Cortex-A55: Implement workaround for erratum 798797

Change-Id: Ic42b37b8500d5e592af2b9fe130f35a0e2db4d14
Signed-off-by: Ambroise Vincent <[email protected]>

diff --git a/docs/cpu-specific-build-macros.rst b/docs/cpu-specific-build-macros.rst
index 77e12d1e39af9a98452e5f01304e6decfd7ecddf..65e1c84af96dc5368ee1480a3dab6f405c7d7c82 100644 (file)
--- a/docs/cpu-specific-build-macros.rst
+++ b/docs/cpu-specific-build-macros.rst
@@ -105,6 +105,9 @@ For Cortex-A55, the following errata build flags are defined :
 -  ``ERRATA_A55_778703``: This applies errata 778703 workaround to Cortex-A55
    CPU. This needs to be enabled only for revision r0p0 of the CPU.
 
+-  ``ERRATA_A55_798797``: This applies errata 798797 workaround to Cortex-A55
+   CPU. This needs to be enabled only for revision r0p0 of the CPU.
+
 For Cortex-A57, the 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_a55.h b/include/lib/cpus/aarch64/cortex_a55.h
index 13f20999403dd4672447c4a45eaaf4a6b61cbfee..feac1d2f0832edf24187354e00f7b849af24560c 100644 (file)
--- a/include/lib/cpus/aarch64/cortex_a55.h
+++ b/include/lib/cpus/aarch64/cortex_a55.h
@@ -27,6 +27,7 @@
 
 #define CORTEX_A55_CPUACTLR_EL1_DISABLE_WRITE_STREAMING        (ULL(1) << 24)
 #define CORTEX_A55_CPUACTLR_EL1_DISABLE_DUAL_ISSUE     (ULL(1) << 31)
+#define CORTEX_A55_CPUACTLR_EL1_DISABLE_L1_PAGEWALKS   (ULL(1) << 49)
 
 /*******************************************************************************
  * CPU Identification register specific definitions.

diff --git a/lib/cpus/aarch64/cortex_a55.S b/lib/cpus/aarch64/cortex_a55.S
index 20d5fe4cd7e5943944b10e313bceae5b09ab6d8f..b0d5d4d526142b7eb58d2a1f0a766af1bd46eda2 100644 (file)
--- a/lib/cpus/aarch64/cortex_a55.S
+++ b/lib/cpus/aarch64/cortex_a55.S
@@ -82,6 +82,34 @@ func check_errata_778703
        ret     x16
 endfunc check_errata_778703
 
+       /* --------------------------------------------------
+        * Errata Workaround for Cortex A55 Errata #798797.
+        * This applies only to revision r0p0 of Cortex A55.
+        * Inputs:
+        * x0: variant[4:7] and revision[0:3] of current cpu.
+        * Shall clobber: x0-x17
+        * --------------------------------------------------
+        */
+func errata_a55_798797_wa
+       /*
+        * Compare x0 against revision r0p0
+        */
+       mov     x17, x30
+       bl      check_errata_798797
+       cbz     x0, 1f
+       mrs     x1, CORTEX_A55_CPUACTLR_EL1
+       orr     x1, x1, #CORTEX_A55_CPUACTLR_EL1_DISABLE_L1_PAGEWALKS
+       msr     CORTEX_A55_CPUACTLR_EL1, x1
+       isb
+1:
+       ret     x17
+endfunc errata_a55_798797_wa
+
+func check_errata_798797
+       mov     x1, #0x00
+       b       cpu_rev_var_ls
+endfunc check_errata_798797
+
 func cortex_a55_reset_func
        mov     x19, x30
 
@@ -102,6 +130,11 @@ func cortex_a55_reset_func
        bl      errata_a55_778703_wa
 #endif
 
+#if ERRATA_A55_798797
+       mov     x0, x18
+       bl      errata_a55_798797_wa
+#endif
+
        ret     x19
 endfunc cortex_a55_reset_func
 
@@ -137,6 +170,7 @@ func cortex_a55_errata_report
        report_errata ERRATA_DSU_936184, cortex_a55, dsu_936184
        report_errata ERRATA_A55_768277, cortex_a55, 768277
        report_errata ERRATA_A55_778703, cortex_a55, 778703
+       report_errata ERRATA_A55_798797, cortex_a55, 798797
 
        ldp     x8, x30, [sp], #16
        ret

diff --git a/lib/cpus/cpu-ops.mk b/lib/cpus/cpu-ops.mk
index ee316b7e2e87be61066d92be3f35e89c192df664..dc1540d8a87e815171b532ee9130c8a82802eb0c 100644 (file)
--- a/lib/cpus/cpu-ops.mk
+++ b/lib/cpus/cpu-ops.mk
@@ -87,6 +87,10 @@ ERRATA_A55_768277    ?=0
 # only to revision r0p0 of the Cortex A55 cpu.
 ERRATA_A55_778703      ?=0
 
+# Flag to apply erratum 798797 workaround during reset. This erratum applies
+# only to revision r0p0 of the Cortex A55 cpu.
+ERRATA_A55_798797      ?=0
+
 # Flag to apply erratum 806969 workaround during reset. This erratum applies
 # only to revision r0p0 of the Cortex A57 cpu.
 ERRATA_A57_806969      ?=0
@@ -164,6 +168,10 @@ $(eval $(call add_define,ERRATA_A55_768277))
 $(eval $(call assert_boolean,ERRATA_A55_778703))
 $(eval $(call add_define,ERRATA_A55_778703))
 
+# Process ERRATA_A55_798797 flag
+$(eval $(call assert_boolean,ERRATA_A55_798797))
+$(eval $(call add_define,ERRATA_A55_798797))
+
 # Process ERRATA_A57_806969 flag
 $(eval $(call assert_boolean,ERRATA_A57_806969))
 $(eval $(call add_define,ERRATA_A57_806969))