[PATCH] MIPS: Kernel: Identify Loongson-2K processors

[Jiaxun Yang <jiaxun.yang@flygoat.com>]

Loongson-2K (Loongson64 Reduced) is a family of SoC shipped with
gs264e core.

Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
---
 arch/mips/include/asm/cpu.h  |  4 ++++
 arch/mips/kernel/cpu-probe.c | 19 ++++++++++++++++++-
 arch/mips/kernel/idle.c      |  3 ++-
 arch/mips/mm/c-r4k.c         | 12 +++++++++---
 4 files changed, 33 insertions(+), 5 deletions(-)

diff --git a/arch/mips/include/asm/cpu.h b/arch/mips/include/asm/cpu.h
index 216a22916740..46c190e78acf 100644
--- a/arch/mips/include/asm/cpu.h
+++ b/arch/mips/include/asm/cpu.h
@@ -250,6 +250,10 @@
 #define PRID_REV_LOONGSON1C		0x0020	/* Same as Loongson-1B */
 #define PRID_REV_LOONGSON2E		0x0002
 #define PRID_REV_LOONGSON2F		0x0003
+#define PRID_REV_LOONGSON2K_R1_0	0x0000
+#define PRID_REV_LOONGSON2K_R1_1	0x0001
+#define PRID_REV_LOONGSON2K_R1_2	0x0002
+#define PRID_REV_LOONGSON2K_R1_3	0x0003
 #define PRID_REV_LOONGSON3A_R1		0x0005
 #define PRID_REV_LOONGSON3B_R1		0x0006
 #define PRID_REV_LOONGSON3B_R2		0x0007
diff --git a/arch/mips/kernel/cpu-probe.c b/arch/mips/kernel/cpu-probe.c
index f21a2304401f..6de14b527c68 100644
--- a/arch/mips/kernel/cpu-probe.c
+++ b/arch/mips/kernel/cpu-probe.c
@@ -1935,7 +1935,24 @@ static inline void cpu_probe_cavium(struct cpuinfo_mips *c, unsigned int cpu)
 static inline void cpu_probe_loongson(struct cpuinfo_mips *c, unsigned int cpu)
 {
 	switch (c->processor_id & PRID_IMP_MASK) {
-	case PRID_IMP_LOONGSON_64C:  /* Loongson-2/3 */
+	case PRID_IMP_LOONGSON_64R: /* Loongson-64 Reduced */
+		switch (c->processor_id & PRID_REV_MASK) {
+		case PRID_REV_LOONGSON2K_R1_0:
+		case PRID_REV_LOONGSON2K_R1_1:
+		case PRID_REV_LOONGSON2K_R1_2:
+		case PRID_REV_LOONGSON2K_R1_3:
+			c->cputype = CPU_LOONGSON64;
+			__cpu_name[cpu] = "Loongson-2K";
+			set_elf_platform(cpu, "gs264e");
+			set_isa(c, MIPS_CPU_ISA_M64R2);
+			break;
+		}
+		decode_configs(c);
+		c->writecombine = _CACHE_UNCACHED_ACCELERATED;
+		c->ases |= (MIPS_ASE_LOONGSON_MMI | MIPS_ASE_LOONGSON_EXT |
+				MIPS_ASE_LOONGSON_EXT2);
+		break;
+	case PRID_IMP_LOONGSON_64C:  /* Loongson-3 Classic */
 		switch (c->processor_id & PRID_REV_MASK) {
 		case PRID_REV_LOONGSON3A_R2_0:
 		case PRID_REV_LOONGSON3A_R2_1:
diff --git a/arch/mips/kernel/idle.c b/arch/mips/kernel/idle.c
index 37f8e78e2869..60d8c2a380fe 100644
--- a/arch/mips/kernel/idle.c
+++ b/arch/mips/kernel/idle.c
@@ -180,7 +180,8 @@ void __init check_wait(void)
 		break;
 	case CPU_LOONGSON64:
 		if ((c->processor_id & (PRID_IMP_MASK | PRID_REV_MASK)) >=
-				(PRID_IMP_LOONGSON_64C | PRID_REV_LOONGSON3A_R2_0))
+				(PRID_IMP_LOONGSON_64C | PRID_REV_LOONGSON3A_R2_0) ||
+				(c->processor_id & PRID_IMP_MASK) == PRID_IMP_LOONGSON_64R)
 			cpu_wait = r4k_wait;
 		break;
 
diff --git a/arch/mips/mm/c-r4k.c b/arch/mips/mm/c-r4k.c
index 36a311348739..378ef5d46bec 100644
--- a/arch/mips/mm/c-r4k.c
+++ b/arch/mips/mm/c-r4k.c
@@ -1303,7 +1303,8 @@ static void probe_pcache(void)
 					  c->dcache.linesz;
 		c->dcache.waybit = 0;
 		if ((c->processor_id & (PRID_IMP_MASK | PRID_REV_MASK)) >=
-				(PRID_IMP_LOONGSON_64C | PRID_REV_LOONGSON3A_R2_0))
+				(PRID_IMP_LOONGSON_64C | PRID_REV_LOONGSON3A_R2_0) ||
+				(c->processor_id & PRID_IMP_MASK) == PRID_IMP_LOONGSON_64R)
 			c->options |= MIPS_CPU_PREFETCH;
 		break;
 
@@ -1629,8 +1630,13 @@ static void __init loongson3_sc_init(void)
 	scache_size = c->scache.sets *
 				  c->scache.ways *
 				  c->scache.linesz;
-	/* Loongson-3 has 4 cores, 1MB scache for each. scaches are shared */
-	scache_size *= 4;
+
+	/* Loongson-3 has 4-Scache banks, while Loongson-2K have only 2 banks */
+	if ((c->processor_id & PRID_IMP_MASK) == PRID_IMP_LOONGSON_64R)
+		scache_size *= 2;
+	else
+		scache_size *= 4;
+
 	c->scache.waybit = 0;
 	c->scache.waysize = scache_size / c->scache.ways;
 	pr_info("Unified secondary cache %ldkB %s, linesize %d bytes.\n",
-- 
2.26.0.rc2