From 9f05027c7cb3cfe56a31892bd83391138d41a667 Mon Sep 17 00:00:00 2001 From: Will Deacon Date: Tue, 14 Sep 2010 09:51:43 +0100 Subject: [PATCH] ARM: 6388/1: errata: DMB operation may be faulty On versions of the Cortex-A9 up to and including r2p2, under rare circumstances, a DMB instruction between 2 write operations may not ensure the correct visibility ordering of the 2 writes. This workaround sets a bit in the diagnostic register of the Cortex-A9, causing the DMB instruction to behave like a DSB, which functions correctly on the affected cores. Acked-by: Catalin Marinas Signed-off-by: Will Deacon Signed-off-by: Russell King --- arch/arm/Kconfig | 12 ++++++++++++ arch/arm/mm/proc-v7.S | 16 ++++++++++++++-- 2 files changed, 26 insertions(+), 2 deletions(-) diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index 553b7cf17bfb..ab14c0a5d21e 100644 --- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig @@ -1051,6 +1051,18 @@ config ARM_ERRATA_460075 ACTLR register. Note that setting specific bits in the ACTLR register may not be available in non-secure mode. +config ARM_ERRATA_742230 + bool "ARM errata: DMB operation may be faulty" + depends on CPU_V7 && SMP + help + This option enables the workaround for the 742230 Cortex-A9 + (r1p0..r2p2) erratum. Under rare circumstances, a DMB instruction + between two write operations may not ensure the correct visibility + ordering of the two writes. This workaround sets a specific bit in + the diagnostic register of the Cortex-A9 which causes the DMB + instruction to behave as a DSB, ensuring the correct behaviour of + the two writes. + config PL310_ERRATA_588369 bool "Clean & Invalidate maintenance operations do not invalidate clean lines" depends on CACHE_L2X0 && ARCH_OMAP4 diff --git a/arch/arm/mm/proc-v7.S b/arch/arm/mm/proc-v7.S index 1f16f9e3f441..945f36341fa6 100644 --- a/arch/arm/mm/proc-v7.S +++ b/arch/arm/mm/proc-v7.S @@ -201,7 +201,7 @@ __v7_setup: mrc p15, 0, r0, c0, c0, 0 @ read main ID register and r10, r0, #0xff000000 @ ARM? teq r10, #0x41000000 - bne 2f + bne 3f and r5, r0, #0x00f00000 @ variant and r6, r0, #0x0000000f @ revision orr r6, r6, r5, lsr #20-4 @ combine variant and revision @@ -231,8 +231,20 @@ __v7_setup: orreq r10, r10, #(1 << 22) @ set the Write Allocate disable bit mcreq p15, 1, r10, c9, c0, 2 @ write the L2 cache aux ctrl register #endif + b 3f + + /* Cortex-A9 Errata */ +2: ldr r10, =0x00000c09 @ Cortex-A9 primary part number + teq r0, r10 + bne 3f +#ifdef CONFIG_ARM_ERRATA_742230 + cmp r6, #0x22 @ only present up to r2p2 + mrcle p15, 0, r10, c15, c0, 1 @ read diagnostic register + orrle r10, r10, #1 << 4 @ set bit #4 + mcrle p15, 0, r10, c15, c0, 1 @ write diagnostic register +#endif -2: mov r10, #0 +3: mov r10, #0 #ifdef HARVARD_CACHE mcr p15, 0, r10, c7, c5, 0 @ I+BTB cache invalidate #endif -- 2.20.1