Commit 92871b94 authored by Rob Herring's avatar Rob Herring Committed by Russell King
Browse files

ARM: 7855/1: Add check for Cortex-A15 errata 798181 ECO 



The work-around for A15 errata 798181 is not needed if appropriate ECO
fixes have been applied to r3p2 and earlier core revisions. This can be
checked by reading REVIDR register bits 4 and 9. If only bit 4 is set,
then the IPI broadcast can be skipped.

Signed-off-by: default avatarRob Herring <rob.herring@calxeda.com>
Reviewed-by: default avatarWill Deacon <will.deacon@arm.com>
Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
parent 0cbad9c9

arch/arm/include/asm/cputype.h

+1 −0
Original line number Diff line number Diff line
@@ -10,6 +10,7 @@ 
#define CPUID_TLBTYPE	3

#define CPUID_MPUIR	4

#define CPUID_MPIDR	5

#define CPUID_REVIDR	6



#ifdef CONFIG_CPU_V7M

#define CPUID_EXT_PFR0	0x40

arch/arm/include/asm/tlbflush.h

+17 −31
Original line number Diff line number Diff line
@@ -560,37 +560,6 @@ static inline void __flush_bp_all(void) 
		asm("mcr p15, 0, %0, c7, c1, 6" : : "r" (zero));

}



#include <asm/cputype.h>

#ifdef CONFIG_ARM_ERRATA_798181

static inline int erratum_a15_798181(void)

{

	unsigned int midr = read_cpuid_id();



	/* Cortex-A15 r0p0..r3p2 affected */

	if ((midr & 0xff0ffff0) != 0x410fc0f0 || midr > 0x413fc0f2)

		return 0;

	return 1;

}



static inline void dummy_flush_tlb_a15_erratum(void)

{

	/*

	 * Dummy TLBIMVAIS. Using the unmapped address 0 and ASID 0.

	 */

	asm("mcr p15, 0, %0, c8, c3, 1" : : "r" (0));

	dsb(ish);

}

#else

static inline int erratum_a15_798181(void)

{

	return 0;

}



static inline void dummy_flush_tlb_a15_erratum(void)

{

}

#endif



/*

 *	flush_pmd_entry

 *
@@ -697,4 +666,21 @@ extern void flush_bp_all(void); 


#endif



#ifndef __ASSEMBLY__

#ifdef CONFIG_ARM_ERRATA_798181

extern void erratum_a15_798181_init(void);

#else

static inline void erratum_a15_798181_init(void) {}

#endif

extern bool (*erratum_a15_798181_handler)(void);



static inline bool erratum_a15_798181(void)

{

	if (unlikely(IS_ENABLED(CONFIG_ARM_ERRATA_798181) &&

		erratum_a15_798181_handler))

		return erratum_a15_798181_handler();

	return false;

}

#endif



#endif

arch/arm/kernel/setup.c

+2 −0
Original line number Diff line number Diff line
@@ -599,6 +599,8 @@ static void __init setup_processor(void) 
	elf_hwcap &= ~(HWCAP_THUMB | HWCAP_IDIVT);

#endif



	erratum_a15_798181_init();



	feat_v6_fixup();



	cacheid_init();

arch/arm/kernel/smp_tlb.c

+34 −2
Original line number Diff line number Diff line
@@ -70,6 +70,40 @@ static inline void ipi_flush_bp_all(void *ignored) 
	local_flush_bp_all();

}



#ifdef CONFIG_ARM_ERRATA_798181

bool (*erratum_a15_798181_handler)(void);



static bool erratum_a15_798181_partial(void)

{

	asm("mcr p15, 0, %0, c8, c3, 1" : : "r" (0));

	dsb(ish);

	return false;

}



static bool erratum_a15_798181_broadcast(void)

{

	asm("mcr p15, 0, %0, c8, c3, 1" : : "r" (0));

	dsb(ish);

	return true;

}



void erratum_a15_798181_init(void)

{

	unsigned int midr = read_cpuid_id();

	unsigned int revidr = read_cpuid(CPUID_REVIDR);



	/* Cortex-A15 r0p0..r3p2 w/o ECO fix affected */

	if ((midr & 0xff0ffff0) != 0x410fc0f0 || midr > 0x413fc0f2 ||

	    (revidr & 0x210) == 0x210) {

		return;

	}

	if (revidr & 0x10)

		erratum_a15_798181_handler = erratum_a15_798181_partial;

	else

		erratum_a15_798181_handler = erratum_a15_798181_broadcast;

}

#endif



static void ipi_flush_tlb_a15_erratum(void *arg)

{

	dmb();
@@ -80,7 +114,6 @@ static void broadcast_tlb_a15_erratum(void) 
	if (!erratum_a15_798181())

		return;



	dummy_flush_tlb_a15_erratum();

	smp_call_function(ipi_flush_tlb_a15_erratum, NULL, 1);

}
@@ -92,7 +125,6 @@ static void broadcast_tlb_mm_a15_erratum(struct mm_struct *mm) 
	if (!erratum_a15_798181())

		return;



	dummy_flush_tlb_a15_erratum();

	this_cpu = get_cpu();

	a15_erratum_get_cpumask(this_cpu, mm, &mask);

	smp_call_function_many(&mask, ipi_flush_tlb_a15_erratum, NULL, 1);

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