From 2e8a5942f8751c03fdd50228a02909654d13f01d Mon Sep 17 00:00:00 2001 From: Gregory CLEMENT Date: Mon, 14 Apr 2014 17:10:08 +0200 Subject: [PATCH] ARM: mvebu: Split low level functions to manipulate HW coherency Actually enabling coherency and adding a CPU on a SMP group are two different operations which can be done separately. This patch splits this in two functions. Moreover as they use common pattern, this patch also creates local low level functions (ll_get_coherency_base and ll_get_cpuid) to be used by the exposed functions (ll_add_cpu_to_smp_group and ll_enable_coherency) Signed-off-by: Gregory CLEMENT Link: https://lkml.kernel.org/r/1397488214-20685-6-git-send-email-gregory.clement@free-electrons.com Signed-off-by: Jason Cooper --- arch/arm/mach-mvebu/coherency.c | 8 ++-- arch/arm/mach-mvebu/coherency_ll.S | 92 +++++++++++++++++++++++++------------- arch/arm/mach-mvebu/headsmp.S | 6 ++- 3 files changed, 71 insertions(+), 35 deletions(-) diff --git a/arch/arm/mach-mvebu/coherency.c b/arch/arm/mach-mvebu/coherency.c index 944372a..9d5ccd3 100644 --- a/arch/arm/mach-mvebu/coherency.c +++ b/arch/arm/mach-mvebu/coherency.c @@ -60,8 +60,9 @@ static struct of_device_id of_coherency_table[] = { { /* end of list */ }, }; -/* Function defined in coherency_ll.S */ -int ll_set_cpu_coherent(void); +/* Functions defined in coherency_ll.S */ +int ll_enable_coherency(void); +void ll_add_cpu_to_smp_group(void); int set_cpu_coherent(void) { @@ -71,7 +72,8 @@ int set_cpu_coherent(void) return 1; } - return ll_set_cpu_coherent(); + ll_add_cpu_to_smp_group(); + return ll_enable_coherency(); } /* diff --git a/arch/arm/mach-mvebu/coherency_ll.S b/arch/arm/mach-mvebu/coherency_ll.S index 98a0b73..f2e2e86 100644 --- a/arch/arm/mach-mvebu/coherency_ll.S +++ b/arch/arm/mach-mvebu/coherency_ll.S @@ -24,52 +24,84 @@ #include .text - -ENTRY(ll_set_cpu_coherent) +/* Returns with the coherency address in r1 (r0 is untouched)*/ +ENTRY(ll_get_coherency_base) mrc p15, 0, r1, c1, c0, 0 tst r1, #CR_M @ Check MMU bit enabled bne 1f - /* use physical address of the coherency register*/ - adr r0, 3f - ldr r3, [r0] - ldr r0, [r0, r3] + /* use physical address of the coherency register */ + adr r1, 3f + ldr r3, [r1] + ldr r1, [r1, r3] b 2f 1: - /* use virtual address of the coherency register*/ - ldr r0, =coherency_base - ldr r0, [r0] + /* use virtual address of the coherency register */ + ldr r1, =coherency_base + ldr r1, [r1] 2: - /* Create bit by cpu index */ - mrc 15, 0, r1, cr0, cr0, 5 - and r1, r1, #15 + mov pc, lr +ENDPROC(ll_get_coherency_base) + +/* Returns with the CPU ID in r3 (r0 is untouched)*/ +ENTRY(ll_get_cpuid) + mrc 15, 0, r3, cr0, cr0, 5 + and r3, r3, #15 mov r2, #(1 << 24) - lsl r1, r2, r1 + lsl r3, r2, r3 ARM_BE8(rev r1, r1) + mov pc, lr +ENDPROC(ll_get_cpuid) - /* Add CPU to SMP group - Atomic */ - add r3, r0, #ARMADA_XP_CFB_CTL_REG_OFFSET -1: - ldrex r2, [r3] - orr r2, r2, r1 - strex r0, r2, [r3] - cmp r0, #0 - bne 1b +/* ll_add_cpu_to_smp_group, ll_enable_coherency and + * ll_disable_coherency use strex/ldrex whereas MMU can be off. The + * Armada XP SoC has an exclusive monitor that can track transactions + * to Device and/or SO and as such also when MMU is disabled the + * exclusive transactions will be functional + */ - /* Enable coherency on CPU - Atomic */ - add r3, r3, #ARMADA_XP_CFB_CFG_REG_OFFSET +ENTRY(ll_add_cpu_to_smp_group) + /* + * r0 being untouched in ll_get_coherency_base and + * ll_get_cpuid, we can use it to save lr modifing it with the + * following bl + */ + mov r0, lr + bl ll_get_coherency_base + bl ll_get_cpuid + mov lr, r0 + add r0, r1, #ARMADA_XP_CFB_CFG_REG_OFFSET 1: - ldrex r2, [r3] - orr r2, r2, r1 - strex r0, r2, [r3] - cmp r0, #0 - bne 1b + ldrex r2, [r0] + orr r2, r2, r3 + strex r1, r2, [r0] + cmp r1, #0 + bne 1b + mov pc, lr +ENDPROC(ll_add_cpu_to_smp_group) +ENTRY(ll_enable_coherency) + /* + * r0 being untouched in ll_get_coherency_base and + * ll_get_cpuid, we can use it to save lr modifing it with the + * following bl + */ + mov r0, lr + bl ll_get_coherency_base + bl ll_get_cpuid + mov lr, r0 + add r0, r1, #ARMADA_XP_CFB_CTL_REG_OFFSET +1: + ldrex r2, [r0] + orr r2, r2, r3 + strex r1, r2, [r0] + cmp r1, #0 + bne 1b dsb - mov r0, #0 mov pc, lr -ENDPROC(ll_set_cpu_coherent) +ENDPROC(ll_enable_coherency) + .align 2 3: diff --git a/arch/arm/mach-mvebu/headsmp.S b/arch/arm/mach-mvebu/headsmp.S index cf7abe6..2c4032e 100644 --- a/arch/arm/mach-mvebu/headsmp.S +++ b/arch/arm/mach-mvebu/headsmp.S @@ -31,8 +31,10 @@ ENTRY(armada_xp_secondary_startup) ARM_BE8(setend be ) @ go BE8 if entered LE - /* Add CPU to coherency fabric */ - bl ll_set_cpu_coherent + bl ll_add_cpu_to_smp_group + + bl ll_enable_coherency + b secondary_startup ENDPROC(armada_xp_secondary_startup) -- 2.7.4