[ARM] nommu: provide a way for correct control register value selection
Most MMU-based CPUs have a restriction on the setting of the data cache
enable and mmu enable bits in the control register, whereby if the data
cache is enabled, the MMU must also be enabled. Enabling the data
cache without the MMU is an invalid combination.
However, there are CPUs where the data cache can be enabled without the
MMU.
In order to allow these CPUs to take advantage of that, provide a
method whereby each proc-*.S file defines the control regsiter value
for use with nommu (with the MMU disabled.) Later on, when we add
support for enabling the MMU on these devices, we can adjust the
"crval" macro to also enable the data cache for nommu.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/arch/arm/mm/proc-arm1026.S b/arch/arm/mm/proc-arm1026.S
index 2796c8e..85d8fb0 100644
--- a/arch/arm/mm/proc-arm1026.S
+++ b/arch/arm/mm/proc-arm1026.S
@@ -399,11 +399,11 @@
mov r0, #4 @ explicitly disable writeback
mcr p15, 7, r0, c15, c0, 0
#endif
+ adr r5, arm1026_crval
+ ldmia r5, {r5, r6}
mrc p15, 0, r0, c1, c0 @ get control register v4
- ldr r5, arm1026_cr1_clear
bic r0, r0, r5
- ldr r5, arm1026_cr1_set
- orr r0, r0, r5
+ orr r0, r0, r6
#ifdef CONFIG_CPU_CACHE_ROUND_ROBIN
orr r0, r0, #0x4000 @ .R.. .... .... ....
#endif
@@ -416,12 +416,9 @@
* .011 1001 ..11 0101
*
*/
- .type arm1026_cr1_clear, #object
- .type arm1026_cr1_set, #object
-arm1026_cr1_clear:
- .word 0x7f3f
-arm1026_cr1_set:
- .word 0x3935
+ .type arm1026_crval, #object
+arm1026_crval:
+ crval clear=0x00007f3f, mmuset=0x00003935, ucset=0x00001934
__INITDATA