[U-Boot] [PATCH] eth: remove usb-ethernet devices before re-enumerating them

[Wolfgang Grandegger <wg@denx.de>]

On 01/09/2012 10:08 PM, Vincent Palatin wrote:
> On Mon, Jan 9, 2012 at 12:57, Marek Vasut <marek.vasut@gmail.com> wrote:
>>> Fix the crash when running several times usb_init() with a USB ethernet
>>> device plugged.
>>>
>>> Signed-off-by: Vincent Palatin <vpalatin@chromium.org>
>>> Tested-by: Wolfgang Grandegger <wg@denx.de>
>>> ---
>>>  drivers/usb/eth/usb_ether.c |    7 +++++--
>>>  include/net.h               |    1 +
>>>  net/eth.c                   |   29 +++++++++++++++++++++++++++++
>>>  3 files changed, 35 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/drivers/usb/eth/usb_ether.c b/drivers/usb/eth/usb_ether.c
>>> index 6565ea5..73a0790 100644
>>> --- a/drivers/usb/eth/usb_ether.c
>>> +++ b/drivers/usb/eth/usb_ether.c
>>> @@ -127,8 +127,11 @@ int usb_host_eth_scan(int mode)
>>>
>>>       old_async = usb_disable_asynch(1); /* asynch transfer not allowed */
>>>
>>> -     for (i = 0; i < USB_MAX_ETH_DEV; i++)
>>> -             memset(&usb_eth[i], 0, sizeof(usb_eth[i]));
>>> +     /* unregister a previously detected device */
>>> +     for (i = 0; i < usb_max_eth_dev; i++)
>>> +             eth_unregister(&usb_eth[i].eth_dev);
>>> +
>>> +     memset(usb_eth, 0, sizeof(usb_eth));
>>>
>>>       for (i = 0; prob_dev[i].probe; i++) {
>>>               if (prob_dev[i].before_probe)
>>> diff --git a/include/net.h b/include/net.h
>>> index e4d42c2..1707a7f 100644
>>> --- a/include/net.h
>>> +++ b/include/net.h
>>> @@ -96,6 +96,7 @@ struct eth_device {
>>>
>>>  extern int eth_initialize(bd_t *bis);        /* Initialize network subsystem
>> */
>>>  extern int eth_register(struct eth_device* dev);/* Register network device
>>> */ +extern int eth_unregister(struct eth_device *dev);/* Remove network
>>> device */ extern void eth_try_another(int first_restart);     /* Change the
>>> device */ extern void eth_set_current(void);          /* set nterface to
>> ethcur
>>> var */ extern struct eth_device *eth_get_dev(void);   /* get the current
>>> device MAC */ diff --git a/net/eth.c b/net/eth.c
>>> index b4b9b43..3fb5fb6 100644
>>> --- a/net/eth.c
>>> +++ b/net/eth.c
>>> @@ -224,6 +224,35 @@ int eth_register(struct eth_device *dev)
>>>       return 0;
>>>  }
>>>
>>> +int eth_unregister(struct eth_device *dev)
>>> +{
>>> +     struct eth_device *cur;
>>> +
>>> +     /* No device */
>>> +     if (!eth_devices)
>>> +             return -1;
>>> +
>>> +     for (cur = eth_devices; cur->next != eth_devices && cur->next != dev;
>>> +          cur = cur->next)
>>> +             ;
>>> +
>>> +     /* Device not found */
>>> +     if (cur->next != dev)
>>> +             return -1;
>>> +
>>> +     cur->next = dev->next;
>>> +
>>> +     if (eth_devices == dev)
>>> +             eth_devices = dev->next == eth_devices ? NULL : dev->next;
>>> +
>>> +     if (eth_current == dev) {
>>> +             eth_current = eth_devices;
>>> +             eth_current_changed();
>>> +     }
>>> +
>>> +     return 0;
>>> +}
>>> +
>>>  int eth_initialize(bd_t *bis)
>>>  {
>>>       int num_devices = 0;
>>
>> Looks sane. On what hardware did this happen (just for the record)?
> 
> I got it on x86 and ARM (tegra2) platforms (both with an EHCI controller).
> I did most of my testing with ASIX-based USB-ethernet dongle, but the
> issue seems pretty generic.

It happens with *any* hardware calling eth_register() more than once
because "struct eth_device *dev*" is memset 0 before calling
eth_register() resulting in an endless loop when scanning the devices.

Viele Gr??e,

Wolfgang