>> > 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. > >I only take code for drivers/staging/ that for some reason is not >meeting the normal coding style/rules/whatever. For stuff that is an >obvious duplicate of existing code like this, and needs to be >rearchitected. It is much more work to try to convert code once it is >in the tree than to just do it out of the tree on your own and resubmit >it, as you don't have to follow the in-kernel rules of "one patch does >one thing" that you would if it was in staging. > >So don't think that staging is the right place for this, just spend a >few weeks to get it right and then resubmit it. > Ok, I try to reuse the code from cdns3. Where such common code should be placed ? Should I move it to e.g. drivers/usb/common/cdns or it should remain in cdns3 directory. thanks, pawel
