Re: [PATCH] powerpc/85xx: remove P1020RDB and P2020RDB CAMP device trees

On Jul 13, 2012, at 5:40 PM, Timur Tabi wrote:

We only need two examples of CAMP device trees in the upstream kernel.
=20
Co-operative Asymmetric Multi-Processing (CAMP) is a technique where =

two

or more operating systems (typically multiple copies of the same Linux =

kernel)

are loaded into memory, and each kernel is given a subset of the =

available

cores to execute on.  For example, on a four-core system, one kernel =

runs on

cores 0 and 1, and the other runs on cores 2 and 3.
=20
The devices are also partitioned among the operating systems, and this =

is

done with customized device trees.  Each kernel gets its own device =

tree

that has only the devices that it should know about.
=20
Unfortunately, this approach is very hackish.  The kernels are trusted =

to

only access devices in their respective device trees, and the =

partitioning

only works for devices that can be handled.  Crafting the device trees =

is a

tricky process, and getting U-Boot to load and start all kernels is =

cumbersome.

=20
But most importantly, each CAMP setup is very application-specific, =

since

the actual partitioning of resources is done in the DTS by the system
designer.  Therefore, it doesn't make a lot of sense to have a lot of =

CAMP

device trees, since we only expect them to be used as examples.
=20
Signed-off-by: Timur Tabi <redacted>
---
arch/powerpc/boot/dts/p1020rdb_camp_core0.dts |   63 -----------
arch/powerpc/boot/dts/p1020rdb_camp_core1.dts |  141 =

-------------------------

arch/powerpc/boot/dts/p2020rdb_camp_core0.dts |   67 ------------
arch/powerpc/boot/dts/p2020rdb_camp_core1.dts |  125 =

----------------------

4 files changed, 0 insertions(+), 396 deletions(-)
delete mode 100644 arch/powerpc/boot/dts/p1020rdb_camp_core0.dts
delete mode 100644 arch/powerpc/boot/dts/p1020rdb_camp_core1.dts
delete mode 100644 arch/powerpc/boot/dts/p2020rdb_camp_core0.dts
delete mode 100644 arch/powerpc/boot/dts/p2020rdb_camp_core1.dts

applied to next

- k=