sim/frv/cache.h

   1 /* Cache support for the FRV simulator
   2    Copyright (C) 1999-2024 Free Software Foundation, Inc.
   3    Contributed by Red Hat.
   4
   5 This file is part of the GNU Simulators.
   6
   7 This program is free software; you can redistribute it and/or modify
   8 it under the terms of the GNU General Public License as published by
   9 the Free Software Foundation; either version 3 of the License, or
  10 (at your option) any later version.
  11
  12 This program is distributed in the hope that it will be useful,
  13 but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 GNU General Public License for more details.
  16
  17 You should have received a copy of the GNU General Public License
  18 along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  19
  20 #ifndef CACHE_H
  21 #define CACHE_H
  22
  23 /* A representation of a set-associative cache with LRU replacement,
  24    cache line locking, non-blocking support and multiple read ports.  */
  25
  26 /* An enumeration of cache pipeline request kinds.  */
  27 typedef enum
  28 {
  29   req_load,
  30   req_store,
  31   req_invalidate,
  32   req_flush,
  33   req_preload,
  34   req_unlock,
  35   req_WAR
  36 } FRV_CACHE_REQUEST_KIND;
  37
  38 /* The cache pipeline requests.  */
  39 typedef struct {
  40   int preload;
  41   int lock;
  42 } FRV_CACHE_WAR_REQUEST;
  43
  44 typedef struct {
  45   char *data;
  46   int length;
  47 } FRV_CACHE_STORE_REQUEST;
  48
  49 typedef struct {
  50   int flush;
  51   int all;
  52 } FRV_CACHE_INVALIDATE_REQUEST;
  53
  54 typedef struct {
  55   int lock;
  56   int length;
  57 } FRV_CACHE_PRELOAD_REQUEST;
  58
  59 /* A cache pipeline request.  */
  60 typedef struct frv_cache_request
  61 {
  62   struct frv_cache_request *next;
  63   struct frv_cache_request *prev;
  64   FRV_CACHE_REQUEST_KIND kind;
  65   unsigned reqno;
  66   unsigned priority;
  67   SI address;
  68   union {
  69     FRV_CACHE_STORE_REQUEST store;
  70     FRV_CACHE_INVALIDATE_REQUEST invalidate;
  71     FRV_CACHE_PRELOAD_REQUEST preload;
  72     FRV_CACHE_WAR_REQUEST WAR;
  73   } u;
  74 } FRV_CACHE_REQUEST;
  75
  76 /* The buffer for returning data to the caller.  */
  77 typedef struct {
  78   unsigned reqno;
  79   SI address;
  80   char *data;
  81   int valid;
  82 } FRV_CACHE_RETURN_BUFFER;
  83
  84 /* The status of flush requests.  */
  85 typedef struct {
  86   unsigned reqno;
  87   SI address;
  88   int valid;
  89 } FRV_CACHE_FLUSH_STATUS;
  90
  91 /* Communicate status of requests to the caller.  */
  92 typedef struct {
  93   FRV_CACHE_FLUSH_STATUS  flush;
  94   FRV_CACHE_RETURN_BUFFER return_buffer;
  95 } FRV_CACHE_STATUS;
  96
  97 /* A cache pipeline stage.  */
  98 typedef struct {
  99   FRV_CACHE_REQUEST *request;
 100 } FRV_CACHE_STAGE;
 101
 102 enum {
 103   FIRST_STAGE,
 104   A_STAGE = FIRST_STAGE, /* Addressing stage */
 105   I_STAGE,               /* Interference stage */
 106   LAST_STAGE = I_STAGE,
 107   FRV_CACHE_STAGES
 108 };
 109
 110 /* Representation of the WAR register.  */
 111 typedef struct {
 112   unsigned reqno;
 113   unsigned priority;
 114   SI address;
 115   int preload;
 116   int lock;
 117   int latency;
 118   int valid;
 119 } FRV_CACHE_WAR;
 120
 121 /* A cache pipeline.  */
 122 #define NUM_WARS 2
 123 typedef struct {
 124   FRV_CACHE_REQUEST      *requests;
 125   FRV_CACHE_STAGE         stages[FRV_CACHE_STAGES];
 126   FRV_CACHE_WAR           WAR[NUM_WARS];
 127   FRV_CACHE_STATUS        status;
 128 } FRV_CACHE_PIPELINE;
 129
 130 enum {LS, LD, FRV_CACHE_PIPELINES};
 131
 132 /* Representation of the xARS registers.  */
 133 typedef struct {
 134   int pipe;
 135   unsigned reqno;
 136   unsigned priority;
 137   SI address;
 138   int preload;
 139   int lock;
 140   int valid;
 141 } FRV_CACHE_ARS;
 142
 143 /* A cache tag.  */
 144 typedef struct {
 145   USI   tag;    /* Address tag.  */
 146   int   lru;    /* Lower values indicates less recently used.  */
 147   char *line;   /* Points to storage for line in data_storage.  */
 148   char  dirty;  /* line has been written to since last stored?  */
 149   char  locked; /* line is locked?  */
 150   char  valid;  /* tag is valid?  */
 151 } FRV_CACHE_TAG;
 152
 153 /* Cache statistics.  */
 154 typedef struct {
 155   unsigned long accesses;   /* number of cache accesses.  */
 156   unsigned long hits;       /* number of cache hits.  */
 157 } FRV_CACHE_STATISTICS;
 158
 159 /* The cache itself.
