drivers/staging/comedi/drivers/8253.h

   1 /*
   2     comedi/drivers/8253.h
   3     Header file for 8253
   4
   5     COMEDI - Linux Control and Measurement Device Interface
   6     Copyright (C) 2000 David A. Schleef <ds@schleef.org>
   7
   8     This program is free software; you can redistribute it and/or modify
   9     it under the terms of the GNU General Public License as published by
  10     the Free Software Foundation; either version 2 of the License, or
  11     (at your option) any later version.
  12
  13     This program is distributed in the hope that it will be useful,
  14     but WITHOUT ANY WARRANTY; without even the implied warranty of
  15     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16     GNU General Public License for more details.
  17
  18     You should have received a copy of the GNU General Public License
  19     along with this program; if not, write to the Free Software
  20     Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  21
  22 */
  23
  24 #ifndef _8253_H
  25 #define _8253_H
  26
  27 #include "../comedi.h"
  28
  29 #define i8253_cascade_ns_to_timer i8253_cascade_ns_to_timer_2div
  30
  31 static inline void i8253_cascade_ns_to_timer_2div_old(int i8253_osc_base,
  32                                                       unsigned int *d1,
  33                                                       unsigned int *d2,
  34                                                       unsigned int *nanosec,
  35                                                       int round_mode)
  36 {
  37         int divider;
  38         int div1, div2;
  39         int div1_glb, div2_glb, ns_glb;
  40         int div1_lub, div2_lub, ns_lub;
  41         int ns;
  42
  43         divider = (*nanosec + i8253_osc_base / 2) / i8253_osc_base;
  44
  45         /* find 2 integers 1<={x,y}<=65536 such that x*y is
  46            close to divider */
  47
  48         div1_lub = div2_lub = 0;
  49         div1_glb = div2_glb = 0;
  50
  51         ns_glb = 0;
  52         ns_lub = 0xffffffff;
  53
  54         div2 = 0x10000;
  55         for (div1 = divider / 65536 + 1; div1 < div2; div1++) {
  56                 div2 = divider / div1;
  57
  58                 ns = i8253_osc_base * div1 * div2;
  59                 if (ns <= *nanosec && ns > ns_glb) {
  60                         ns_glb = ns;
  61                         div1_glb = div1;
  62                         div2_glb = div2;
  63                 }
  64
  65                 div2++;
  66                 if (div2 <= 65536) {
  67                         ns = i8253_osc_base * div1 * div2;
  68                         if (ns > *nanosec && ns < ns_lub) {
  69                                 ns_lub = ns;
  70                                 div1_lub = div1;
  71                                 div2_lub = div2;
  72                         }
  73                 }
  74         }
  75
  76         *nanosec = div1_lub * div2_lub * i8253_osc_base;
  77         *d1 = div1_lub & 0xffff;
  78         *d2 = div2_lub & 0xffff;
  79         return;
  80 }
  81
  82 static inline void i8253_cascade_ns_to_timer_power(int i8253_osc_base,
  83                                                    unsigned int *d1,
  84                                                    unsigned int *d2,
  85                                                    unsigned int *nanosec,
  86                                                    int round_mode)
  87 {
  88         int div1, div2;
  89         int base;
  90
  91         for (div1 = 2; div1 <= (1 << 16); div1 <<= 1) {
  92                 base = i8253_osc_base * div1;
  93                 round_mode &= TRIG_ROUND_MASK;
  94                 switch (round_mode) {
  95                 case TRIG_ROUND_NEAREST:
  96                 default:
  97                         div2 = (*nanosec + base / 2) / base;
  98                         break;
  99                 case TRIG_ROUND_DOWN:
 100                         div2 = (*nanosec) / base;
 101                         break;
 102                 case TRIG_ROUND_UP:
 103                         div2 = (*nanosec + base - 1) / base;
 104                         break;
 105                 }
 106                 if (div2 < 2)
 107                         div2 = 2;
 108                 if (div2 <= 65536) {
