arch/arm/plat-s3c24xx/s3c2410-iotiming.c

   1 /* linux/arch/arm/plat-s3c24xx/s3c2410-iotiming.c
   2  *
   3  * Copyright (c) 2006-2009 Simtec Electronics
   4  *      http://armlinux.simtec.co.uk/
   5  *      Ben Dooks <ben@simtec.co.uk>
   6  *
   7  * S3C24XX CPU Frequency scaling - IO timing for S3C2410/S3C2440/S3C2442
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License version 2 as
  11  * published by the Free Software Foundation.
  12 */
  13
  14 #include <linux/init.h>
  15 #include <linux/kernel.h>
  16 #include <linux/errno.h>
  17 #include <linux/cpufreq.h>
  18 #include <linux/seq_file.h>
  19 #include <linux/io.h>
  20 #include <linux/slab.h>
  21
  22 #include <mach/map.h>
  23 #include <mach/regs-mem.h>
  24 #include <mach/regs-clock.h>
  25
  26 #include <plat/cpu-freq-core.h>
  27
  28 #define print_ns(x) ((x) / 10), ((x) % 10)
  29
  30 /**
  31  * s3c2410_print_timing - print bank timing data for debug purposes
  32  * @pfx: The prefix to put on the output
  33  * @timings: The timing inforamtion to print.
  34 */
  35 static void s3c2410_print_timing(const char *pfx,
  36                                  struct s3c_iotimings *timings)
  37 {
  38         struct s3c2410_iobank_timing *bt;
  39         int bank;
  40
  41         for (bank = 0; bank < MAX_BANKS; bank++) {
  42                 bt = timings->bank[bank].io_2410;
  43                 if (!bt)
  44                         continue;
  45
  46                 printk(KERN_DEBUG "%s %d: Tacs=%d.%d, Tcos=%d.%d, Tacc=%d.%d, "
  47                        "Tcoh=%d.%d, Tcah=%d.%d\n", pfx, bank,
  48                        print_ns(bt->tacs),
  49                        print_ns(bt->tcos),
  50                        print_ns(bt->tacc),
  51                        print_ns(bt->tcoh),
  52                        print_ns(bt->tcah));
  53         }
  54 }
  55
  56 /**
  57  * bank_reg - convert bank number to pointer to the control register.
  58  * @bank: The IO bank number.
  59  */
  60 static inline void __iomem *bank_reg(unsigned int bank)
  61 {
  62         return S3C2410_BANKCON0 + (bank << 2);
  63 }
  64
  65 /**
  66  * bank_is_io - test whether bank is used for IO
  67  * @bankcon: The bank control register.
  68  *
  69  * This is a simplistic test to see if any BANKCON[x] is not an IO
  70  * bank. It currently does not take into account whether BWSCON has
  71  * an illegal width-setting in it, or if the pin connected to nCS[x]
  72  * is actually being handled as a chip-select.
  73  */
  74 static inline int bank_is_io(unsigned long bankcon)
  75 {
  76         return !(bankcon & S3C2410_BANKCON_SDRAM);
  77 }
  78
  79 /**
  80  * to_div - convert cycle time to divisor
  81  * @cyc: The cycle time, in 10ths of nanoseconds.
  82  * @hclk_tns: The cycle time for HCLK, in 10ths of nanoseconds.
  83  *
  84  * Convert the given cycle time into the divisor to use to obtain it from
  85  * HCLK.
  86 */
  87 static inline unsigned int to_div(unsigned int cyc, unsigned int hclk_tns)
  88 {
  89         if (cyc == 0)
  90                 return 0;
  91
  92         return DIV_ROUND_UP(cyc, hclk_tns);
  93 }
  94
  95 /**
  96  * calc_0124 - calculate divisor control for divisors that do /0, /1. /2 and /4
  97  * @cyc: The cycle time, in 10ths of nanoseconds.
  98  * @hclk_tns: The cycle time for HCLK, in 10ths of nanoseconds.
  99  * @v: Pointer to register to alter.
 100  * @shift: The shift to get to the control bits.
 101  *
 102  * Calculate the divisor, and turn it into the correct control bits to
 103  * set in the result, @v.
