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: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Tested-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 20 insertions, 0 deletions

diff --git a/arch/arm/mm/cache-v7.S b/arch/arm/mm/cache-v7.S
index 3b24bfa3b828..07c4bc8ea0a4 100644
--- a/arch/arm/mm/cache-v7.S
+++ b/arch/arm/mm/cache-v7.S
@@ -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