1 /* 2 * (C) Copyright 2000-2004 3 * Wolfgang Denk, DENX Software Engineering, wd@denx.de. 4 * 5 * See file CREDITS for list of people who contributed to this 6 * project. 7 * 8 * This program is free software; you can redistribute it and/or 9 * modify it under the terms of the GNU General Public License as 10 * published by the Free Software Foundation; either version 2 of 11 * the License, or (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., 59 Temple Place, Suite 330, Boston, 21 * MA 02111-1307 USA 22 */ 23 24 #include <common.h> 25 #include <mpc8xx.h> 26 #include <asm/processor.h> 27 28 DECLARE_GLOBAL_DATA_PTR; 29 30 #if !defined(CONFIG_8xx_CPUCLK_DEFAULT) || defined(CONFIG_SYS_MEASURE_CPUCLK) || defined(DEBUG) 31 32 #define PITC_SHIFT 16 33 #define PITR_SHIFT 16 34 /* pitc values to time for 58/8192 seconds (about 70.8 milliseconds) */ 35 #define SPEED_PIT_COUNTS 58 36 #define SPEED_PITC ((SPEED_PIT_COUNTS - 1) << PITC_SHIFT) 37 #define SPEED_PITC_INIT ((SPEED_PIT_COUNTS + 1) << PITC_SHIFT) 38 39 /* Access functions for the Machine State Register */ 40 static __inline__ unsigned long get_msr(void) 41 { 42 unsigned long msr; 43 44 asm volatile("mfmsr %0" : "=r" (msr) :); 45 return msr; 46 } 47 48 static __inline__ void set_msr(unsigned long msr) 49 { 50 asm volatile("mtmsr %0" : : "r" (msr)); 51 } 52 53 /* ------------------------------------------------------------------------- */ 54 55 /* 56 * Measure CPU clock speed (core clock GCLK1, GCLK2), 57 * also determine bus clock speed (checking bus divider factor) 58 * 59 * (Approx. GCLK frequency in Hz) 60 * 61 * Initializes timer 2 and PIT, but disables them before return. 62 * [Use timer 2, because MPC823 CPUs mask 0.x do not have timers 3 and 4] 63 * 64 * When measuring the CPU clock against the PIT, we count cpu clocks 65 * for 58/8192 seconds with a prescale divide by 177 for the cpu clock. 66 * These strange values for the timing interval and prescaling are used 67 * because the formula for the CPU clock is: 68 * 69 * CPU clock = count * (177 * (8192 / 58)) 70 * 71 * = count * 24999.7241 72 * 73 * which is very close to 74 * 75 * = count * 25000 76 * 77 * Since the count gives the CPU clock divided by 25000, we can get 78 * the CPU clock rounded to the nearest 0.1 MHz by 79 * 80 * CPU clock = ((count + 2) / 4) * 100000; 81 * 82 * The rounding is important since the measurement is sometimes going 83 * to be high or low by 0.025 MHz, depending on exactly how the clocks 84 * and counters interact. By rounding we get the exact answer for any 85 * CPU clock that is an even multiple of 0.1 MHz. 86 */ 87 88 unsigned long measure_gclk(void) 89 { 90 volatile immap_t *immr = (immap_t *) CONFIG_SYS_IMMR; 91 volatile cpmtimer8xx_t *timerp = &immr->im_cpmtimer; 92 ulong timer2_val; 93 ulong msr_val; 94 95 #ifdef CONFIG_SYS_8XX_XIN 96 /* dont use OSCM, only use EXTCLK/512 */ 97 immr->im_clkrst.car_sccr |= SCCR_RTSEL | SCCR_RTDIV; 98 #else 99 immr->im_clkrst.car_sccr &= ~(SCCR_RTSEL | SCCR_RTDIV); 100 #endif 101 102 /* Reset + Stop Timer 