From: Roger Quadros <rogerq@ti.com>
To: Jun Li <jun.li@nxp.com>, Peter Chen <hzpeterchen@gmail.com>
Cc: "peter.chen@freescale.com" <peter.chen@freescale.com>,
"stern@rowland.harvard.edu" <stern@rowland.harvard.edu>,
"balbi@kernel.org" <balbi@kernel.org>,
"gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>,
"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>,
"yoshihiro.shimoda.uh@renesas.com"
<yoshihiro.shimoda.uh@renesas.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>,
"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>
Subject: Re: [PATCH v7 03/14] usb: hcd.h: Add OTG to HCD interface
Date: Tue, 10 May 2016 12:20:28 +0300 [thread overview]
Message-ID: <5731A7DC.7060502@ti.com> (raw)
In-Reply-To: <AM4PR04MB2130A378F6E7A103FAF3486989710@AM4PR04MB2130.eurprd04.prod.outlook.com>
On 10/05/16 11:03, Jun Li wrote:
> Hi
>
>> -----Original Message-----
>> From: Roger Quadros [mailto:rogerq@ti.com]
>> Sent: Tuesday, May 10, 2016 3:35 PM
>> To: Peter Chen <hzpeterchen@gmail.com>
>> Cc: peter.chen@freescale.com; stern@rowland.harvard.edu; balbi@kernel.org;
>> gregkh@linuxfoundation.org; dan.j.williams@intel.com; jun.li@freescale.com;
>> mathias.nyman@linux.intel.com; tony@atomide.com; Joao.Pinto@synopsys.com;
>> abrestic@chromium.org; yoshihiro.shimoda.uh@renesas.com; linux-
>> usb@vger.kernel.org; linux-kernel@vger.kernel.org; linux-
>> omap@vger.kernel.org; devicetree@vger.kernel.org
>> Subject: Re: [PATCH v7 03/14] usb: hcd.h: Add OTG to HCD interface
>>
>> On 10/05/16 06:14, Peter Chen wrote:
>>> On Mon, May 09, 2016 at 12:45:38PM +0300, Roger Quadros wrote:
>>>> On 06/05/16 12:41, Peter Chen wrote:
>>>>> On Mon, May 02, 2016 at 03:18:46PM +0300, Roger Quadros wrote:
>>>>>> The OTG core will use struct otg_hcd_ops to interface with the HCD
>>>>>> controller.
>>>>>>
>>>>>> The main purpose of this interface is to avoid directly calling HCD
>>>>>> APIs from the OTG core as they wouldn't be defined in the built-in
>>>>>> symbol table if CONFIG_USB is m.
>>>>>>
>>>>>> Signed-off-by: Roger Quadros <rogerq@ti.com>
>>>>>> Acked-by: Peter Chen <peter.chen@nxp.com>
>>>>>
>>>>> Roger, after thinking more, I still think current dependency between
>>>>> OTG, HCD and gadget are too complicated. Since the OTG can't work if
>>>>> it is built as module, I suggest letting OTG depends on HCD &&
>>>>> USB_GADGET, and it is a boolean, in that case, we don't need to
>>>>> export any HCD and gadget ops, things will be much simpler.
>>>>> What's your opinion?
>>>>
>>>> How will it work if HCD and USB_GADGET are modules and OTG is built-in?
>>>>
>>>
>>> The OTG will not be compiled at this situation, since it is boolean.
>>> In fact, like I mentioned at above, OTG or USB function can't work if
>>> it is built as module.
>>
>> Isn't this a limitation?
>> As per the current implementation dual role works fine even with both
>> USB_GADGET and HCD as module.
>
> My understand: only make sense for pass build, host can't work before
> gadget modules loaded; gadget can't work before hcd loaded, nothing
> can work before all drivers are loaded.
I can make OTG depend on GADGET and HCD, no issue with that.
But we can't get rid of the OTG to HCD/Gadged interfaces as we want things
to work with GADGET and HCD as modules.
>
>>
>> In the real world it is unlikely that GADGET and HCD will be built-in.
>
> Why? User enable USB_OTG means both drivers should be enabled anyway.
Enabled, but not necessarily built-in. Most distributions don't have them
as built-in.
But let's not argue in that direction. Let's say that they can be either
built-in or modules.
> Even in non-OTG case, both may be built-in for machine with 2 ports
> (one port is host only, the other one is peripheral only).
Sure. Every system designer is free to select the configuration.
>
> A general question, 2 drivers depends on each other, allowable?
