Merge pull request #1523 from jts-arm/dsu

DSU erratum 936184 workaround

bl1/bl1.mk

 #
-# Copyright (c) 2013-2017, ARM Limited and Contributors. All rights reserved.
+# Copyright (c) 2013-2018, ARM Limited and Contributors. All rights reserved.
 #
 # SPDX-License-Identifier: BSD-3-Clause
 #
@@ -17,7 +17,8 @@ BL1_SOURCES		+=	bl1/bl1_main.c				\
 				${MBEDTLS_SOURCES}
 
 ifeq (${ARCH},aarch64)
-BL1_SOURCES		+=	lib/el3_runtime/aarch64/context.S
+BL1_SOURCES		+=	lib/cpus/aarch64/dsu_helpers.S		\
+				lib/el3_runtime/aarch64/context.S
 endif
 
 ifeq (${TRUSTED_BOARD_BOOT},1)

bl2/bl2.mk

 #
-# Copyright (c) 2013-2017, ARM Limited and Contributors. All rights reserved.
+# Copyright (c) 2013-2018, ARM Limited and Contributors. All rights reserved.
 #
 # SPDX-License-Identifier: BSD-3-Clause
 #
@@ -29,5 +29,10 @@ BL2_SOURCES		+=	bl2/${ARCH}/bl2_el3_entrypoint.S	\
 				bl2/${ARCH}/bl2_el3_exceptions.S	\
 				lib/cpus/${ARCH}/cpu_helpers.S		\
 				lib/cpus/errata_report.c
+
+ifeq (${ARCH},aarch64)
+BL2_SOURCES		+=	lib/cpus/aarch64/dsu_helpers.S
+endif
+
 BL2_LINKERFILE		:=	bl2/bl2_el3.ld.S
 endif

bl31/bl31.mk

@@ -24,6 +24,7 @@ BL31_SOURCES		+=	bl31/bl31_main.c				\
 				bl31/bl31_context_mgmt.c			\
 				common/runtime_svc.c				\
 				lib/aarch64/setjmp.S				\
+				lib/cpus/aarch64/dsu_helpers.S			\
 				plat/common/aarch64/platform_mp_stack.S		\
 				services/arm_arch_svc/arm_arch_svc_setup.c	\
 				services/std_svc/std_svc_setup.c		\

docs/cpu-specific-build-macros.rst

@@ -68,10 +68,10 @@ In the current implementation, a platform which has more than 1 variant
 with different revisions of a processor has no runtime mechanism available
 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.
+The value of the build flags is 0 by default, that is, disabled. A value of 1
+will enable it.
 
-For Cortex-A53, following errata build flags are defined :
+For Cortex-A53, the 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.
@@ -97,7 +97,7 @@ For Cortex-A53, following errata build flags are defined :
    Earlier revisions of the CPU have other errata which require the same
    workaround in software, so they should be covered anyway.
 
-For Cortex-A57, following errata build flags are defined :
+For Cortex-A57, the following errata build flags are defined :
 
 -  ``ERRATA_A57_806969``: This applies errata 806969 workaround to Cortex-A57
    CPU. This needs to be enabled only for revision r0p0 of the CPU.
@@ -127,11 +127,33 @@ For Cortex-A57, following errata build flags are defined :
    CPU. This needs to be enabled only for revision <= r1p3 of the CPU.
 
 
-For Cortex-A72, following errata build flags are defined :
+For Cortex-A72, the following errata build flags are defined :
 
 -  ``ERRATA_A72_859971``: This applies errata 859971 workaround to Cortex-A72
    CPU. This needs to be enabled only for revision <= r0p3 of the CPU.
 
+DSU Errata Workarounds
+----------------------
+
+Similar to CPU errata, TF-A also implements workarounds for DSU (DynamIQ
+Shared Unit) errata. The DSU errata details can be found in the respective Arm
+documentation:
+
+- `Arm DSU Software Developers Errata Notice`_.
+
+Each erratum is identified by an ``ID``, as defined in the DSU errata notice
+document. Thus, the build flags which enable/disable the errata workarounds
+have the format ``ERRATA_DSU_<ID>``. The implementation and application logic
+of DSU errata workarounds are similar to `CPU errata workarounds`_.
+
+For DSU errata, the following build flags are defined:
+
+-  ``ERRATA_DSU_936184``: This applies errata 936184 workaround for the
+   affected DSU configurations. This errata applies only for those DSUs that
+   contain the ACP interface **and** the DSU revision is older than r2p0 (on
+   r2p0 it is fixed). However, please note that this workaround results in
+   increased DSU power consumption on idle.
+
 CPU Specific optimizations
 --------------------------
 
