On 23.11.2020 18.37, Tejas Joglekar wrote: > The Synopsys xHC has an internal TRB cache of size TRB_CACHE_SIZE for > each endpoint. The default value for TRB_CACHE_SIZE is 16 for SS and 8 > for HS. The controller loads and updates the TRB cache from the > transfer ring in system memory whenever the driver issues a start > transfer or update transfer command. > > For chained TRBs, the Synopsys xHC requires that the total amount of > bytes for all TRBs loaded in the TRB cache be greater than or equal to > 1 MPS. Or the chain ends within the TRB cache (with a last TRB). > > If this requirement is not met, the controller will not be able to > send or receive a packet and it will hang causing a driver timeout and > error. > > This patch set adds logic to the XHCI driver to detect and prevent this > from happening along with the quirk to enable this logic for Synopsys > HAPS platform. > > Based on Mathias's feedback on previous implementation where consolidation > was done in TRB cache, with this patch series the implementation is done > during mapping of the URB by consolidating the SG list into a temporary > buffer if the SG list buffer sizes within TRB_CACHE_SIZE is less than MPS. > > Changes since v5: > - Update the quirk macro to have next number [Patch 1/3] > - Fixed the issues reported by kernel test robot [Patch 2/3] > > Changes since v4: > - Updated [Patch 3/3] platform data structure initialization > - Trivial changes in commit wordings > > Changes since v3: > - Removed the dt-binding patch > - Added new patch to pass the quirk as platform data > - Modified the patch to set the quirk > > Changes since v2: > - Modified the xhci_unmap_temp_buffer function to unmap dma and c > the dma flag > - Removed RFC tag > > Changes since v1: > - Comments from Greg are addressed on [PATCH 4/4] and [PATCH 1/4] > - Renamed the property and quirk as in other patches based on [PATCH 1/4] > > > > Tejas Joglekar (3): > usb: xhci: Set quirk for XHCI_SG_TRB_CACHE_SIZE_QUIRK > usb: xhci: Use temporary buffer to consolidate SG > usb: dwc3: Pass quirk as platform data > > drivers/usb/dwc3/host.c | 10 +++ > drivers/usb/host/xhci-plat.c | 3 + > drivers/usb/host/xhci-ring.c | 2 +- > drivers/usb/host/xhci.c | 129 ++++++++++++++++++++++++++++++++++- > drivers/usb/host/xhci.h | 5 ++ > 5 files changed, 147 insertions(+), 2 deletions(-) > Dropped last version and picked first two patches from this series. -Mathias
