arch/mips/mm/sc-mips.c

   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 #include <asm/mips-cm.h>
  18
  19 /*
  20  * MIPS32/MIPS64 L2 cache handling
  21  */
  22
  23 /*
  24  * Writeback and invalidate the secondary cache before DMA.
  25  */
  26 static void mips_sc_wback_inv(unsigned long addr, unsigned long size)
  27 {
  28         blast_scache_range(addr, addr + size);
  29 }
  30
  31 /*
  32  * Invalidate the secondary cache before DMA.
  33  */
  34 static void mips_sc_inv(unsigned long addr, unsigned long size)
  35 {
  36         unsigned long lsize = cpu_scache_line_size();
  37         unsigned long almask = ~(lsize - 1);
  38
  39         cache_op(Hit_Writeback_Inv_SD, addr & almask);
  40         cache_op(Hit_Writeback_Inv_SD, (addr + size - 1) & almask);
  41         blast_inv_scache_range(addr, addr + size);
  42 }
  43
  44 static void mips_sc_enable(void)
  45 {
  46         /* L2 cache is permanently enabled */
  47 }
  48
  49 static void mips_sc_disable(void)
  50 {
  51         /* L2 cache is permanently enabled */
  52 }
  53
  54 static void mips_sc_prefetch_enable(void)
  55 {
  56         unsigned long pftctl;
  57
  58         if (mips_cm_revision() < CM_REV_CM2_5)
  59                 return;
  60
  61         /*
  62          * If there is one or more L2 prefetch unit present then enable
  63          * prefetching for both code & data, for all ports.
  64          */
  65         pftctl = read_gcr_l2_pft_control();
  66         if (pftctl & CM_GCR_L2_PFT_CONTROL_NPFT_MSK) {
  67                 pftctl &= ~CM_GCR_L2_PFT_CONTROL_PAGEMASK_MSK;
  68                 pftctl |= PAGE_MASK & CM_GCR_L2_PFT_CONTROL_PAGEMASK_MSK;
  69                 pftctl |= CM_GCR_L2_PFT_CONTROL_PFTEN_MSK;
  70                 write_gcr_l2_pft_control(pftctl);
  71
  72                 pftctl = read_gcr_l2_pft_control_b();
  73                 pftctl |= CM_GCR_L2_PFT_CONTROL_B_PORTID_MSK;
  74                 pftctl |= CM_GCR_L2_PFT_CONTROL_B_CEN_MSK;
  75                 write_gcr_l2_pft_control_b(pftctl);
  76         }
  77 }
  78
  79 static void mips_sc_prefetch_disable(void)
  80 {
  81         unsigned long pftctl;
  82
  83         if (mips_cm_revision() < CM_REV_CM2_5)
  84                 return;
  85
  86         pftctl = read_gcr_l2_pft_control();
  87         pftctl &= ~CM_GCR_L2_PFT_CONTROL_PFTEN_MSK;
  88         write_gcr_l2_pft_control(pftctl);
  89
  90         pftctl = read_gcr_l2_pft_control_b();
  91         pftctl &= ~CM_GCR_L2_PFT_CONTROL_B_PORTID_MSK;
  92         pftctl &= ~CM_GCR_L2_PFT_CONTROL_B_CEN_MSK;
  93         write_gcr_l2_pft_control_b(pftctl);
  94 }
  95
  96 static bool mips_sc_prefetch_is_enabled(void)
  97 {
  98         unsigned long pftctl;
  99
 100         if (mips_cm_revision() < CM_REV_CM2_5)
 101                 return false;
 102
 103         pftctl = read_gcr_l2_pft_control();
 104         if (!(pftctl & CM_GCR_L2_PFT_CONTROL_NPFT_MSK))
 105                 return false;
 106         return !!(pftctl & CM_GCR_L2_PFT_CONTROL_PFTEN_MSK);
 107 }
 108
 109 static struct bcache_ops mips_sc_ops = {
 110         .bc_enable = mips_sc_enable,
 111         .bc_disable = mips_sc_disable,
 112         .bc_wback_inv = mips_sc_wback_inv,
 113         .bc_inv = mips_sc_inv,
 114         .bc_prefetch_enable = mips_sc_prefetch_enable,
 115         .bc_prefetch_disable = mips_sc_prefetch_disable,
 116         .bc_prefetch_is_enabled = mips_sc_prefetch_is_enabled,
 117 };
 118
 119 /*
 120  * Check if the L2 cache controller is activated on a particular platform.
 121  * MTI's L2 controller and the L2 cache controller of Broadcom's BMIPS
 122  * cores both use c0_config2's bit 12 as "L2 Bypass" bit, that is the
 123  * cache being disabled.  However there is no guarantee for this to be
 124  * true on all platforms.  In an act of stupidity the spec defined bits
 125  * 12..15 as implementation defined so below function will eventually have
 126  * to be replaced by a platform specific probe.
