arch/arm/mach-sa1100/cpu-sa1110.c

   1 /*
   2  *  linux/arch/arm/mach-sa1100/cpu-sa1110.c
   3  *
   4  *  Copyright (C) 2001 Russell King
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  *
  10  * Note: there are two erratas that apply to the SA1110 here:
  11  *  7 - SDRAM auto-power-up failure (rev A0)
  12  * 13 - Corruption of internal register reads/writes following
  13  *      SDRAM reads (rev A0, B0, B1)
  14  *
  15  * We ignore rev. A0 and B0 devices; I don't think they're worth supporting.
  16  *
  17  * The SDRAM type can be passed on the command line as cpu_sa1110.sdram=type
  18  */
  19 #include <linux/cpufreq.h>
  20 #include <linux/delay.h>
  21 #include <linux/init.h>
  22 #include <linux/io.h>
  23 #include <linux/kernel.h>
  24 #include <linux/moduleparam.h>
  25 #include <linux/types.h>
  26
  27 #include <asm/cputype.h>
  28 #include <asm/mach-types.h>
  29
  30 #include <mach/hardware.h>
  31
  32 #include "generic.h"
  33
  34 #undef DEBUG
  35
  36 struct sdram_params {
  37         const char name[20];
  38         u_char  rows;           /* bits                          */
  39         u_char  cas_latency;    /* cycles                        */
  40         u_char  tck;            /* clock cycle time (ns)         */
  41         u_char  trcd;           /* activate to r/w (ns)          */
  42         u_char  trp;            /* precharge to activate (ns)    */
  43         u_char  twr;            /* write recovery time (ns)      */
  44         u_short refresh;        /* refresh time for array (us)   */
  45 };
  46
  47 struct sdram_info {
  48         u_int   mdcnfg;
  49         u_int   mdrefr;
  50         u_int   mdcas[3];
  51 };
  52
  53 static struct sdram_params sdram_tbl[] __initdata = {
  54         {       /* Toshiba TC59SM716 CL2 */
  55                 .name           = "TC59SM716-CL2",
  56                 .rows           = 12,
  57                 .tck            = 10,
  58                 .trcd           = 20,
  59                 .trp            = 20,
  60                 .twr            = 10,
  61                 .refresh        = 64000,
  62                 .cas_latency    = 2,
  63         }, {    /* Toshiba TC59SM716 CL3 */
  64                 .name           = "TC59SM716-CL3",
  65                 .rows           = 12,
  66                 .tck            = 8,
  67                 .trcd           = 20,
  68                 .trp            = 20,
  69                 .twr            = 8,
  70                 .refresh        = 64000,
  71                 .cas_latency    = 3,
  72         }, {    /* Samsung K4S641632D TC75 */
  73                 .name           = "K4S641632D",
  74                 .rows           = 14,
  75                 .tck            = 9,
  76                 .trcd           = 27,
  77                 .trp            = 20,
  78                 .twr            = 9,
  79                 .refresh        = 64000,
  80                 .cas_latency    = 3,
  81         }, {    /* Samsung K4S281632B-1H */
  82                 .name           = "K4S281632B-1H",
  83                 .rows           = 12,
  84                 .tck            = 10,
  85                 .trp            = 20,
  86                 .twr            = 10,
  87                 .refresh        = 64000,
  88                 .cas_latency    = 3,
  89         }, {    /* Samsung KM416S4030CT */
  90                 .name           = "KM416S4030CT",
  91                 .rows           = 13,
  92                 .tck            = 8,
  93                 .trcd           = 24,   /* 3 CLKs */
  94                 .trp            = 24,   /* 3 CLKs */
  95                 .twr            = 16,   /* Trdl: 2 CLKs */
  96                 .refresh        = 64000,
  97                 .cas_latency    = 3,
  98         }, {    /* Winbond W982516AH75L CL3 */
  99                 .name           = "W982516AH75L",
 100                 .rows           = 16,
 101                 .tck            = 8,
 102                 .trcd           = 20,
 103                 .trp            = 20,
 104                 .twr            = 8,
 105                 .refresh        = 64000,
 106                 .cas_latency    = 3,
 107         }, {    /* Micron MT48LC8M16A2TG-75 */
 108                 .name           = "MT48LC8M16A2TG-75",
 109                 .rows           = 12,
 110                 .tck            = 8,
 111                 .trcd           = 20,
 112                 .trp            = 20,
 113                 .twr            = 8,
 114                 .refresh        = 64000,
 115                 .cas_latency    = 3,
 116         },
 117 };
 118
 119 static struct sdram_params sdram_params;
 120
 121 /*
 122  * Given a period in ns and frequency in khz, calculate the number of
 123  * cycles of frequency in period.  Note that we round up to the next
 124  * cycle, even if we are only slightly over.
