MIPS: Add support for the 1074K core.

Signed-off-by: Steven J. Hill <[e-mail]>

arch/mips/include/asm/cpu.h

···
 #define PRID_IMP_24KE		0x9600
 #define PRID_IMP_74K		0x9700
 #define PRID_IMP_1004K		0x9900
+#define PRID_IMP_1074K		0x9a00
 #define PRID_IMP_M14KC		0x9c00
 
 /*

arch/mips/include/asm/mipsregs.h

···
 #define MIPS_CONF4_MMUEXTDEF	(_ULCAST_(3) << 14)
 #define MIPS_CONF4_MMUEXTDEF_MMUSIZEEXT (_ULCAST_(1) << 14)
 
+#define MIPS_CONF6_SYND		(_ULCAST_(1) << 13)
+
 #define MIPS_CONF7_WII		(_ULCAST_(1) << 31)
 
 #define MIPS_CONF7_RPS		(_ULCAST_(1) << 2)

arch/mips/kernel/cpu-probe.c

···
 		c->cputype = CPU_1004K;
 		__cpu_name[cpu] = "MIPS 1004Kc";
 		break;
+	case PRID_IMP_1074K:
+		c->cputype = CPU_74K;
+		__cpu_name[cpu] = "MIPS 1074Kc";
+		break;
 	}
 
 	spram_config();

arch/mips/mm/c-r4k.c

···
 	}
 }
 
+static inline void alias_74k_erratum(struct cpuinfo_mips *c)
+{
+	/*
+	 * Early versions of the 74K do not update the cache tags on a
+	 * vtag miss/ptag hit which can occur in the case of KSEG0/KUSEG
+	 * aliases. In this case it is better to treat the cache as always
+	 * having aliases.
+	 */
+	if ((c->processor_id & 0xff) <= PRID_REV_ENCODE_332(2, 4, 0))
+		c->dcache.flags |= MIPS_CACHE_VTAG;
+	if ((c->processor_id & 0xff) == PRID_REV_ENCODE_332(2, 4, 0))
+		write_c0_config6(read_c0_config6() | MIPS_CONF6_SYND);
+	if (((c->processor_id & 0xff00) == PRID_IMP_1074K) &&
+	    ((c->processor_id & 0xff) <= PRID_REV_ENCODE_332(1, 1, 0))) {
+		c->dcache.flags |= MIPS_CACHE_VTAG;
+		write_c0_config6(read_c0_config6() | MIPS_CONF6_SYND);
+	}
+}
+
 static char *way_string[] __cpuinitdata = { NULL, "direct mapped", "2-way",
 	"3-way", "4-way", "5-way", "6-way", "7-way", "8-way"
 };
···
 	case CPU_34K:
 	case CPU_74K:
 	case CPU_1004K:
+		if (c->cputype == CPU_74K)
+			alias_74k_erratum(c);
 		if ((read_c0_config7() & (1 << 16))) {
 			/* effectively physically indexed dcache,
 			   thus no virtual aliases. */