On 12/29/2017 3:34 AM, Marc Zyngier wrote:
> On Wed, 27 Dec 2017 20:37:07 +0000,
> Troy Kisky wrote:
>>
>> On 12/27/2017 2:37 AM, Marc Zyngier wrote:
>>> On Tue, 26 Dec 2017 21:57:58 +0000,
>>> Troy Kisky wrote:
>>>>
>>>> On 12/26/2017 1:52 PM, Troy Kisky wrote:
>>>>> On 12/25/2017 2:10 AM, Marc Zyngier wrote:
>>>>>> On Sun, 24 Dec 2017 23:01:33 +0000,
>>>>>> Troy Kisky wrote:
>>>>>>>
>>>>>>> commit 8466489ef5ba48272ba4fa4ea9f8f403306de4c7
>>>>>>> Author: Marc Zyngier <marc.zyngier@xxxxxxx>
>>>>>>> Date: Tue Aug 1 20:11:08 2017 -0500
>>>>>>>
>>>>>>> xhci: Reset Renesas uPD72020x USB controller for 32-bit DMA issue
>>>>>>> ...
>>>>>>> ...
>>>>>>> ...
>>>>>>> --- a/drivers/usb/host/xhci-pci.c
>>>>>>> +++ b/drivers/usb/host/xhci-pci.c
>>>>>>> @@ -284,6 +284,13 @@ static int xhci_pci_probe(struct pci_dev *dev, const struct pci_device_id *id)
>>>>>>>
>>>>>>> driver = (struct hc_driver *)id->driver_data;
>>>>>>>
>>>>>>> + /* For some HW implementation, a XHCI reset is just not enough... */
>>>>>>> + if (usb_xhci_needs_pci_reset(dev)) {
>>>>>>> + dev_info(&dev->dev, "Resetting\n");
>>>>>>> + if (pci_reset_function_locked(dev))
>>>>>>> + dev_warn(&dev->dev, "Reset failed");
>>>>>>> + }
>>>>>>> +
>>>>>>> ________
>>>>>>>
>>>>>>>
>>>>>>> This pci_reset_function_locked call, causes my i.mx6qp processor to
>>>>>>> hang. It no longer responds to the MAGIC_SYSRQ key (break on serial
>>>>>>> port).
>>>>>>>
>>>>>>>
>>>>>>> If I comment it out, things return to normal when testing on
>>>>>>> Linux-next (20171222).
>>>>>>>
>>>>>>> If you need more info, let me know.
>>>>>>
>>>>>> Well, for a start:
>>>>>>
>>>>>> - Does it fail with 4.13 or 4.14 too?
>>>>>
>>>>> v4.13-rc4 - good
>>>>> v4.13-rc5 - fail
>>>>> v4.13 - fail
>>>>> v4.14 - fail
>>>>>
>>>>>
>>>>>
>>>>>> - Can you work out where it is locking up exactly (going slightly
>>>>>> deeper than the pci_reset_function_locked() call)?
>>>>>
>>>>> With this patch
>>>>> diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
>>>>> index 05104bd2b611..8782945a9f70 100644
>>>>> --- a/drivers/usb/host/xhci.c
>>>>> +++ b/drivers/usb/host/xhci.c
>>>>> @@ -4808,8 +4808,10 @@ int xhci_gen_setup(struct usb_hcd *hcd, xhci_get_quirks_t get_quirks)
>>>>>
>>>>> mutex_init(&xhci->mutex);
>>>>> xhci->cap_regs = hcd->regs;
>>>>> + pr_err("%s: 1\n", __func__);
>>>>> xhci->op_regs = hcd->regs +
>>>>> HC_LENGTH(readl(&xhci->cap_regs->hc_capbase));
>>>>> + pr_err("%s: 2\n", __func__);
>>>>> xhci->run_regs = hcd->regs +
>>>>> (readl(&xhci->cap_regs->run_regs_off) & RTSOFF_MASK);
>>>>> /* Cache read-only capability registers */
>>>>> _____________________
>>>>>
>>>>> The last thing printed is
>>>>> [ OK ] Reached target System Initialization.
>>>>> [ OK ] Listening on D-Bus System Message Bus Socket.
>>>>> [ OK ] Reached target Sockets.
>>>>> [ OK ] Started Daily Cleanup of Temporary Directories.
