On 1/24/2017 3:14 PM, Bryan O'Donoghue wrote:
>
>
> On 24/01/17 19:25, John Youn wrote:
>> On 1/24/2017 3:05 AM, Bryan O'Donoghue wrote:
>>> On 23/01/17 22:34, John Youn wrote:
>>>> On 1/23/2017 2:10 PM, Alan Stern wrote:
>>>>> On Mon, 23 Jan 2017, John Youn wrote:
>>>>>
>>>>>> On 1/22/2017 5:29 PM, Bryan O'Donoghue wrote:
>>>>>>> - DWC_USB3_NUM indicates the number of Device mode single directional
>>>>>>> endpoints, including OUT and IN endpoint 0.
>>>>>>>
>>>>>>> - DWC_USB3_NUM_IN_EPS indicates the maximum number of Device mode IN
>>>>>>> endpoints active at any time, including control endpoint 0.
>>>>>>>
>>>>>>> It's possible to configure RTL such that DWC_USB3_NUM_EPS is equal to
>>>>>>> DWC_USB3_NUM_IN_EPS.
>>>>>>>
>>>>>>> dwc3-core calculates the number of OUT endpoints as DWC_USB3_NUM minus
>>>>>>> DWC_USB3_NUM_IN_EPS. If RTL has been configured with DWC_USB3_NUM_IN_EPS
>>>>>>> equal to DWC_USB3_NUM then dwc3-core will calculate the number of OUT
>>>>>>> endpoints as zero.
>>>>>>>
>>>>>>> For example a from dwc3_core_num_eps() shows:
>>>>>>> [ 1.565000] /usb0@f01d0000: found 8 IN and 0 OUT endpoints
>>>>>>>
>>>>>>> This patch works around this case by detecting when DWC_USB3_NUM_EPS is
>>>>>>> equal to DWC3_USB3_NUM_IN_EPS and over-rides the calculation of the number
>>>>>>
>>>>>> What if NUM_IN_EPS=7 and NUM_EPS=8? You will still have a problem.
>>>>>>
>>>>>> It's possible to fix this for the general case rather than for this
>>>>>> specific case.
>>>>>
>>>>> What is the reason for computing NUM_OUT_EPS in the first place?
>>>>> Isn't it true that any endpoint can be used as an OUT endpoint?
>>>>>
>>>>> So the real restrictions on a configuration are:
>>>>>
>>>>> number of IN endpoints <= NUM_IN_EPS, and
>>>>>
>>>>> number of IN endpoints + number of OUT endpoints <= NUM_EPS,
>>>>>
>>>>> where ep0 must be counted twice, as both an IN and an OUT endpoint.
>>>>> The value of NUM_OUT_EPS isn't used and shouldn't matter.
>>>>>
>>>>
>>>> Yes that's correct. The general fix should take all that into account
>>>> so that any combination of NUM_EPS and NUM_IN_EPS will work fine.
>>>>
>>>> However it must also account for FPGA configs where each HW endpoint
>>>> has a fixed number/direction, which the current code is compatible
>>>> with.
>>>
>>> I'm not scanning something here..
>>>
>>> If FPGA configurations can have fixed endpoint directions then you could
>>> conceivably have a control IN/OUT pair plus a number a fixed
>>> configuration of all IN or all OUT endpoints, even checking
>>> GHWPARAMS6.EN_FPGA wouldn't let you know which direction those endpoints
>>> had been configured to.
>>>
>>> If I understand you correctly an FPGA could have pretty much any bit-map
>>> of fixed endpoint directions - so just calculating the number of IN/OUT
>>> endpoints based on some combination of DWC_USB3_NUM_IN_EPS and
>>> DWC_USB3_NUM_EPS wouldn't inform you of the fixed direction of an
>>> individual endpoint ... You'd need a descriptor specifying the fixed
>>> direction of each endpoint right ?
>>>
>>
>> Hi Bryan,
>>
>> The EP num and direction are fixed in a predefined way.
>
> Fair enough.
>
> See
>> DWC_USB3_EN_LOG_PHYS_EP_SUPT in the databook and my earlier reply to
>> Felipe.
>
> Thanks, I'll take a look tomorrow when I have the databook in front of me.
>
>> Unfortunately GHWPARAMS6.EN_FPGA doesn't directly tell you that
>> DWC_USB3_EN_LOG_PHYS_EP_SUPT is disabled. We just have to make that
>> assumption. Or add a quirk.
>
> So, if I'm understanding the conclusion.
>
> 1. We'll go ahead and make a change to just grab the # of endpoints
> I'll send out that patch once its tested.
> 2. For 4.12 Filipe will do something for the # of IN endpoints
Up to here, it should be fine, and it will fix your case. It will work
with all cores but in a more limited fashion by not allowing endpoints
to be truly bidirectional.
> 3. A quirk may eventually be required for DWC_USB3_EN_LOG_PHYS_EP_SUPT
> but lets no do anything on that unless someone actually complains.
I think it should be that if someone complains about the above
limitations:
3. Rework endpoint code to remove the limitations and work correctly
for any direction. This should be the default behavior.
4. Then based on EN_FPGA and/or a quirk, revert to previous behavior.
Regards,
John
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