powerpc: Add TLB size detection for TYPE_3E MMUs

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

arch/powerpc/include/asm/mmu-book3e.h

@@ -137,6 +137,21 @@
 #define MMUCSR0_TLB2PS	0x00078000	/* TLB2 Page Size */
 #define MMUCSR0_TLB3PS	0x00780000	/* TLB3 Page Size */
 
+/* MMUCFG bits */
+#define MMUCFG_MAVN_NASK	0x00000003
+#define MMUCFG_MAVN_V1_0	0x00000000
+#define MMUCFG_MAVN_V2_0	0x00000001
+#define MMUCFG_NTLB_MASK	0x0000000c
+#define MMUCFG_NTLB_SHIFT	2
+#define MMUCFG_PIDSIZE_MASK	0x000007c0
+#define MMUCFG_PIDSIZE_SHIFT	6
+#define MMUCFG_TWC		0x00008000
+#define MMUCFG_LRAT		0x00010000
+#define MMUCFG_RASIZE_MASK	0x00fe0000
+#define MMUCFG_RASIZE_SHIFT	17
+#define MMUCFG_LPIDSIZE_MASK	0x0f000000
+#define MMUCFG_LPIDSIZE_SHIFT	24
+
 /* TLBnCFG encoding */
 #define TLBnCFG_N_ENTRY		0x00000fff	/* number of entries */
 #define TLBnCFG_HES		0x00002000	/* HW select supported */

arch/powerpc/mm/mmu_context_nohash.c

@@ -409,7 +409,17 @@ void __init mmu_context_init(void)
 	} else if (mmu_has_feature(MMU_FTR_TYPE_47x)) {
 		first_context = 1;
 		last_context = 65535;
-	} else {
+	} else
+#ifdef CONFIG_PPC_BOOK3E_MMU
+	if (mmu_has_feature(MMU_FTR_TYPE_3E)) {
+		u32 mmucfg = mfspr(SPRN_MMUCFG);
+		u32 pid_bits = (mmucfg & MMUCFG_PIDSIZE_MASK)
+				>> MMUCFG_PIDSIZE_SHIFT;
+		first_context = 1;
+		last_context = (1UL << (pid_bits + 1)) - 1;
+	} else
+#endif
+	{
 		first_context = 1;
 		last_context = 255;
 	}