arch/mips/mm/sc-rm7k.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * sc-rm7k.c: RM7000 cache management functions.
   4  *
   5  * Copyright (C) 1997, 2001, 2003, 2004 Ralf Baechle (ralf@linux-mips.org)
   6  */
   7
   8 #undef DEBUG
   9
  10 #include <linux/kernel.h>
  11 #include <linux/mm.h>
  12 #include <linux/bitops.h>
  13
  14 #include <asm/addrspace.h>
  15 #include <asm/bcache.h>
  16 #include <asm/cacheops.h>
  17 #include <asm/mipsregs.h>
  18 #include <asm/processor.h>
  19 #include <asm/sections.h>
  20 #include <asm/cacheflush.h> /* for run_uncached() */
  21
  22 /* Primary cache parameters. */
  23 #define sc_lsize        32
  24 #define tc_pagesize     (32*128)
  25
  26 /* Secondary cache parameters. */
  27 #define scache_size     (256*1024)      /* Fixed to 256KiB on RM7000 */
  28
  29 /* Tertiary cache parameters */
  30 #define tc_lsize        32
  31
  32 extern unsigned long icache_way_size, dcache_way_size;
  33 static unsigned long tcache_size;
  34
  35 #include <asm/r4kcache.h>
  36
  37 static int rm7k_tcache_init;
  38
  39 /*
  40  * Writeback and invalidate the primary cache dcache before DMA.
  41  * (XXX These need to be fixed ...)
  42  */
  43 static void rm7k_sc_wback_inv(unsigned long addr, unsigned long size)
  44 {
  45         unsigned long end, a;
  46
  47         pr_debug("rm7k_sc_wback_inv[%08lx,%08lx]", addr, size);
  48
  49         /* Catch bad driver code */
  50         BUG_ON(size == 0);
  51
  52         blast_scache_range(addr, addr + size);
  53
  54         if (!rm7k_tcache_init)
  55                 return;
  56
  57         a = addr & ~(tc_pagesize - 1);
  58         end = (addr + size - 1) & ~(tc_pagesize - 1);
  59         while(1) {
  60                 invalidate_tcache_page(a);      /* Page_Invalidate_T */
  61                 if (a == end)
  62                         break;
  63                 a += tc_pagesize;
  64         }
  65 }
  66
  67 static void rm7k_sc_inv(unsigned long addr, unsigned long size)
  68 {
  69         unsigned long end, a;
  70
  71         pr_debug("rm7k_sc_inv[%08lx,%08lx]", addr, size);
  72
  73         /* Catch bad driver code */
  74         BUG_ON(size == 0);
  75
  76         blast_inv_scache_range(addr, addr + size);
  77
  78         if (!rm7k_tcache_init)
  79                 return;
  80
  81         a = addr & ~(tc_pagesize - 1);
  82         end = (addr + size - 1) & ~(tc_pagesize - 1);
  83         while(1) {
  84                 invalidate_tcache_page(a);      /* Page_Invalidate_T */
  85                 if (a == end)
  86                         break;
  87                 a += tc_pagesize;
  88         }
  89 }
  90
  91 static void blast_rm7k_tcache(void)
  92 {
  93         unsigned long start = CKSEG0ADDR(0);
  94         unsigned long end = start + tcache_size;
  95
  96         write_c0_taglo(0);
  97
  98         while (start < end) {
  99                 cache_op(Page_Invalidate_T, start);
 100                 start += tc_pagesize;
 101         }
 102 }
 103
 104 /*
 105  * This function is executed in uncached address space.
 106  */
 107 static void __rm7k_tc_enable(void)
 108 {
 109         int i;
 110
 111         set_c0_config(RM7K_CONF_TE);
 112
 113         write_c0_taglo(0);
 114         write_c0_taghi(0);
 115
 116         for (i = 0; i < tcache_size; i += tc_lsize)
 117                 cache_op(Index_Store_Tag_T, CKSEG0ADDR(i));
 118 }
 119
 120 static void rm7k_tc_enable(void)
 121 {
 122         if (read_c0_config() & RM7K_CONF_TE)
 123                 return;
 124
 125         BUG_ON(tcache_size == 0);
 126
 127         run_uncached(__rm7k_tc_enable);
 128 }
 129
 130 /*
 131  * This function is executed in uncached address space.
