cortex_a53: Add A53 errata #826319, #836870

- Apply a53 errata #826319 to revision <= r0p2
- Apply a53 errata #836870 to revision <= r0p3
- Update docs/cpu-specific-build-macros.md for newly added errata build flags

Change-Id: I44918e36b47dca1fa29695b68700ff9bf888865e
Signed-off-by: Jimmy Huang <jimmy.huang@mediatek.com>

4 files changed, 126 insertions, 3 deletions

diff --git a/docs/cpu-specific-build-macros.md b/docs/cpu-specific-build-macros.md
index 2368fd22..d9b7108c 100644
--- a/docs/cpu-specific-build-macros.md
+++ b/docs/cpu-specific-build-macros.md
@@ -43,6 +43,15 @@ for it to specify which errata workarounds should be enabled or not.
 The value of the build flags are 0 by default, that is, disabled. Any other
 value will enable it.
 
+For Cortex-A53, following errata build flags are defined :
+
+*   `ERRATA_A53_826319`: This applies errata 826319 workaround to Cortex-A53
+     CPU. This needs to be enabled only for revision <= r0p2 of the CPU.
+
+*   `ERRATA_A53_836870`: This applies errata 836870 workaround to Cortex-A53
+     CPU. This needs to be enabled only for revision <= r0p3 of the CPU. From
+     r0p4 and onwards, this errata is enabled by default.
+
 For Cortex-A57, following errata build flags are defined :
 
 *   `ERRATA_A57_806969`: This applies errata 806969 workaround to Cortex-A57
diff --git a/include/lib/cpus/aarch64/cortex_a53.h b/include/lib/cpus/aarch64/cortex_a53.h
index 14821ab6..6e71f9ca 100644
--- a/include/lib/cpus/aarch64/cortex_a53.h
+++ b/include/lib/cpus/aarch64/cortex_a53.h
@@ -41,4 +41,19 @@
 
 #define CPUECTLR_SMP_BIT		(1 << 6)
 
+/*******************************************************************************
+ * CPU Auxiliary Control register specific definitions.
+ ******************************************************************************/
+#define CPUACTLR_EL1			S3_1_C15_C2_0	/* Instruction def. */
+
+#define CPUACTLR_DTAH			(1 << 24)
+
+/*******************************************************************************
+ * L2 Auxiliary Control register specific definitions.
+ ******************************************************************************/
+#define L2ACTLR_EL1			S3_1_C15_C0_0	/* Instruction def. */
+
+#define L2ACTLR_ENABLE_UNIQUECLEAN	(1 << 14)
+#define L2ACTLR_DISABLE_CLEAN_PUSH	(1 << 3)
+
 #endif /* __CORTEX_A53_H__ */
diff --git a/lib/cpus/aarch64/cortex_a53.S b/lib/cpus/aarch64/cortex_a53.S
index e149e6e6..e4b94e80 100644
--- a/lib/cpus/aarch64/cortex_a53.S
+++ b/lib/cpus/aarch64/cortex_a53.S
@@ -59,11 +59,93 @@ func cortex_a53_disable_smp
 	ret
 endfunc cortex_a53_disable_smp
 
