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    SubjectRe: [RFC][PATCH] axi: add AXI bus driver
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    > 2011/4/13 Arend van Spriel <arend@broadcom.com>:
    > > On Tue, 12 Apr 2011 22:44:01 +0200, Rafał Miłecki <zajec5@gmail.com> wrote:
    > >
    > >> 2011/4/12 George Kashperko <george@znau.edu.ua>:
    > >>>>
    > >>>> 2011/4/12 Rafał Miłecki <zajec5@gmail.com>:
    > >>>> That way I see really low (or not at all) relation between out
    > >>>> (not)Broadcom bus and present AMBA bus.
    > >>>>
    > >>> Agree.
    > >>
    > >> Ehh, sounds like one more renaming to functions, defines, prefixes.
    > >>
    > >> Let's wait for Arend comments, he was the one voting for not-bcm-specific
    > >> name.
    > >>
    > >
    > > Hi Rafał,
    > >
    > > Still think its better to stick with a generic name even if currently you
    > > only come across this in Broadcom chips right now. I do agree that the term
    > > 'axi' is implying something else than what this bus driver is providing. The
    > > name 'axi-dmp' I gave earlier may be more to the point.
    > >
    > > I also looked at the amba driver after receiving comments on the brcmaxi
    > > library module (this is what Hauke Mehrtens referred to) and came to similar
    > > conclusion as you did. It does however support PM properly so you may want
    > > to get inspiration in that area. I also noticed a reference to AMBA term APB
    > > which is a different bus in the AMBA family. AXI was introduced later as
    > > higher performance bus (in AMBA rev3 if I remember correctly).
    >
    > I don't focus on PM yet, do not consider it a problem, it just needs some time.
    >
    > Note for not involved: AMBA is family with few buses/interfaces
    > possible: AXI, AHB, ASB, APB, ATB [1].
    >
    > So what are you saying is that drivers/amba/ is for AMBA APB? OK, I
    > can accept such a explanation and it makes me even more sure we need
    > another AMBA driver (this time: AMBA AXI).
    AMBA is AMBA. axi/apb/ahb etc are all subsets of AMBA and as of current
    all fit to what already is in drivers/amba.

    >
    > The left question is: how much of the implemented code is AMBA AXI
    > specific and how much is Broadcom specific?

    Answers to 1. and 2. are there in drivers/amba/bus.c
    Look _probe and _register fn for more details.
    > 1) Does AMBA AXI identify cores by manuf, id, rev and class? Is this
    > really AMBA AXI specific and a evolution from simple "id" in AMBA APB?
    During amba device registration amba bus code read component/peripheral
    id registers from known locations, exactly where
    peripherialid/componentid registers of master port (agent) core are.
    Look brcm80211/inclue/aidmp.h for those.
    > 2) Is this standard for AMBA AXI to keep list of available cores in
    > some specific memory (is this always EPROM like in case of Bcm?)?
    > 3) Does every AMBA AXI device need enabling/disabling/resetting
    > routine we implemented? Is that really Bcm independent?
    Enable/disable abstracted by clocks interface.

    It would be really great if someone could enligten us on 2).

    > This is mostly what I already asked, but didn't get answer. Please,
    > explain to us what is AMBA AXI specific and what is Broadcom specific.
    >
    > [1] http://en.wikipedia.org/wiki/Advanced_Microcontroller_Bus_Architecture
    >

    Have nice day,
    George


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