Re: [BUG] rk3399-rockpro64 pcie synchronous external abort

[Peter Geis <pgwipeout@gmail.com>]

On Mon, Nov 11, 2019 at 9:29 PM Bjorn Helgaas <helgaas@kernel.org> wrote:
>
> On Mon, Nov 11, 2019 at 07:30:15PM -0500, Peter Geis wrote:
> > On Mon, Nov 11, 2019 at 7:13 PM Bjorn Helgaas <helgaas@kernel.org> wrote:
> > > On Mon, Nov 04, 2019 at 01:55:40PM -0500, Peter Geis wrote:
> > > > Good Morning,
> > > >
> > > > I'm attempting to debug an issue with the rockpro64 pcie port.
> > > > It would appear that the port does not like various cards, including
> > > > cards of the same make that randomly work or do not work, such as
> > > > Intel i340 based NICs.
> > > > I'm experiencing it with a GTX645 gpu.
> > > >
> > > > This seems to be a long running issue, referenced both at [0], and [1].
> > > > There was an attempt to rectify it, by adding a delay between training
> > > > and probing [2], but that doesn't seem to be the issue here.
> > > > It appears that when we probe further into the card, such as devfn >
> > > > 1, we trigger the bug.
> > > > I've added a print statement that prints the devfn, address, and size
> > > > information, which you can see below.
> > > >
> > > > I've attempted setting the available number of lanes to 1 as well, to
> > > > no difference.
> > > >
> > > > If anyone could point me in the right direction as to where to
> > > > continue debugging, I'd greatly appreciate it.
> > > >
> > > > [0] https://github.com/ayufan-rock64/linux-build/issues/254
> > > > [1] https://github.com/rockchip-linux/kernel/issues/116
> > > > [2] https://github.com/ayufan-rock64/linux-kernel/commit/3cde5c624c9c39aa03251a55c2d26a48b5bdca5b
> > > >
> > > > [  198.491458] rockchip-pcie f8000000.pcie: missing legacy phy; search
> > > > for per-lane PHY
> > > > [  198.492986] rockchip-pcie f8000000.pcie: no vpcie1v8 regulator found
> > > > [  198.493060] rockchip-pcie f8000000.pcie: no vpcie0v9 regulator found
> > > > [  198.550444] rockchip-pcie f8000000.pcie: current link width is x1
> > > > [  198.550458] rockchip-pcie f8000000.pcie: idling lane 1
> > > > [  198.550479] rockchip-pcie f8000000.pcie: idling lane 2
> > > > [  198.550490] rockchip-pcie f8000000.pcie: idling lane 3
> > > > [  198.550608] rockchip-pcie f8000000.pcie: host bridge /pcie@f8000000 ranges:
> > > > [  198.550625] rockchip-pcie f8000000.pcie: Parsing ranges property...
> > > > [  198.550656] rockchip-pcie f8000000.pcie:   MEM
> > > > 0xfa000000..0xfbdfffff -> 0xfa000000
> > > > [  198.550676] rockchip-pcie f8000000.pcie:    IO
> > > > 0xfbe00000..0xfbefffff -> 0xfbe00000
> > > > [  198.552908] rockchip-pcie f8000000.pcie: PCI host bridge to bus 0000:00
> > > > [  198.552933] pci_bus 0000:00: root bus resource [bus 00-1f]
> > > > [  198.552943] pci_bus 0000:00: root bus resource [mem 0xfa000000-0xfbdfffff]
> > > > [  198.552954] pci_bus 0000:00: root bus resource [io  0x0000-0xfffff]
> > > > (bus address [0xfbe00000-0xfbefffff])
> > > > [  198.552965] pci_bus 0000:00: scanning bus
> > > > [  198.554198] pci 0000:00:00.0: [1d87:0100] type 01 class 0x060400
> > > > [  198.555508] pci 0000:00:00.0: supports D1
> > > > [  198.555516] pci 0000:00:00.0: PME# supported from D0 D1 D3hot
> > > > [  198.556023] pci 0000:00:00.0: PME# disabled
> > > > [  198.561245] pci_bus 0000:00: fixups for bus
> > > > [  198.561269] pci 0000:00:00.0: scanning [bus 00-00] behind bridge, pass 0
> > > > [  198.561277] pci 0000:00:00.0: bridge configuration invalid ([bus
> > > > 00-00]), reconfiguring
> > > > [  198.566429] pci 0000:00:00.0: scanning [bus 00-00] behind bridge, pass 1
> > > > [  198.567008] pci_bus 0000:01: scanning bus
> > > > [  198.567171] pci 0000:01:00.0: [10de:11c4] type 00 class 0x030000
> > > > [  198.567420] pci 0000:01:00.0: reg 0x10: [mem 0x00000000-0x00ffffff]