 104  */
 105 static unsigned int calc_0124(unsigned int cyc, unsigned long hclk_tns,
 106                               unsigned long *v, int shift)
 107 {
 108         unsigned int div = to_div(cyc, hclk_tns);
 109         unsigned long val;
 110
 111         s3c_freq_iodbg("%s: cyc=%d, hclk=%lu, shift=%d => div %d\n",
 112                        __func__, cyc, hclk_tns, shift, div);
 113
 114         switch (div) {
 115         case 0:
 116                 val = 0;
 117                 break;
 118         case 1:
 119                 val = 1;
 120                 break;
 121         case 2:
 122                 val = 2;
 123                 break;
 124         case 3:
 125         case 4:
 126                 val = 3;
 127                 break;
 128         default:
 129                 return -1;
 130         }
 131
 132         *v |= val << shift;
 133         return 0;
 134 }
 135
 136 int calc_tacp(unsigned int cyc, unsigned long hclk, unsigned long *v)
 137 {
 138         /* Currently no support for Tacp calculations. */
 139         return 0;
 140 }
 141
 142 /**
 143  * calc_tacc - calculate divisor control for tacc.
 144  * @cyc: The cycle time, in 10ths of nanoseconds.
 145  * @nwait_en: IS nWAIT enabled for this bank.
 146  * @hclk_tns: The cycle time for HCLK, in 10ths of nanoseconds.
 147  * @v: Pointer to register to alter.
 148  *
 149  * Calculate the divisor control for tACC, taking into account whether
 150  * the bank has nWAIT enabled. The result is used to modify the value
 151  * pointed to by @v.
 152 */
 153 static int calc_tacc(unsigned int cyc, int nwait_en,
 154                      unsigned long hclk_tns, unsigned long *v)
 155 {
 156         unsigned int div = to_div(cyc, hclk_tns);
 157         unsigned long val;
 158
 159         s3c_freq_iodbg("%s: cyc=%u, nwait=%d, hclk=%lu => div=%u\n",
 160                        __func__, cyc, nwait_en, hclk_tns, div);
 161
 162         /* if nWait enabled on an bank, Tacc must be at-least 4 cycles. */
 163         if (nwait_en && div < 4)
 164                 div = 4;
 165
 166         switch (div) {
 167         case 0:
 168                 val = 0;
 169                 break;
 170
 171         case 1:
 172         case 2:
 173         case 3:
 174         case 4:
 175                 val = div - 1;
 176                 break;
 177
 178         case 5:
 179         case 6:
 180                 val = 4;
 181                 break;
 182
 183         case 7:
 184         case 8:
 185                 val = 5;
 186                 break;
 187
 188         case 9:
 189         case 10:
 190                 val = 6;
 191                 break;
 192
 193         case 11:
 194         case 12:
 195         case 13:
 196         case 14:
 197                 val = 7;
 198                 break;
 199
 200         default:
 201                 return -1;
 202         }
 203
 204         *v |= val << 8;
 205         return 0;
 206 }
 207
 208 /**
 209  * s3c2410_calc_bank - calculate bank timing infromation
 210  * @cfg: The configuration we need to calculate for.
 211  * @bt: The bank timing information.
 212  *
 213  * Given the cycle timine for a bank @bt, calculate the new BANKCON
 214  * setting for the @cfg timing. This updates the timing information
 215  * ready for the cpu frequency change.
 216  */
 217 static int s3c2410_calc_bank(struct s3c_cpufreq_config *cfg,
 218                              struct s3c2410_iobank_timing *bt)
 219 {
 220         unsigned long hclk = cfg->freq.hclk_tns;
 221         unsigned long res;
 222         int ret;
 223
 224         res  = bt->bankcon;
 225         res &= (S3C2410_BANKCON_SDRAM | S3C2410_BANKCON_PMC16);
 226
 227         /* tacp: 2,3,4,5 */
 228         /* tcah: 0,1,2,4 */
 229         /* tcoh: 0,1,2,4 */
 230         /* tacc: 1,2,3,4,6,7,10,14 (>4 for nwait) */
 231         /* tcos: 0,1,2,4 */
 232         /* tacs: 0,1,2,4 */
 233
 234         ret  = calc_0124(bt->tacs, hclk, &res, S3C2410_BANKCON_Tacs_SHIFT);
 235         ret |= calc_0124(bt->tcos, hclk, &res, S3C2410_BANKCON_Tcos_SHIFT);
 236         ret |= calc_0124(bt->tcah, hclk, &res, S3C2410_BANKCON_Tcah_SHIFT);
 237         ret |= calc_0124(bt->tcoh, hclk, &res, S3C2410_BANKCON_Tcoh_SHIFT);
 238
 239         if (ret)
 240                 return -EINVAL;
 241
 242         ret |= calc_tacp(bt->tacp, hclk, &res);
 243         ret |= calc_tacc(bt->tacc, bt->nwait_en, hclk, &res);
 244
 245         if (ret)
 246                 return -EINVAL;
 247
 248         bt->bankcon = res;
 249         return 0;
 250 }
 251
 252 static unsigned int tacc_tab[] = {
 253         [0]     = 1,
 254         [1]     = 2,
 255         [2]     = 3,
 256         [3]     = 4,
 257         [4]     = 6,
 258         [5]     = 9,
 259         [6]     = 10,
 260         [7]     = 14,
 261 };
 262
 263 /**
 264  * get_tacc - turn tACC value into cycle time
 265  * @hclk_tns: The cycle time for HCLK, in 10ths of nanoseconds.
