+Tom for question below Hi,
On 20 July 2017 at 03:40, Marek Vasut <[email protected]> wrote: > On 07/20/2017 11:38 AM, Bin Meng wrote: >> +Simon, >> >> On Thu, Jul 20, 2017 at 5:00 PM, Marek Vasut <[email protected]> wrote: >>> On 07/20/2017 09:49 AM, Masahiro Yamada wrote: >>>> 2017-07-20 2:33 GMT+09:00 Marek Vasut <[email protected]>: >>>>> On 07/19/2017 05:38 PM, Masahiro Yamada wrote: >>>>>> 2017-07-15 21:57 GMT+09:00 Marek Vasut <[email protected]>: >>>>>>> On 07/15/2017 01:30 AM, Benoît Thébaudeau wrote: >>>>>>>> On Sat, Jul 15, 2017 at 12:06 AM, Marek Vasut <[email protected]> wrote: >>>>>>>>> On 07/14/2017 11:46 PM, Benoît Thébaudeau wrote: >>>>>>>>>> On Fri, Jul 14, 2017 at 1:50 PM, Marek Vasut <[email protected]> wrote: >>>>>>>>>>> On 07/14/2017 01:03 PM, Masahiro Yamada wrote: >>>>>>>>>>>> 2017-07-14 19:07 GMT+09:00 Marek Vasut <[email protected]>: >>>>>>>>>>>>> On 07/14/2017 04:31 AM, Masahiro Yamada wrote: >>>>>>>>>>>>>> Prior to DM, we could not enable different types of USB >>>>>>>>>>>>>> controllers >>>>>>>>>>>>>> at the same time. DM was supposed to loosen the limitation. It >>>>>>>>>>>>>> is >>>>>>>>>>>>>> true that we can compile drivers, but they do not work. >>>>>>>>>>>>>> >>>>>>>>>>>>>> For example, if EHCI is enabled, xHCI fails as follows: >>>>>>>>>>>>>> >>>>>>>>>>>>>> => usb read 82000000 0 2000 >>>>>>>>>>>>>> >>>>>>>>>>>>>> USB read: device 0 block # 0, count 8192 ... WARN halted >>>>>>>>>>>>>> endpoint, queueing URB anyway. >>>>>>>>>>>>>> Unexpected XHCI event TRB, skipping... (3fb54010 00000001 >>>>>>>>>>>>>> 13000000 01008401) >>>>>>>>>>>>>> BUG: failure at drivers/usb/host/xhci-ring.c:489/abort_td()! >>>>>>>>>>>>>> BUG! >>>>>>>>>>>>>> ### ERROR ### Please RESET the board ### >>>>>>>>>>>>>> >>>>>>>>>>>>>> The cause of the error seems the following code: >>>>>>>>>>>>>> >>>>>>>>>>>>>> #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. >>>>>>>>>>>>>> */ >>>>>>>>>>>>>> #define USB_MAX_XFER_BLK 65535 >>>>>>>>>>>>>> #else >>>>>>>>>>>>>> #define USB_MAX_XFER_BLK 20 >>>>>>>>>>>>>> #endif >>>>>>>>>>>>>> >>>>>>>>>>>>>> To fix the problem, choose the chunk size at run-time for >>>>>>>>>>>>>> CONFIG_BLK. >>>>>>>>>>>>> >>>>>>>>>>>>> What happens if CONFIG_BLK is not set ? >>>>>>>>>>>> >>>>>>>>>>>> USB_MAX_XFER_BLK is chosen. >>>>>>>>>>> >>>>>>>>>>> And can we fix that even for non-CONFIG_BLK ? >>>>>>>>>>> >>>>>>>>>>>>> Why is it 20 for XHCI anyway ? >>>>>>>>>>>> >>>>>>>>>>>> You are the maintainer. >>>>>>>>>>>> (I hope) you have better knowledge with this. >>>>>>>>>>> >>>>>>>>>>> Heh, way to deflect the question. I seem to remember some discussion >>>>>>>>>>> about the DMA (?) limitation on XHCI, but I'd have to dig through >>>>>>>>>>> the ML >>>>>>>>>>> archives myself. >>>>>>>>>>> >>>>>>>>>>>> Looks like the following commit was picked up by you. >>>>>>>>>>> >>>>>>>>>>> 5 years ago, way before DM was what it is today . >>>>>>>>>> >>>>>>>>>> And even way before the introduction of XHCI into U-Boot, which means >>>>>>>>>> that this 20 was targeting OHCI or proprietary HCDs, not XHCI. >>>>>>>>>> USB_MAX_READ_BLK was already set to 20 in the initial revision of >>>>>>>>>> usb_storage.c. As I said in the commit message, this 20 was certainly >>>>>>>>>> not optimal for these non-EHCI HCDs, but it restored the previous >>>>>>>>>> (i.e. pre-5dd95cf) behavior for these HCDs instead of using the 5 * 4 >>>>>>>>>> KiB code, which was specific to ehci-hcd.c at that time. Without >>>>>>>>>> knowing the rationale for the legacy 20 blocks, the safest approach >>>>>>>>>> for non-EHCI HCDs was to use this value in order to avoid breaking a >>>>>>>>>> platform or something. Looking at ohci-hcd.c, it limits the transfer >>>>>>>>>> size to (N_URB_TD - 2) * 4 KiB, with N_URB_TD set to 48, so the >>>>>>>>>> maximum number of transfers would depend on the MSC block size. >>>>>>>>>> dwc2.c, isp116x-hcd.c, r8a66597-hcd.c, and sl811-hcd.c do not seem to >>>>>>>>>> have any limit caused by these drivers. The limit with the current >>>>>>>>>> XHCI code seems to be 64 * 64 KiB. So, nowadays, USB_MAX_XFER_BLK >>>>>>>>>> could be set to 65535 for all HCDs but OHCI and XHCI, which require >>>>>>>>>> specific rules depending on the MSC block size. >>>>>>>>> >>>>>>>>> For whatever reason, something tells me that setting the block size to >>>>>>>>> 64k for XHCI broke things, but I cannot locate the thread. But there's >>>>>>>>> something in the back of my head ... >>>>>>>> >>>>>>>> Indeed: according to what I said above, USB_MAX_XFER_BLK cannot be set >>>>>>>> to 65535 for XHCI. With an MSC block size of blksz = 512 bytes / >>>>>>>> block, USB_MAX_XFER_BLK can be set to at most 1 segment * >>>>>>>> (TRBS_PER_SEGMENT = 64 TRBs / segment) * (TRB_MAX_BUFF_SIZE = 65536 >>>>>>>> bytes / TRB) / blksz = 8192 blocks for XHCI. And for OHCI, the limit >>>>>>>> is (N_URB_TD - 2 = 46 TDs) * (4096 bytes / TD) / blksz = 368 blocks. >>>>>>>> The buffer alignment may also have to be taken into account to adjust >>>>>>>> these values, which would require a USB_MAX_XFER_BLK(host_if, start, >>>>>>>> blksz) macro or function. USB_MAX_XFER_BLK can however be set to 65535 >>>>>>>> regardless of blksz for all the other HCDs (i.e. EHCI, dwc2.c, >>>>>>>> isp116x-hcd.c, r8a66597-hcd.c, and sl811-hcd.c). >>>>>>> >>>>>>> That's probably what I was looking for, thanks. >>>>>>> >>>>>> >>>>>> >>>>>> So, how shall we handle this? >>>>>> >>>>>> If somebody can fix this in a correct way, >>>>>> I am happy to hand over this. >>>>> >>>>> Any way to fix it for !CONFIG_BLK ? >>>> >>>> >>>> common/usb_storage.c is sprinkled with ugly #ifdef CONFIG_BLK >>>> >>>> IIUC, !CONFIG_BLK code will be removed after migration. >>>> >>>> Is it worthwhile to save !CONFIG_BLK case? >>> >>> Hmmmmmm, sigh. When is the migration happening, how far is it ? >> >> One idea is to force all board to switch to driver model at a preset >> timeline. After the deadline, boards do not switch to DM will get >> dropped by the mainline. I noticed that not all boards are actively >> maintained... > > Be my guest, there's a few which I'd like to see removed myself :-) That makes sense although I'm not sure what the deadline should be. CONFIG_BLK is invasive and it is a pain to carry the #ifdefs. Maybe end of year, or is that too short? > > -- > Best regards, > Marek Vasut _______________________________________________ U-Boot mailing list [email protected] https://lists.denx.de/listinfo/u-boot