> > > > [  198.567515] pci 0000:01:00.0: reg 0x14: [mem 0x00000000-0x07ffffff
> > > > 64bit pref]
> > > > [  198.567608] pci 0000:01:00.0: reg 0x1c: [mem 0x00000000-0x01ffffff
> > > > 64bit pref]
> > > > [  198.567665] pci 0000:01:00.0: reg 0x24: initial BAR value 0x00000000 invalid
> > > > [  198.567673] pci 0000:01:00.0: reg 0x24: [io  size 0x0080]
> > > > [  198.567730] pci 0000:01:00.0: reg 0x30: [mem 0x00000000-0x0007ffff pref]
> > > > [  198.567815] pci 0000:01:00.0: Max Payload Size set to 256 (was 128, max 256)
> > > > [  198.569051] pci 0000:01:00.0: 2.000 Gb/s available PCIe bandwidth,
> > > > limited by 2.5 GT/s x1 link at 0000:00:00.0 (capable of 126.016 Gb/s
> > > > with 8 GT/s x16 link)
> > > > [  198.570225] pci 0000:01:00.0: vgaarb: VGA device added:
> > > > decodes=io+mem,owns=none,locks=none
> > > > [  198.570481] pci 0000:01:00.1: [10de:0e0b] type 00 class 0x040300
> > > > [  198.570663] pci 0000:01:00.1: reg 0x10: [mem 0x00000000-0x00003fff]
> > > > [  198.571039] pci 0000:01:00.1: Max Payload Size set to 256 (was 128, max 256)
> > > > <snip>
> > > > [  198.749857] pci_bus 0000:01: read pcie, devfn 1, at 100, size 2
> > > > [  198.750252] pci_bus 0000:01: read pcie, devfn 2, at 0, size 4
> > > > [  198.750881] Internal error: synchronous external abort: 96000210
> > > > [#1] PREEMPT SMP
> > >
> > > Is there really supposed to be a device at 01:00.2?
> > >
> > > Maybe this is just the PCIe Unsupported Request error that we expect
> > > to get when trying to read config space of a device that doesn't
> > > exist.
> > >
> > > On "most" platforms, we just get ~0 data back when that happens, but
> > > I'm not sure that's always the case on arm64.  I think it depends on
> > > how the PCIe host bridge is designed, and there might be some CPU
> > > configuration, too.
> >
> > Yes, this is a GTX645 video card.
> > Nvidia cards usually have two to three devices,
> > The GPU proper, the audio device for the hdmi output, and the i2c controller.
> >
> > I do think that this driver is missing sanity checking on the
> > addressing, since the BRCM driver for the RPI4 doesn't try to
> > enumerate a video card, since it checks if the MMIO space is large
> > enough to fit the BAR before assigning the addresses. See [3]. Also in
> > that thread he was able to increase the address space provided to the
> > BRCM driver and fix the issue, but I don't see how we could do that on
> > the rk3399.
> >
> > pci 0000:01:00.0: reg 0x14: [mem 0x00000000-0x07ffffff 64bit pref] is
> > 128 MB, which already exceeds our address space.
> > I think the driver is just overflowing the address space.
>
> If we don't have enough space to assign all the device BARs, I think a
> driver will still be able to claim the device, but when the driver
> calls pci_enable_device(), it should fail.  Lack of address space
> should not cause a PCIe error.
>
> But in this case, none of that matters because we're still enumerating
> devices in pci_scan_root_bus_bridge().  We haven't gotten to the point
> of trying to bind drivers to devices, so the driver isn't involved at
> all yet.
For clarification, the driver I'm referring to is the rk3399-pcie host driver.
>
> The backtrace says we're trying to read the Vendor ID of a device, and
> your debug output suggests we're trying to enumerate 01:00.2.  If you
> put that card in another system, you could find out how many functions
> it has.
>
> Or if you swapped this with other cards where you know the number of
> functions, you could see if the external abort always happens when
> probing for the first unimplemented function.
This card definitely has more than one function.
Before my original message I hacked in some code to make the driver
return 0xff when devfn > 1, and the scan passed, but as soon as
nouveau attempted to access the device, the entire kernel exploded.

