Thread (14 messages) 14 messages, 7 authors, 2010-07-11

Re: [PATCH] arch/powerpc/lib/copy_32.S: Use alternate memcpy for MPC512x and MPC52xx

From: Segher Boessenkool <hidden>
Date: 2010-07-09 12:58:27

quoted
quoted
Actually, this is something which might need closer attention -
and maybe some support in the device tree indicating which read or
write width a device can accept?
There already is "device-width"; the drivers never should use any
other access width unless they *know* that will work.
Wouldn't you want to use "bank-width" instead?
We were talking about single devices.  But, sure, when you have
multiple devices in parallel the driver needs to know about that.
It would be nice to have a device tree property that can specify that
all access widths supported by the CPU will work, though.
Oh please no.  A device binding should not depend on what CPU there
is in the system.  There could be multiple CPUs of different
architectures, even.

To figure out how to access a device, the driver looks at the device's
node, and all its parent nodes (or asks generic code to do that, or
platform code).


Segher
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