On 15/08/2019 17:39, Alan Stern wrote:
> On Thu, 15 Aug 2019, Roger Quadros wrote:
>
>> Felipe & Alan,
>>
>> On 21/07/2019 21:32, Pawel Laszczak wrote:
>>> This patch introduce new Cadence USBSS DRD driver to linux kernel.
>>>
>>> The Cadence USBSS DRD Controller is a highly configurable IP Core which
>>> can be instantiated as Dual-Role Device (DRD), Peripheral Only and
>>> Host Only (XHCI)configurations.
>>>
>>> The current driver has been validated with FPGA burned. We have support
>>> for PCIe bus, which is used on FPGA prototyping.
>>>
>>> The host side of USBSS-DRD controller is compliance with XHCI
>>> specification, so it works with standard XHCI Linux driver.
>>
>> While testing this driver I encountered the following issue if I do the
>> following.
>>
>> 1) USB port is "otg" and nothing connected so it is in IDLE mode to begin
>> with.
>> i.e. HCD & UDC not registered.
>>
>> 2) Load mass storage gadget with backing medium.
>> > modprobe g_mass_storage file=lun stall=0
>>
>> [ 28.172142] udc-core: couldn't find an available UDC - added
>> [g_mass_storage] to list of pending drivers
>>
>> 3) Connect port to PC host
>>
>> [ 30.564767] cdns-usb3 6000000.usb: Initialized ep0 support:
>> [ 30.570591] cdns-usb3 6000000.usb: Initialized ep1out support: BULK, INT
>> ISO
>> [ 30.577713] cdns-usb3 6000000.usb: Initialized ep2out support: BULK, INT
>> ISO
>> [ 30.584835] cdns-usb3 6000000.usb: Initialized ep3out support: BULK, INT
>> ISO
>> [ 30.591957] cdns-usb3 6000000.usb: Initialized ep4out support: BULK, INT
>> ISO
>> [ 30.599078] cdns-usb3 6000000.usb: Initialized ep5out support: BULK, INT
>> ISO
>> [ 30.606199] cdns-usb3 6000000.usb: Initialized ep6out support: BULK, INT
>> ISO
>> [ 30.613320] cdns-usb3 6000000.usb: Initialized ep7out support: BULK, INT
>> ISO
>> [ 30.620441] cdns-usb3 6000000.usb: Initialized ep8out support: BULK, INT
>> ISO
>> [ 30.627562] cdns-usb3 6000000.usb: Initialized ep9out support: BULK, INT
>> ISO
>> [ 30.634684] cdns-usb3 6000000.usb: Initialized ep10out support: BULK,
>> INT ISO
>> [ 30.641893] cdns-usb3 6000000.usb: Initialized ep11out support: BULK,
>> INT ISO
>> [ 30.649100] cdns-usb3 6000000.usb: Initialized ep12out support: BULK,
>> INT ISO
>> [ 30.656309] cdns-usb3 6000000.usb: Initialized ep13out support: BULK,
>> INT ISO
>> [ 30.663516] cdns-usb3 6000000.usb: Initialized ep14out support: BULK,
>> INT ISO
>> [ 30.670724] cdns-usb3 6000000.usb: Initialized ep15out support: BULK,
>> INT ISO
>> [ 30.677935] cdns-usb3 6000000.usb: Initialized ep1in support: BULK, INT
>> ISO
>> [ 30.684979] cdns-usb3 6000000.usb: Initialized ep2in support: BULK, INT
>> ISO
>> [ 30.692020] cdns-usb3 6000000.usb: Initialized ep3in support: BULK, INT
>> ISO
>> [ 30.699057] cdns-usb3 6000000.usb: Initialized ep4in support: BULK, INT
>> ISO
>> [ 30.706097] cdns-usb3 6000000.usb: Initialized ep5in support: BULK, INT
>> ISO
>> [ 30.713135] cdns-usb3 6000000.usb: Initialized ep6in support: BULK, INT
>> ISO
>> [ 30.720175] cdns-usb3 6000000.usb: Initialized ep7in support: BULK, INT
>> ISO
>> [ 30.727213] cdns-usb3 6000000.usb: Initialized ep8in support: BULK, INT
>> ISO
>> [ 30.734252] cdns-usb3 6000000.usb: Initialized ep9in support: BULK, INT
>> ISO
>> [ 30.741289] cdns-usb3 6000000.usb: Initialized ep10in support: BULK, INT
>> ISO
>> [ 30.748414] cdns-usb3 6000000.usb: Initialized ep11in support: BULK, INT
>> ISO
>> [ 30.755536] cdns-usb3 6000000.usb: Initialized ep12in support: BULK, INT
>> ISO
>> [ 30.762661] cdns-usb3 6000000.usb: Initialized ep13in support: BULK, INT
>> ISO
>> [ 30.769785] cdns-usb3 6000000.usb: Initialized ep14in support: BULK, INT
>> ISO
>> [ 30.776910] cdns-usb3 6000000.usb: Initialized ep15in support: BULK, INT
>> ISO
>> [ 30.786313] Mass Storage Function, version: 2009/09/11
>> [ 30.791455] LUN: removable file: (no medium)
>> [ 31.039497] lun0: unable to open backing file: 500M.bin
>> [ 31.158689] g_mass_storage 6000000.usb: failed to start g_mass_storage: -2
>> [ 31.165606] cdns-usb3 6000000.usb: Failed to register USB device
>> controller
>> [ 31.172585] cdns-usb3 6000000.usb: set 2 has failed, back to 0
>>
>> Now, -2 is ENOENT i.e. /* No such file or directory */
>> The file is present so that's not the real issue.
>>
>> The call trace to fsg_lun_open is below
>>
>> [ 30.952877] fsg_lun_open+0x24/0x42c [usb_f_mass_storage]
>> [ 30.958259] fsg_common_create_lun+0xc8/0x2b8 [usb_f_mass_storage]
>> [ 30.964422] fsg_common_create_luns+0xa4/0x104 [usb_f_mass_storage]
>> [ 30.970670] msg_bind+0xd8/0x1e0 [g_mass_storage]
>> [ 30.975360] composite_bind+0x7c/0x180 [libcomposite]
>> [ 30.980396] udc_bind_to_driver+0x68/0x110 [udc_core]
>> [ 30.985432] check_pending_gadget_drivers+0x74/0xd8 [udc_core]
>> [ 30.991247] usb_add_gadget_udc_release+0x180/0x1e8 [udc_core]
>> [ 30.997062] usb_add_gadget_udc+0x10/0x18 [udc_core]
>> [ 31.002010] __cdns3_gadget_init+0x3a0/0x628 [cdns3]
>> [ 31.006959] cdns3_role_start+0x6c/0xd0 [cdns3]
>> [ 31.011473] cdns3_hw_role_switch+0x80/0xe8 [cdns3]
>> [ 31.016336] cdns3_drd_thread_irq+0x10/0x20 [cdns3]
>> [ 31.021197] irq_thread_fn+0x28/0x78
>> [ 31.024757] irq_thread+0x124/0x1b8
>> [ 31.028233] kthread+0x124/0x128
>> [ 31.031447] ret_from_fork+0x10/0x18
>>
>> Is opening the backing file from irq_thread_fn the issue here?
>> If yes, how to resolve this?
>
> I would guess that it probably is related to that.
>
> In any case, the backing filename should be an explicit complete path.
> Who knows what the current directory will be when the actual open call
> takes place?
This seems to be the case. It works fine with complete path.
Do we need to care about this in the mass storage gadget or just
rely on the user to provide the full path?
cheers,
-roger
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