Commit 304009a1 authored by Doug Anderson's avatar Doug Anderson Committed by Russell King
Browse files

ARM: 8861/1: errata: Workaround errata A12 857271 / A17 857272 

This adds support for working around errata A12 857271 / A17 857272.
These errata were causing hangs on rk3288-based Chromebooks and it was
confirmed that this workaround fixed the problems.  In the Chrome OS
3.14 kernel this was treated as two errata: ERRATA_FOOBAR [1] and
ERRATA_CR711784 [2].  Apparently the two errata got lumped together at
some point in time.

Let's actually get the workaround landed.

[1] https://crrev.com/c/342753
[2] https://crbug.com/711784



Signed-off-by: default avatarDouglas Anderson <dianders@chromium.org>
Signed-off-by: default avatarSonny Rao <sonnyrao@chromium.org>
Signed-off-by: default avatarRussell King <rmk+kernel@armlinux.org.uk>
parent b777a981

arch/arm/Kconfig

+18 −0
Original line number Diff line number Diff line
@@ -1175,6 +1175,14 @@ config ARM_ERRATA_825619 
	  DMB NSHST or DMB ISHST instruction followed by a mix of Cacheable

	  and Device/Strongly-Ordered loads and stores might cause deadlock



config ARM_ERRATA_857271

	bool "ARM errata: A12: CPU might deadlock under some very rare internal conditions"

	depends on CPU_V7

	help

	  This option enables the workaround for the 857271 Cortex-A12

	  (all revs) erratum. Under very rare timing conditions, the CPU might

	  hang. The workaround is expected to have a < 1% performance impact.



config ARM_ERRATA_852421

	bool "ARM errata: A17: DMB ST might fail to create order between stores"

	depends on CPU_V7
@@ -1196,6 +1204,16 @@ config ARM_ERRATA_852423 
	  config option from the A12 erratum due to the way errata are checked

	  for and handled.



config ARM_ERRATA_857272

	bool "ARM errata: A17: CPU might deadlock under some very rare internal conditions"

	depends on CPU_V7

	help

	  This option enables the workaround for the 857272 Cortex-A17 erratum.

	  This erratum is not known to be fixed in any A17 revision.

	  This is identical to Cortex-A12 erratum 857271.  It is a separate

	  config option from the A12 erratum due to the way errata are checked

	  for and handled.



endmenu



source "arch/arm/common/Kconfig"

arch/arm/mm/proc-v7.S

+10 −0
Original line number Diff line number Diff line
@@ -391,6 +391,11 @@ __ca12_errata: 
	mrc	p15, 0, r10, c15, c0, 1		@ read diagnostic register

	orr	r10, r10, #1 << 24		@ set bit #24

	mcr	p15, 0, r10, c15, c0, 1		@ write diagnostic register

#endif

#ifdef CONFIG_ARM_ERRATA_857271

	mrc	p15, 0, r10, c15, c0, 1		@ read diagnostic register

	orr	r10, r10, #3 << 10		@ set bits #10 and #11

	mcr	p15, 0, r10, c15, c0, 1		@ write diagnostic register

#endif

	b	__errata_finish
@@ -406,6 +411,11 @@ __ca17_errata: 
	mrcle	p15, 0, r10, c15, c0, 1		@ read diagnostic register

	orrle	r10, r10, #1 << 12		@ set bit #12

	mcrle	p15, 0, r10, c15, c0, 1		@ write diagnostic register

#endif

#ifdef CONFIG_ARM_ERRATA_857272

	mrc	p15, 0, r10, c15, c0, 1		@ read diagnostic register

	orr	r10, r10, #3 << 10		@ set bits #10 and #11

	mcr	p15, 0, r10, c15, c0, 1		@ write diagnostic register

#endif

	b	__errata_finish

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