>>>>> [ 15.770319] xhci_gen_setup: 1
>>>
>>> OK, so it looks like the CPU is blocked reading from the
>>> device. Almost feels like the device is not clocked (that's about the
>>> only reason why the CPU would be stuck on such a read).
>>>
>>>>>
>>>>>
>>>>>> - Do you get the symptom at boot time?
>>>>>
>>>>> Boot
>>>>>
>>>>>> On resume? Is the USB driver
>>>>>> compiled as a module or built-in?
>>>>>
>>>>> INSTALL drivers/usb/host/xhci-hcd.ko
>>>>> INSTALL drivers/usb/host/xhci-pci.ko
>>>>> INSTALL drivers/usb/host/xhci-renesas.ko
>>>>>
>>>>>> - What is your exact platform (something a bit more precise than just
>>>>>> i.MX6...)?
>>>>>
>>>>> It is a custom board not in mainline. It does need to load firmware.
>>>>>
>>>>> I tried moving pci_reset_function_locked before renesas_check_if_fw_dl_is_needed
>>>>> but that did not help.
>>>>>
>>>>
>>>>
>>>>
>>>> Which I should say I also have this patch
>>>>
>>>>
>>>> commit 01ac5cfd811088b5fe8c97f28f96086e30393c66
>>>> Author: Christian Lamparter <chunkeey@xxxxxxxxx>
>>>> Date: Wed Jun 8 00:14:57 2016 +0200
>>>>
>>>> usb: xhci: handle uPD720201 and uPD720202 w/o ROM
>>>>
>>>> This patch adds a firmware check for the uPD720201K8-711-BAC-A
>>>> and uPD720202K8-711-BAA-A variant. Both of these chips are listed
>>>> in Renesas' R19UH0078EJ0500 Rev.5.00 "User's Manual: Hardware" as
>>>> devices which need a firmware in order to work as they do not have
>>>> support to load the firmware from an external ROM.
>>>>
>>>> __________
>>>>
>>>> Sorry for not saying earlier.
>>>
>>> That's a very interesting piece of information. Looking at that
>>> patch[1], it doesn't provide any FW loader, and simply detects whether
>>> the firmware is correctly present and running.
>>>
>>> What is probably happening is that your bootloader loads the XHCI
>>> firmware, the driver resets the XHCI device, and the firmware is
>>> lost. Assuming my hunch is right, what would be required here is for
>>> the firmware to be loaded after the reset, but that'd require writing
>>> a firmware loader for xhci-pci (probably not a huge undertaking)
>>>
>>> Could you please investigate whether my hunch is correct or not?
>>>
>>> Thanks,
>>>
>>> M.
>>>
>>> [1]: https://patchwork.kernel.org/patch/9162693/
>>>
>>
>> Hi Marc
>>
>>
>> It already had a firmware downloader, and I tried reset both before and after that. No change.
>>
>>
>> So, now I've tried the same thing with 0 patches to linux-next. A nitrogen6_max board
>> with a Renesas USB3.0 PCIe card that has a firmware ROM, and so does not need the extra patch.
>>
>> 01:00.0 USB controller: Renesas Technology Corp. uPD720201 USB 3.0 Host Controller (rev 03)
>>
>> It behaves identically to the other board. So, the firmware issue is a red herring.
>>
>> [ OK ] Found device /dev/ttymxc0.
>> [ OK ] Found device /dev/ttymxc1.
>> [ 11.916718] xhci_gen_setup: 1
>
> Fair enough. Can you try reseting another endpoint? I'm trying to work
> out whether this is an iMX6 issue or something else. You should be
> able to unload/unbind the driver, reset the device by writing to
> /sys/bus/pci/devices/0000:01:00.0/reset (for example), and reload the driver.
>
> Thanks,
>
> M.
>
That makes it hang as well...
root@nitrogen:/sys/bus/pci/devices/0000:01:00.0# echo 1 >reset
root@nitrogen:/sys/bus/pci/devices/0000:01:00.0#
root@nitrogen:/sys/bus/pci/devices/0000:01:00.0#
root@nitrogen:/sys/bus/pci/devices/0000:01:00.0# modprobe xhci_pci
[ 236.369271] xhci_hcd 0000:01:00.0: Resetting
[ 236.374916] xhci_hcd 0000:01:00.0: xHCI Host Controller
[ 236.380444] xhci_hcd 0000:01:00.0: new USB bus registered, assigned bus number 2
Sorry for the delay
Troy
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