Commit f630c1bd authored by Will Deacon's avatar Will Deacon Committed by Russell King
Browse files

ARM: 7091/1: errata: D-cache line maintenance operation by MVA may not succeed 



This patch implements a workaround for erratum 764369 affecting
Cortex-A9 MPCore with two or more processors (all current revisions).
Under certain timing circumstances, a data cache line maintenance
operation by MVA targeting an Inner Shareable memory region may fail to
proceed up to either the Point of Coherency or to the Point of
Unification of the system. This workaround adds a DSB instruction before
the relevant cache maintenance functions and sets a specific bit in the
diagnostic control register of the SCU.

Cc: <stable@kernel.org>
Signed-off-by: default avatarWill Deacon <will.deacon@arm.com>
Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
Tested-by: default avatarMark Rutland <mark.rutland@arm.com>
Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
parent 279b1e0f

arch/arm/Kconfig

+14 −0
Original line number Diff line number Diff line
@@ -1283,6 +1283,20 @@ config ARM_ERRATA_364296 
	  processor into full low interrupt latency mode. ARM11MPCore

	  is not affected.



config ARM_ERRATA_764369

	bool "ARM errata: Data cache line maintenance operation by MVA may not succeed"

	depends on CPU_V7 && SMP

	help

	  This option enables the workaround for erratum 764369

	  affecting Cortex-A9 MPCore with two or more processors (all

	  current revisions). Under certain timing circumstances, a data

	  cache line maintenance operation by MVA targeting an Inner

	  Shareable memory region may fail to proceed up to either the

	  Point of Coherency or to the Point of Unification of the

	  system. This workaround adds a DSB instruction before the

	  relevant cache maintenance functions and sets a specific bit

	  in the diagnostic control register of the SCU.



endmenu



source "arch/arm/common/Kconfig"

arch/arm/kernel/smp_scu.c

+10 −0
Original line number Diff line number Diff line
@@ -13,6 +13,7 @@ 


#include <asm/smp_scu.h>

#include <asm/cacheflush.h>

#include <asm/cputype.h>



#define SCU_CTRL		0x00

#define SCU_CONFIG		0x04
@@ -37,6 +38,15 @@ void __init scu_enable(void __iomem *scu_base) 
{

	u32 scu_ctrl;



#ifdef CONFIG_ARM_ERRATA_764369

	/* Cortex-A9 only */

	if ((read_cpuid(CPUID_ID) & 0xff0ffff0) == 0x410fc090) {

		scu_ctrl = __raw_readl(scu_base + 0x30);

		if (!(scu_ctrl & 1))

			__raw_writel(scu_ctrl | 0x1, scu_base + 0x30);

	}

#endif



	scu_ctrl = __raw_readl(scu_base + SCU_CTRL);

	/* already enabled? */

	if (scu_ctrl & 1)

arch/arm/mm/cache-v7.S

+20 −0
Original line number Diff line number Diff line
@@ -174,6 +174,10 @@ ENTRY(v7_coherent_user_range) 
	dcache_line_size r2, r3

	sub	r3, r2, #1

	bic	r12, r0, r3

#ifdef CONFIG_ARM_ERRATA_764369

	ALT_SMP(W(dsb))

	ALT_UP(W(nop))

#endif

1:

 USER(	mcr	p15, 0, r12, c7, c11, 1	)	@ clean D line to the point of unification

	add	r12, r12, r2
@@ -223,6 +227,10 @@ ENTRY(v7_flush_kern_dcache_area) 
	add	r1, r0, r1

	sub	r3, r2, #1

	bic	r0, r0, r3

#ifdef CONFIG_ARM_ERRATA_764369

	ALT_SMP(W(dsb))

	ALT_UP(W(nop))

#endif

1:

	mcr	p15, 0, r0, c7, c14, 1		@ clean & invalidate D line / unified line

	add	r0, r0, r2
@@ -247,6 +255,10 @@ v7_dma_inv_range: 
	sub	r3, r2, #1

	tst	r0, r3

	bic	r0, r0, r3

#ifdef CONFIG_ARM_ERRATA_764369

	ALT_SMP(W(dsb))

	ALT_UP(W(nop))

#endif

	mcrne	p15, 0, r0, c7, c14, 1		@ clean & invalidate D / U line



	tst	r1, r3
@@ -270,6 +282,10 @@ v7_dma_clean_range: 
	dcache_line_size r2, r3

	sub	r3, r2, #1

	bic	r0, r0, r3

#ifdef CONFIG_ARM_ERRATA_764369

	ALT_SMP(W(dsb))

	ALT_UP(W(nop))

#endif

1:

	mcr	p15, 0, r0, c7, c10, 1		@ clean D / U line

	add	r0, r0, r2
@@ -288,6 +304,10 @@ ENTRY(v7_dma_flush_range) 
	dcache_line_size r2, r3

	sub	r3, r2, #1

	bic	r0, r0, r3

#ifdef CONFIG_ARM_ERRATA_764369

	ALT_SMP(W(dsb))

	ALT_UP(W(nop))

#endif

1:

	mcr	p15, 0, r0, c7, c14, 1		@ clean & invalidate D / U line

	add	r0, r0, r2

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