 109                         *nanosec = div2 * base;
 110                         *d1 = div1 & 0xffff;
 111                         *d2 = div2 & 0xffff;
 112                         return;
 113                 }
 114         }
 115
 116         /* shouldn't get here */
 117         div1 = 0x10000;
 118         div2 = 0x10000;
 119         *nanosec = div1 * div2 * i8253_osc_base;
 120         *d1 = div1 & 0xffff;
 121         *d2 = div2 & 0xffff;
 122 }
 123
 124 static inline void i8253_cascade_ns_to_timer_2div(int i8253_osc_base,
 125                                                   unsigned int *d1,
 126                                                   unsigned int *d2,
 127                                                   unsigned int *nanosec,
 128                                                   int round_mode)
 129 {
 130         unsigned int divider;
 131         unsigned int div1, div2;
 132         unsigned int div1_glb, div2_glb, ns_glb;
 133         unsigned int div1_lub, div2_lub, ns_lub;
 134         unsigned int ns;
 135         unsigned int start;
 136         unsigned int ns_low, ns_high;
 137         static const unsigned int max_count = 0x10000;
 138         /* exit early if everything is already correct (this can save time
 139          * since this function may be called repeatedly during command tests
 140          * and execution) */
 141         div1 = *d1 ? *d1 : max_count;
 142         div2 = *d2 ? *d2 : max_count;
 143         divider = div1 * div2;
 144         if (div1 * div2 * i8253_osc_base == *nanosec &&
 145             div1 > 1 && div1 <= max_count && div2 > 1 && div2 <= max_count &&
 146             /* check for overflow */
 147             divider > div1 && divider > div2 &&
 148             divider * i8253_osc_base > divider &&
 149             divider * i8253_osc_base > i8253_osc_base) {
 150                 return;
 151         }
 152
 153         divider = *nanosec / i8253_osc_base;
 154
 155         div1_lub = div2_lub = 0;
 156         div1_glb = div2_glb = 0;
 157
 158         ns_glb = 0;
 159         ns_lub = 0xffffffff;
 160
 161         div2 = max_count;
 162         start = divider / div2;
 163         if (start < 2)
 164                 start = 2;
 165         for (div1 = start; div1 <= divider / div1 + 1 && div1 <= max_count;
 166              div1++) {
 167                 for (div2 = divider / div1;
 168                      div1 * div2 <= divider + div1 + 1 && div2 <= max_count;
 169                      div2++) {
 170                         ns = i8253_osc_base * div1 * div2;
 171                         if (ns <= *nanosec && ns > ns_glb) {
 172                                 ns_glb = ns;
 173                                 div1_glb = div1;
 174                                 div2_glb = div2;
 175                         }
 176                         if (ns >= *nanosec && ns < ns_lub) {
 177                                 ns_lub = ns;
 178                                 div1_lub = div1;
 179                                 div2_lub = div2;
 180                         }
 181                 }
 182         }
 183
 184         round_mode &= TRIG_ROUND_MASK;
 185         switch (round_mode) {
 186         case TRIG_ROUND_NEAREST:
 187         default:
 188                 ns_high = div1_lub * div2_lub * i8253_osc_base;
 189                 ns_low = div1_glb * div2_glb * i8253_osc_base;
 190                 if (ns_high - *nanosec < *nanosec - ns_low) {
 191                         div1 = div1_lub;
 192                         div2 = div2_lub;
 193                 } else {
 194                         div1 = div1_glb;
 195                         div2 = div2_glb;
 196                 }
 197                 break;
 198         case TRIG_ROUND_UP:
 199                 div1 = div1_lub;
 200                 div2 = div2_lub;
 201                 break;
 202         case TRIG_ROUND_DOWN:
 203                 div1 = div1_glb;
 204                 div2 = div2_glb;
 205                 break;
 206         }
 207
 208         *nanosec = div1 * div2 * i8253_osc_base;
 209         /*  masking is done since counter maps zero to 0x10000 */
 210         *d1 = div1 & 0xffff;
 211         *d2 = div2 & 0xffff;
 212         return;
 213 }
 214
 215 #ifndef CMDTEST
 216 /* i8254_load programs 8254 counter chip.  It should also work for the 8253.