2, no cascading 103 */ 104 timerp->cpmt_tgcr &= ~(TGCR_CAS2 | TGCR_RST2); 105 106 /* Keep stopped, halt in debug mode 107 */ 108 timerp->cpmt_tgcr |= (TGCR_FRZ2 | TGCR_STP2); 109 110 /* Timer 2 setup: 111 * Output ref. interrupt disable, int. clock 112 * Prescale by 177. Note that prescaler divides by value + 1 113 * so we must subtract 1 here. 114 */ 115 timerp->cpmt_tmr2 = ((177 - 1) << TMR_PS_SHIFT) | TMR_ICLK_IN_GEN; 116 117 timerp->cpmt_tcn2 = 0; /* reset state */ 118 timerp->cpmt_tgcr |= TGCR_RST2; /* enable timer 2 */ 119 120 /* 121 * PIT setup: 122 * 123 * We want to time for SPEED_PITC_COUNTS counts (of 8192 Hz), 124 * so the count value would be SPEED_PITC_COUNTS - 1. 125 * But there would be an uncertainty in the start time of 1/4 126 * count since when we enable the PIT the count is not 127 * synchronized to the 32768 Hz oscillator. The trick here is 128 * to start the count higher and wait until the PIT count 129 * changes to the required value before starting timer 2. 130 * 131 * One count high should be enough, but occasionally the start 132 * is off by 1 or 2 counts of 32768 Hz. With the start value 133 * set two counts high it seems very reliable. 134 */ 135 136 immr->im_sitk.sitk_pitck = KAPWR_KEY; /* PIT initialization */ 137 immr->im_sit.sit_pitc = SPEED_PITC_INIT; 138 139 immr->im_sitk.sitk_piscrk = KAPWR_KEY; 140 immr->im_sit.sit_piscr = CONFIG_SYS_PISCR; 141 142 /* 143 * Start measurement - disable interrupts, just in case 144 */ 145 msr_val = get_msr (); 146 set_msr (msr_val & ~MSR_EE); 147 148 immr->im_sit.sit_piscr |= PISCR_PTE; 149 150 /* spin until get exact count when we want to start */ 151 while (immr->im_sit.sit_pitr > SPEED_PITC); 152 153 timerp->cpmt_tgcr &= ~TGCR_STP2; /* Start Timer 2 */ 154 while ((immr->im_sit.sit_piscr & PISCR_PS) == 0); 155 timerp->cpmt_tgcr |= TGCR_STP2; /* Stop Timer 2 */ 156 157 /* re-enable external interrupts if they were on */ 158 set_msr (msr_val); 159 160 /* Disable timer and PIT 161 */ 162 timer2_val = timerp->cpmt_tcn2; /* save before reset timer */ 163 164 timerp->cpmt_tgcr &= ~(TGCR_RST2 | TGCR_FRZ2 | TGCR_STP2); 165 immr->im_sit.sit_piscr &= ~PISCR_PTE; 166 167 #if defined(CONFIG_SYS_8XX_XIN) 168 /* not using OSCM, using XIN, so scale appropriately */ 169 return (((timer2_val + 2) / 4) * (CONFIG_SYS_8XX_XIN/512))/8192 * 100000L; 170 #else 171 return ((timer2_val + 2) / 4) * 100000L; /* convert to Hz */ 172 #endif 173 } 174 175 #endif 176 177 void get_brgclk(uint sccr) 178 { 179 uint divider = 0; 180 181 switch((sccr&SCCR_DFBRG11)>>11){ 182 case 0: 183 divider = 1; 184 break; 185 case 1: 186 divider = 4; 187 break; 188 case 2: 189 divider = 16; 190 break; 191 case 3: 192 divider = 64; 193 break; 194 } 195 gd->brg_clk = gd->cpu_clk/divider; 196 } 197 198 #if !defined(CONFIG_8xx_CPUCLK_DEFAULT) 199 200 /* 201 * get_clocks() fills in gd->cpu_clock depending on CONFIG_8xx_GCLK_FREQ 202 * or (if it is not defined) measure_gclk() (which uses the ref clock) 203 * from above. 