linux-kernel - Re: [PATCH v3 02/11] usb: otg-fsm: support multiple instances

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Date:	Fri, 17 Jul 2015 14:17:18 +0300
From:	Roger Quadros <rogerq@...com>
To:	Peter Chen <peter.chen@...escale.com>,
	Li Jun <b47624@...escale.com>
CC:	<stern@...land.harvard.edu>, <balbi@...com>,
	<gregkh@...uxfoundation.org>, <dan.j.williams@...el.com>,
	<jun.li@...escale.com>, <mathias.nyman@...ux.intel.com>,
	<tony@...mide.com>, <Joao.Pinto@...opsys.com>,
	<linux-usb@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
	<linux-omap@...r.kernel.org>
Subject: Re: [PATCH v3 02/11] usb: otg-fsm: support multiple instances

On 13/07/15 04:39, Peter Chen wrote:
> On Fri, Jul 10, 2015 at 04:06:43PM +0800, Li Jun wrote:
>> On Wed, Jul 08, 2015 at 01:19:28PM +0300, Roger Quadros wrote:
>>> Move the state_changed variable into struct otg_fsm
>>> so that we can support multiple instances.
>>>
>> I am not sure if multiple instances may happen since OTG protocol requires
>> only one OTG port can be equipped on OTG device.
>>
> 
> It is ok the software can support more than spec requires, the user can
> only use one and the spec may change in future :)
> 
>> Li Jun
>>  
>>> Signed-off-by: Roger Quadros <rogerq@...com>
>>> ---
>>>  drivers/usb/common/usb-otg-fsm.c | 10 ++++------
>>>  include/linux/usb/otg-fsm.h      |  1 +
>>>  2 files changed, 5 insertions(+), 6 deletions(-)
>>>
>>> diff --git a/drivers/usb/common/usb-otg-fsm.c b/drivers/usb/common/usb-otg-fsm.c
>>> index 61d538a..42c6376 100644
>>> --- a/drivers/usb/common/usb-otg-fsm.c
>>> +++ b/drivers/usb/common/usb-otg-fsm.c
>>> @@ -61,8 +61,6 @@ static int otg_set_protocol(struct otg_fsm *fsm, int protocol)
>>>  	return 0;
>>>  }
>>>  
>>> -static int state_changed;
>>> -
>>>  /* Called when leaving a state.  Do state clean up jobs here */
>>>  static void otg_leave_state(struct otg_fsm *fsm, enum usb_otg_state old_state)
>>>  {
>>> @@ -123,7 +121,7 @@ static void otg_leave_state(struct otg_fsm *fsm, enum usb_otg_state old_state)
>>>  /* Called when entering a state */
>>>  static int otg_set_state(struct otg_fsm *fsm, enum usb_otg_state new_state)
>>>  {
>>> -	state_changed = 1;
>>> +	fsm->state_changed = 1;
>>>  	if (fsm->otg->state == new_state)
>>>  		return 0;
>>
>> "fsm->state_changed = 1;" should be put here, I think.
>>
> 
> Yes, seems it is the problem at current code.

Right. But I'll fix it as per Li's suggestion.

cheers,
-roger

> 
>> Li Jun
>>
>>>  	VDBG("Set state: %s\n", usb_otg_state_string(new_state));
>>> @@ -248,7 +246,7 @@ int otg_statemachine(struct otg_fsm *fsm)
>>>  	mutex_lock(&fsm->lock);
>>>  
>>>  	state = fsm->otg->state;
>>> -	state_changed = 0;
>>> +	fsm->state_changed = 0;
>>>  	/* State machine state change judgement */
>>>  
>>>  	switch (state) {
>>> @@ -361,7 +359,7 @@ int otg_statemachine(struct otg_fsm *fsm)
>>>  	}
>>>  	mutex_unlock(&fsm->lock);
>>>  
>>> -	VDBG("quit statemachine, changed = %d\n", state_changed);
>>> -	return state_changed;
>>> +	VDBG("quit statemachine, changed = %d\n", fsm->state_changed);
>>> +	return fsm->state_changed;
>>>  }
>>>  EXPORT_SYMBOL_GPL(otg_statemachine);
>>> diff --git a/include/linux/usb/otg-fsm.h b/include/linux/usb/otg-fsm.h
>>> index ca508c2..243274f 100644
>>> --- a/include/linux/usb/otg-fsm.h
>>> +++ b/include/linux/usb/otg-fsm.h
>>> @@ -194,6 +194,7 @@ struct otg_fsm {
>>>  	/* Current usb protocol used: 0:undefine; 1:host; 2:client */
>>>  	int protocol;
>>>  	struct mutex lock;
>>> +	bool state_changed;
>>>  };
>>>  
>>>  struct otg_fsm_ops {
>>> -- 
>>> 2.1.4
>>>
> 
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