Re: Could I (ab)use bus (struct bus_type) for virtual Broadcombus?

From: Arend van Spriel
Date: Wed Apr 20 2011 - 02:40:44 EST


On Tue, 19 Apr 2011 16:02:57 +0200, Greg KH <greg@xxxxxxxxx> 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." â H.P. Lovecraft

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/