Could I (ab)use bus (struct bus_type) for virtual Broadcom bus?

Arend van Spriel arend at broadcom.com
Wed Apr 20 02:39:59 EDT 2011


On Tue, 19 Apr 2011 16:02:57 +0200, Greg KH <greg at kroah.com> wrote:

> Please don't use a platform device, unless there is no other way for
> your device to work.  For this device, you are connected to the PCI bus,
> so a platform device does not make sense at all.

Hi Greg,

This is only true for a particular usage model. There are two models as  
shown below:

1) PCI(e) card
                       ...........
+----------+          :   x y z :     x, y, and z are cores.
|    uC    |__________:___|_|_| :
|          |  PCI-bus : axi-bus :
+----------+          :.........:
                       bcm chipset

2) SoC
           ...............
           : uC    x y z :
           :  |____|_|_| :
           :    axi-bus  :
           :.............:
             bcm chipset

Your statement is true for 1) but in usage model 2) there is no PCI bus.  
Also you refer to the chipset when you say 'device'. In the axi bus type  
each individual core is registered as a device in the linux device tree.

Gr. AvS
-- 
"The world is indeed comic, but the joke is on mankind." — H.P. Lovecraft




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