204 */ 205 int get_clocks (void) 206 { 207 uint immr = get_immr (0); /* Return full IMMR contents */ 208 volatile immap_t *immap = (immap_t *) (immr & 0xFFFF0000); 209 uint sccr = immap->im_clkrst.car_sccr; 210 /* 211 * If for some reason measuring the gclk frequency won't 212 * work, we return the hardwired value. 213 * (For example, the cogent CMA286-60 CPU module has no 214 * separate oscillator for PITRTCLK) 215 */ 216 #if defined(CONFIG_8xx_GCLK_FREQ) 217 gd->cpu_clk = CONFIG_8xx_GCLK_FREQ; 218 #elif defined(CONFIG_8xx_OSCLK) 219 #define PLPRCR_val(a) ((pll & PLPRCR_ ## a ## _MSK) >> PLPRCR_ ## a ## _SHIFT) 220 uint pll = immap->im_clkrst.car_plprcr; 221 uint clk; 222 223 if ((immr & 0x0FFF) >= MPC8xx_NEW_CLK) { /* MPC866/87x/88x series */ 224 clk = ((CONFIG_8xx_OSCLK / (PLPRCR_val(PDF)+1)) * 225 (PLPRCR_val(MFI) + PLPRCR_val(MFN) / (PLPRCR_val(MFD)+1))) / 226 (1<<PLPRCR_val(S)); 227 } else { 228 clk = CONFIG_8xx_OSCLK * (PLPRCR_val(MF)+1); 229 } 230 if (pll & PLPRCR_CSRC) { /* Low frequency division factor is used */ 231 gd->cpu_clk = clk / (2 << ((sccr >> 8) & 7)); 232 } else { /* High frequency division factor is used */ 233 gd->cpu_clk = clk / (1 << ((sccr >> 5) & 7)); 234 } 235 #else 236 gd->cpu_clk = measure_gclk(); 237 #endif /* CONFIG_8xx_GCLK_FREQ */ 238 239 if ((sccr & SCCR_EBDF11) == 0) { 240 /* No Bus Divider active */ 241 gd->bus_clk = gd->cpu_clk; 242 } else { 243 /* The MPC8xx has only one BDF: half clock speed */ 244 gd->bus_clk = gd->cpu_clk / 2; 245 } 246 247 get_brgclk(sccr); 248 249 return (0); 250 } 251 252 #else /* CONFIG_8xx_CPUCLK_DEFAULT defined, use dynamic clock setting */ 253 254 static long init_pll_866 (long clk); 255 256 /* This function sets up PLL (init_pll_866() is called) and 257 * fills gd->cpu_clk and gd->bus_clk according to the environment 258 * variable 'cpuclk' or to CONFIG_8xx_CPUCLK_DEFAULT (if 'cpuclk' 259 * contains invalid value). 260 * This functions requires an MPC866 or newer series CPU. 261 */ 262 int get_clocks_866 (void) 263 { 264 volatile immap_t *immr = (immap_t *) CONFIG_SYS_IMMR; 265 char tmp[64]; 266 long cpuclk = 0; 267 long sccr_reg; 268 269 if (getenv_f("cpuclk", tmp, sizeof (tmp)) > 0) 270 cpuclk = simple_strtoul (tmp, NULL, 10) * 1000000; 271 272 if ((CONFIG_SYS_8xx_CPUCLK_MIN > cpuclk) || (CONFIG_SYS_8xx_CPUCLK_MAX < cpuclk)) 273 cpuclk = CONFIG_8xx_CPUCLK_DEFAULT; 274 275 gd->cpu_clk = init_pll_866 (cpuclk); 276 #if defined(CONFIG_SYS_MEASURE_CPUCLK) 277 gd->cpu_clk = measure_gclk (); 278 #endif 279 280 get_brgclk(immr->im_clkrst.car_sccr); 281 282 /* if cpu clock <= 66 MHz then set bus division factor to 1, 283 * otherwise set it to 2 284 */ 285 sccr_reg = immr->im_clkrst.car_sccr; 286 sccr_reg &= ~SCCR_EBDF11; 287 288 if (gd->cpu_clk <= 66000000) { 289 sccr_reg |= SCCR_EBDF00; /* bus division factor = 1 */ 290 gd->bus_clk = gd->cpu_clk; 291 } else { 292 sccr_reg |= SCCR_EBDF01; /* bus division factor = 2 */ 293 gd->bus_clk = gd->cpu_clk / 2; 294 } 295 immr->im_clkrst.car_sccr = sccr_reg; 296 297 return (0); 298 } 299 300 /* Adjust sdram refresh rate to actual CPU clock. 