Re: [PATCH 1/2] ARM: mvebu: correct the usb node name from usb@ to ehci@

On Tue, Mar 29, 2016 at 4:37 PM, Gregory CLEMENT
[off-list ref] wrote:

Hi Arnd,

 On mar., mars 29 2016, Arnd Bergmann [off-list ref] wrote:

quoted

On Tuesday 29 March 2016 13:56:52 Patrick Uiterwijk wrote:

quoted

According to Documentation/devicetree/bindings/usb/ehci-orion.txt,
the Orion Marvell variant of EHCI controllers should have names
ehci@50000 for example.

Signed-off-by: Patrick Uiterwijk <redacted>

I think it's better to follow the generic USB binding that suggests
the name of 'usb', unless we understand what the specific bug is
you run into. Do you think it is the boot loader that messes
up the hardware, or something in the kernel that goes wrong? Did
it work on earlier kernels?

I am pretty sure that this issue is caused by the Marvell U-Boot which
tries to modify the dts on the fly. But the device tree reference of
this U-boot is not the one we use in mainline, so at end it mess up the
dtb!

There is an option to ask Marvell bootloader to not modify the dts, I
think it is something like ftd_skip.

Thank you for this pointer, setting fdt_skip_update no did fix this
issue indeed.
That only leaves my second patch as needed, so I'll submit just that separately.

Patrick

Gregory

quoted

We had a regression based on the USB device probing, but that
should be fixed now with the patch below. Do you have that?

      Arnd


commit 7222c832254a75dcd67d683df75753d4a4e125bb
Author: Nicolai Stange [off-list ref]
Date:   Thu Mar 17 23:53:02 2016 +0100

    usb/core: usb_alloc_dev(): fix setting of ->portnum

    With commit 69bec7259853 ("USB: core: let USB device know device node"),
    the port1 argument of usb_alloc_dev() gets overwritten as follows:

      ... usb_alloc_dev(..., unsigned port1)
      {
        ...
        if (!parent->parent) {
          port1 = usb_hcd_find_raw_port_number(..., port1);
        }
        ...
      }

    Later on, this now overwritten port1 gets assigned to ->portnum:

      dev->portnum = port1;

    However, since xhci_find_raw_port_number() isn't idempotent, the
    aforementioned commit causes a number of KASAN splats like the following:

      BUG: KASAN: slab-out-of-bounds in xhci_find_raw_port_number+0x98/0x170
                                           at addr ffff8801d9311670
      Read of size 8 by task kworker/2:1/87
      [...]
      Workqueue: usb_hub_wq hub_event
       0000000000000188 000000005814b877 ffff8800cba17588 ffffffff8191447e
       0000000041b58ab3 ffffffff82a03209 ffffffff819143a2 ffffffff82a252f4
       ffff8801d93115e0 0000000000000188 ffff8801d9311628 ffff8800cba17588
      Call Trace:
       [<ffffffff8191447e>] dump_stack+0xdc/0x15e
       [<ffffffff819143a2>] ? _atomic_dec_and_lock+0xa2/0xa2
       [<ffffffff814e2cd1>] ? print_section+0x61/0xb0
       [<ffffffff814e4939>] print_trailer+0x179/0x2c0
       [<ffffffff814f0d84>] object_err+0x34/0x40
       [<ffffffff814f4388>] kasan_report_error+0x2f8/0x8b0
       [<ffffffff814eb91e>] ? __slab_alloc+0x5e/0x90
       [<ffffffff812178c0>] ? __lock_is_held+0x90/0x130
       [<ffffffff814f5091>] kasan_report+0x71/0xa0
       [<ffffffff814ec082>] ? kmem_cache_alloc_trace+0x212/0x560
       [<ffffffff81d99468>] ? xhci_find_raw_port_number+0x98/0x170
       [<ffffffff814f33d4>] __asan_load8+0x64/0x70
       [<ffffffff81d99468>] xhci_find_raw_port_number+0x98/0x170
       [<ffffffff81db0105>] xhci_setup_addressable_virt_dev+0x235/0xa10
       [<ffffffff81d9ea51>] xhci_setup_device+0x3c1/0x1430
       [<ffffffff8121cddd>] ? trace_hardirqs_on+0xd/0x10
       [<ffffffff81d9fac0>] ? xhci_setup_device+0x1430/0x1430
       [<ffffffff81d9fad3>] xhci_address_device+0x13/0x20
       [<ffffffff81d2081a>] hub_port_init+0x55a/0x1550
       [<ffffffff81d28705>] hub_event+0xef5/0x24d0
       [<ffffffff81d27810>] ? hub_port_debounce+0x2f0/0x2f0
       [<ffffffff8195e1ee>] ? debug_object_deactivate+0x1be/0x270
       [<ffffffff81210203>] ? print_rt_rq+0x53/0x2d0
       [<ffffffff8121657d>] ? trace_hardirqs_off+0xd/0x10
       [<ffffffff8226acfb>] ? _raw_spin_unlock_irqrestore+0x5b/0x60
       [<ffffffff81250000>] ? irq_domain_set_hwirq_and_chip+0x30/0xb0
       [<ffffffff81256339>] ? debug_lockdep_rcu_enabled+0x39/0x40
       [<ffffffff812178c0>] ? __lock_is_held+0x90/0x130
       [<ffffffff81196877>] process_one_work+0x567/0xec0
      [...]

    Afterwards, xhci reports some functional errors:

      xhci_hcd 0000:00:14.0: ERROR: unexpected setup address command completion
                                    code 0x11.
      xhci_hcd 0000:00:14.0: ERROR: unexpected setup address command completion
                                    code 0x11.
      usb 4-3: device not accepting address 2, error -22

    Fix this by not overwriting the port1 argument in usb_alloc_dev(), but
    storing the raw port number as required by OF in an additional variable,
    raw_port.

    Fixes: 69bec7259853 ("USB: core: let USB device know device node")
    Signed-off-by: Nicolai Stange [off-list ref]
    Acked-by: Alan Stern [off-list ref]
    Signed-off-by: Greg Kroah-Hartman [off-list ref]

diff --git a/drivers/usb/core/usb.c b/drivers/usb/core/usb.c
index ffa5cf13ffe1..dcb85e3cd5a7 100644
--- a/drivers/usb/core/usb.c
+++ b/drivers/usb/core/usb.c

@@ -424,6 +424,7 @@ struct usb_device *usb_alloc_dev(struct usb_device *parent,
      struct usb_device *dev;
      struct usb_hcd *usb_hcd = bus_to_hcd(bus);
      unsigned root_hub = 0;
+     unsigned raw_port = port1;

      dev = kzalloc(sizeof(*dev), GFP_KERNEL);
      if (!dev)

@@ -498,11 +499,11 @@ struct usb_device *usb_alloc_dev(struct usb_device *parent,

              if (!parent->parent) {
                      /* device under root hub's port */
-                     port1 = usb_hcd_find_raw_port_number(usb_hcd,
+                     raw_port = usb_hcd_find_raw_port_number(usb_hcd,
                              port1);
              }
              dev->dev.of_node = usb_of_get_child_node(parent->dev.of_node,
-                             port1);
+                             raw_port);

              /* hub driver sets up TT records */
      }

--
Gregory Clement, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com

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