 266  * @val: The bank timing register value, shifed down.
 267  */
 268 static unsigned int get_tacc(unsigned long hclk_tns,
 269                              unsigned long val)
 270 {
 271         val &= 7;
 272         return hclk_tns * tacc_tab[val];
 273 }
 274
 275 /**
 276  * get_0124 - turn 0/1/2/4 divider into cycle time
 277  * @hclk_tns: The cycle time for HCLK, in 10ths of nanoseconds.
 278  * @val: The bank timing register value, shifed down.
 279  */
 280 static unsigned int get_0124(unsigned long hclk_tns,
 281                              unsigned long val)
 282 {
 283         val &= 3;
 284         return hclk_tns * ((val == 3) ? 4 : val);
 285 }
 286
 287 /**
 288  * s3c2410_iotiming_getbank - turn BANKCON into cycle time information
 289  * @cfg: The frequency configuration
 290  * @bt: The bank timing to fill in (uses cached BANKCON)
 291  *
 292  * Given the BANKCON setting in @bt and the current frequency settings
 293  * in @cfg, update the cycle timing information.
 294  */
 295 void s3c2410_iotiming_getbank(struct s3c_cpufreq_config *cfg,
 296                               struct s3c2410_iobank_timing *bt)
 297 {
 298         unsigned long bankcon = bt->bankcon;
 299         unsigned long hclk = cfg->freq.hclk_tns;
 300
 301         bt->tcah = get_0124(hclk, bankcon >> S3C2410_BANKCON_Tcah_SHIFT);
 302         bt->tcoh = get_0124(hclk, bankcon >> S3C2410_BANKCON_Tcoh_SHIFT);
 303         bt->tcos = get_0124(hclk, bankcon >> S3C2410_BANKCON_Tcos_SHIFT);
 304         bt->tacs = get_0124(hclk, bankcon >> S3C2410_BANKCON_Tacs_SHIFT);
 305         bt->tacc = get_tacc(hclk, bankcon >> S3C2410_BANKCON_Tacc_SHIFT);
 306 }
 307
 308 /**
 309  * s3c2410_iotiming_debugfs - debugfs show io bank timing information
 310  * @seq: The seq_file to write output to using seq_printf().
 311  * @cfg: The current configuration.
 312  * @iob: The IO bank information to decode.
 313  */
 314 void s3c2410_iotiming_debugfs(struct seq_file *seq,
 315                               struct s3c_cpufreq_config *cfg,
 316                               union s3c_iobank *iob)
 317 {
 318         struct s3c2410_iobank_timing *bt = iob->io_2410;
 319         unsigned long bankcon = bt->bankcon;
 320         unsigned long hclk = cfg->freq.hclk_tns;
 321         unsigned int tacs;
 322         unsigned int tcos;
 323         unsigned int tacc;
 324         unsigned int tcoh;
 325         unsigned int tcah;
 326
 327         seq_printf(seq, "BANKCON=0x%08lx\n", bankcon);
 328
 329         tcah = get_0124(hclk, bankcon >> S3C2410_BANKCON_Tcah_SHIFT);
 330         tcoh = get_0124(hclk, bankcon >> S3C2410_BANKCON_Tcoh_SHIFT);
 331         tcos = get_0124(hclk, bankcon >> S3C2410_BANKCON_Tcos_SHIFT);
 332         tacs = get_0124(hclk, bankcon >> S3C2410_BANKCON_Tacs_SHIFT);
 333         tacc = get_tacc(hclk, bankcon >> S3C2410_BANKCON_Tacc_SHIFT);
 334
 335         seq_printf(seq,
 336                    "\tRead: Tacs=%d.%d, Tcos=%d.%d, Tacc=%d.%d, Tcoh=%d.%d, Tcah=%d.%d\n",
 337                    print_ns(bt->tacs),
 338                    print_ns(bt->tcos),
 339                    print_ns(bt->tacc),
 340                    print_ns(bt->tcoh),
 341                    print_ns(bt->tcah));
 342
 343         seq_printf(seq,
 344                    "\t Set: Tacs=%d.%d, Tcos=%d.%d, Tacc=%d.%d, Tcoh=%d.%d, Tcah=%d.%d\n",
 345                    print_ns(tacs),
 346                    print_ns(tcos),
 347                    print_ns(tacc),
 348                    print_ns(tcoh),
 349                    print_ns(tcah));
 350 }
 351
 352 /**
 353  * s3c2410_iotiming_calc - Calculate bank timing for frequency change.
