Re: [patch/rfc 2.6.29 1/2] MTD: driver model updates

Juergen Beisert
2009-04-01T13:44:03Z

Hi David, Kay,

On Mittwoch, 1. April 2009, Kay Sievers wrote:
> On Tue, Mar 31, 2009 at 23:18, David Brownell <david-b@pacbell.net> wrote:
> > On Thursday 26 March 2009, David Brownell wrote:
> >> From: David Brownell <dbrownell@users.sourceforge.net>
> >>
> >> Update driver model support in the MTD framework, so it fits
> >> better into the current udev-based hotplug framework:
> >
> > Hmm, no comments?  I had understood there was interest over on
> > the MTD side of things in exposing more information through
> > sysfs, to help avoid the need to add Even More Ioctls as part
> > of support for things like NAND chips with 4KB pages, or which
> > handle more than 4GBytes ...
>
> Please have a look at this. We got asked repeatedly to provide better
> hotplug/udev integration, and the patches, and having the parent
> device properly assigned, would solve some of the problems people run
> into currently.

Without patch:
--------------

$ udevadm info -a -p /sys/block/mtdblock0
[...]
looking at device '/devices/virtual/block/mtdblock0':
KERNEL=="mtdblock0"
SUBSYSTEM=="block"
DRIVER==""
ATTR{range}=="1"
ATTR{removable}=="0"
ATTR{size}=="256"
ATTR{capability}=="10"
ATTR{stat}==" 0 0 0 0 0 0 0 0 0 0 0"

And nearly the same data for the other flash device. No chance to detect if
this one is the NOR or the NAND type...

With the patch:
---------------

$ udevadm info -a -p /sys/block/mtdblock0
[...]
looking at parent device '/devices/platform/physmap-flash.0':
KERNELS=="physmap-flash.0"
SUBSYSTEMS=="platform"
DRIVERS=="physmap-flash"
ATTRS{modalias}=="platform:physmap-flash"

The second flash device is of NAND type and 'udevadm' shows:

$ udevadm info -a -p /sys/block/mtdblock4
[...]
looking at parent device '/devices/platform/mxc_nand.0':
KERNELS=="mxc_nand.0"
SUBSYSTEMS=="platform"
DRIVERS=="mxc_nand"
ATTRS{modalias}=="platform:mxc_nand"

\o/

I will try now to define some udev rules to match for my different flash
memories.

Thank you,
Juergen

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