linux-kernel - Re: [PATCH] usb: musb: dsps: handle the otg_state_a_wait_vrise

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Date:	Tue, 8 Dec 2015 08:35:04 -0600
From:	Felipe Balbi <balbi@...com>
To:	Bin Liu <b-liu@...com>,
	Gregory CLEMENT <gregory.clement@...e-electrons.com>
CC:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	<linux-usb@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
	<linux-arm-kernel@...ts.infradead.org>, <stable@...r.kernel.org>
Subject: Re: [PATCH] usb: musb: dsps: handle the otg_state_a_wait_vrise_timeout case


Hi,

Bin Liu <b-liu@...com> writes:
> Felipe,
>
> On 12/08/2015 08:20 AM, Felipe Balbi wrote:
>>
>> Hi,
>>
>> Gregory CLEMENT <gregory.clement@...e-electrons.com> writes:
>>>>>> if it is the case then it didn't fix the issue I had.
>>>>>>
>>>>>> I activated the following debug line:
>>>>>>
>>>>>> [musb_hdrc]musb_interrupt =_ "** IRQ %s usb%04x tx%04x rx%04x\012"
>>>>>> [musb_dsps]dsps_interrupt =p "usbintr (%x) epintr(%x)\012"
>>>>>>
>>>>>> But I didn't get any interrupt while disconnecting the cable without any
>>>>>> device connected on it (whereas I got an interrupt when I connected it).
>>>>>>
>>>>>> Note that I applied this patch instead of the "usb: musb: dsps: handle
>>>>>> the otg_state_a_wait_vrise_timeout case", is what you had in mind ?
>>>>
>>>> yeah, that's what I had in mind. But your patch seems wrong :-)
>>>>
>>>> I tried writing a more correct version here and found 2 issues:
>>>>
>>>> a) bit 3 doesn't do anything :-p I cannot read IRQs from mentor's
>>>> registers
>>>>
>>>> b) when setting RESET_ISOLATION bit, reads of CTRL register hang. Note
>>>> that according to TRM, RESET_ISOLATION _must_ be set prior to a soft
>>>> reset and cleared afterwards. But right after setting RESET_ISOLATION,
>>>> if I try a read of CTRL, it'll hang forever.
>>>
>>> The datasheet seems not very coherent about it,
>>>
>>> on one side we have:
>>> "This bit should be set high prior to setting bit 0 and cleared after bit 0
>>> is cleared."
>>>
>>> and on the other side:
>>> "Both the soft_reset and soft_reset_isolation bits should be asserted
>>> simultaneously."
>>>
>>> The hang you saw could be explained by the following:
>>> "Setting only the soft_reset_isolation bit will cause all USB0 output
>>> signals to go to a known constant value via multiplexers.
>>> This will
>>> prevent future access to USB0."  page 2567
>>
>> good catch. Setting them together makes the hang go away.
>>
>> I still have the other problem, which is legacy IRQ reporting mode not
>> really working.
>>
>
> I never tried to change the IRQ mapping. The 8 MUSB interrupt will be 
> the same no matter where they are reported from. What do you expect when 
> switch to the MUSB IRQ reporting mode?

read events from MUSB's registers instead of TI's :-) so, MUSB_INTRUSB,
MUSB_INTRRX and MUSB_INTRTX.

-- 
balbi

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