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.
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