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         *d1 = div1 & 0xffff;    /*  masking is done since counter maps zero to 0x10000 */
 210         *d2 = div2 & 0xffff;
 211         return;
 212 }
 213
 214 #ifndef CMDTEST
 215 /* i8254_load programs 8254 counter chip.  It should also work for the 8253.
 216  * base_address is the lowest io address for the chip (the address of counter 0).
 217  * counter_number is the counter you want to load (0,1 or 2)
 218  * count is the number to load into the counter.
 219  *
 220  * You probably want to use mode 2.
 221  *
 222  * Use i8254_mm_load() if you board uses memory-mapped io, it is
 223  * the same as i8254_load() except it uses writeb() instead of outb().
 224  *
 225  * Neither i8254_load() or i8254_read() do their loading/reading
 226  * atomically.  The 16 bit read/writes are performed with two successive
 227  * 8 bit read/writes.  So if two parts of your driver do a load/read on
 228  * the same counter, it may be necessary to protect these functions
 229  * with a spinlock.
 230  *
 231  * FMH
 232  */
 233
 234 #define i8254_control_reg       3
 235
 236 static inline int i8254_load(unsigned long base_address, unsigned int regshift,
 237                              unsigned int counter_number, unsigned int count,
 238                              unsigned int mode)
 239 {
 240         unsigned int byte;
 241
 242         if (counter_number > 2)
 243                 return -1;
 244         if (count > 0xffff)
 245                 return -1;
 246         if (mode > 5)
 247                 return -1;
 248         if ((mode == 2 || mode == 3) && count == 1)
 249                 return -1;
 250
 251         byte = counter_number << 6;
 252         byte |= 0x30;           /*  load low then high byte */
 253         byte |= (mode << 1);    /*  set counter mode */
 254         outb(byte, base_address + (i8254_control_reg << regshift));
 255         byte = count & 0xff;    /*  lsb of counter value */
 256         outb(byte, base_address + (counter_number << regshift));
 257         byte = (count >> 8) & 0xff;     /*  msb of counter value */
 258         outb(byte, base_address + (counter_number << regshift));
 259
 260         return 0;
 261 }
 262
 263 static inline int i8254_mm_load(void *base_address, unsigned int regshift,
 264                                 unsigned int counter_number, unsigned int count,
 265                                 unsigned int mode)
 266 {
 267         unsigned int byte;
 268
 269         if (counter_number > 2)
 270                 return -1;
 271         if (count > 0xffff)
 272                 return -1;
 273         if (mode > 5)
 274                 return -1;
 275         if ((mode == 2 || mode == 3) && count == 1)
 276                 return -1;
 277
 278         byte = counter_number << 6;
 279         byte |= 0x30;           /*  load low then high byte */
 280         byte |= (mode << 1);    /*  set counter mode */
 281         writeb(byte, base_address + (i8254_control_reg << regshift));
 282         byte = count & 0xff;    /*  lsb of counter value */
 283         writeb(byte, base_address + (counter_number << regshift));
 284         byte = (count >> 8) & 0xff;     /*  msb of counter value */
 285         writeb(byte, base_address + (counter_number << regshift));
 286
 287         return 0;
 288 }
 289
 290 /* Returns 16 bit counter value, should work for 8253 also.*/
 291 static inline int i8254_read(unsigned long base_address, unsigned int regshift,
 292                              unsigned int counter_number)
 293 {
 294         unsigned int byte;
 295         int ret;
 296
 297         if (counter_number > 2)
 298                 return -1;
 299
 300         /*  latch counter */
 301         byte = counter_number << 6;
 302         outb(byte, base_address + (i8254_control_reg << regshift));
 303
 304         /*  read lsb */
 305         ret = inb(base_address + (counter_number << regshift));
 306         /*  read msb */
 307         ret += inb(base_address + (counter_number << regshift)) << 8;
 308
 309         return ret;
 310 }
 311
 312 static inline int i8254_mm_read(void *base_address, unsigned int regshift,
 313                                 unsigned int counter_number)
 314 {
 315         unsigned int byte;
 316         int ret;
 317
 318         if (counter_number > 2)