I don't thing that's possible. Kconfig will complain.
http://lxr.free-electrons.com/source/Documentation/kbuild/kconfig-language.txt#L397
cheers,
-roger
>>>>>
>>>>>> ---
>>>>>> include/linux/usb/hcd.h | 24 ++++++++++++++++++++++++
>>>>>> 1 file changed, 24 insertions(+)
>>>>>>
>>>>>> diff --git a/include/linux/usb/hcd.h b/include/linux/usb/hcd.h
>>>>>> index b98f831..861ccaa 100644
>>>>>> --- a/include/linux/usb/hcd.h
>>>>>> +++ b/include/linux/usb/hcd.h
>>>>>> @@ -399,6 +399,30 @@ struct hc_driver {
>>>>>>
>>>>>> };
>>>>>>
>>>>>> +/**
>>>>>> + * struct otg_hcd_ops - Interface between OTG core and HCD
>>>>>> + *
>>>>>> + * Provided by the HCD core to allow the OTG core to interface
>>>>>> +with the HCD
>>>>>> + *
>>>>>> + * @add: function to add the HCD
>>>>>> + * @remove: function to remove the HCD
>>>>>> + * @usb_bus_start_enum: function to immediately start bus
>>>>>> +enumeration
>>>>>> + * @usb_control_msg: function to build and send of a control urb
>>>>>> + * @usb_hub_find_child: function to get pointer to the child
>>>>>> +device */ struct otg_hcd_ops {
>>>>>> + int (*add)(struct usb_hcd *hcd,
>>>>>> + unsigned int irqnum, unsigned long irqflags);
>>>>>> + void (*remove)(struct usb_hcd *hcd);
>>>>>> + int (*usb_bus_start_enum)(struct usb_bus *bus, unsigned int
>> port_num);
>>>>>> + int (*usb_control_msg)(struct usb_device *dev, unsigned int
>> pipe,
>>>>>> + __u8 request, __u8 requesttype, __u16 value,
>>>>>> + __u16 index, void *data, __u16 size,
>>>>>> + int timeout);
>>>>>> + struct usb_device * (*usb_hub_find_child)(struct usb_device
>> *hdev,
>>>>>> + int port1);
>>>>>> +};
>>>>>> +
>>>>>> static inline int hcd_giveback_urb_in_bh(struct usb_hcd *hcd) {
>>>>>> return hcd->driver->flags & HCD_BH;
>>>>>> --
>>>>>> 2.7.4
>>>>>>
>>>>>> --
>>>>>> To unsubscribe from this list: send the line "unsubscribe
>>>>>> linux-usb" in the body of a message to majordomo@vger.kernel.org
>>>>>> More majordomo info at http://vger.kernel.org/majordomo-info.html
>>>>>
>>>
next prev parent reply other threads:[~2016-05-10 9:20 UTC|newest]
Thread overview: 60+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-05-02 12:18 [PATCH v7 00/14] USB OTG/dual-role framework Roger Quadros
2016-05-02 12:18 ` [PATCH v7 01/14] usb: hcd: Initialize hcd->flags to 0 Roger Quadros
[not found] ` <1462191537-10314-2-git-send-email-rogerq-l0cyMroinI0@public.gmane.org>
2016-05-06 9:05 ` Peter Chen
2016-05-02 12:18 ` [PATCH v7 02/14] usb: otg-fsm: Prevent build warning "VDBG" redefined Roger Quadros
2016-05-11 8:17 ` Peter Chen
2016-05-02 12:18 ` [PATCH v7 03/14] usb: hcd.h: Add OTG to HCD interface Roger Quadros
2016-05-06 9:41 ` Peter Chen
[not found] ` <20160506094103.GF32359-Fb7DQEYuewWctlrPMvKcciBecyulp+rMXqFh9Ls21Oc@public.gmane.org>
2016-05-09 9:45 ` Roger Quadros
[not found] ` <57305C42.90300-l0cyMroinI0@public.gmane.org>
2016-05-10 3:14 ` Peter Chen
2016-05-10 7:34 ` Roger Quadros
2016-05-10 8:03 ` Jun Li
2016-05-10 9:20 ` Roger Quadros [this message]
2016-05-11 6:19 ` Peter Chen
2016-05-10 8:12 ` Felipe Balbi
2016-05-10 9:12 ` Roger Quadros
[not found] ` <1462191537-10314-1-git-send-email-rogerq-l0cyMroinI0@public.gmane.org>
2016-05-02 12:18 ` [PATCH v7 04/14] usb: otg-fsm: use usb_otg wherever possible Roger Quadros
2016-05-02 12:18 ` [PATCH v7 05/14] usb: otg-fsm: move host controller operations into usb_otg->hcd_ops Roger Quadros
[not found] ` <1462191537-10314-6-git-send-email-rogerq-l0cyMroinI0@public.gmane.org>
2016-05-11 6:10 ` Peter Chen
[not found] ` <20160511061001.GA16910-Fb7DQEYuewWctlrPMvKcciBecyulp+rMXqFh9Ls21Oc@public.gmane.org>
2016-05-11 11:02 ` Roger Quadros