 125  */
 126 static inline u_int ns_to_cycles(u_int ns, u_int khz)
 127 {
 128         return (ns * khz + 999999) / 1000000;
 129 }
 130
 131 /*
 132  * Create the MDCAS register bit pattern.
 133  */
 134 static inline void set_mdcas(u_int *mdcas, int delayed, u_int rcd)
 135 {
 136         u_int shift;
 137
 138         rcd = 2 * rcd - 1;
 139         shift = delayed + 1 + rcd;
 140
 141         mdcas[0]  = (1 << rcd) - 1;
 142         mdcas[0] |= 0x55555555 << shift;
 143         mdcas[1]  = mdcas[2] = 0x55555555 << (shift & 1);
 144 }
 145
 146 static void
 147 sdram_calculate_timing(struct sdram_info *sd, u_int cpu_khz,
 148                        struct sdram_params *sdram)
 149 {
 150         u_int mem_khz, sd_khz, trp, twr;
 151
 152         mem_khz = cpu_khz / 2;
 153         sd_khz = mem_khz;
 154
 155         /*
 156          * If SDCLK would invalidate the SDRAM timings,
 157          * run SDCLK at half speed.
 158          *
 159          * CPU steppings prior to B2 must either run the memory at
 160          * half speed or use delayed read latching (errata 13).
 161          */
 162         if ((ns_to_cycles(sdram->tck, sd_khz) > 1) ||
 163             (CPU_REVISION < CPU_SA1110_B2 && sd_khz < 62000))
 164                 sd_khz /= 2;
 165
 166         sd->mdcnfg = MDCNFG & 0x007f007f;
 167
 168         twr = ns_to_cycles(sdram->twr, mem_khz);
 169
 170         /* trp should always be >1 */
 171         trp = ns_to_cycles(sdram->trp, mem_khz) - 1;
 172         if (trp < 1)
 173                 trp = 1;
 174
 175         sd->mdcnfg |= trp << 8;
 176         sd->mdcnfg |= trp << 24;
 177         sd->mdcnfg |= sdram->cas_latency << 12;
 178         sd->mdcnfg |= sdram->cas_latency << 28;
 179         sd->mdcnfg |= twr << 14;
 180         sd->mdcnfg |= twr << 30;
 181
 182         sd->mdrefr = MDREFR & 0xffbffff0;
 183         sd->mdrefr |= 7;
 184
 185         if (sd_khz != mem_khz)
 186                 sd->mdrefr |= MDREFR_K1DB2;
 187
 188         /* initial number of '1's in MDCAS + 1 */
 189         set_mdcas(sd->mdcas, sd_khz >= 62000,
 190                 ns_to_cycles(sdram->trcd, mem_khz));
 191
 192 #ifdef DEBUG
 193         printk(KERN_DEBUG "MDCNFG: %08x MDREFR: %08x MDCAS0: %08x MDCAS1: %08x MDCAS2: %08x\n",
 194                 sd->mdcnfg, sd->mdrefr, sd->mdcas[0], sd->mdcas[1],
 195                 sd->mdcas[2]);
 196 #endif
 197 }
 198
 199 /*
 200  * Set the SDRAM refresh rate.
