Erratum A-003999: Running Floating Point instructions requires special initialization.
Impact: Floating point arithmetic operations may result in an incorrect value.
Workaround: Perform a read modify write to set bit 7 to a 1 in SPR 977 before executing any floating point arithmetic operation. This bit can be set when setting MSR[FP], and can be cleared when clearing MSR[FP]. Alternatively, the bit can be set once at boot time, and never cleared. There will be no performance degradation due to setting this bit.
Signed-off-by: Kumar Gala galak@kernel.crashing.org --- arch/powerpc/cpu/mpc85xx/cmd_errata.c | 3 +++ arch/powerpc/cpu/mpc85xx/release.S | 6 ++++++ arch/powerpc/cpu/mpc85xx/start.S | 6 ++++++ arch/powerpc/include/asm/config_mpc85xx.h | 6 ++++++ 4 files changed, 21 insertions(+), 0 deletions(-)
diff --git a/arch/powerpc/cpu/mpc85xx/cmd_errata.c b/arch/powerpc/cpu/mpc85xx/cmd_errata.c index 07be03e..f7c0934 100644 --- a/arch/powerpc/cpu/mpc85xx/cmd_errata.c +++ b/arch/powerpc/cpu/mpc85xx/cmd_errata.c @@ -53,6 +53,9 @@ static int do_errata(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]) #if defined(CONFIG_SYS_P4080_ERRATUM_CPU22) puts("Work-around for Erratum CPU22 enabled\n"); #endif +#if defined(CONFIG_SYS_FSL_ERRATUM_CPU_A003999) + puts("Work-around for Erratum CPU-A003999 enabled\n"); +#endif #if defined(CONFIG_SYS_FSL_ERRATUM_DDR_MSYNC_IN) puts("Work-around for DDR MSYNC_IN Erratum enabled\n"); #endif diff --git a/arch/powerpc/cpu/mpc85xx/release.S b/arch/powerpc/cpu/mpc85xx/release.S index 6678ed4..c81e19c 100644 --- a/arch/powerpc/cpu/mpc85xx/release.S +++ b/arch/powerpc/cpu/mpc85xx/release.S @@ -68,6 +68,12 @@ __secondary_start_page: mtspr SPRN_HID1,r3 #endif
+#ifdef CONFIG_SYS_FSL_ERRATUM_CPU_A003999 + mfspr r3,977 + oris r3,r3,0x0100 + mtspr 977,r3 +#endif + /* Enable branch prediction */ lis r3,BUCSR_ENABLE@h ori r3,r3,BUCSR_ENABLE@l diff --git a/arch/powerpc/cpu/mpc85xx/start.S b/arch/powerpc/cpu/mpc85xx/start.S index 39f1438..d032788 100644 --- a/arch/powerpc/cpu/mpc85xx/start.S +++ b/arch/powerpc/cpu/mpc85xx/start.S @@ -264,6 +264,12 @@ l2_disabled: mtspr HID1,r0 #endif
+#ifdef CONFIG_SYS_FSL_ERRATUM_CPU_A003999 + mfspr r3,977 + oris r3,r3,0x0100 + mtspr 977,r3 +#endif + /* Enable Branch Prediction */ #if defined(CONFIG_BTB) lis r0,BUCSR_ENABLE@h diff --git a/arch/powerpc/include/asm/config_mpc85xx.h b/arch/powerpc/include/asm/config_mpc85xx.h index 424ab79..dba9eda 100644 --- a/arch/powerpc/include/asm/config_mpc85xx.h +++ b/arch/powerpc/include/asm/config_mpc85xx.h @@ -316,6 +316,7 @@ #define CONFIG_SYS_FSL_USB_INTERNAL_UTMI_PHY #define CONFIG_SYS_FSL_ERRATUM_ESDHC111 #define CONFIG_SYS_FSL_ERRATUM_USB138 +#define CONFIG_SYS_FSL_ERRATUM_CPU_A003999
#elif defined(CONFIG_PPC_P2041) #define CONFIG_MAX_CPUS 4 @@ -335,6 +336,7 @@ #define CONFIG_SYS_FSL_USB_INTERNAL_UTMI_PHY #define CONFIG_SYS_FSL_ERRATUM_ESDHC111 #define CONFIG_SYS_FSL_ERRATUM_USB138 +#define CONFIG_SYS_FSL_ERRATUM_CPU_A003999
#elif defined(CONFIG_PPC_P3041) #define CONFIG_MAX_CPUS 4 @@ -354,6 +356,7 @@ #define CONFIG_SYS_FSL_USB_INTERNAL_UTMI_PHY #define CONFIG_SYS_FSL_ERRATUM_ESDHC111 #define CONFIG_SYS_FSL_ERRATUM_USB138 +#define CONFIG_SYS_FSL_ERRATUM_CPU_A003999
#elif defined(CONFIG_PPC_P3060) #define CONFIG_MAX_CPUS 8 @@ -369,6 +372,7 @@ #define CONFIG_SYS_FSL_PCIE_COMPAT "fsl,qoriq-pcie-v2.2" #define CONFIG_SYS_CCSRBAR_DEFAULT 0xfe000000 #define CONFIG_SYS_FSL_ERRATUM_DDR_A003 +#define CONFIG_SYS_FSL_ERRATUM_CPU_A003999
#elif defined(CONFIG_PPC_P4040) #define CONFIG_MAX_CPUS 4 @@ -379,6 +383,7 @@ #define CONFIG_SYS_FSL_TBCLK_DIV 16 #define CONFIG_SYS_FSL_PCIE_COMPAT "fsl,p4080-pcie" #define CONFIG_SYS_CCSRBAR_DEFAULT 0xfe000000 +#define CONFIG_SYS_FSL_ERRATUM_CPU_A003999
#elif defined(CONFIG_PPC_P4080) #define CONFIG_MAX_CPUS 8 @@ -407,6 +412,7 @@ #define CONFIG_SYS_P4080_ERRATUM_SERDES9 #define CONFIG_SYS_P4080_ERRATUM_SERDES_A001 #define CONFIG_SYS_P4080_ERRATUM_SERDES_A005 +#define CONFIG_SYS_FSL_ERRATUM_CPU_A003999
/* P5010 is single core version of P5020 */ #elif defined(CONFIG_PPC_P5010)