
> > ADP), since this patch set does not cover fully otg features, the users
>
> But this series isn't preventing full otg implementation. You can
> still do that via config->otg_work.
>
> I can modify the following condition to return -ENOTSUPP instead of
> defaulting to dual-role
>
> struct usb_otg *usb_otg_register(...)
> {
> ...
> if ((otg->caps->hnp_support || otg->caps->srp_support ||
> otg->caps->adp_support) && !config->otg_work) {
> dev_err(dev, "otg: otg_work must be provided for OTG support\n");
> return -ENOTSUPP;
> }
> ...
> }
>
According to Jun, this framework still needs to improve (maybe small) even
using user work item for fully OTG, so the first step is let the drd
work well:)
--
Best Regards,
Peter Chen
next prev parent reply other threads:[~2016-04-28 2:02 UTC|newest]
Thread overview: 100+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-04-05 14:05 [PATCH v6 00/12] USB OTG/dual-role framework Roger Quadros
2016-04-05 14:05 ` [PATCH v6 01/12] usb: hcd: Initialize hcd->flags to 0 Roger Quadros
2016-04-06 6:09 ` Felipe Balbi
2016-04-06 6:32 ` Roger Quadros
2016-04-07 9:42 ` Peter Chen
2016-04-07 10:40 ` Roger Quadros
2016-04-08 1:01 ` Peter Chen
2016-04-08 7:16 ` Roger Quadros
2016-04-08 7:45 ` Peter Chen
2016-04-18 2:29 ` Peter Chen
2016-04-18 14:11 ` Alan Stern
2016-04-19 1:56 ` Peter Chen
2016-04-20 8:15 ` Roger Quadros
2016-04-20 9:40 ` Peter Chen
2016-04-05 14:05 ` [PATCH v6 02/12] usb: hcd.h: Add OTG to HCD interface Roger Quadros
2016-04-18 7:41 ` Peter Chen
2016-04-05 14:05 ` [PATCH v6 03/12] usb: otg-fsm: use usb_otg wherever possible Roger Quadros
2016-04-18 7:42 ` Peter Chen
2016-04-05 14:05 ` [PATCH v6 04/12] usb: otg-fsm: move host controller operations into usb_otg->hcd_ops Roger Quadros
2016-04-18 8:00 ` Peter Chen
2016-04-05 14:05 ` [PATCH v6 05/12] usb: gadget.h: Add OTG to gadget interface Roger Quadros
2016-04-05 14:05 ` [PATCH v6 06/12] usb: otg: get rid of CONFIG_USB_OTG_FSM in favour of CONFIG_USB_OTG Roger Quadros
2016-04-18 8:05 ` Peter Chen
2016-04-20 8:12 ` Roger Quadros
2016-04-05 14:05 ` [PATCH v6 07/12] usb: otg: add OTG/dual-role core Roger Quadros
2016-04-07 8:52 ` Yoshihiro Shimoda
2016-04-07 11:45 ` Roger Quadros
2016-04-08 11:22 ` Yoshihiro Shimoda
2016-04-11 10:54 ` Roger Quadros
2016-04-14 8:36 ` Yoshihiro Shimoda
2016-04-14 10:59 ` Roger Quadros
2016-04-14 11:15 ` Yoshihiro Shimoda
2016-04-14 11:32 ` Roger Quadros
2016-04-15 9:59 ` Yoshihiro Shimoda
2016-04-15 10:57 ` Roger Quadros
2016-04-15 10:03 ` Yoshihiro Shimoda
2016-04-19 9:18 ` Peter Chen
2016-04-20 5:08 ` Yoshihiro Shimoda
2016-04-20 7:03 ` Roger Quadros
2016-04-22 6:05 ` Peter Chen
2016-04-22 1:26 ` Peter Chen
2016-04-22 3:34 ` Peter Chen
2016-04-22 5:57 ` Yoshihiro Shimoda
2016-04-15 9:25 ` Peter Chen
2016-04-15 11:00 ` Roger Quadros
2016-04-18 2:09 ` Peter Chen
2016-04-20 6:54 ` Roger Quadros
2016-04-20 9:26 ` Peter Chen
2016-04-19 8:06 ` Peter Chen
2016-04-20 7:02 ` Roger Quadros
2016-04-20 9:39 ` Peter Chen
2016-04-21 6:52 ` Peter Chen
2016-04-25 14:05 ` Roger Quadros
2016-04-26 2:07 ` Jun Li
2016-04-26 3:47 ` Peter Chen
2016-04-26 5:11 ` Jun Li
2016-04-26 6:28 ` Peter Chen
2016-04-26 7:00 ` Jun Li
2016-04-26 8:21 ` Peter Chen
2016-04-27 3:15 ` Peter Chen
2016-04-27 10:59 ` Roger Quadros
2016-04-28 1:54 ` Peter Chen [this message]
2016-04-28 8:01 ` Roger Quadros
2016-04-27 11:15 ` Roger Quadros
2016-04-05 14:05 ` [PATCH v6 08/12] usb: hcd: Adapt to OTG core Roger Quadros
2016-04-18 6:29 ` Peter Chen
2016-04-19 8:14 ` Peter Chen
2016-04-20 6:47 ` Roger Quadros
2016-04-20 6:46 ` Roger Quadros
2016-04-27 10:16 ` Jun Li
2016-04-27 11:00 ` Roger Quadros
2016-04-27 11:11 ` Roger Quadros
2016-04-27 12:49 ` Jun Li
2016-04-27 13:18 ` Jun Li
2016-04-05 14:05 ` [PATCH v6 09/12] usb: gadget: udc: adapt " Roger Quadros
2016-04-18 6:59 ` Peter Chen
2016-04-20 6:51 ` Roger Quadros
2016-04-21 6:38 ` Jun Li
2016-04-25 14:04 ` Roger Quadros
2016-04-26 0:07 ` Jun Li
2016-04-27 11:22 ` Roger Quadros
2016-04-28 9:54 ` Roger Quadros
2016-04-28 10:23 ` Jun Li
2016-04-28 12:22 ` Roger Quadros
2016-05-03 7:06 ` Jun Li
2016-05-03 15:44 ` Roger Quadros
2016-05-04 1:47 ` Peter Chen
2016-05-04 3:35 ` Peter Chen
2016-05-04 6:37 ` Roger Quadros
2016-05-04 7:53 ` Peter Chen
2016-05-04 8:03 ` Jun Li
2016-05-04 8:40 ` Roger Quadros
2016-05-04 8:39 ` Peter Chen
2016-04-05 14:05 ` [PATCH v6 10/12] usb: doc: dt-binding: Add otg-controller property Roger Quadros
2016-04-05 14:05 ` [PATCH v6 11/12] usb: core: hub: Notify OTG fsm when A device sets b_hnp_enable Roger Quadros
2016-04-18 7:08 ` Peter Chen
2016-04-27 14:35 ` Roger Quadros
2016-04-05 14:05 ` [PATCH v6 12/12] usb: host: xhci-plat: Add otg device to platform data Roger Quadros
2016-04-06 3:23 ` Yoshihiro Shimoda
2016-04-06 6:30 ` Roger Quadros
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