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

[gregory.clement@free-electrons.com (Gregory CLEMENT)]

Hi Arnd,
 
 On mar., mars 29 2016, Arnd Bergmann <arnd@arndb.de> wrote:

> On Tuesday 29 March 2016 13:56:52 Patrick Uiterwijk wrote:
>> According to Documentation/devicetree/bindings/usb/ehci-orion.txt,
>> the Orion Marvell variant of EHCI controllers should have names
>> ehci at 50000 for example.
>> 
>> Signed-off-by: Patrick Uiterwijk <patrick@puiterwijk.org>
>> 
>
> 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.

Gregory

> 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 <nicstange@gmail.com>
> 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 <nicstange@gmail.com>
>     Acked-by: Alan Stern <stern@rowland.harvard.edu>
>     Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
>
> 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