+	/* --------------------------------------------------
+	 * Errata Workaround for Cortex A53 Errata #826319.
+	 * This applies only to revision <= r0p2 of Cortex A53.
+	 * Inputs:
+	 * x0: variant[4:7] and revision[0:3] of current cpu.
+	 * Clobbers : x0 - x5
+	 * --------------------------------------------------
+	 */
+func errata_a53_826319_wa
+	/*
+	 * Compare x0 against revision r0p2
+	 */
+	cmp	x0, #2
+	b.ls	apply_826319
+#if DEBUG
+	b	print_revision_warning
+#else
+	ret
+#endif
+apply_826319:
+	mrs	x1, L2ACTLR_EL1
+	bic	x1, x1, #L2ACTLR_ENABLE_UNIQUECLEAN
+	orr	x1, x1, #L2ACTLR_DISABLE_CLEAN_PUSH
+	msr	L2ACTLR_EL1, x1
+	ret
+endfunc errata_a53_826319_wa
+
+	/* --------------------------------------------------
+	 * Errata Workaround for Cortex A53 Errata #836870.
+	 * This applies only to revision <= r0p3 of Cortex A53.
+	 * From r0p4 and onwards, this errata is enabled by
+	 * default.
+	 * Inputs:
+	 * x0: variant[4:7] and revision[0:3] of current cpu.
+	 * Clobbers : x0 - x5
+	 * --------------------------------------------------
+	 */
+func errata_a53_836870_wa
+	/*
+	 * Compare x0 against revision r0p3
+	 */
+	cmp	x0, #3
+	b.ls	apply_836870
+#if DEBUG
+	b	print_revision_warning
+#else
+	ret
+#endif
+apply_836870:
+	mrs	x1, CPUACTLR_EL1
+	orr	x1, x1, #CPUACTLR_DTAH
+	msr	CPUACTLR_EL1, x1
+	ret
+endfunc errata_a53_836870_wa
+
+	/* -------------------------------------------------
+	 * The CPU Ops reset function for Cortex-A53.
+	 * Clobbers: x0-x5, x15, x19, x30
+	 * -------------------------------------------------
+	 */
 func cortex_a53_reset_func
+	mov	x19, x30
+	mrs	x0, midr_el1
+
+	/*
+	 * Extract the variant[20:23] and revision[0:3] from x0
+	 * and pack it in x15[0:7] as variant[4:7] and revision[0:3].
+	 * First extract x0[16:23] to x15[0:7] and zero fill the rest.
+	 * Then extract x0[0:3] into x15[0:3] retaining other bits.
+	 */
+	ubfx	x15, x0, #(MIDR_VAR_SHIFT - MIDR_REV_BITS), \
+			#(MIDR_REV_BITS + MIDR_VAR_BITS)
+	bfxil	x15, x0, #MIDR_REV_SHIFT, #MIDR_REV_BITS
+
+#if ERRATA_A53_826319
+	mov	x0, x15
+	bl	errata_a53_826319_wa
+#endif
+
+#if ERRATA_A53_836870
+	mov	x0, x15
+	bl	errata_a53_836870_wa
+#endif
+
 	/* ---------------------------------------------
 	 * As a bare minimum enable the SMP bit if it is
 	 * not already set.
-	 * Clobbers : x0
 	 * ---------------------------------------------
 	 */
 	mrs	x0, CPUECTLR_EL1
@@ -71,9 +153,9 @@ func cortex_a53_reset_func
 	b.ne	skip_smp_setup
 	orr	x0, x0, #CPUECTLR_SMP_BIT
 	msr	CPUECTLR_EL1, x0
-	isb
 skip_smp_setup:
-	ret
+	isb
+	ret	x19
 endfunc cortex_a53_reset_func
 
 func cortex_a53_core_pwr_dwn
diff --git a/lib/cpus/cpu-ops.mk b/lib/cpus/cpu-ops.mk
index 1c5512e9..a872360e 100644
--- a/lib/cpus/cpu-ops.mk
+++ b/lib/cpus/cpu-ops.mk
@@ -40,6 +40,15 @@ $(eval $(call add_define,SKIP_A57_L1_FLUSH_PWR_DWN))
 # CPU Errata Build flags. These should be enabled by the
 # platform if the errata needs to be applied.
 
+# Flag to apply errata 826319 during reset. This errata applies only to
+# revision <= r0p2 of the Cortex A53 cpu.
+ERRATA_A53_826319	?=0
+
+# Flag to apply errata 836870 during reset. This errata applies only to
+# revision <= r0p3 of the Cortex A53 cpu. From r0p4 and onwards, this
+# errata is enabled by default.
+ERRATA_A53_836870	?=0
+
 # Flag to apply errata 806969 during reset. This errata applies only to
 # revision r0p0 of the Cortex A57 cpu.
 ERRATA_A57_806969	?=0
@@ -48,6 +57,14 @@ ERRATA_A57_806969	?=0
 # revision r0p0 of the Cortex A57 cpu.
 ERRATA_A57_813420	?=0
 
+# Process ERRATA_A53_826319 flag
+$(eval $(call assert_boolean,ERRATA_A53_826319))
+$(eval $(call add_define,ERRATA_A53_826319))
+
+# Process ERRATA_A53_836870 flag
+$(eval $(call assert_boolean,ERRATA_A53_836870))
+$(eval $(call add_define,ERRATA_A53_836870))
+
 # Process ERRATA_A57_806969 flag
 $(eval $(call assert_boolean,ERRATA_A57_806969))
 $(eval $(call add_define,ERRATA_A57_806969))