 354  * @cfg: The frequency configuration
 355  * @iot: The IO timing information to fill out.
 356  *
 357  * Calculate the new values for the banks in @iot based on the new
 358  * frequency information in @cfg. This is then used by s3c2410_iotiming_set()
 359  * to update the timing when necessary.
 360  */
 361 int s3c2410_iotiming_calc(struct s3c_cpufreq_config *cfg,
 362                           struct s3c_iotimings *iot)
 363 {
 364         struct s3c2410_iobank_timing *bt;
 365         unsigned long bankcon;
 366         int bank;
 367         int ret;
 368
 369         for (bank = 0; bank < MAX_BANKS; bank++) {
 370                 bankcon = __raw_readl(bank_reg(bank));
 371                 bt = iot->bank[bank].io_2410;
 372
 373                 if (!bt)
 374                         continue;
 375
 376                 bt->bankcon = bankcon;
 377
 378                 ret = s3c2410_calc_bank(cfg, bt);
 379                 if (ret) {
 380                         printk(KERN_ERR "%s: cannot calculate bank %d io\n",
 381                                __func__, bank);
 382                         goto err;
 383                 }
 384
 385                 s3c_freq_iodbg("%s: bank %d: con=%08lx\n",
 386                                __func__, bank, bt->bankcon);
 387         }
 388
 389         return 0;
 390  err:
 391         return ret;
 392 }
 393
 394 /**
 395  * s3c2410_iotiming_set - set the IO timings from the given setup.
 396  * @cfg: The frequency configuration
 397  * @iot: The IO timing information to use.
 398  *
 399  * Set all the currently used IO bank timing information generated
 400  * by s3c2410_iotiming_calc() once the core has validated that all
 401  * the new values are within permitted bounds.
 402  */
 403 void s3c2410_iotiming_set(struct s3c_cpufreq_config *cfg,
 404                           struct s3c_iotimings *iot)
 405 {
 406         struct s3c2410_iobank_timing *bt;
 407         int bank;
 408
 409         /* set the io timings from the specifier */
 410
 411         for (bank = 0; bank < MAX_BANKS; bank++) {
 412                 bt = iot->bank[bank].io_2410;
 413                 if (!bt)
 414                         continue;
 415
 416                 __raw_writel(bt->bankcon, bank_reg(bank));
 417         }
 418 }
 419
 420 /**
 421  * s3c2410_iotiming_get - Get the timing information from current registers.
 422  * @cfg: The frequency configuration
 423  * @timings: The IO timing information to fill out.
 424  *
 425  * Calculate the @timings timing information from the current frequency
 426  * information in @cfg, and the new frequency configur
 427  * through all the IO banks, reading the state and then updating @iot
 428  * as necessary.
 429  *
 430  * This is used at the moment on initialisation to get the current
 431  * configuration so that boards do not have to carry their own setup
 432  * if the timings are correct on initialisation.
 433  */
 434
 435 int s3c2410_iotiming_get(struct s3c_cpufreq_config *cfg,
 436                          struct s3c_iotimings *timings)
 437 {
 438         struct s3c2410_iobank_timing *bt;
 439         unsigned long bankcon;
 440         unsigned long bwscon;
 441         int bank;
 442
 443         bwscon = __raw_readl(S3C2410_BWSCON);
 444
 445         /* look through all banks to see what is currently set. */
 446
 447         for (bank = 0; bank < MAX_BANKS; bank++) {
 448                 bankcon = __raw_readl(bank_reg(bank));
 449
 450                 if (!bank_is_io(bankcon))
 451                         continue;
 452
 453                 s3c_freq_iodbg("%s: bank %d: con %08lx\n",
 454                                __func__, bank, bankcon);
 455
 456                 bt = kzalloc(sizeof(struct s3c2410_iobank_timing), GFP_KERNEL);
 457                 if (!bt) {
 458                         printk(KERN_ERR "%s: no memory for bank\n", __func__);
 459                         return -ENOMEM;
 460                 }
 461
 462                 /* find out in nWait is enabled for bank. */
 463
 464                 if (bank != 0) {
 465                         unsigned long tmp  = S3C2410_BWSCON_GET(bwscon, bank);
 466                         if (tmp & S3C2410_BWSCON_WS)
 467                                 bt->nwait_en = 1;
 468                 }
 469
 470                 timings->bank[bank].io_2410 = bt;
 471                 bt->bankcon = bankcon;
 472
 473                 s3c2410_iotiming_getbank(cfg, bt);
 474         }
 475
 476         s3c2410_print_timing("get", timings);
 477         return 0;
 478 }