[PATCH 3/3] ARM PJ4B: Add support for errata 4611

[Gregory CLEMENT]

From: Lior Amsalem <alior at marvell.com>

A CP15 clean operation can result in a dead lock state if it is hit by
an incoming snoop event. the fiw to this issue is the following:
before any CP15 clean type operation in Cache Coherency mode, issue a
Data Memory Barrier (DMB) or a Data Synchronization Barrier (DSB)
instruction.

[gregory.clement at free-electrons.com:add errata description in changelog]
[gregory.clement at free-electrons.com:make this errata depend on Aramda
370]
Signed-off-by: Lior Amsalem <alior at marvell.com>
Signed-off-by: Gregory CLEMENT <gregory.clement at free-electrons.com>
---
 arch/arm/Kconfig                | 11 +++++++++++
 arch/arm/include/asm/tlbflush.h | 22 ++++++++++++++++++++++
 arch/arm/mm/copypage-v6.c       | 11 +++++++++++
 arch/arm/mm/proc-macros.S       | 13 +++++++++++++
 4 files changed, 57 insertions(+)

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 48cdbea..05c13f9 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -1087,6 +1087,17 @@ if !MMU
 source "arch/arm/Kconfig-nommu"
 endif
 
+config PJ4B_ERRATA_4611
+        bool "PJ4B Errata 4611: A Deadlock can Occur if a CP15 Clean/Clean and Invalidate Operation is Hit By a Snoop Event"
+        depends on CPU_PJ4B && MACH_ARMADA_370
+        help
+          A CP15 clean operation can result in a dead lock state if it is hit by
+          an incoming snoop event.
+          Workaround:
+	  Before any CP15 clean type operation in Cache Coherency mode, issue
+          a Data Memory Barrier (DMB) or a Data Synchronization Barrier (DSB)
+          instruction.
+
 config PJ4B_ERRATA_4742
         bool "PJ4B Errata 4742: IDLE Wake Up Commands can Cause the CPU Core to Cease Operation"
         depends on CPU_PJ4B && MACH_ARMADA_370
diff --git a/arch/arm/include/asm/tlbflush.h b/arch/arm/include/asm/tlbflush.h
index e3a8064..112f778 100644
--- a/arch/arm/include/asm/tlbflush.h
+++ b/arch/arm/include/asm/tlbflush.h
@@ -475,11 +475,22 @@ static inline void flush_pmd_entry(void *pmd)
 {
 	const unsigned int __tlb_flag = __cpu_tlb_flags;
 
+#ifdef CONFIG_PJ4B_ERRATA_4611
+	unsigned long flags;
+	raw_local_irq_save(flags);
+	dmb();
+#endif
+
 #ifdef CONFIG_PJ4B_ERRATA_6124
 	tlb_op(TLB_DCLEAN, "c7, c14, 1	@ flush_pmd", pmd);
 #else
 	tlb_op(TLB_DCLEAN, "c7, c10, 1	@ flush_pmd", pmd);
 #endif
+
+#ifdef CONFIG_PJ4B_ERRATA_4611
+	raw_local_irq_restore(flags);
+#endif
+
 	tlb_l2_op(TLB_L2CLEAN_FR, "c15, c9, 1  @ L2 flush_pmd", pmd);
 
 	if (tlb_flag(TLB_WB))
@@ -490,11 +501,22 @@ static inline void clean_pmd_entry(void *pmd)
 {
 	const unsigned int __tlb_flag = __cpu_tlb_flags;
 
+#ifdef CONFIG_PJ4B_ERRATA_4611
+	unsigned long flags;
+	raw_local_irq_save(flags);
+	dmb();
+#endif
+
 #ifdef CONFIG_PJ4B_ERRATA_6124
 	tlb_op(TLB_DCLEAN, "c7, c14, 1	@ flush_pmd", pmd);
 #else
 	tlb_op(TLB_DCLEAN, "c7, c10, 1	@ flush_pmd", pmd);
 #endif
+
+#ifdef CONFIG_PJ4B_ERRATA_4611
+	raw_local_irq_restore(flags);
+#endif
+
 	tlb_l2_op(TLB_L2CLEAN_FR, "c15, c9, 1  @ L2 flush_pmd", pmd);
 }
 
diff --git a/arch/arm/mm/copypage-v6.c b/arch/arm/mm/copypage-v6.c
index b9bcc9d..20b69ad 100644
--- a/arch/arm/mm/copypage-v6.c
+++ b/arch/arm/mm/copypage-v6.c
@@ -59,11 +59,22 @@ static void v6_clear_user_highpage_nonaliasing(struct page *page, unsigned long
  */
 static void discard_old_kernel_data(void *kto)
 {
+#ifdef CONFIG_PJ4B_ERRATA_4611
+        unsigned long flags;
+
+        raw_local_irq_save(flags);
+        dmb();
+#endif
+
 	__asm__("mcrr	p15, 0, %1, %0, c6	@ 0xec401f06"
 	   :
 	   : "r" (kto),
 	     "r" ((unsigned long)kto + PAGE_SIZE - L1_CACHE_BYTES)
 	   : "cc");
+
+#ifdef CONFIG_PJ4B_ERRATA_4611
+        raw_local_irq_restore(flags);
+#endif
 }
 
 /*
diff --git a/arch/arm/mm/proc-macros.S b/arch/arm/mm/proc-macros.S
index f9a0aa7..ca81291 100644
--- a/arch/arm/mm/proc-macros.S
+++ b/arch/arm/mm/proc-macros.S
@@ -178,7 +178,20 @@
 #endif
 
 	str	r3, [r0]
+
+#ifdef CONFIG_PJ4B_ERRATA_4611
+	mrs     r2, cpsr
+	orr     r3, r2, #PSR_F_BIT | PSR_I_BIT
+	msr     cpsr_c, r3                      @ Disable interrupts
+	dmb                                     @ ensure ordering with previous memory accesses
+#endif
+
 	mcr	p15, 0, r0, c7, c10, 1		@ flush_pte
+
+#ifdef CONFIG_PJ4B_ERRATA_4611
+	msr     cpsr_c, r2                      @ Restore interrupts
+	mcr     p15, 0, r0, c7, c10, 4          @ drain write buffer
+#endif
 	.endm
 
 
-- 
1.8.1.2