MIPS: Loongson64: Set timer mode in cpu-probe

commit 1cb6ab446424649f03c82334634360c2e3043684 upstream.

Loongson64 C and G processors have EXTIMER feature which
is conflicting with CP0 counter.

Although the processor resets in EXTIMER disabled & INTIMER
enabled mode, which is compatible with MIPS CP0 compare, firmware
may attempt to enable EXTIMER and interfere CP0 compare.

Set timer mode back to MIPS compatible mode to fix booting on
systems with such firmware before we have an actual driver for
EXTIMER.

Cc: stable@vger.kernel.org
Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/arch/mips/kernel/cpu-probe.c b/arch/mips/kernel/cpu-probe.c
index f8d1933bfe823f2f38a431b988767b0e575a478c..24d2ab277d78e7ce56cf5b0a0a9f155830d24146 100644 (file)
--- a/arch/mips/kernel/cpu-probe.c
+++ b/arch/mips/kernel/cpu-probe.c
@@ -1769,12 +1769,16 @@ static inline void cpu_probe_loongson(struct cpuinfo_mips *c, unsigned int cpu)
                c->ases |= (MIPS_ASE_LOONGSON_MMI | MIPS_ASE_LOONGSON_CAM |
                        MIPS_ASE_LOONGSON_EXT | MIPS_ASE_LOONGSON_EXT2);
                c->ases &= ~MIPS_ASE_VZ; /* VZ of Loongson-3A2000/3000 is incomplete */
+               change_c0_config6(LOONGSON_CONF6_EXTIMER | LOONGSON_CONF6_INTIMER,
+                                 LOONGSON_CONF6_INTIMER);
                break;
        case PRID_IMP_LOONGSON_64G:
                __cpu_name[cpu] = "ICT Loongson-3";
                set_elf_platform(cpu, "loongson3a");
                set_isa(c, MIPS_CPU_ISA_M64R2);
                decode_cpucfg(c);
+               change_c0_config6(LOONGSON_CONF6_EXTIMER | LOONGSON_CONF6_INTIMER,
+                                 LOONGSON_CONF6_INTIMER);
                break;
        default:
                panic("Unknown Loongson Processor ID!");