@@ -171,3 +193,4 @@ architecture that can be enabled by the platform as desired.
 .. _Cortex-A72 MPCore Software Developers Errata Notice: http://infocenter.arm.com/help/topic/com.arm.doc.epm012079/index.html
 .. _Firmware Design guide: firmware-design.rst
 .. _Cortex-A57 Software Optimization Guide: http://infocenter.arm.com/help/topic/com.arm.doc.uan0015b/Cortex_A57_Software_Optimization_Guide_external.pdf
+.. _Arm DSU Software Developers Errata Notice: http://infocenter.arm.com/help/topic/com.arm.doc.epm138168/index.html
\ No newline at end of file

include/lib/cpus/aarch64/dsu_def.h

+/*
+ * Copyright (c) 2018, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#ifndef DSU_DEF_H
+#define DSU_DEF_H
+
+#include <utils_def.h>
+
+/********************************************************************
+ * DSU control registers definitions				    *
+ ********************************************************************/
+#define CLUSTERCFR_EL1		S3_0_C15_C3_0
+#define CLUSTERIDR_EL1		S3_0_C15_C3_1
+#define CLUSTERACTLR_EL1	S3_0_C15_C3_3
+
+/********************************************************************
+ * DSU control registers bit fields				    *
+ ********************************************************************/
+#define CLUSTERIDR_REV_SHIFT	U(0)
+#define CLUSTERIDR_REV_BITS	U(4)
+#define CLUSTERIDR_VAR_SHIFT	U(4)
+#define CLUSTERIDR_VAR_BITS	U(4)
+#define CLUSTERCFR_ACP_SHIFT	U(11)
+
+/********************************************************************
+ * Masks applied for DSU errata workarounds			    *
+ ********************************************************************/
+#define DSU_ERRATA_936184_MASK	(ULL(0x3) << 15)
+
+#endif /* DSU_DEF_H */

lib/cpus/aarch64/cortex_a55.S

 /*
- * Copyright (c) 2017, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2017-2018, ARM Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -11,6 +11,14 @@
 #include <cpu_macros.S>
 #include <plat_macros.S>
 
+func cortex_a55_reset_func
+	mov	x19, x30
+#if ERRATA_DSU_936184
+	bl	errata_dsu_936184_wa
+#endif
+	ret	x19
+endfunc cortex_a55_reset_func
+
 	/* ---------------------------------------------
 	 * HW will do the cache maintenance while powering down
 	 * ---------------------------------------------
@@ -27,6 +35,26 @@ func cortex_a55_core_pwr_dwn
 	ret
 endfunc cortex_a55_core_pwr_dwn
 
+#if REPORT_ERRATA
+/*
+ * Errata printing function for Cortex A55. Must follow AAPCS & can use stack.
+ */
+func cortex_a55_errata_report
+	stp	x8, x30, [sp, #-16]!
+	bl	cpu_get_rev_var
+	mov	x8, x0
+
+	/*
+	 * Report all errata. The revision variant information is at x8, where
+	 * "report_errata" is expecting it and it doesn't corrupt it.
+	 */
+	report_errata ERRATA_DSU_936184, cortex_a55, dsu_936184
+
+	ldp	x8, x30, [sp], #16
+	ret
+endfunc cortex_a55_errata_report
+#endif
+
 	/* ---------------------------------------------
 	 * This function provides cortex_a55 specific
 	 * register information for crash reporting.
@@ -47,5 +75,5 @@ func cortex_a55_cpu_reg_dump
 endfunc cortex_a55_cpu_reg_dump
 
 declare_cpu_ops cortex_a55, CORTEX_A55_MIDR, \
-	CPU_NO_RESET_FUNC, \
+	cortex_a55_reset_func, \
 	cortex_a55_core_pwr_dwn

lib/cpus/aarch64/cortex_a75.S

@@ -11,6 +11,7 @@
 #include <cpu_macros.S>
 
 func cortex_a75_reset_func
+	mov	x19, x30
 #if IMAGE_BL31 && WORKAROUND_CVE_2017_5715
 	cpu_check_csv2	x0, 1f
 	adr	x0, wa_cve_2017_5715_bpiall_vbar
@@ -26,6 +27,10 @@ func cortex_a75_reset_func
 	isb
 #endif
 
+#if ERRATA_DSU_936184
+	bl	errata_dsu_936184_wa
+#endif
+
 #if ENABLE_AMU
 	/* Make sure accesses from EL0/EL1 and EL2 are not trapped to EL3 */
 	mrs	x0, actlr_el3
@@ -49,7 +54,7 @@ func cortex_a75_reset_func
 	msr	CPUAMCNTENSET_EL0, x0
 	isb
 #endif
-	ret
+	ret	x19
 endfunc cortex_a75_reset_func
 
 func check_errata_cve_2017_5715
@@ -106,6 +111,7 @@ func cortex_a75_errata_report
 	 */
 	report_errata WORKAROUND_CVE_2017_5715, cortex_a75, cve_2017_5715
 	report_errata WORKAROUND_CVE_2018_3639, cortex_a75, cve_2018_3639
+	report_errata ERRATA_DSU_936184, cortex_a75, dsu_936184
 
