MIPS: Netlogic: Handle XLP hardware errata

Core configuration register IFU_BRUB_RESERVE has to be setup to handle
a silicon errata which can result in a CPU hang.

Signed-off-by: Jayachandran C <jchandra@broadcom.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/8902/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

1 files changed, 20 insertions, 0 deletions

diff --git a/arch/mips/netlogic/common/reset.S b/arch/mips/netlogic/common/reset.S
index 701c4bcb9e47..e3e518974e0b 100644
--- a/arch/mips/netlogic/common/reset.S
+++ b/arch/mips/netlogic/common/reset.S
@@ -235,6 +235,26 @@ EXPORT(nlm_boot_siblings)
         mfc0    v0, CP0_EBASE, 1
         andi    v0, 0x3ff               /* v0 <- node/core */
 
+        /*
+         * Errata: to avoid potential live lock, setup IFU_BRUB_RESERVE
+         * when running 4 threads per core
+         */
+        andi    v1, v0, 0x3             /* v1 <- thread id */
+        bnez    v1, 2f
+        nop
+
+        /* thread 0 of each core. */
+        li      t0, CKSEG1ADDR(RESET_DATA_PHYS)
+        lw      t1, BOOT_THREAD_MODE(t0)        /* t1 <- thread mode */
+        subu    t1, 0x3                         /* 4-thread per core mode? */
+        bnez    t1, 2f
+        nop
+
+        li      t0, IFU_BRUB_RESERVE
+        li      t1, 0x55
+        mtcr    t1, t0
+        _ehb
+2:
         beqz    v0, 4f          /* boot cpu (cpuid == 0)? */
         nop