 127  */
 128 static inline int mips_sc_is_activated(struct cpuinfo_mips *c)
 129 {
 130         unsigned int config2 = read_c0_config2();
 131         unsigned int tmp;
 132
 133         /* Check the bypass bit (L2B) */
 134         switch (current_cpu_type()) {
 135         case CPU_34K:
 136         case CPU_74K:
 137         case CPU_1004K:
 138         case CPU_1074K:
 139         case CPU_INTERAPTIV:
 140         case CPU_PROAPTIV:
 141         case CPU_P5600:
 142         case CPU_BMIPS5000:
 143         case CPU_QEMU_GENERIC:
 144                 if (config2 & (1 << 12))
 145                         return 0;
 146         }
 147
 148         tmp = (config2 >> 4) & 0x0f;
 149         if (0 < tmp && tmp <= 7)
 150                 c->scache.linesz = 2 << tmp;
 151         else
 152                 return 0;
 153         return 1;
 154 }
 155
 156 static int __init mips_sc_probe_cm3(void)
 157 {
 158         struct cpuinfo_mips *c = &current_cpu_data;
 159         unsigned long cfg = read_gcr_l2_config();
 160         unsigned long sets, line_sz, assoc;
 161
 162         if (cfg & CM_GCR_L2_CONFIG_BYPASS_MSK)
 163                 return 0;
 164
 165         sets = cfg & CM_GCR_L2_CONFIG_SET_SIZE_MSK;
 166         sets >>= CM_GCR_L2_CONFIG_SET_SIZE_SHF;
 167         c->scache.sets = 64 << sets;
 168
 169         line_sz = cfg & CM_GCR_L2_CONFIG_LINE_SIZE_MSK;
 170         line_sz >>= CM_GCR_L2_CONFIG_LINE_SIZE_SHF;
 171         c->scache.linesz = 2 << line_sz;
 172
 173         assoc = cfg & CM_GCR_L2_CONFIG_ASSOC_MSK;
 174         assoc >>= CM_GCR_L2_CONFIG_ASSOC_SHF;
 175         c->scache.ways = assoc + 1;
 176         c->scache.waysize = c->scache.sets * c->scache.linesz;
 177         c->scache.waybit = __ffs(c->scache.waysize);
 178
 179         c->scache.flags &= ~MIPS_CACHE_NOT_PRESENT;
 180
 181         return 1;
 182 }
 183
 184 void __weak platform_early_l2_init(void)
 185 {
 186 }
 187
 188 static inline int __init mips_sc_probe(void)
 189 {
 190         struct cpuinfo_mips *c = &current_cpu_data;
 191         unsigned int config1, config2;
 192         unsigned int tmp;
 193
 194         /* Mark as not present until probe completed */
 195         c->scache.flags |= MIPS_CACHE_NOT_PRESENT;
 196
 197         /*
 198          * Do we need some platform specific probing before
 199          * we configure L2?
 200          */
 201         platform_early_l2_init();
 202
 203         if (mips_cm_revision() >= CM_REV_CM3)
 204                 return mips_sc_probe_cm3();
 205
 206         /* Ignore anything but MIPSxx processors */
 207         if (!(c->isa_level & (MIPS_CPU_ISA_M32R1 | MIPS_CPU_ISA_M32R2 |
 208                               MIPS_CPU_ISA_M32R6 | MIPS_CPU_ISA_M64R1 |
 209                               MIPS_CPU_ISA_M64R2 | MIPS_CPU_ISA_M64R6)))
 210                 return 0;
 211
 212         /* Does this MIPS32/MIPS64 CPU have a config2 register? */
 213         config1 = read_c0_config1();
 214         if (!(config1 & MIPS_CONF_M))
 215                 return 0;
 216
 217         config2 = read_c0_config2();
 218
 219         if (!mips_sc_is_activated(c))
 220                 return 0;
 221
 222         tmp = (config2 >> 8) & 0x0f;
 223         if (tmp <= 7)
 224                 c->scache.sets = 64 << tmp;
 225         else
 226                 return 0;
 227
 228         tmp = (config2 >> 0) & 0x0f;
 229         if (tmp <= 7)
 230                 c->scache.ways = tmp + 1;
 231         else
 232                 return 0;
 233
 234         c->scache.waysize = c->scache.sets * c->scache.linesz;
 235         c->scache.waybit = __ffs(c->scache.waysize);
 236
 237         c->scache.flags &= ~MIPS_CACHE_NOT_PRESENT;
 238
 239         return 1;
 240 }
 241
 242 int mips_sc_init(void)
 243 {
 244         int found = mips_sc_probe();
 245         if (found) {
 246                 mips_sc_enable();
 247                 mips_sc_prefetch_enable();
 248                 bcops = &mips_sc_ops;
 249         }
 250         return found;
 251 }