> 2011/4/12 RafaÅ MiÅecki <zajec5@xxxxxxxxx>: > > 2011/4/12 Hauke Mehrtens <hauke@xxxxxxxxxx>: > >> Hi RafaÅ, > >> > >> On 04/12/2011 09:27 PM, RafaÅ MiÅecki wrote: > >>> 2011/4/12 George Kashperko <george@xxxxxxxxxxx>: > >>>> > >>>>> 2011/4/12 George Kashperko <george@xxxxxxxxxxx>: > >>>>>> > >>>>>>> Hi, > >>>>>>> > >>>>>>> On Tue, Apr 12, 2011 at 01:57:07AM +0200, RafaÅ MiÅecki wrote: > >>>>>>>> Cc: Michael BÃsch <mb@xxxxxxxxx> > >>>>>>>> Cc: Larry Finger <Larry.Finger@xxxxxxxxxxxx> > >>>>>>>> Cc: George Kashperko <george@xxxxxxxxxxx> > >>>>>>>> Cc: Arend van Spriel <arend@xxxxxxxxxxxx> > >>>>>>>> Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx > >>>>>>>> Cc: Russell King <rmk@xxxxxxxxxxxxxxxx> > >>>>>>>> Cc: Arnd Bergmann <arnd@xxxxxxxx> > >>>>>>>> Cc: Andy Botting <andy@xxxxxxxxxxxxxxx> > >>>>>>>> Cc: linuxdriverproject <devel@xxxxxxxxxxxxxxxxxxxxxx> > >>>>>>>> Cc: linux-kernel@xxxxxxxxxxxxxxx <linux-kernel@xxxxxxxxxxxxxxx> > >>>>>>>> Signed-off-by: RafaÅ MiÅecki <zajec5@xxxxxxxxx> > >>>>>>>> --- > >>>>>>>> V2: Rename to axi > >>>>>>>> Use DEFINE_PCI_DEVICE_TABLE in bridge > >>>>>>>> Make use of pr_fmt and pr_* > >>>>>>>> Store core class > >>>>>>>> Rename bridge to not b43 specific > >>>>>>>> Replace magic 0x1000 with BCMAI_CORE_SIZE > >>>>>>>> Remove some old "ssb" names and defines > >>>>>>>> Move BCMAI_ADDR_BASE def > >>>>>>>> Add drvdata field > >>>>>>>> V3: Fix reloading (kfree issue) > >>>>>>>> Add 14e4:0x4331 > >>>>>>>> Fix non-initialized struct issue > >>>>>>>> Drop useless inline functions wrappers for pci core drv > >>>>>>>> Proper pr_* usage > >>>>>>>> V3.1: Include forgotten changes (pr_* and include related) > >>>>>>>> Explain why we dare to implement empty release function > >>>>>>> > >>>>>>> I'm not sure we need this. If you have an IP Core which talks AXI and > >>>>>>> you want to put it on a PCI bus, you will have a PCI Bus wrapper around > >>>>>>> that IP Core, so you should go and let the kernel know about that. See > >>>>>>> [1] for a core IP which talks AXI and [2] for a PCI bus glue layer. > >>>>>>> > >>>>>>> Besides, if you introduce this bus layer, it'll be more difficult for > >>>>>>> other licensees of the same core to re-use the same driver, since it's > >>>>>>> now talking a PCI emulated on top of AXI. The same can be achieved with > >>>>>>> the platform_bus which is more widely used, specially on ARM SoCs. > >>>>>>> > >>>>>>> [1] http://gitorious.org/usb/usb/blobs/dwc3/drivers/usb/dwc3/core.c > >>>>>>> [2] http://gitorious.org/usb/usb/blobs/dwc3/drivers/usb/dwc3/dwc3-haps.c > >>>>>>> > >>>>>> > >>>>>> Already noticed earlier that AXI isnt really good name for > >>>>>> Broadcom-specific axi bus customization. As of tech docs available from > >>>>>> arm, corelink AXI cores use own identification registers which feature > >>>>>> different format and layout comparing to that we use for Broadcom cores. > >>>>>> > >>>>>> Maybe there is something "standartized" by the DMP specs? If so I'm > >>>>>> curious if that DMP is obligatory for every axi bus ? > >>>>>> > >>>>>> Naming particular Broadcom's implementation just axi limits other > >>>>>> licensees in reusing axi bus name/code or will require hacks/workarounds > >>>>>> from them to fit Broadcom-like core scanning/identificating techniques. > >>>>>> You use bus named AXI to group and manage Broadcom cores, while never > >>>>>> even publish device records for native axi cores Broadcom use to talk to > >>>>>> the interconnect through. Yet again, something like bcmb/bcmai looks > >>>>>> like better name for this bus. > >>>>> > >>>>> I don't know, I'm really tired of this. Earlier I was told to not use > >>>>> anything like bcmai, because it is not Broadcom specific. Now it seems > >>>>> (and I'm afraid I agree) there is quite a lot of Broadcom specific > >>>>> stuff. > >>>> Well, _if_ that "magic" EROM core layout is arm's "standard" for axi > >>>> ports identification _and_ _if_ that EROM core is obligatory axi > >>>> component then sure axi name is good one as soon as you consider > >>>> registering master port (agent) cores with device subsystem as well. > >>>> I have no clue here about how resolve those _if_'s, hopefully Broadcom > >>>> guys can enlighten us on the subject. > >>> > >>> Do you think that in my code only scanning is Broadcom specific? In > >>> such a case we could keep it "axi", and just s/scan/bcmscan/. This is > >>> only correct choice if the rest (addressing, core enabling, host > >>> management) is AXI specific. > >> > >> The specification for the AMBA AXI Interface is available for free > >> download from ARM if you register to their website and accept their license: > >> http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.set.amba/index.html > >> I got it from there without any problems and the license does not look > >> too bad for me, by having a quick look at it. I do not know if it will > >> help you in any way or if it is completely unrelated. > >> > >> Why is the existing support for the amba bus not extended or used in any > >> way for this? It exists for some time in drivers/amba/. There already > >> was a discussion about this in https://lkml.org/lkml/2011/3/30/186 , but > >> with no result as I see. > > > > I can see exactly nothing I could use from whatever driver/amba is. > > What does it do from things we need? How do you imagine using that > > with out (non)Broadcom buses? > > 1) I checked for amba_device_register: > http://lxr.free-electrons.com/ident?i=amba_device_register > and do not understand that. There are a lot of drivers registering > some pre-defined devices. I could not find any driver scanning for > amba devices and registering them. Are we going to be the first driver > registering devices dynamically or do I get this totally wrong > > 2) amba_id contains only some interesting "id". How can we relate this > with our core id/rev/manuf/class? I guess that id corresponds to corelink-compatible peripheral/component 4x8bit registers' layout. > 3) There is no code for managing AMBA cores (enable, checking status, > disabling, resetting)... These could be of interest for DMP core driver if someone decide to publish agent cores on amba_bustype. > > That way I see really low (or not at all) relation between out > (not)Broadcom bus and present AMBA bus. > Agree. 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