1 /* 2 * Copyright (C) 2006 Chris Dearman (chris@mips.com), 3 */ 4 #include <linux/init.h> 5 #include <linux/kernel.h> 6 #include <linux/sched.h> 7 #include <linux/mm.h> 8 9 #include <asm/cpu-type.h> 10 #include <asm/mipsregs.h> 11 #include <asm/bcache.h> 12 #include <asm/cacheops.h> 13 #include <asm/page.h> 14 #include <asm/pgtable.h> 15 #include <asm/mmu_context.h> 16 #include <asm/r4kcache.h> 17 18 /* 19 * MIPS32/MIPS64 L2 cache handling 20 */ 21 22 /* 23 * Writeback and invalidate the secondary cache before DMA. 24 */ 25 static void mips_sc_wback_inv(unsigned long addr, unsigned long size) 26 { 27 blast_scache_range(addr, addr + size); 28 } 29 30 /* 31 * Invalidate the secondary cache before DMA. 32 */ 33 static void mips_sc_inv(unsigned long addr, unsigned long size) 34 { 35 unsigned long lsize = cpu_scache_line_size(); 36 unsigned long almask = ~(lsize - 1); 37 38 cache_op(Hit_Writeback_Inv_SD, addr & almask); 39 cache_op(Hit_Writeback_Inv_SD, (addr + size - 1) & almask); 40 blast_inv_scache_range(addr, addr + size); 41 } 42 43 static void mips_sc_enable(void) 44 { 45 /* L2 cache is permanently enabled */ 46 } 47 48 static void mips_sc_disable(void) 49 { 50 /* L2 cache is permanently enabled */ 51 } 52 53 static struct bcache_ops mips_sc_ops = { 54 .bc_enable = mips_sc_enable, 55 .bc_disable = mips_sc_disable, 56 .bc_wback_inv = mips_sc_wback_inv, 57 .bc_inv = mips_sc_inv 58 }; 59 60 /* 61 * Check if the L2 cache controller is activated on a particular platform. 62 * MTI's L2 controller and the L2 cache controller of Broadcom's BMIPS 63 * cores both use c0_config2's bit 12 as "L2 Bypass" bit, that is the 64 * cache being disabled. However there is no guarantee for this to be 65 * true on all platforms. In an act of stupidity the spec defined bits 66 * 12..15 as implementation defined so below function will eventually have 67 * to be replaced by a platform specific probe. 68 */ 69 static inline int mips_sc_is_activated(struct cpuinfo_mips *c) 70 { 71 unsigned int config2 = read_c0_config2(); 72 unsigned int tmp; 73 74 /* Check the bypass bit (L2B) */ 75 switch (current_cpu_type()) { 76 case CPU_34K: 77 case CPU_74K: 78 case CPU_1004K: 79 case CPU_BMIPS5000: 80 if (config2 & (1 << 12)) 81 return 0; 82 } 83 84 tmp = (config2 >> 4) & 0x0f; 85 if (0 < tmp && tmp <= 7) 86 c->scache.linesz = 2 << tmp; 87 else 88 return 0; 89 return 1; 90 } 91 92 static inline int __init mips_sc_probe(void) 93 { 94 struct cpuinfo_mips *c = ¤t_cpu_data; 95 unsigned int config1, config2; 96 unsigned int tmp; 97 98 /* Mark as not present until probe completed */ 99 c->scache.flags |= MIPS_CACHE_NOT_PRESENT; 100 101 /* Ignore anything but MIPSxx processors */ 102 if (!(c->isa_level & (MIPS_CPU_ISA_M32R1 | MIPS_CPU_ISA_M32R2 | 103 MIPS_CPU_ISA_M64R1 | MIPS_CPU_ISA_M64R2))) 104 return 0; 105 106 /* Does this MIPS32/MIPS64 CPU have a config2 register? */ 107 config1 = read_c0_config1(); 108 if (!(config1 & MIPS_CONF_M)) 109 return 0; 110 111 config2 = read_c0_config2(); 112 113 if (!mips_sc_is_activated(c)) 114 return 0; 115 116 tmp = (config2 >> 8) & 0x0f; 117 if (0 <= tmp && tmp <= 7) 118 c->scache.sets = 64 << tmp; 119 else 120 return 0; 121 122 tmp = (config2 >> 0) & 0x0f; 123 if (0 <= tmp && tmp <= 7) 124 c->scache.ways = tmp + 1; 125 else 126 return 0; 127 128 c->scache.waysize = c->scache.sets * c->scache.linesz; 129 c->scache.waybit = __ffs(c->scache.waysize); 130 131 c->scache.flags &= ~MIPS_CACHE_NOT_PRESENT; 132 133 return 1; 134 } 135 136 int mips_sc_init(void) 137 { 138 int found = mips_sc_probe(); 139 if (found) { 140 mips_sc_enable(); 141 bcops = &mips_sc_ops; 142 } 143 return found; 144 } 145