Change ARM Cache Type from Write-Back Cached Write Allocate to Write-Back, No Allocate

Change ARM Cache Type from Write-Back Cached Write Allocate to Write-Back, No Allocate

[Richard Liu]

Based on ARM11 MPCore TRM r1p0
Page 5-16

At TLB table, TEX cache memory support 4 type cache types
1) Noncachabled
2) Write-Back cached Write Allocate, Buffered
3) Write-Through cached, No Allocate on Write, Buffered
4) Write-Back cached, No Allocate on Write, Buffered.

 From ARM's information, if change the TEX type to Write-Through,
the L1 Cache would be "behavior is noncacheable"
I think we can disable L1/L2 cache to reach the same result.

If want to change the default setting from "Write-Back cached Write 
Allocate, Buffered" to "Write-Back cached, No Allocate on Write, Buffered".
How to modify the build_mem_type_table in file mmu.c?
And should it need more patches on others part like L1 or L2 coherence 
function?

Change ARM Cache Type from Write-Back Cached Write Allocate to Write-Back, No Allocate

[Russell King - ARM Linux]

On Mon, Apr 19, 2010 at 11:09:11AM +0800, Richard Liu wrote:
> Based on ARM11 MPCore TRM r1p0
> Page 5-16
>
> At TLB table, TEX cache memory support 4 type cache types
> 1) Noncachabled
> 2) Write-Back cached Write Allocate, Buffered
> 3) Write-Through cached, No Allocate on Write, Buffered
> 4) Write-Back cached, No Allocate on Write, Buffered.
>
> From ARM's information, if change the TEX type to Write-Through,
> the L1 Cache would be "behavior is noncacheable"
> I think we can disable L1/L2 cache to reach the same result.
>
> If want to change the default setting from "Write-Back cached Write  
> Allocate, Buffered" to "Write-Back cached, No Allocate on Write, 
> Buffered".
> How to modify the build_mem_type_table in file mmu.c?
> And should it need more patches on others part like L1 or L2 coherence  
> function?

MPCore hardware only supports write-back write-allocate or non-cacheable
modes; so you can't change this.