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>

arch/mips/include/asm/netlogic/xlp-hal/cpucontrol.h

@@ -46,6 +46,8 @@
 #define CPU_BLOCKID_FPU		9
 #define CPU_BLOCKID_MAP		10
 
+#define IFU_BRUB_RESERVE	0x007
+
 #define ICU_DEFEATURE		0x100
 
 #define LSU_DEFEATURE		0x304

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