 201  */
 202 static inline void sdram_set_refresh(u_int dri)
 203 {
 204         MDREFR = (MDREFR & 0xffff000f) | (dri << 4);
 205         (void) MDREFR;
 206 }
 207
 208 /*
 209  * Update the refresh period.  We do this such that we always refresh
 210  * the SDRAMs within their permissible period.  The refresh period is
 211  * always a multiple of the memory clock (fixed at cpu_clock / 2).
 212  *
 213  * FIXME: we don't currently take account of burst accesses here,
 214  * but neither do Intels DM nor Angel.
 215  */
 216 static void
 217 sdram_update_refresh(u_int cpu_khz, struct sdram_params *sdram)
 218 {
 219         u_int ns_row = (sdram->refresh * 1000) >> sdram->rows;
 220         u_int dri = ns_to_cycles(ns_row, cpu_khz / 2) / 32;
 221
 222 #ifdef DEBUG
 223         mdelay(250);
 224         printk(KERN_DEBUG "new dri value = %d\n", dri);
 225 #endif
 226
 227         sdram_set_refresh(dri);
 228 }
 229
 230 /*
 231  * Ok, set the CPU frequency.
 232  */
 233 static int sa1110_target(struct cpufreq_policy *policy,
 234                          unsigned int target_freq,
 235                          unsigned int relation)
 236 {
 237         struct sdram_params *sdram = &sdram_params;
 238         struct cpufreq_freqs freqs;
 239         struct sdram_info sd;
 240         unsigned long flags;
 241         unsigned int ppcr, unused;
 242
 243         switch (relation) {
 244         case CPUFREQ_RELATION_L:
 245                 ppcr = sa11x0_freq_to_ppcr(target_freq);
 246                 if (sa11x0_ppcr_to_freq(ppcr) > policy->max)
 247                         ppcr--;
 248                 break;
 249         case CPUFREQ_RELATION_H:
 250                 ppcr = sa11x0_freq_to_ppcr(target_freq);
 251                 if (ppcr && (sa11x0_ppcr_to_freq(ppcr) > target_freq) &&
 252                     (sa11x0_ppcr_to_freq(ppcr-1) >= policy->min))
 253                         ppcr--;
 254                 break;
 255         default:
 256                 return -EINVAL;
 257         }
 258
 259         freqs.old = sa11x0_getspeed(0);
 260         freqs.new = sa11x0_ppcr_to_freq(ppcr);
 261         freqs.cpu = 0;
 262
 263         sdram_calculate_timing(&sd, freqs.new, sdram);
 264
 265 #if 0
 266         /*
 267          * These values are wrong according to the SA1110 documentation
 268          * and errata, but they seem to work.  Need to get a storage
 269          * scope on to the SDRAM signals to work out why.
 270          */
 271         if (policy->max < 147500) {
 272                 sd.mdrefr |= MDREFR_K1DB2;
 273                 sd.mdcas[0] = 0xaaaaaa7f;
 274         } else {
 275                 sd.mdrefr &= ~MDREFR_K1DB2;
 276                 sd.mdcas[0] = 0xaaaaaa9f;
 277         }
 278         sd.mdcas[1] = 0xaaaaaaaa;
 279         sd.mdcas[2] = 0xaaaaaaaa;
 280 #endif
 281
 282         cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
 283
 284         /*
 285          * The clock could be going away for some time.  Set the SDRAMs
 286          * to refresh rapidly (every 64 memory clock cycles).  To get
 287          * through the whole array, we need to wait 262144 mclk cycles.
 288          * We wait 20ms to be safe.
 289          */
 290         sdram_set_refresh(2);
 291         if (!irqs_disabled())
 292                 msleep(20);
 293         else
 294                 mdelay(20);
 295
 296         /*
 297          * Reprogram the DRAM timings with interrupts disabled, and
 298          * ensure that we are doing this within a complete cache line.
 299          * This means that we won't access SDRAM for the duration of
 300          * the programming.
