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Message-ID: <5742D609.6040203@ti.com>
Date: Mon, 23 May 2016 13:06:01 +0300
From: Roger Quadros <rogerq@...com>
To: Peter Chen <hzpeterchen@...il.com>
CC: Peter Chen <peter.chen@...escale.com>, <balbi@...nel.org>,
<tony@...mide.com>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
<dan.j.williams@...el.com>, <mathias.nyman@...ux.intel.com>,
<Joao.Pinto@...opsys.com>, <sergei.shtylyov@...entembedded.com>,
<jun.li@...escale.com>, <grygorii.strashko@...com>,
<yoshihiro.shimoda.uh@...esas.com>, <robh@...nel.org>,
<nsekhar@...com>, <b-liu@...com>,
"linux-usb@...r.kernel.org" <linux-usb@...r.kernel.org>,
<linux-omap@...r.kernel.org>, lkml <linux-kernel@...r.kernel.org>,
<devicetree@...r.kernel.org>
Subject: Re: [PATCH v8 08/14] usb: otg: add OTG/dual-role core
On 20/05/16 12:53, Peter Chen wrote:
> On Fri, May 20, 2016 at 12:19:07PM +0300, Roger Quadros wrote:
>> On 20/05/16 11:31, Roger Quadros wrote:
>>> On 18/05/16 15:59, Roger Quadros wrote:
>>>> Hi Peter,
>>>>
>>>> On 18/05/16 10:45, Peter Chen wrote:
>>>>>
>>>>>
>>>>> On Mon, May 16, 2016 at 5:00 PM, Roger Quadros <rogerq@...com <mailto:rogerq@...com>> wrote:
>>>>>
>>>>> On 13/05/16 13:03, Roger Quadros wrote:
>>>>> > It provides APIs for the following tasks
>>>>> >
>>>>> > - Registering an OTG/dual-role capable controller
>>>>> > - Registering Host and Gadget controllers to OTG core
>>>>> > - Providing inputs to and kicking the OTG state machine
>>>>> >
>>>>> > Provide a dual-role device (DRD) state machine.
>>>>> > DRD mode is a reduced functionality OTG mode. In this mode
>>>>> > we don't support SRP, HNP and dynamic role-swap.
>>>>> >
>>>>> > In DRD operation, the controller mode (Host or Peripheral)
>>>>> > is decided based on the ID pin status. Once a cable plug (Type-A
>>>>> > or Type-B) is attached the controller selects the state
>>>>> > and doesn't change till the cable in unplugged and a different
>>>>> > cable type is inserted.
>>>>> >
>>>>> > As we don't need most of the complex OTG states and OTG timers
>>>>> > we implement a lean DRD state machine in usb-otg.c.
>>>>> > The DRD state machine is only interested in 2 hardware inputs
>>>>> > 'id' and 'b_sess_vld'.
>>>>> >
>>>>> > Signed-off-by: Roger Quadros <rogerq@...com <mailto:rogerq@...com>>
>>>>> > ---
>>>>> > drivers/usb/common/Makefile | 2 +-
>>>>> > drivers/usb/common/usb-otg.c | 1042 ++++++++++++++++++++++++++++++++++++++++++
>>>>> > drivers/usb/core/Kconfig | 4 +-
>>>>> > include/linux/usb/gadget.h | 2 +
>>>>> > include/linux/usb/hcd.h | 1 +
>>>>> > include/linux/usb/otg-fsm.h | 7 +
>>>>> > include/linux/usb/otg.h | 154 ++++++-
>>>>> > 7 files changed, 1206 insertions(+), 6 deletions(-)
>>>>> > create mode 100644 drivers/usb/common/usb-otg.c
>>>>>
>>>>>
>>>>> This patch causes the following build issues when CONFIG_USB_GADGET=m, CONFIG_USB=m,
>>>>> CONFIG_USB_COMMON=m and CONFIG_USB_OTG=y
>>>>>
>>>>> ERROR: "usb_otg_register_gadget" [drivers/usb/gadget/udc/udc-core.ko] undefined!
>>>>> ERROR: "usb_otg_unregister_gadget" [drivers/usb/gadget/udc/udc-core.ko] undefined!
>>>>> ERROR: "usb_otg_register_hcd" [drivers/usb/core/usbcore.ko] undefined!
>>>>> ERROR: "usb_otg_unregister_hcd" [drivers/usb/core/usbcore.ko] undefined!
>>>>> ERROR: "otg_statemachine" [drivers/usb/chipidea/ci_hdrc.ko] undefined!
>>>>> scripts/Makefile.modpost:91: recipe for target '__modpost' failed
>>>>> make[1]: *** [__modpost] Error 1
>>>>> Makefile:1141: recipe for target 'modules' failed
>>>>> make: *** [modules] Error 2
>>>>> make: *** Waiting for unfinished jobs....
