On Fri, Jul 12, 2019 at 02:42:05PM +0800, Ran Wang wrote: > Some Layerscape paltforms (such as LS1088A, LS2088A, etc) encounter USB > detect failues when adding dma-coherent to DWC3 node. This is because the > HW default cache type configuration of those SoC are not right, need to > be updated in DTS. > > Signed-off-by: Ran Wang <ran.wang_1@xxxxxxx> > --- > Change in v2: > - New file. > > Documentation/devicetree/bindings/usb/dwc3.txt | 43 ++++++++++++++++++++++++++ > 1 file changed, 43 insertions(+) > > diff --git a/Documentation/devicetree/bindings/usb/dwc3.txt b/Documentation/devicetree/bindings/usb/dwc3.txt > index 8e5265e..7bc1cef 100644 > --- a/Documentation/devicetree/bindings/usb/dwc3.txt > +++ b/Documentation/devicetree/bindings/usb/dwc3.txt > @@ -110,6 +110,43 @@ Optional properties: > - in addition all properties from usb-xhci.txt from the current directory are > supported as well > > +* Cache type nodes (optional) > + > +The Cache type node is used to tell how to configure cache type on 4 different > +transfer types: Data Read, Desc Read, Data Write and Desc write. For each > +treasfer type, controller has a 4-bit register field to enable different cache > +type. Quoted from DWC3 data book Table 6-5 Cache Type Bit Assignments: > +---------------------------------------------------------------- > +MBUS_TYPE| bit[3] |bit[2] |bit[1] |bit[0] > +---------------------------------------------------------------- > +AHB |Cacheable |Bufferable |Privilegge |Data > +AXI3 |Write Allocate|Read Allocate|Cacheable |Bufferable > +AXI4 |Allocate Other|Allocate |Modifiable |Bufferable > +AXI4 |Other Allocate|Allocate |Modifiable |Bufferable > +Native |Same as AXI |Same as AXI |Same as AXI|Same as AXI > +---------------------------------------------------------------- > +Note: The AHB, AXI3, AXI4, and PCIe busses use different names for certain > +signals, which have the same meaning: > + Bufferable = Posted > + Cacheable = Modifiable = Snoop (negation of No Snoop) This should all be implied from the SoC specific compatible strings. Rob