 319                 return -1;
 320
 321         /*  latch counter */
 322         byte = counter_number << 6;
 323         writeb(byte, base_address + (i8254_control_reg << regshift));
 324
 325         /*  read lsb */
 326         ret = readb(base_address + (counter_number << regshift));
 327         /*  read msb */
 328         ret += readb(base_address + (counter_number << regshift)) << 8;
 329
 330         return ret;
 331 }
 332
 333 /* Loads 16 bit initial counter value, should work for 8253 also. */
 334 static inline void i8254_write(unsigned long base_address,
 335                                unsigned int regshift,
 336                                unsigned int counter_number, unsigned int count)
 337 {
 338         unsigned int byte;
 339
 340         if (counter_number > 2)
 341                 return;
 342
 343         byte = count & 0xff;    /*  lsb of counter value */
 344         outb(byte, base_address + (counter_number << regshift));
 345         byte = (count >> 8) & 0xff;     /*  msb of counter value */
 346         outb(byte, base_address + (counter_number << regshift));
 347 }
 348
 349 static inline void i8254_mm_write(void *base_address,
 350                                   unsigned int regshift,
 351                                   unsigned int counter_number,
 352                                   unsigned int count)
 353 {
 354         unsigned int byte;
 355
 356         if (counter_number > 2)
 357                 return;
 358
 359         byte = count & 0xff;    /*  lsb of counter value */
 360         writeb(byte, base_address + (counter_number << regshift));
 361         byte = (count >> 8) & 0xff;     /*  msb of counter value */
 362         writeb(byte, base_address + (counter_number << regshift));
 363 }
 364
 365 /* Set counter mode, should work for 8253 also.
 366  * Note: the 'mode' value is different to that for i8254_load() and comes
 367  * from the INSN_CONFIG_8254_SET_MODE command:
 368  *   I8254_MODE0, I8254_MODE1, ..., I8254_MODE5
 369  * OR'ed with:
 370  *   I8254_BCD, I8254_BINARY
 371  */
 372 static inline int i8254_set_mode(unsigned long base_address,
 373                                  unsigned int regshift,
 374                                  unsigned int counter_number, unsigned int mode)
 375 {
 376         unsigned int byte;
 377
 378         if (counter_number > 2)
 379                 return -1;
 380         if (mode > (I8254_MODE5 | I8254_BINARY))
 381                 return -1;
 382
 383         byte = counter_number << 6;
 384         byte |= 0x30;           /*  load low then high byte */
 385         byte |= mode;           /*  set counter mode and BCD|binary */
 386         outb(byte, base_address + (i8254_control_reg << regshift));
 387
 388         return 0;
 389 }
 390
 391 static inline int i8254_mm_set_mode(void *base_address,
 392                                     unsigned int regshift,
 393                                     unsigned int counter_number,
 394                                     unsigned int mode)
 395 {
 396         unsigned int byte;
 397
 398         if (counter_number > 2)
 399                 return -1;
 400         if (mode > (I8254_MODE5 | I8254_BINARY))
 401                 return -1;
 402
 403         byte = counter_number << 6;
 404         byte |= 0x30;           /*  load low then high byte */
 405         byte |= mode;           /*  set counter mode and BCD|binary */
 406         writeb(byte, base_address + (i8254_control_reg << regshift));
 407
 408         return 0;
 409 }
 410
 411 static inline int i8254_status(unsigned long base_address,
 412                                unsigned int regshift,
 413                                unsigned int counter_number)
 414 {
 415         outb(0xE0 | (2 << counter_number),
 416              base_address + (i8254_control_reg << regshift));
 417         return inb(base_address + (counter_number << regshift));
 418 }
 419
 420 static inline int i8254_mm_status(void *base_address,
 421                                   unsigned int regshift,
 422                                   unsigned int counter_number)
 423 {
 424         writeb(0xE0 | (2 << counter_number),
 425                base_address + (i8254_control_reg << regshift));
 426         return readb(base_address + (counter_number << regshift));
 427 }
 428
 429 #endif
 430
 431 #endif