MIPS: Loongson: Add Loongson-3A R2 basic support

Loongson-3 CPU family:

Code-name       Brand-name       PRId
Loongson-3A R1  Loongson-3A1000  0x6305
Loongson-3A R2  Loongson-3A2000  0x6308
Loongson-3B R1  Loongson-3B1000  0x6306
Loongson-3B R2  Loongson-3B1500  0x6307

Features of R2 revision of Loongson-3A:

  - Primary cache includes I-Cache, D-Cache and V-Cache (Victim Cache).
  - I-Cache, D-Cache and V-Cache are 16-way set-associative, linesize is
     64 bytes.
  - 64 entries of VTLB (classic TLB), 1024 entries of FTLB (8-way
     set-associative).
  - Supports DSP/DSPv2 instructions, UserLocal register and Read-Inhibit/
     Execute-Inhibit.

[ralf@linux-mips.org: Resolved merge conflicts.]

Signed-off-by: Huacai Chen <chenhc@lemote.com>
Cc: Aurelien Jarno <aurelien@aurel32.net>
Cc: Steven J . Hill <sjhill@realitydiluted.com>
Cc: Fuxin Zhang <zhangfx@lemote.com>
Cc: Zhangjin Wu <wuzhangjin@gmail.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/12751/
Patchwork: https://patchwork.linux-mips.org/patch/13136/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

3 files changed, 44 insertions, 2 deletions

diff --git a/arch/mips/kernel/cpu-probe.c b/arch/mips/kernel/cpu-probe.c
index d72bd7e..2bfd483 100644
--- a/arch/mips/kernel/cpu-probe.c
+++ b/arch/mips/kernel/cpu-probe.c
@@ -562,6 +562,16 @@ static int set_ftlb_enable(struct cpuinfo_mips *c, int enable)
 		write_c0_config7(config | (calculate_ftlb_probability(c)
 					   << MIPS_CONF7_FTLBP_SHIFT));
 		break;
+	case CPU_LOONGSON3:
+		/* Loongson-3 cores use Config6 to enable the FTLB */
+		config = read_c0_config6();
+		if (enable)
+			/* Enable FTLB */
+			write_c0_config6(config & ~MIPS_CONF6_FTLBDIS);
+		else
+			/* Disable FTLB */
+			write_c0_config6(config | MIPS_CONF6_FTLBDIS);
+		break;
 	default:
 		return 1;
 	}
@@ -1178,7 +1188,7 @@ static inline void cpu_probe_legacy(struct cpuinfo_mips *c, unsigned int cpu)
 			set_isa(c, MIPS_CPU_ISA_III);
 			c->fpu_msk31 |= FPU_CSR_CONDX;
 			break;
-		case PRID_REV_LOONGSON3A:
+		case PRID_REV_LOONGSON3A_R1:
 			c->cputype = CPU_LOONGSON3;
 			__cpu_name[cpu] = "ICT Loongson-3";
 			set_elf_platform(cpu, "loongson3a");
@@ -1512,6 +1522,29 @@ platform:
 	}
 }
 
+static inline void cpu_probe_loongson(struct cpuinfo_mips *c, unsigned int cpu)
+{
+	switch (c->processor_id & PRID_IMP_MASK) {
+	case PRID_IMP_LOONGSON_64:  /* Loongson-2/3 */
+		switch (c->processor_id & PRID_REV_MASK) {
+		case PRID_REV_LOONGSON3A_R2:
+			c->cputype = CPU_LOONGSON3;
+			__cpu_name[cpu] = "ICT Loongson-3";
+			set_elf_platform(cpu, "loongson3a");
+			set_isa(c, MIPS_CPU_ISA_M64R2);
+			break;
+		}
+
+		decode_configs(c);
+		c->options |= MIPS_CPU_TLBINV;
+		c->writecombine = _CACHE_UNCACHED_ACCELERATED;
+		break;
+	default:
+		panic("Unknown Loongson Processor ID!");
+		break;
+	}
+}
+
 static inline void cpu_probe_ingenic(struct cpuinfo_mips *c, unsigned int cpu)
 {
 	decode_configs(c);
@@ -1659,6 +1692,9 @@ void cpu_probe(void)
 	case PRID_COMP_CAVIUM:
 		cpu_probe_cavium(c, cpu);
 		break;
+	case PRID_COMP_LOONGSON:
+		cpu_probe_loongson(c, cpu);
+		break;
 	case PRID_COMP_INGENIC_D0:
 	case PRID_COMP_INGENIC_D1:
 	case PRID_COMP_INGENIC_E1:
diff --git a/arch/mips/kernel/idle.c b/arch/mips/kernel/idle.c
index 46794d6..60ab4c4 100644
--- a/arch/mips/kernel/idle.c
+++ b/arch/mips/kernel/idle.c
@@ -181,6 +181,11 @@ void __init check_wait(void)
 	case CPU_XLP:
 		cpu_wait = r4k_wait;
 		break;
+	case CPU_LOONGSON3:
+		if ((c->processor_id & PRID_REV_MASK) >= PRID_REV_LOONGSON3A_R2)
+			cpu_wait = r4k_wait;
+		break;
+
 	case CPU_BMIPS5000:
 		cpu_wait = r4k_wait_irqoff;
 		break;
diff --git a/arch/mips/kernel/traps.c b/arch/mips/kernel/traps.c
index dcda63e..38864dc 100644
--- a/arch/mips/kernel/traps.c
+++ b/arch/mips/kernel/traps.c
@@ -1772,7 +1772,8 @@ asmlinkage void do_ftlb(void)
 
 	/* For the moment, report the problem and hang. */
 	if ((cpu_has_mips_r2_r6) &&
-	    ((current_cpu_data.processor_id & 0xff0000) == PRID_COMP_MIPS)) {
+	    (((current_cpu_data.processor_id & 0xff0000) == PRID_COMP_MIPS) ||
+	    ((current_cpu_data.processor_id & 0xff0000) == PRID_COMP_LOONGSON))) {
 		pr_err("FTLB error exception, cp0_ecc=0x%08x:\n",
 		       read_c0_ecc());
 		pr_err("cp0_errorepc == %0*lx\n", field, read_c0_errorepc());