 217  * base_address is the lowest io address
 218  * for the chip (the address of counter 0).
 219  * counter_number is the counter you want to load (0,1 or 2)
 220  * count is the number to load into the counter.
 221  *
 222  * You probably want to use mode 2.
 223  *
 224  * Use i8254_mm_load() if you board uses memory-mapped io, it is
 225  * the same as i8254_load() except it uses writeb() instead of outb().
 226  *
 227  * Neither i8254_load() or i8254_read() do their loading/reading
 228  * atomically.  The 16 bit read/writes are performed with two successive
 229  * 8 bit read/writes.  So if two parts of your driver do a load/read on
 230  * the same counter, it may be necessary to protect these functions
 231  * with a spinlock.
 232  *
 233  * FMH
 234  */
 235
 236 #define i8254_control_reg       3
 237
 238 static inline int i8254_load(unsigned long base_address, unsigned int regshift,
 239                              unsigned int counter_number, unsigned int count,
 240                              unsigned int mode)
 241 {
 242         unsigned int byte;
 243
 244         if (counter_number > 2)
 245                 return -1;
 246         if (count > 0xffff)
 247                 return -1;
 248         if (mode > 5)
 249                 return -1;
 250         if ((mode == 2 || mode == 3) && count == 1)
 251                 return -1;
 252
 253         byte = counter_number << 6;
 254         byte |= 0x30;           /*  load low then high byte */
 255         byte |= (mode << 1);    /*  set counter mode */
 256         outb(byte, base_address + (i8254_control_reg << regshift));
 257         byte = count & 0xff;    /*  lsb of counter value */
 258         outb(byte, base_address + (counter_number << regshift));
 259         byte = (count >> 8) & 0xff;     /*  msb of counter value */
 260         outb(byte, base_address + (counter_number << regshift));
 261
 262         return 0;
 263 }
 264
 265 static inline int i8254_mm_load(void *base_address, unsigned int regshift,
 266                                 unsigned int counter_number, unsigned int count,
 267                                 unsigned int mode)
 268 {
 269         unsigned int byte;
 270
 271         if (counter_number > 2)
 272                 return -1;
 273         if (count > 0xffff)
 274                 return -1;
 275         if (mode > 5)
 276                 return -1;
 277         if ((mode == 2 || mode == 3) && count == 1)
 278                 return -1;
 279
 280         byte = counter_number << 6;
 281         byte |= 0x30;           /*  load low then high byte */
 282         byte |= (mode << 1);    /*  set counter mode */
 283         writeb(byte, base_address + (i8254_control_reg << regshift));
 284         byte = count & 0xff;    /*  lsb of counter value */
 285         writeb(byte, base_address + (counter_number << regshift));
 286         byte = (count >> 8) & 0xff;     /*  msb of counter value */
 287         writeb(byte, base_address + (counter_number << regshift));
 288
 289         return 0;
 290 }
 291
 292 /* Returns 16 bit counter value, should work for 8253 also.*/
 293 static inline int i8254_read(unsigned long base_address, unsigned int regshift,
 294                              unsigned int counter_number)
 295 {
 296         unsigned int byte;
 297         int ret;
 298
 299         if (counter_number > 2)
 300                 return -1;
 301
 302         /*  latch counter */
 303         byte = counter_number << 6;
 304         outb(byte, base_address + (i8254_control_reg << regshift));
 305
 306         /*  read lsb */
 307         ret = inb(base_address + (counter_number << regshift));
 308         /*  read msb */
 309         ret += inb(base_address + (counter_number << regshift)) << 8;
 310
 311         return ret;
 312 }
 313
 314 static inline int i8254_mm_read(void *base_address, unsigned int regshift,
 315                                 unsigned int counter_number)
 316 {
 317         unsigned int byte;
 318         int ret;
 319
 320         if (counter_number > 2)
 321                 return -1;
 322
 323         /*  latch counter */
 324         byte = counter_number << 6;
 325         writeb(byte, base_address + (i8254_control_reg << regshift));
