On 20-06-26 07:19:56, Pawel Laszczak wrote: > Hi Felipe, > > > > >Hi, > > > >Pawel Laszczak <pawell@xxxxxxxxxxx> writes: > >> This patch introduce new Cadence USBSS DRD driver to linux kernel. > >> > >> The Cadence USBSS DRD Controller is a highly configurable IP Core which > >> can be instantiated as Dual-Role Device (DRD), Peripheral Only and > >> Host Only (XHCI)configurations. > >> > >> The current driver has been validated with FPGA burned. We have support > >> for PCIe bus, which is used on FPGA prototyping. > >> > >> The host side of USBSS-DRD controller is compliance with XHCI > >> specification, so it works with standard XHCI Linux driver. > >> > >> The host side of USBSS DRD controller is compliant with XHCI. > >> The architecture for device side is almost the same as for host side, > >> and most of the XHCI specification can be used to understand how > >> this controller operates. > >> > >> This controller and driver support Full Speed, Hight Speed, Supper Speed > >> and Supper Speed Plus USB protocol. > >> > >> The prefix cdnsp used in driver has chosen by analogy to cdn3 driver. > >> The last letter of this acronym means PLUS. The formal name of controller > >> is USBSSP but it's to generic so I've decided to use CDNSP. > >> > >> The patch 1: adds DT binding. > >> The patch 2: adds PCI to platform wrapper used on Cadnece testing > >> platform. It is FPGA based on platform. > >> The patches 3-5: add the main part of driver and has been intentionally > >> split into 3 part. In my opinion such division should not > >> affect understanding and reviewing the driver, and cause that > >> main patch (4/5) is little smaller. Patch 3 introduces main > >> header file for driver, 4 is the main part that implements all > >> functionality of driver and 5 introduces tracepoints. > > > >I'm more interested in how is this different from CDNS3. Aren't they SW compatible? > > In general, the controller can be split into 2 part- DRD part and the rest UDC. > > The second part UDC which consist gadget.c, ring.c and mem.c file is completely different. > > The DRD part contains drd.c and core.c. > cdnsp drd.c is similar to cdns3 drd.c but it's little different. CDNSP has similar, but has different register space. > Some register was moved, some was removed and some was added. > > core.c is very similar and eventually could be common for both drivers. I thought about this but > I wanted to avoid interfering with cdns3 driver at this point CDNSP is still under testing and > CDNS3 is used by some products on the market. Pawel, I suggest adding CDNSP at driver/staging first since it is still under testing. When you are thinking the driver (as well as hardware) are mature, you could try to add gadget part (eg, gadget-v2) and make necessary changes for core.c. -- Thanks, Peter Chen
