powerpc/85xx: Add workaround for erratum CPU-A003999
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>
diff --git a/arch/powerpc/cpu/mpc85xx/cmd_errata.c b/arch/powerpc/cpu/mpc85xx/cmd_errata.c
index 253bf08..523f297 100644
--- a/arch/powerpc/cpu/mpc85xx/cmd_errata.c
+++ b/arch/powerpc/cpu/mpc85xx/cmd_errata.c
@@ -53,6 +53,9 @@
#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 @@
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 7bd5cc0..4d37d6e 100644
--- a/arch/powerpc/cpu/mpc85xx/start.S
+++ b/arch/powerpc/cpu/mpc85xx/start.S
@@ -253,6 +253,12 @@
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 981d639..f1da82e 100644
--- a/arch/powerpc/include/asm/config_mpc85xx.h
+++ b/arch/powerpc/include/asm/config_mpc85xx.h
@@ -313,6 +313,7 @@
#define CONFIG_SYS_FSL_USB2_PHY_ENABLE
#define CONFIG_SYS_FSL_USB_INTERNAL_UTMI_PHY
#define CONFIG_SYS_FSL_ERRATUM_ESDHC111
+#define CONFIG_SYS_FSL_ERRATUM_CPU_A003999
#elif defined(CONFIG_PPC_P2041)
#define CONFIG_MAX_CPUS 4
@@ -331,6 +332,7 @@
#define CONFIG_SYS_FSL_USB2_PHY_ENABLE
#define CONFIG_SYS_FSL_USB_INTERNAL_UTMI_PHY
#define CONFIG_SYS_FSL_ERRATUM_ESDHC111
+#define CONFIG_SYS_FSL_ERRATUM_CPU_A003999
#elif defined(CONFIG_PPC_P3041)
#define CONFIG_MAX_CPUS 4
@@ -349,6 +351,7 @@
#define CONFIG_SYS_FSL_USB2_PHY_ENABLE
#define CONFIG_SYS_FSL_USB_INTERNAL_UTMI_PHY
#define CONFIG_SYS_FSL_ERRATUM_ESDHC111
+#define CONFIG_SYS_FSL_ERRATUM_CPU_A003999
#elif defined(CONFIG_PPC_P3060)
#define CONFIG_MAX_CPUS 8
@@ -364,6 +367,7 @@
#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
@@ -374,6 +378,7 @@
#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
@@ -402,6 +407,7 @@
#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)