 326
 327         /*  read lsb */
 328         ret = readb(base_address + (counter_number << regshift));
 329         /*  read msb */
 330         ret += readb(base_address + (counter_number << regshift)) << 8;
 331
 332         return ret;
 333 }
 334
 335 /* Loads 16 bit initial counter value, should work for 8253 also. */
 336 static inline void i8254_write(unsigned long base_address,
 337                                unsigned int regshift,
 338                                unsigned int counter_number, unsigned int count)
 339 {
 340         unsigned int byte;
 341
 342         if (counter_number > 2)
 343                 return;
 344
 345         byte = count & 0xff;    /*  lsb of counter value */
 346         outb(byte, base_address + (counter_number << regshift));
 347         byte = (count >> 8) & 0xff;     /*  msb of counter value */
 348         outb(byte, base_address + (counter_number << regshift));
 349 }
 350
 351 static inline void i8254_mm_write(void *base_address,
 352                                   unsigned int regshift,
 353                                   unsigned int counter_number,
 354                                   unsigned int count)
 355 {
 356         unsigned int byte;
 357
 358         if (counter_number > 2)
 359                 return;
 360
 361         byte = count & 0xff;    /*  lsb of counter value */
 362         writeb(byte, base_address + (counter_number << regshift));
 363         byte = (count >> 8) & 0xff;     /*  msb of counter value */
 364         writeb(byte, base_address + (counter_number << regshift));
 365 }
 366
 367 /* Set counter mode, should work for 8253 also.
 368  * Note: the 'mode' value is different to that for i8254_load() and comes
 369  * from the INSN_CONFIG_8254_SET_MODE command:
 370  *   I8254_MODE0, I8254_MODE1, ..., I8254_MODE5
 371  * OR'ed with:
 372  *   I8254_BCD, I8254_BINARY
 373  */
 374 static inline int i8254_set_mode(unsigned long base_address,
 375                                  unsigned int regshift,
 376                                  unsigned int counter_number, unsigned int mode)
 377 {
 378         unsigned int byte;
 379
 380         if (counter_number > 2)
 381                 return -1;
 382         if (mode > (I8254_MODE5 | I8254_BINARY))
 383                 return -1;
 384
 385         byte = counter_number << 6;
 386         byte |= 0x30;           /*  load low then high byte */
 387         byte |= mode;           /*  set counter mode and BCD|binary */
 388         outb(byte, base_address + (i8254_control_reg << regshift));
 389
 390         return 0;
 391 }
 392
 393 static inline int i8254_mm_set_mode(void *base_address,
 394                                     unsigned int regshift,
 395                                     unsigned int counter_number,
 396                                     unsigned int mode)
 397 {
 398         unsigned int byte;
 399
 400         if (counter_number > 2)
 401                 return -1;
 402         if (mode > (I8254_MODE5 | I8254_BINARY))
 403                 return -1;
 404
 405         byte = counter_number << 6;
 406         byte |= 0x30;           /*  load low then high byte */
 407         byte |= mode;           /*  set counter mode and BCD|binary */
 408         writeb(byte, base_address + (i8254_control_reg << regshift));
 409
 410         return 0;
 411 }
 412
 413 static inline int i8254_status(unsigned long base_address,
 414                                unsigned int regshift,
 415                                unsigned int counter_number)
 416 {
 417         outb(0xE0 | (2 << counter_number),
 418              base_address + (i8254_control_reg << regshift));
 419         return inb(base_address + (counter_number << regshift));
 420 }
 421
 422 static inline int i8254_mm_status(void *base_address,
 423                                   unsigned int regshift,
 424                                   unsigned int counter_number)
 425 {
 426         writeb(0xE0 | (2 << counter_number),
 427                base_address + (i8254_control_reg << regshift));
 428         return readb(base_address + (counter_number << regshift));
 429 }
 430
 431 #endif
 432
 433 #endif