Subject: Re: rbus
To: None <>
From: Hayakawa Koichi <>
List: tech-kern
Date: 05/09/2000 11:43:35

Thank you for your patch of rbus.c.

From: Lennart Augustsson <>
Subject: rbus
Date: Sun, 7 May 2000 19:55:40 +0200 (CEST)
Message-ID: <>

 > Can someone explain to me what the rbus code in the Cardbus driver
 > does?  I can't understand what it's doing nor what it is supposed to
 > do.  I do understand that it's broken.

I should assume the responsibility of explaining it as an

1. Some ports do not have bus_space_alloc, because they do
   not know which memory area is usable.

        I don't want to use different memory and io space
        interface for each port.  I wrote rbus as a wRapper
        BUS interface.

2. I want to model relocatable devices' address line.

        Usually a relocatable device has a address line
        which can be sepalated in two parts: fixed part and
        variable part.  For example, according to a pcmcia
        modem, six significant bits are variable and 10 less
        significant bits are fixed.

        Rbus has an argument 'mask', which represents where
        is the variable part and fixed part.  The bits
        according to fixed part is turned on.

# I know the implementation around 'mask' is incomplete.

BTW, I don't stick to rbus.  I don't think rbus is mandatory
and can be removed when the all ports implement
bus_space_alloc properly.