 160    Notes:
 161    - line_size must be a power of 2
 162    - sets must be a power of 2
 163    - ways must be a power of 2
 164 */
 165 typedef struct {
 166   SIM_CPU *cpu;
 167   unsigned configured_ways;   /* Number of ways configured in each set.  */
 168   unsigned configured_sets;   /* Number of sets configured in the cache.  */
 169   unsigned ways;              /* Number of ways in each set.  */
 170   unsigned sets;              /* Number of sets in the cache.  */
 171   unsigned line_size;         /* Size of each cache line.  */
 172   unsigned memory_latency;    /* Latency of main memory in cycles.  */
 173   FRV_CACHE_TAG *tag_storage; /* Storage for tags.  */
 174   char *data_storage;         /* Storage for data (cache lines).  */
 175   FRV_CACHE_PIPELINE pipeline[2];  /* Cache pipelines.  */
 176   FRV_CACHE_ARS BARS;         /* BARS register.  */
 177   FRV_CACHE_ARS NARS;         /* BARS register.  */
 178   FRV_CACHE_STATISTICS statistics; /* Operation statistics.  */
 179 } FRV_CACHE;
 180
 181 /* The tags are stored by ways within sets in order to make computations
 182    easier.  */
 183 #define CACHE_TAG(cache, set, way) ( \
 184   & ((cache)->tag_storage[(set) * (cache)->ways + (way)]) \
 185 )
 186
 187 /* Compute the address tag corresponding to the given address.  */
 188 #define CACHE_ADDRESS_TAG(cache, address) ( \
 189   (address) & ~(((cache)->line_size * (cache)->sets) - 1) \
 190 )
 191
 192 /* Determine the index at which the set containing this tag starts.  */
 193 #define CACHE_TAG_SET_START(cache, tag) ( \
 194   ((tag) - (cache)->tag_storage) & ~((cache)->ways - 1) \
 195 )
 196
 197 /* Determine the number of the set which this cache tag is in.  */
 198 #define CACHE_TAG_SET_NUMBER(cache, tag) ( \
 199   CACHE_TAG_SET_START ((cache), (tag)) / (cache)->ways \
 200 )
 201
 202 #define CACHE_RETURN_DATA(cache, slot, address, mode, N) (               \
 203   T2H_##N (*(mode *)(& (cache)->pipeline[slot].status.return_buffer.data \
 204                      [((address) & ((cache)->line_size - 1))]))          \
 205 )
 206 #define CACHE_RETURN_DATA_ADDRESS(cache, slot, address, N) (              \
 207   ((void *)& (cache)->pipeline[slot].status.return_buffer.data[(address)  \
 208                                                & ((cache)->line_size - 1)]) \
 209 )
 210
 211 #define DATA_CROSSES_CACHE_LINE(cache, address, size) ( \
 212   ((address) & ((cache)->line_size - 1)) + (size) > (cache)->line_size \
 213 )
 214
 215 #define CACHE_INITIALIZED(cache) ((cache)->data_storage != NULL)
 216
 217 /* These functions are used to initialize and terminate a cache.  */
 218 void
 219 frv_cache_init (SIM_CPU *, FRV_CACHE *);
 220 void
 221 frv_cache_term (FRV_CACHE *);
 222 void
 223 frv_cache_reconfigure (SIM_CPU *, FRV_CACHE *);
 224 int
 225 frv_cache_enabled (FRV_CACHE *);
 226
 227 /* These functions are used to operate the cache in non-cycle-accurate mode.
 228    Each request is handled individually and immediately using the current
 229    cache internal state.  */
 230 int
 231 frv_cache_read (FRV_CACHE *, int, SI);
 232 int
 233 frv_cache_write (FRV_CACHE *, SI, char *, unsigned);
 234 int
 235 frv_cache_preload (FRV_CACHE *, SI, USI, int);
 236 int
 237 frv_cache_unlock (FRV_CACHE *, SI);
 238 int
 239 frv_cache_invalidate (FRV_CACHE *, SI, int);
 240 int
 241 frv_cache_invalidate_all (FRV_CACHE *, int);
 242
 243 /* These functions are used to operate the cache in cycle-accurate mode.
 244    The internal operation of the cache is simulated down to the cycle level.  */
 245 #define NO_REQNO 0xffffffff
 246 void
 247 frv_cache_request_load (FRV_CACHE *, unsigned, SI, int);
 248 void
 249 frv_cache_request_store (FRV_CACHE *, SI, int, char *, unsigned);
 250 void
 251 frv_cache_request_invalidate (FRV_CACHE *, unsigned, SI, int, int, int);
 252 void
 253 frv_cache_request_preload (FRV_CACHE *, SI, int, int, int);
 254 void
 255 frv_cache_request_unlock (FRV_CACHE *, SI, int);
 256
 257 void
 258 frv_cache_run (FRV_CACHE *, int);
 259
 260 int
 261 frv_cache_data_in_buffer (FRV_CACHE*, int, SI, unsigned);
 262 int
 263 frv_cache_data_flushed (FRV_CACHE*, int, SI, unsigned);
 264
 265 int
 266 frv_cache_read_passive_SI (FRV_CACHE *, SI, SI *);
 267
 268 #endif /* CACHE_H */