Another reason I believe the address assignments are overflowing and
corrupting other address assignments is after the external abort, the
entire PCIE controller is inaccessible.
$ lspci
pcilib: Cannot open /sys/bus/pci/devices/0000:01:00.1/config
lspci: Unable to read the standard configuration space header of
device 0000:01:00.1
pcilib: Cannot open /sys/bus/pci/devices/0000:00:00.0/config
lspci: Unable to read the standard configuration space header of
device 0000:00:00.0
pcilib: Cannot open /sys/bus/pci/devices/0000:01:00.0/config
lspci: Unable to read the standard configuration space header of
device 0000:01:00.0

Attempting to rescan the bus or any other pci function results in a
hung kernel task.
>
> If the Root Port (00:00.0) supports AER, you could also dump out the
> status registers from the AER capability and figure out whether it
> logged a PCIe error.  This would be sort of like what
> aer_process_err_devices() does.  A bit of a hassle to do this by hand
> in the exception path, but could be enlightening, just as a debug
> tool.

Is there a way to handle external synchronous aborts in a device driver?
If so, I'll definitely look into plugging in the aer status functions.

>
> > [3] https://twitter.com/domipheus/status/1167586160077627393
> > >
> > > > [  198.751581] Modules linked in: drm_panel_orientation_quirks
> > > > pcie_rockchip_host(+) cpufreq_dt sch_fq_codel ip_tables x_tables ipv6
> > > > crc_ccitt nf_defrag_ipv6
> > > > [  198.752861] CPU: 1 PID: 1686 Comm: systemd-udevd Not tainted
> > > > 5.4.0-rc5-next-20191031-00001-gddbfb17ac1c4-dirty #5
> > > > [  198.753791] Hardware name: Pine64 RockPro64 (DT)
> > > > [  198.754215] pstate: 60400085 (nZCv daIf +PAN -UAO)
> > > > [  198.754672] pc : __raw_readl+0x0/0x8 [pcie_rockchip_host]
> > > > [  198.755172] lr : rockchip_pcie_rd_conf+0x140/0x1dc [pcie_rockchip_host]
> > > > [  198.755773] sp : ffff8000132af530
> > > > [  198.756079] x29: ffff8000132af530 x28: 0000000000000000
> > > > [  198.756565] x27: 0000000000000001 x26: 0000000000000000
> > > > [  198.757049] x25: ffff0000c20ac000 x24: 0000000000002000
> > > > [  198.757534] x23: ffff0000c20ae5c0 x22: ffff8000132af5d4
> > > > [  198.758018] x21: 0000000000002000 x20: 0000000000000004
> > > > [  198.758502] x19: 0000000000102000 x18: 0000000000000001
> > > > [  198.758987] x17: 0000000000000000 x16: 0000000000000000
> > > > [  198.759472] x15: ffffffffffffffff x14: ffff80001159bcc8
> > > > [  198.759957] x13: 0000000000000000 x12: ffff800011b2c000
> > > > [  198.760441] x11: ffff8000115bf000 x10: ffff800011310018
> > > > [  198.760926] x9 : 00000000fffb9fff x8 : 0000000000000001
> > > > [  198.761410] x7 : 0000000000000000 x6 : ffff0000f7492548
> > > > [  198.761894] x5 : 0000000000000001 x4 : ffff0000f7492548
> > > > [  198.762379] x3 : 0000000000000000 x2 : 0000000000c00008
> > > > [  198.762863] x1 : ffff80001dc00008 x0 : ffff80001a102000
> > > > [  198.763348] Call trace:
> > > > [  198.763583]  __raw_readl+0x0/0x8 [pcie_rockchip_host]
> > > > [  198.764057]  pci_bus_read_config_dword+0x88/0xd0
> > > > [  198.764484]  pci_bus_generic_read_dev_vendor_id+0x40/0x1b8
> > > > [  198.764982]  pci_bus_read_dev_vendor_id+0x58/0x88
> > > > [  198.765413]  pci_scan_single_device+0x84/0xf8
> > > > [  198.765812]  pci_scan_slot+0x7c/0x120
> > > > [  198.766149]  pci_scan_child_bus_extend+0x68/0x2dc
> > > > [  198.766579]  pci_scan_bridge_extend+0x350/0x588
> > > > [  198.766992]  pci_scan_child_bus_extend+0x21c/0x2dc
> > > > [  198.767430]  pci_scan_child_bus+0x24/0x30
> > > > [  198.767797]  pci_scan_root_bus_bridge+0xc4/0xd0
> > > > [  198.768215]  rockchip_pcie_probe+0x610/0x74c [pcie_rockchip_host]
> > > > [  198.768770]  platform_drv_probe+0x58/0xa8
> > > > [  198.769139]  really_probe+0xe0/0x318
> > > > [  198.769468]  driver_probe_device+0x5c/0xf0
> > > > [  198.769844]  device_driver_attach+0x74/0x80
> > > > [  198.770227]  __driver_attach+0x64/0xe8
> > > > [  198.770572]  bus_for_each_dev+0x84/0xd8
> > > > [  198.770924]  driver_attach+0x30/0x40
> > > > [  198.771253]  bus_add_driver+0x188/0x1e8
> > > > [  198.771605]  driver_register+0x64/0x110
> > > > [  198.771956]  __platform_driver_register+0x54/0x60
> > > > [  198.772388]  rockchip_pcie_driver_init+0x28/0x10000 [pcie_rockchip_host]
> > > > [  198.772998]  do_one_initcall+0x94/0x390
> > > > [  198.773353]  do_init_module+0x88/0x268
> > > > [  198.773697]  load_module+0x1e18/0x2198
> > > > [  198.774043]  __do_sys_finit_module+0xd0/0xe8
> > > > [  198.774435]  __arm64_sys_finit_module+0x28/0x38
> > > > [  198.774858]  el0_svc_common.constprop.3+0xa4/0x1d8
> > > > [  198.775297]  el0_svc_handler+0x34/0xa0
> > > > [  198.775645]  el0_svc+0x14/0x40
> > > > [  198.775928]  el0_sync_handler+0x118/0x290
> > > > [  198.776295]  el0_sync+0x164/0x180
> > > > [  198.776609] Code: bad PC value
> > > > [  198.776897] ---[ end trace 88fc77651b5e2909 ]---