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

[Tom Rini]

On Sat, Feb 29, 2020 at 08:20:57AM +0100, Marek Vasut wrote:
> 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 ?

It's a usb ethernet device.

> 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.

I'll pencil in some time to try that, thanks.

-- 
Tom
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