 132  */
 133 static void __rm7k_sc_enable(void)
 134 {
 135         int i;
 136
 137         set_c0_config(RM7K_CONF_SE);
 138
 139         write_c0_taglo(0);
 140         write_c0_taghi(0);
 141
 142         for (i = 0; i < scache_size; i += sc_lsize)
 143                 cache_op(Index_Store_Tag_SD, CKSEG0ADDR(i));
 144 }
 145
 146 static void rm7k_sc_enable(void)
 147 {
 148         if (read_c0_config() & RM7K_CONF_SE)
 149                 return;
 150
 151         pr_info("Enabling secondary cache...\n");
 152         run_uncached(__rm7k_sc_enable);
 153
 154         if (rm7k_tcache_init)
 155                 rm7k_tc_enable();
 156 }
 157
 158 static void rm7k_tc_disable(void)
 159 {
 160         unsigned long flags;
 161
 162         local_irq_save(flags);
 163         blast_rm7k_tcache();
 164         clear_c0_config(RM7K_CONF_TE);
 165         local_irq_restore(flags);
 166 }
 167
 168 static void rm7k_sc_disable(void)
 169 {
 170         clear_c0_config(RM7K_CONF_SE);
 171
 172         if (rm7k_tcache_init)
 173                 rm7k_tc_disable();
 174 }
 175
 176 static struct bcache_ops rm7k_sc_ops = {
 177         .bc_enable = rm7k_sc_enable,
 178         .bc_disable = rm7k_sc_disable,
 179         .bc_wback_inv = rm7k_sc_wback_inv,
 180         .bc_inv = rm7k_sc_inv
 181 };
 182
 183 /*
 184  * This is a probing function like the one found in c-r4k.c, we look for the
 185  * wrap around point with different addresses.
 186  */
 187 static void __probe_tcache(void)
 188 {
 189         unsigned long flags, addr, begin, end, pow2;
 190
 191         begin = (unsigned long) &_stext;
 192         begin  &= ~((8 * 1024 * 1024) - 1);
 193         end = begin + (8 * 1024 * 1024);
 194
 195         local_irq_save(flags);
 196
 197         set_c0_config(RM7K_CONF_TE);
 198
 199         /* Fill size-multiple lines with a valid tag */
 200         pow2 = (256 * 1024);
 201         for (addr = begin; addr <= end; addr = (begin + pow2)) {
 202                 unsigned long *p = (unsigned long *) addr;
 203                 __asm__ __volatile__("nop" : : "r" (*p));
 204                 pow2 <<= 1;
 205         }
 206
 207         /* Load first line with a 0 tag, to check after */
 208         write_c0_taglo(0);
 209         write_c0_taghi(0);
 210         cache_op(Index_Store_Tag_T, begin);
 211
 212         /* Look for the wrap-around */
 213         pow2 = (512 * 1024);
 214         for (addr = begin + (512 * 1024); addr <= end; addr = begin + pow2) {
 215                 cache_op(Index_Load_Tag_T, addr);
 216                 if (!read_c0_taglo())
 217                         break;
 218                 pow2 <<= 1;
 219         }
 220
 221         addr -= begin;
 222         tcache_size = addr;
 223
 224         clear_c0_config(RM7K_CONF_TE);
 225
 226         local_irq_restore(flags);
 227 }
 228
 229 void rm7k_sc_init(void)
 230 {
 231         struct cpuinfo_mips *c = &current_cpu_data;
 232         unsigned int config = read_c0_config();
 233
 234         if ((config & RM7K_CONF_SC))
 235                 return;
 236
 237         c->scache.linesz = sc_lsize;
 238         c->scache.ways = 4;
 239         c->scache.waybit= __ffs(scache_size / c->scache.ways);
 240         c->scache.waysize = scache_size / c->scache.ways;
 241         c->scache.sets = scache_size / (c->scache.linesz * c->scache.ways);
 242         printk(KERN_INFO "Secondary cache size %dK, linesize %d bytes.\n",
 243                (scache_size >> 10), sc_lsize);
 244
 245         if (!(config & RM7K_CONF_SE))
 246                 rm7k_sc_enable();
 247
 248         bcops = &rm7k_sc_ops;
 249
 250         /*
 251          * While we're at it let's deal with the tertiary cache.
 252          */
 253
 254         rm7k_tcache_init = 0;
 255         tcache_size = 0;
 256
 257         if (config & RM7K_CONF_TC)
 258                 return;
 259
 260         /*
 261          * No efficient way to ask the hardware for the size of the tcache,
 262          * so must probe for it.
 263          */
 264         run_uncached(__probe_tcache);
 265         rm7k_tc_enable();
 266         rm7k_tcache_init = 1;
 267         c->tcache.linesz = tc_lsize;
 268         c->tcache.ways = 1;
 269         pr_info("Tertiary cache size %ldK.\n", (tcache_size >> 10));
 270 }