From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tony Lindgren Subject: Re: [PATCH] usb: dwc3: omap: Fix imprecise external abort and oops on boot Date: Thu, 8 Dec 2016 10:25:25 -0800 Message-ID: <20161208182521.GA4920@atomide.com> References: <20161208032108.21962-1-tony@atomide.com> <87lgvqkb6f.fsf@linux.intel.com> <20161208153734.GF4264@atomide.com> <87a8c6pavm.fsf@linux.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <87a8c6pavm.fsf-VuQAYsv1563Yd54FQh9/CA@public.gmane.org> Sender: linux-usb-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Felipe Balbi Cc: Greg Kroah-Hartman , Grygorii Strashko , Roger Quadros , Sekhar Nori , linux-usb-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-omap-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Nishanth Menon List-Id: linux-omap@vger.kernel.org * Felipe Balbi [161208 09:52]: > > Hi, > > Tony Lindgren writes: > > * Felipe Balbi [161208 01:45]: > >> > >> Hi, > >> > >> Tony Lindgren writes: > >> > Somehow starting with v4.9-rc7 there have been imprecise > >> > >> There's nothing touching dwc3 since v4.9-rc5. > > > > Right, nothing obvious has changed. I think it's just a slight timing > > change in the code that started triggering it. > > could be > > >> > external aborts on omap5-uevm dwc3 controller. I have not been > >> > able to bisect what exactly triggered this as it does not always > >> > happen. It seems that something changed with probing that > >> > now exposes the issue: > >> > > >> > Unhandled fault: imprecise external abort (0x1406) at 0x00000000 > >> > >> hmmm, clock disabled... dwc3-omap shouldn't have pm runtime at all. > > > > It does for the interconnect target module clkctrl register via PM > > runtime. That's the "usb_otg_ss" module. > > but that's all hidden in omap_device.c, we don't touch it from driver > perspective. The call to pm_runtime_get_sync() in dwc3_omap_probe() will use it. Is there also some dwc3 internal clock? If we assume the usb_otg_ss module is properly enabled it could be some dwc3 internal clock not enabled? We do have a srst_udelay needed for enabling musb controller for some SoCs, I'll check if that's the case here. > >> > ... > >> > PC is at dwc3_omap_interrupt_thread+0x20/0x80 > >> > LR is at irq_thread_fn+0x1c/0x54 > >> > ... > >> > [] (dwc3_omap_interrupt_thread) from [] > >> > (irq_thread_fn+0x1c/0x54) > >> > [] (irq_thread_fn) from [] (irq_thread+0x12c/0x1f0) > >> > [] (irq_thread) from [] (kthread+0xdc/0xf4) > >> > [] (kthread) from [] (ret_from_fork+0x14/0x3c) > >> > ... > >> > > >> > Unable to handle kernel paging request at virtual address ffffffec > >> > ... > >> > Internal error: Oops: 37 [#2] SMP ARM > >> > PC is at kthread_data+0x4/0xc > >> > LR is at irq_thread_dtor+0x28/0xd0 > >> > ... > >> > [] (kthread_data) from [] (irq_thread_dtor+0x28/0xd0) > >> > [] (irq_thread_dtor) from [] (task_work_run+0xb8/0xdc) > >> > [] (task_work_run) from [] (do_exit+0x314/0xa20) > >> > [] (do_exit) from [] (die+0x410/0x474) > >> > [] (die) from [] (do_DataAbort+0xb4/0xb8) > >> > [] (do_DataAbort) from [] (__dabt_svc+0x58/0x80) > >> > Exception stack(0xee777ec8 to 0xee777f10) > >> > 7ec0: 0000014d ee6e6f10 00000034 fc020034 ee6e6f10 ee1eec00 > >> > 7ee0: 00000000 00000000 ee6ec640 c038a4bc 00000000 00000000 00000000 ee777f18 > >> > 7f00: c038a4d8 c0989fa8 60000013 ffffffff > >> > [] (__dabt_svc) from [] (dwc3_omap_interrupt_thread+0x20/0x80) > >> > [] (dwc3_omap_interrupt_thread) from [] (irq_thread_fn+0x1c/0x54) > >> > [] (irq_thread_fn) from [] (irq_thread+0x12c/0x1f0) > >> > [] (irq_thread) from [] (kthread+0xdc/0xf4) > >> > [] (kthread) from [] (ret_from_fork+0x14/0x3c) > >> > > >> > Fix the issue by making sure the dwc3 interrupts are disabled > >> > before we call devm_request_threaded_irq(). > >> > >> that should already be the case. Are you sure that register isn't zero > >> in probe? > > > > Looks like irq0_status = 0 and irqmisc_status = 0x2121. Also just > > clearing irqmisc with dwc3_omap_write_irqmisc_clr(omap, 0xffffffff) > > stops the issue from happening. > > > > There is some deferred probing happening but irqmisc is always 0x2121. > > some spurious irq status from ROM code, perhaps? Are you not resetting > usb_otg_ss hwmod? We shouldn't have any pending interrupts when we get > to probe(), if we do have them, then we need an erratum for it. I have u-boot use it to download the kernel and that is probably using the ROM code USB support. > You could try making usb_otg_ss is reset by hwmod. It would also be good > to check other OMAP-ish devices sporting dwc3 (DRA7x, AM437x, AM57x) if > they have the same behavior. It should be reset by default by hwmod. > Adding Nishanth to the loop too for reference. Regards, Tony -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html