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ARM: mvebu: make the coherency_ll.S functions work with no coherency fabric 

The ll_add_cpu_to_smp_group(), ll_enable_coherency() and
ll_disable_coherency() are used on Armada XP to control the coherency
fabric. However, they make the assumption that the coherency fabric is
always available, which is currently a correct assumption but will no
longer be true with a followup commit that disables the usage of the
coherency fabric when the conditions are not met to use it.

Therefore, this commit modifies those functions so that they check the
return value of ll_get_coherency_base(), and if the return value is 0,
they simply return without configuring anything in the coherency
fabric.

The ll_get_coherency_base() function is also modified to properly
return 0 when the function is called with the MMU disabled. In this
case, it normally returns the physical address of the coherency
fabric, but we now check if the virtual address is 0, and if that's
case, return a physical address of 0 to indicate that the coherency
fabric is not enabled.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Cc: <stable@vger.kernel.org> # v3.8+
Acked-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
Link: https://lkml.kernel.org/r/1415871540-20302-2-git-send-email-thomas.petazzoni@free-electrons.com
Signed-off-by: Jason Cooper <jason@lakedaemon.net>
This commit is contained in:
Thomas Petazzoni 2014-11-13 10:38:56 +01:00 committed by Jason Cooper
parent 93a93d19c7
commit 30cdef9710
1 changed files with 19 additions and 2 deletions
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21
arch/arm/mach-mvebu/coherency_ll.S
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@ -24,7 +24,10 @@
#include <asm/cp15.h> #include <asm/cp15.h>
.text .text
/* Returns the coherency base address in r1 (r0 is untouched) */ /*
* Returns the coherency base address in r1 (r0 is untouched), or 0 if
* the coherency fabric is not enabled.
*/
ENTRY(ll_get_coherency_base) ENTRY(ll_get_coherency_base)
mrc p15, 0, r1, c1, c0, 0 mrc p15, 0, r1, c1, c0, 0
tst r1, #CR_M @ Check MMU bit enabled tst r1, #CR_M @ Check MMU bit enabled
@ -32,8 +35,13 @@ ENTRY(ll_get_coherency_base)
/* /*
* MMU is disabled, use the physical address of the coherency * MMU is disabled, use the physical address of the coherency
* base address. * base address. However, if the coherency fabric isn't mapped
* (i.e its virtual address is zero), it means coherency is
* not enabled, so we return 0.
*/ */
ldr r1, =coherency_base
cmp r1, #0
beq 2f
adr r1, 3f adr r1, 3f
ldr r3, [r1] ldr r3, [r1]
ldr r1, [r1, r3] ldr r1, [r1, r3]
@ -85,6 +93,9 @@ ENTRY(ll_add_cpu_to_smp_group)
*/ */
mov r0, lr mov r0, lr
bl ll_get_coherency_base bl ll_get_coherency_base
/* Bail out if the coherency is not enabled */
cmp r1, #0
reteq r0
bl ll_get_coherency_cpumask bl ll_get_coherency_cpumask
mov lr, r0 mov lr, r0
add r0, r1, #ARMADA_XP_CFB_CFG_REG_OFFSET add r0, r1, #ARMADA_XP_CFB_CFG_REG_OFFSET
@ -107,6 +118,9 @@ ENTRY(ll_enable_coherency)
*/ */
mov r0, lr mov r0, lr
bl ll_get_coherency_base bl ll_get_coherency_base
/* Bail out if the coherency is not enabled */
cmp r1, #0
reteq r0
bl ll_get_coherency_cpumask bl ll_get_coherency_cpumask
mov lr, r0 mov lr, r0
add r0, r1, #ARMADA_XP_CFB_CTL_REG_OFFSET add r0, r1, #ARMADA_XP_CFB_CTL_REG_OFFSET
@ -131,6 +145,9 @@ ENTRY(ll_disable_coherency)
*/ */
mov r0, lr mov r0, lr
bl ll_get_coherency_base bl ll_get_coherency_base
/* Bail out if the coherency is not enabled */
cmp r1, #0
reteq r0
bl ll_get_coherency_cpumask bl ll_get_coherency_cpumask
mov lr, r0 mov lr, r0
add r0, r1, #ARMADA_XP_CFB_CTL_REG_OFFSET add r0, r1, #ARMADA_XP_CFB_CTL_REG_OFFSET