>>>>>
>>>>> drivers/built-in.o: In function `drd_set_state':
>>>>> usb-otg.c:(.text+0x2b4242): undefined reference to `usb_otg_state_string'
>>>>> drivers/built-in.o: In function `drd_statemachine':
>>>>> (.text+0x2b4b4c): undefined reference to `usb_otg_state_string'
>>>>> Makefile:937: recipe for target 'vmlinux' failed
>>>>>
>>>>> I'll fix it up with the following diff.
>>>>>
>>>>> diff --git a/drivers/usb/Makefile b/drivers/usb/Makefile
>>>>> index dca7856..16a5b55 100644
>>>>> --- a/drivers/usb/Makefile
>>>>> +++ b/drivers/usb/Makefile
>>>>> @@ -59,5 +59,6 @@ obj-$(CONFIG_USB_RENESAS_USBHS) += renesas_usbhs/
>>>>> obj-$(CONFIG_USB_GADGET) += gadget/
>>>>>
>>>>> obj-$(CONFIG_USB_COMMON) += common/
>>>>> +obj-$(CONFIG_USB_OTG) += common/
>>>>>
>>>>> obj-$(CONFIG_USBIP_CORE) += usbip/
>>>>> diff --git a/drivers/usb/common/usb-otg.c b/drivers/usb/common/usb-otg.c
>>>>> index 77048aa..17e449e 100644
>>>>> --- a/drivers/usb/common/usb-otg.c
>>>>> +++ b/drivers/usb/common/usb-otg.c
>>>>> @@ -56,6 +56,30 @@ static int usb_otg_hcd_is_primary_hcd(struct usb_hcd *hcd)
>>>>> return hcd == hcd->primary_hcd;
>>>>> }
>>>>>
>>>>> +static const char *otg_state_string(enum usb_otg_state state)
>>>>> +{
>>>>> + static const char *const names[] = {
>>>>> + [OTG_STATE_A_IDLE] = "a_idle",
>>>>> + [OTG_STATE_A_WAIT_VRISE] = "a_wait_vrise",
>>>>> + [OTG_STATE_A_WAIT_BCON] = "a_wait_bcon",
>>>>> + [OTG_STATE_A_HOST] = "a_host",
>>>>> + [OTG_STATE_A_SUSPEND] = "a_suspend",
>>>>> + [OTG_STATE_A_PERIPHERAL] = "a_peripheral",
>>>>> + [OTG_STATE_A_WAIT_VFALL] = "a_wait_vfall",
>>>>> + [OTG_STATE_A_VBUS_ERR] = "a_vbus_err",
>>>>> + [OTG_STATE_B_IDLE] = "b_idle",
>>>>> + [OTG_STATE_B_SRP_INIT] = "b_srp_init",
>>>>> + [OTG_STATE_B_PERIPHERAL] = "b_peripheral",
>>>>> + [OTG_STATE_B_WAIT_ACON] = "b_wait_acon",
>>>>> + [OTG_STATE_B_HOST] = "b_host",
>>>>> + };
>>>>> +
>>>>> + if (state < 0 || state >= ARRAY_SIZE(names))
>>>>> + return "UNDEFINED";
>>>>> +
>>>>> + return names[state];
>>>>> +}
>>>>> +
>>>>>
>>>>>
>>>>>
>>>>> From my point, make another copy for otg stuff is not a good way,
>>>>> could we make folder under usb/ named otg for dedicated otg stuffs,
>>>>> in that case, build otg stuffs can not depend on USB_COMMON.
>>>>
>>>> OK. I can try that. I'll delete otg_state_string from usb-common.c and
>>>> move it into usb/otg/usb-otg.c
>>>>
>>>> I'll also move usb-otg-fsm.c to usb/otg/.
>>>
>>> But we can't delete usb_otg_state_string() from usb-common.c. That is used at a
>>> number of places whether OTG is enabled or not.
>>>
>>> One option is to make usb-common built in when otg is enabled. What do you say?
>>>
>>
>> This should also get solved if we make USB_OTG tristate so that it is same as
>> USB_COMMON.
>>
>> However I haven't had success in making Kconfig behave like this.
>>
>> USB_OTG = y if USB == y && GADGET = m
>> USB_OTG = y if USB == m && GADGET = y
>>
>> Is there any Kconfig trickery to get this behaviour?
>>
>
> Unless let the USB_OTG works like USB_COMMON which is selected by GADGET
> or HCD. In fact, HCD and Gadget code uses USB OTG symbol directly in
> this framework, it seems like HCD and Gadget depends on OTG, but not
> otherwise.
Not necessarily for build. We have dummy otg functions if USB_OTG is not defined,
and we have checks in place if OTG drivers use OTG related functions while
USB_OTG is not enabled.
>
> If we want OTG to depend on HCD && GADGET, we need not to use OTG symbol
> at HCD and GADGET, and the OTG can use HCD and GADGET symbol directly.
>
We can't use select as we don't want USB_OTG enabled when only one of HCD or GADGET
is enabled. We also want users to be able to disable USB_OTG when both HCD and
GADGET are enabled.
cheers,
-roger
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