[ARM] add ARMv5TEJ aware cache flush method to compressed/head.S

The default ARMv4 method consisting of reading through some memory
area isn't compatible with the cache replacement policy of some
ARMv5TEJ compatible cache implementations.  It is also a bit wasteful
when a dedicated instruction can do the needed work optimally.

It is hard to tell if all ARMv5TEJ cores will support the used CP15
instruction, but at least all those implementations Linux currently
knows about (ARM926 and ARM1026) do support it.

Tested on an OMAP1610 H2 target.

Signed-off-by: Nicolas Pitre <nico@marvell.com>
Tested-by: George G. Davis <gdavis@mvista.com>
Acked-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 8 insertions, 1 deletions

diff --git a/arch/arm/boot/compressed/head.S b/arch/arm/boot/compressed/head.S
index 5cac46a19bb7..2073bf080523 100644
--- a/arch/arm/boot/compressed/head.S
+++ b/arch/arm/boot/compressed/head.S
@@ -641,7 +641,7 @@ proc_types:
                 .word   0x000f0000
                 b       __armv4_mmu_cache_on
                 b       __armv4_mmu_cache_off
-                b       __armv4_mmu_cache_flush
+                b       __armv5tej_mmu_cache_flush
 
                 .word   0x0007b000              @ ARMv6
                 .word   0x000ff000
@@ -821,6 +821,13 @@ iflush:
                 mcr     p15, 0, r10, c7, c10, 4 @ drain WB
                 mov     pc, lr
 
+__armv5tej_mmu_cache_flush:
+1:              mrc     p15, 0, r15, c7, c14, 3 @ test,clean,invalidate D cache
+                bne     1b
+                mcr     p15, 0, r0, c7, c5, 0   @ flush I cache
+                mcr     p15, 0, r0, c7, c10, 4  @ drain WB
+                mov     pc, lr
+
 __armv4_mmu_cache_flush:
                 mov     r2, #64*1024            @ default: 32K dcache size (*2)
                 mov     r11, #32                @ default: 32 byte line size