 	ldp	x8, x30, [sp], #16
 	ret

lib/cpus/aarch64/cortex_a76.S

 /*
- * Copyright (c) 2017, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2017-2018, ARM Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -207,6 +207,7 @@ func cortex_a76_disable_wa_cve_2018_3639
 endfunc cortex_a76_disable_wa_cve_2018_3639
 
 func cortex_a76_reset_func
+	mov	x19, x30
 #if WORKAROUND_CVE_2018_3639
 	mrs	x0, CORTEX_A76_CPUACTLR2_EL1
 	orr	x0, x0, #CORTEX_A76_CPUACTLR2_EL1_DISABLE_LOAD_PASS_STORE
@@ -224,7 +225,11 @@ func cortex_a76_reset_func
 	msr	vbar_el3, x0
 	isb
 #endif
-	ret
+
+#if ERRATA_DSU_936184
+	bl	errata_dsu_936184_wa
+#endif
+	ret	x19
 endfunc cortex_a76_reset_func
 
 	/* ---------------------------------------------
@@ -258,6 +263,7 @@ func cortex_a76_errata_report
 	 * checking functions of each errata.
 	 */
 	report_errata WORKAROUND_CVE_2018_3639, cortex_a76, cve_2018_3639
+	report_errata ERRATA_DSU_936184, cortex_a76, dsu_936184
 
 	ldp	x8, x30, [sp], #16
 	ret

lib/cpus/aarch64/dsu_helpers.S

+/*
+ * Copyright (c) 2018, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <asm_macros.S>
+#include <dsu_def.h>
+#include <errata_report.h>
+
+/*
+ * DSU erratum 936184
+ * Check the DSU variant, revision and configuration to determine if the
+ * erratum applies. This erratum was fixed in r2p0.
+ *
+ * This function is called from both assembly and C environment. So it
+ * follows AAPCS.
+ *
+ * Clobbers: x0-x3
+ */
+	.globl	check_errata_dsu_936184
+	.globl	errata_dsu_936184_wa
+
+func check_errata_dsu_936184
+	mov	x2, #ERRATA_NOT_APPLIES
+	mov	x3, #ERRATA_APPLIES
+
+	/* Erratum applies only if ACP interface is present in DSU */
+	mov	x0, x2
+	mrs	x1, CLUSTERCFR_EL1
+	ubfx	x1, x1, #CLUSTERCFR_ACP_SHIFT, #1
+	cbz	x1, 1f
+
+	/* If ACP is present, check if DSU is older than r2p0 */
+	mrs	x1, CLUSTERIDR_EL1
+
+	/* DSU variant and revision bitfields in CLUSTERIDR are adjacent */
+	ubfx	x0, x1, #CLUSTERIDR_REV_SHIFT,\
+			#(CLUSTERIDR_REV_BITS + CLUSTERIDR_VAR_BITS)
+	mov	x1, #(0x2 << CLUSTERIDR_REV_BITS)
+	cmp	x0, x1
+	csel	x0, x2, x3, hs
+1:
+	ret
+endfunc check_errata_dsu_936184
+
+func errata_dsu_936184_wa
+	mov	x20, x30
+	bl	check_errata_dsu_936184
+	cbz	x0, 1f
+
+	/* If erratum applies, we set a mask to a DSU control register */
+	mrs	x0, CLUSTERACTLR_EL1
+	ldr	x1, =DSU_ERRATA_936184_MASK
+	orr	x0, x0, x1
+	msr	CLUSTERACTLR_EL1, x0
+	isb
+1:
+	ret	x20
+endfunc errata_dsu_936184_wa

lib/cpus/cpu-ops.mk

@@ -123,6 +123,11 @@ ERRATA_A72_859971	?=0
 # only to r0p0 and r1p0 of the Ares cpu.
 ERRATA_ARES_1043202	?=1
 
+# Flag to apply DSU erratum 936184. This erratum applies to DSUs containing
+# the ACP interface and revision < r2p0. Applying the workaround results in
+# higher DSU power consumption on idle.
+ERRATA_DSU_936184	?=0
+
 # Process ERRATA_A53_826319 flag
 $(eval $(call assert_boolean,ERRATA_A53_826319))
 $(eval $(call add_define,ERRATA_A53_826319))
@@ -187,6 +192,10 @@ $(eval $(call add_define,ERRATA_A72_859971))
 $(eval $(call assert_boolean,ERRATA_ARES_1043202))
 $(eval $(call add_define,ERRATA_ARES_1043202))
 
+# Process ERRATA_DSU_936184 flag
+$(eval $(call assert_boolean,ERRATA_DSU_936184))
+$(eval $(call add_define,ERRATA_DSU_936184))
+
 # Errata build flags
 ifneq (${ERRATA_A53_843419},0)
 TF_LDFLAGS_aarch64	+= --fix-cortex-a53-843419