 301          */
 302         local_irq_save(flags);
 303         asm("mcr p15, 0, %0, c7, c10, 4" : : "r" (0));
 304         udelay(10);
 305         __asm__ __volatile__("\n\
 306                 b       2f                                      \n\
 307                 .align  5                                       \n\
 308 1:              str     %3, [%1, #0]            @ MDCNFG        \n\
 309                 str     %4, [%1, #28]           @ MDREFR        \n\
 310                 str     %5, [%1, #4]            @ MDCAS0        \n\
 311                 str     %6, [%1, #8]            @ MDCAS1        \n\
 312                 str     %7, [%1, #12]           @ MDCAS2        \n\
 313                 str     %8, [%2, #0]            @ PPCR          \n\
 314                 ldr     %0, [%1, #0]                            \n\
 315                 b       3f                                      \n\
 316 2:              b       1b                                      \n\
 317 3:              nop                                             \n\
 318                 nop"
 319                 : "=&r" (unused)
 320                 : "r" (&MDCNFG), "r" (&PPCR), "0" (sd.mdcnfg),
 321                   "r" (sd.mdrefr), "r" (sd.mdcas[0]),
 322                   "r" (sd.mdcas[1]), "r" (sd.mdcas[2]), "r" (ppcr));
 323         local_irq_restore(flags);
 324
 325         /*
 326          * Now, return the SDRAM refresh back to normal.
 327          */
 328         sdram_update_refresh(freqs.new, sdram);
 329
 330         cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
 331
 332         return 0;
 333 }
 334
 335 static int __init sa1110_cpu_init(struct cpufreq_policy *policy)
 336 {
 337         if (policy->cpu != 0)
 338                 return -EINVAL;
 339         policy->cur = policy->min = policy->max = sa11x0_getspeed(0);
 340         policy->cpuinfo.min_freq = 59000;
 341         policy->cpuinfo.max_freq = 287000;
 342         policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;
 343         return 0;
 344 }
 345
 346 /* sa1110_driver needs __refdata because it must remain after init registers
 347  * it with cpufreq_register_driver() */
 348 static struct cpufreq_driver sa1110_driver __refdata = {
 349         .flags          = CPUFREQ_STICKY,
 350         .verify         = sa11x0_verify_speed,
 351         .target         = sa1110_target,
 352         .get            = sa11x0_getspeed,
 353         .init           = sa1110_cpu_init,
 354         .name           = "sa1110",
 355 };
 356
 357 static struct sdram_params *sa1110_find_sdram(const char *name)
 358 {
 359         struct sdram_params *sdram;
 360
 361         for (sdram = sdram_tbl; sdram < sdram_tbl + ARRAY_SIZE(sdram_tbl);
 362              sdram++)
 363                 if (strcmp(name, sdram->name) == 0)
 364                         return sdram;
 365
 366         return NULL;
 367 }
 368
 369 static char sdram_name[16];
 370
 371 static int __init sa1110_clk_init(void)
 372 {
 373         struct sdram_params *sdram;
 374         const char *name = sdram_name;
 375
 376         if (!cpu_is_sa1110())
 377                 return -ENODEV;
 378
 379         if (!name[0]) {
 380                 if (machine_is_assabet())
 381                         name = "TC59SM716-CL3";
 382                 if (machine_is_pt_system3())
 383                         name = "K4S641632D";
 384                 if (machine_is_h3100())
 385                         name = "KM416S4030CT";
 386                 if (machine_is_jornada720())
 387                         name = "K4S281632B-1H";
 388                 if (machine_is_nanoengine())
 389                         name = "MT48LC8M16A2TG-75";
 390         }
 391
 392         sdram = sa1110_find_sdram(name);
 393         if (sdram) {
 394                 printk(KERN_DEBUG "SDRAM: tck: %d trcd: %d trp: %d"
 395                         " twr: %d refresh: %d cas_latency: %d\n",
 396                         sdram->tck, sdram->trcd, sdram->trp,
 397                         sdram->twr, sdram->refresh, sdram->cas_latency);
 398
 399                 memcpy(&sdram_params, sdram, sizeof(sdram_params));
 400
 401                 return cpufreq_register_driver(&sa1110_driver);
 402         }
 403
 404         return 0;
 405 }
 406
 407 module_param_string(sdram, sdram_name, sizeof(sdram_name), 0);
 408 arch_initcall(sa1110_clk_init);