From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wolfgang Grandegger Subject: Re: [PATCH net-next-2.6 v2 1/1] can: c_can: Added support for Bosch C_CAN controller Date: Wed, 22 Dec 2010 09:10:39 +0100 Message-ID: <4D11B27F.9030306@grandegger.com> References: <1292407130-19791-1-git-send-email-bhupesh.sharma@st.com> <4D0BD454.3060503@grandegger.com> <4D0FBEF6.8020207@grandegger.com> <4D10FF97.1070703@grandegger.com> <4D11A039.5090006@pengutronix.de> <4D11ADD2.40506@grandegger.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: "Socketcan-core-0fE9KPoRgkgATYTw5x5z8w@public.gmane.org" , "netdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , Marc Kleine-Budde To: Bhupesh SHARMA Return-path: In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: socketcan-core-bounces-0fE9KPoRgkgATYTw5x5z8w@public.gmane.org Errors-To: socketcan-core-bounces-0fE9KPoRgkgATYTw5x5z8w@public.gmane.org List-Id: netdev.vger.kernel.org On 12/22/2010 09:03 AM, Bhupesh SHARMA wrote: > Hi Marc and Wolfgang, > >> -----Original Message----- >> From: Wolfgang Grandegger [mailto:wg-5Yr1BZd7O62+XT7JhA+gdA@public.gmane.org] >> Sent: Wednesday, December 22, 2010 1:21 PM >> To: Marc Kleine-Budde >> Cc: Bhupesh SHARMA; Socketcan-core-0fE9KPoRgkgATYTw5x5z8w@public.gmane.org; >> netdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.org >> Subject: Re: [PATCH net-next-2.6 v2 1/1] can: c_can: Added support for >> Bosch C_CAN controller >> >> On 12/22/2010 07:52 AM, Marc Kleine-Budde wrote: >>> On 12/22/2010 04:36 AM, Bhupesh SHARMA wrote: >>>> Hi Wolfgang, >>>> >>>>> Hi Bhupesh, >>>>> >>>>> On 12/21/2010 05:48 AM, Bhupesh SHARMA wrote: >>>>>> Hi Wolfgang, >>>>> ... >>>>>>> In the meantime I compared the CAN chapter of the PCH manual with >>>>> the >>>>>>> C_CAN manual. The paragraphs I checked are *identical*. This >> makes >>>>>>> clear, that the "pch_can" is a clone of the C_CAN CAN >> controller, >>>>> with >>>>>>> a few extensions, though. Therefore it would make sense, to >>>>> implement a >>>>>>> bus sensitive interface like for the SJA1000 allowing to handle >> both >>>>>>> CAN >>>>>>> controllers with one driver sooner than later. Therefore, could >> you >>>>>>> please implement: >>>>>>> >>>>>>> drivers/net/can/c_can/c_can.c >>>>>>> /c_can_platform.c >>>>>>> >>>>>>> Then an interface to the PCI based PCH CAN controller could be >> added >>>>>>> easily, e.g. as "pch_pci.c". You already had something similar in >>>>> your >>>>>>> RFC version of the patch, IIRC. >>>>>> >>>>>> This was the approach I initially proposed in my RFC V1 patch :) >>>>>> But unfortunately we could not agree to it. >>>>> >>>>> I know. But at that time I was not aware of any other bus used for >> the >>>>> C_CAN controller. >>>>> >>>>>> So, please let me reiterate what I understood and what was present >>>>>> in RFC version of the patch. Please add your comments/views: >>>>>> >>>>>> - drivers/net/can/c_can/c_can.c (similar on lines of >>>>> sja1000.c) >>>>>> i.e. a)no *probe* / *remove* functions here, >>>>>> b)register read/write implemented here. >>>>>> >>>>>> - drivers/net/can/c_can/c_can_platform.c (similar on lines >> of >>>>> sja1000_platform.c) >>>>>> i.e. *probe* / *remove* implemented here, >>>>> >>>>> Yes, that's what I'm thinking about. >>>>> >>>>>> Marc and Tomoya can also add their suggestions so that I can >> finalize >>>>> V3 a.s.a.p. >>>>> >>>>> That would be nice, indeed. Also have a look to Tomoya's PCH >> driver, >>>>> which also looks very good in the meantime. >>>> >>>> I am having a look at Tomoya's PCH driver, but as I mentioned in >>>> RFC V1 patch, I would rather like to have a bus sensitive `c_can` >> driver >>> >>> What do you mean by a "bus sensitive" driver? >> >> I was thinking about a "bus independent interface" like for the >> SJA1000. >> A bus sensitive driver would the be in c_can_platform.c. >> >>>> on top of which we can have the platform driver `c_can_platform` >> which >>>> essentially caters to the details of registers mapping/arch >> differences. >>>> Any other functionality like USB/PCI should be present in a separate >> file >>>> like `usb_c_can.c` or `pci_c_can.c` >>> >>> Sounds like the sja1000 approach, which is a good choice. >> >> I fully agree. >> >>>> If you agree I will try to circulate V3 a.s.ap. >>> >>> go ahead. >>> >> >> Yes, please. > > Ok, so I would try to circulate V3 by tomorrow with a sja1000 *like* approach that ensures > in-order packet reception as well. That would be nice. But well, no hurry. It's Xmas time :-), Wolfgang.