[not found] ` <5733113D.2030009-l0cyMroinI0@public.gmane.org>
2016-05-11 12:32 ` Roger Quadros
[not found] ` <5733265E.2040105-l0cyMroinI0@public.gmane.org>
2016-05-12 8:18 ` Peter Chen
[not found] ` <20160512081843.GA23083-Fb7DQEYuewWctlrPMvKcciBecyulp+rMXqFh9Ls21Oc@public.gmane.org>
2016-05-12 8:29 ` Roger Quadros
2016-05-02 12:18 ` [PATCH v7 06/14] usb: gadget.h: Add OTG to gadget interface Roger Quadros
2016-05-02 12:18 ` [PATCH v7 07/14] usb: otg: get rid of CONFIG_USB_OTG_FSM in favour of CONFIG_USB_OTG Roger Quadros
[not found] ` <1462191537-10314-8-git-send-email-rogerq-l0cyMroinI0@public.gmane.org>
2016-05-11 8:21 ` Peter Chen
2016-05-02 12:18 ` [PATCH v7 08/14] usb: otg: add OTG/dual-role core Roger Quadros
2016-05-11 8:34 ` Peter Chen
2016-05-11 11:03 ` Roger Quadros
2016-05-02 12:18 ` [PATCH v7 09/14] usb: of: add an API to get OTG device from USB controller node Roger Quadros
[not found] ` <1462191537-10314-10-git-send-email-rogerq-l0cyMroinI0@public.gmane.org>
2016-05-04 13:15 ` Rob Herring
2016-05-11 8:40 ` Peter Chen
2016-05-11 11:04 ` Roger Quadros
2016-05-02 12:18 ` [PATCH v7 10/14] usb: otg: add hcd companion support Roger Quadros
[not found] ` <1462191537-10314-11-git-send-email-rogerq-l0cyMroinI0@public.gmane.org>
2016-05-04 13:17 ` Rob Herring
2016-05-04 13:47 ` Roger Quadros
2016-05-11 13:54 ` Rob Herring
2016-05-11 14:13 ` Roger Quadros
[not found] ` <57333DFF.3090609-l0cyMroinI0@public.gmane.org>
2016-05-11 14:47 ` Alan Stern
[not found] ` <Pine.LNX.4.44L0.1605111043030.1882-100000-IYeN2dnnYyZXsRXLowluHWD2FQJk+8+b@public.gmane.org>
2016-05-12 4:00 ` Yoshihiro Shimoda
[not found] ` <SG2PR06MB09194AB523C3ABDB425285C7D8730-ESzmfEwOt/zNQ8RBPPB5A20DtJ1/0DrXvxpqHgZTriW3zl9H0oFU5g@public.gmane.org>
2016-05-12 8:34 ` Roger Quadros
[not found] ` <57343FFC.9090105-l0cyMroinI0@public.gmane.org>
2016-05-12 9:31 ` Roger Quadros
[not found] ` <57344D7B.3050005-l0cyMroinI0@public.gmane.org>
2016-05-12 10:31 ` Yoshihiro Shimoda
[not found] ` <SG2PR06MB091923EEBAA67EC1D1E48B6DD8730-ESzmfEwOt/zNQ8RBPPB5A20DtJ1/0DrXvxpqHgZTriW3zl9H0oFU5g@public.gmane.org>
2016-05-12 12:13 ` Roger Quadros
2016-05-16 2:13 ` Peter Chen
[not found] ` <20160516021350.GA24609-Fb7DQEYuewWctlrPMvKcciBecyulp+rMXqFh9Ls21Oc@public.gmane.org>
2016-05-16 8:01 ` Roger Quadros
[not found] ` <57397E57.8060903-l0cyMroinI0@public.gmane.org>
2016-05-16 8:13 ` Peter Chen
[not found] ` <20160516081326.GC24609-Fb7DQEYuewWctlrPMvKcciBecyulp+rMXqFh9Ls21Oc@public.gmane.org>
2016-05-16 8:35 ` Roger Quadros
2016-05-12 18:16 ` Alan Stern
2016-05-11 8:43 ` Peter Chen
2016-05-02 12:18 ` [PATCH v7 11/14] usb: otg: use dev_dbg() instead of VDBG() Roger Quadros
[not found] ` <1462191537-10314-12-git-send-email-rogerq-l0cyMroinI0@public.gmane.org>
2016-05-06 9:04 ` Peter Chen
[not found] ` <20160506090425.GD32359-Fb7DQEYuewWctlrPMvKcciBecyulp+rMXqFh9Ls21Oc@public.gmane.org>
2016-05-09 9:48 ` Roger Quadros
2016-05-11 8:43 ` Peter Chen
2016-05-02 12:18 ` [PATCH v7 13/14] usb: gadget: udc: adapt to OTG core Roger Quadros
2016-05-11 8:36 ` [PATCH v7 00/14] USB OTG/dual-role framework Peter Chen
[not found] ` <20160511083619.GF16910-Fb7DQEYuewWctlrPMvKcciBecyulp+rMXqFh9Ls21Oc@public.gmane.org>
2016-05-11 11:05 ` Roger Quadros
2016-05-02 12:18 ` [PATCH v7 12/14] usb: hcd: Adapt to OTG core Roger Quadros
[not found] ` <1462191537-10314-13-git-send-email-rogerq-l0cyMroinI0@public.gmane.org>
2016-05-11 8:57 ` Peter Chen
2016-05-02 12:18 ` [PATCH v7 14/14] usb: host: xhci-plat: Add otg device to platform data Roger Quadros
2016-05-11 9:00 ` Peter Chen
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