301 */ 302 int sdram_adjust_866 (void) 303 { 304 volatile immap_t *immr = (immap_t *) CONFIG_SYS_IMMR; 305 long mamr; 306 307 mamr = immr->im_memctl.memc_mamr; 308 mamr &= ~MAMR_PTA_MSK; 309 mamr |= ((gd->cpu_clk / CONFIG_SYS_PTA_PER_CLK) << MAMR_PTA_SHIFT); 310 immr->im_memctl.memc_mamr = mamr; 311 312 return (0); 313 } 314 315 /* Configure PLL for MPC866/859/885 CPU series 316 * PLL multiplication factor is set to the value nearest to the desired clk, 317 * assuming a oscclk of 10 MHz. 318 */ 319 static long init_pll_866 (long clk) 320 { 321 extern void plprcr_write_866 (long); 322 323 volatile immap_t *immr = (immap_t *) CONFIG_SYS_IMMR; 324 long n, plprcr; 325 char mfi, mfn, mfd, s, pdf; 326 long step_mfi, step_mfn; 327 328 if (clk < 20000000) { 329 clk *= 2; 330 pdf = 1; 331 } else { 332 pdf = 0; 333 } 334 335 if (clk < 40000000) { 336 s = 2; 337 step_mfi = CONFIG_8xx_OSCLK / 4; 338 mfd = 7; 339 step_mfn = CONFIG_8xx_OSCLK / 30; 340 } else if (clk < 80000000) { 341 s = 1; 342 step_mfi = CONFIG_8xx_OSCLK / 2; 343 mfd = 14; 344 step_mfn = CONFIG_8xx_OSCLK / 30; 345 } else { 346 s = 0; 347 step_mfi = CONFIG_8xx_OSCLK; 348 mfd = 29; 349 step_mfn = CONFIG_8xx_OSCLK / 30; 350 } 351 352 /* Calculate integer part of multiplication factor 353 */ 354 n = clk / step_mfi; 355 mfi = (char)n; 356 357 /* Calculate numerator of fractional part of multiplication factor 358 */ 359 n = clk - (n * step_mfi); 360 mfn = (char)(n / step_mfn); 361 362 /* Calculate effective clk 363 */ 364 n = ((mfi * step_mfi) + (mfn * step_mfn)) / (pdf + 1); 365 366 immr->im_clkrstk.cark_plprcrk = KAPWR_KEY; 367 368 plprcr = (immr->im_clkrst.car_plprcr & ~(PLPRCR_MFN_MSK 369 | PLPRCR_MFD_MSK | PLPRCR_S_MSK 370 | PLPRCR_MFI_MSK | PLPRCR_DBRMO 371 | PLPRCR_PDF_MSK)) 372 | (mfn << PLPRCR_MFN_SHIFT) 373 | (mfd << PLPRCR_MFD_SHIFT) 374 | (s << PLPRCR_S_SHIFT) 375 | (mfi << PLPRCR_MFI_SHIFT) 376 | (pdf << PLPRCR_PDF_SHIFT); 377 378 if( (mfn > 0) && ((mfd / mfn) > 10) ) 379 plprcr |= PLPRCR_DBRMO; 380 381 plprcr_write_866 (plprcr); /* set value using SIU4/9 workaround */ 382 immr->im_clkrstk.cark_plprcrk = 0x00000000; 383 384 return (n); 385 } 386 387 #endif /* CONFIG_8xx_CPUCLK_DEFAULT */ 388 389 #if defined(CONFIG_TQM8xxL) && !defined(CONFIG_TQM866M) \ 390 && !defined(CONFIG_TQM885D) 391 /* 392 * Adjust sdram refresh rate to actual CPU clock 393 * and set timebase source according to actual CPU clock 394 */ 395 int adjust_sdram_tbs_8xx (void) 396 { 397 volatile immap_t *immr = (immap_t *) CONFIG_SYS_IMMR; 398 long mamr; 399 long sccr; 400 401 mamr = immr->im_memctl.memc_mamr; 402 mamr &= ~MAMR_PTA_MSK; 403 mamr |= ((gd->cpu_clk / CONFIG_SYS_PTA_PER_CLK) << MAMR_PTA_SHIFT); 404 immr->im_memctl.memc_mamr = mamr; 405 406 if (gd->cpu_clk < 67000000) { 407 sccr = immr->im_clkrst.car_sccr; 408 sccr |= SCCR_TBS; 409 immr->im_clkrst.car_sccr = sccr; 410 } 411 412 return (0); 413 } 414 #endif /* CONFIG_TQM8xxL/M, !TQM866M, !TQM885D */ 415 416 /* ------------------------------------------------------------------------- */ 417