MIPS: Add Loongson-3B support

Loongson-3B is a 8-cores processor. In general it looks like there are
two Loongson-3A integrated in one chip: 8 cores are separated into two
groups (two NUMA node), each node has its own local memory.

Of course there are some differences between one Loongson-3B and two
Loongson-3A. E.g., the base addresses of IPI registers of each node are
not the same; Loongson-3A use ChipConfig register to enable/disable
clock, but Loongson-3B use FreqControl register instead.

There are two revision of Loongson-3B, the first revision is called as
Loongson-3B1000, whose frequency is 1GHz and has a PRid 0x6306, the
second revision is called as Loongson-3B1500, whose frequency is 1.5GHz
and has a PRid 0x6307. Both revisions has a bug that clock cannot be
disabled at runtime, but this will be fixed in future.

Signed-off-by: Huacai Chen <chenhc@lemote.com>
Cc: John Crispin <john@phrozen.org>
Cc: Steven J. Hill <Steven.Hill@imgtec.com>
Cc: Aurelien Jarno <aurelien@aurel32.net>
Cc: linux-mips@linux-mips.org
Cc: Fuxin Zhang <zhangfx@lemote.com>
Cc: Zhangjin Wu <wuzhangjin@gmail.com>
Patchwork: https://patchwork.linux-mips.org/patch/7188/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

1 files changed, 6 insertions, 0 deletions

diff --git a/arch/mips/kernel/cpu-probe.c b/arch/mips/kernel/cpu-probe.c
index d74f957c561e..2d2e2877b1ea 100644
--- a/arch/mips/kernel/cpu-probe.c
+++ b/arch/mips/kernel/cpu-probe.c
@@ -740,6 +740,12 @@ static inline void cpu_probe_legacy(struct cpuinfo_mips *c, unsigned int cpu)
 			__cpu_name[cpu] = "ICT Loongson-3";
 			set_elf_platform(cpu, "loongson3a");
 			break;
+		case PRID_REV_LOONGSON3B_R1:
+		case PRID_REV_LOONGSON3B_R2:
+			c->cputype = CPU_LOONGSON3;
+			__cpu_name[cpu] = "ICT Loongson-3";
+			set_elf_platform(cpu, "loongson3b");
+			break;
 		}
 
 		set_isa(c, MIPS_CPU_ISA_III);