[PATCH] usb: ehci: Fix "EHCI timed out on TD - token=XXXX" error on ehci-hcd

[Marek Vasut]

On 2/29/20 4:20 AM, Tom Rini wrote:
> On Sat, Feb 29, 2020 at 12:32:57AM +0100, Marek Vasut wrote:
>> On 2/26/20 12:29 PM, Lukasz Majewski wrote:
>>> This patch aims to improve robustness of 'usb' command operation on the
>>> ehci-hcd IP block as it ports to contemporary U-Boot the patch described
>>> and provided in [1] (originally applicable to U-Boot 2016.05).
>>>
>>> According to the fix author - "rayvt" (from [1]):
>>
>> [...]
>>
>>> diff --git a/common/usb_storage.c b/common/usb_storage.c
>>> index 097b6729c1..48c8c2ae64 100644
>>> --- a/common/usb_storage.c
>>> +++ b/common/usb_storage.c
>>> @@ -111,6 +111,18 @@ int usb_stor_get_info(struct usb_device *dev, struct us_data *us,
>>>  		      struct blk_desc *dev_desc);
>>>  int usb_storage_probe(struct usb_device *dev, unsigned int ifnum,
>>>  		      struct us_data *ss);
>>> +
>>> +#ifdef CONFIG_USB_EHCI_HCD
>>> +	/*
>>> +	 * The U-Boot EHCI driver can handle any transfer length as long as
>>> +	 * there is enough free heap space left, but the SCSI READ(10) and
>>> +	 * WRITE(10) commands are limited to 65535 blocks.
>>> +	 */
>>> +int usb_max_xfer_blk = 4096;
>>> +#else
>>> +int usb_max_xfer_blk = 20;
>>> +#endif
>>
>> This all looks horribly wrong and exactly what
>> 7d6fd7f0ba71cd93d94079132f958d9630f27a89 and
>> 02b0e1a36c5bc20174299312556ec4e266872bd6 fixed properly.
>>
>> All those "dynamic reduction of transfer size" attempts are nonsensical,
>> the real solution (sadly) is to reduce the transfer size to cater for
>> the most limited devices and profile/fix the remaining delays in the USB
>> stack (which should have already been done, see the commits above). This
>> is also what the Linux USB stack does.
>>
>> What is the problem you are trying to solve here ?
> 
> Things like the following (omap3_beagle_defconfig):
> U-Boot SPL 2020.04-rc3-00009-g9e1d65f36b83 (Feb 28 2020 - 19:08:53 -0500)
> Trying to boot from MMC1

[...]

> EHCI timed out on TD - token=0x80008c80
> EHCI timed out on TD - token=0x80008c80
> EHCI timed out on TD - token=0x80008d80
> 3 USB Device(s) found
>        scanning usb for ethernet devices... 0 Ethernet Device(s) found
> Hit any key to stop autoboot:  2  0 
> BeagleBoard # usb tree
> USB device tree:
>   1  Hub (480 Mb/s, 0mA)
>   |  u-boot EHCI Host Controller 
>   |
>   |+-2  Hub (480 Mb/s, 2mA)
>     |
>     |+-3  See Interface (480 Mb/s, 0mA)
>          ??????????? ??????????? ???????????
>        
> BeagleBoard # 
> 
> Note that the hub and ethernet are on-SBC and not something I'm plugging
> in.  Thanks!

The device #3 is a usb mass storage or what is it ?

Can you try and implement usb_get_max_xfer_size for musb and make it
report 240*512 unconditionally (*size = 240*512; return 0;) ? I think
that would "fix" it for you on omap too.