1 /* 2 * (C) Copyright 2000-2004 3 * Wolfgang Denk, DENX Software Engineering, wd@denx.de. 4 * 5 * SPDX-License-Identifier: GPL-2.0+ 6 */ 7 8 #include <common.h> 9 #include <mpc8xx.h> 10 #include <asm/processor.h> 11 12 DECLARE_GLOBAL_DATA_PTR; 13 14 #if !defined(CONFIG_8xx_CPUCLK_DEFAULT) || defined(CONFIG_SYS_MEASURE_CPUCLK) || defined(DEBUG) 15 16 #define PITC_SHIFT 16 17 #define PITR_SHIFT 16 18 /* pitc values to time for 58/8192 seconds (about 70.8 milliseconds) */ 19 #define SPEED_PIT_COUNTS 58 20 #define SPEED_PITC ((SPEED_PIT_COUNTS - 1) << PITC_SHIFT) 21 #define SPEED_PITC_INIT ((SPEED_PIT_COUNTS + 1) << PITC_SHIFT) 22 23 /* Access functions for the Machine State Register */ 24 static __inline__ unsigned long get_msr(void) 25 { 26 unsigned long msr; 27 28 asm volatile("mfmsr %0" : "=r" (msr) :); 29 return msr; 30 } 31 32 static __inline__ void set_msr(unsigned long msr) 33 { 34 asm volatile("mtmsr %0" : : "r" (msr)); 35 } 36 37 /* ------------------------------------------------------------------------- */ 38 39 /* 40 * Measure CPU clock speed (core clock GCLK1, GCLK2), 41 * also determine bus clock speed (checking bus divider factor) 42 * 43 * (Approx. GCLK frequency in Hz) 44 * 45 * Initializes timer 2 and PIT, but disables them before return. 46 * [Use timer 2, because MPC823 CPUs mask 0.x do not have timers 3 and 4] 47 * 48 * When measuring the CPU clock against the PIT, we count cpu clocks 49 * for 58/8192 seconds with a prescale divide by 177 for the cpu clock. 50 * These strange values for the timing interval and prescaling are used 51 * because the formula for the CPU clock is: 52 * 53 * CPU clock = count * (177 * (8192 / 58)) 54 * 55 * = count * 24999.7241 56 * 57 * which is very close to 58 * 59 * = count * 25000 60 * 61 * Since the count gives the CPU clock divided by 25000, we can get 62 * the CPU clock rounded to the nearest 0.1 MHz by 63 * 64 * CPU clock = ((count + 2) / 4) * 100000; 65 * 66 * The rounding is important since the measurement is sometimes going 67 * to be high or low by 0.025 MHz, depending on exactly how the clocks 68 * and counters interact. By rounding we get the exact answer for any 69 * CPU clock that is an even multiple of 0.1 MHz. 70 */ 71 72 unsigned long measure_gclk(void) 73 { 74 volatile immap_t *immr = (immap_t *) CONFIG_SYS_IMMR; 75 volatile cpmtimer8xx_t *timerp = &immr->im_cpmtimer; 76 ulong timer2_val; 77 ulong msr_val; 78 79 #ifdef CONFIG_SYS_8XX_XIN 80 /* dont use OSCM, only use EXTCLK/512 */ 81 immr->im_clkrst.car_sccr |= SCCR_RTSEL | SCCR_RTDIV; 82 #else 83 immr->im_clkrst.car_sccr &= ~(SCCR_RTSEL | SCCR_RTDIV); 84 #endif 85 86 /* Reset + Stop Timer 2, no cascading 87 */ 88 timerp->cpmt_tgcr &= ~(TGCR_CAS2 | TGCR_RST2); 89 90 /* Keep stopped, halt in debug mode 91 */ 92 timerp->cpmt_tgcr |= (TGCR_FRZ2 | TGCR_STP2); 93 94 /* Timer 2 setup: 95 * Output ref. interrupt disable, int. clock 96 * Prescale by 177. Note that prescaler divides by value + 1 97 * so we must subtract 1 here. 98 */ 99 timerp->cpmt_tmr2 = ((177 - 1) << TMR_PS_SHIFT) | TMR_ICLK_IN_GEN; 100 101 timerp->cpmt_tcn2 = 0; /* reset state */ 102 timerp->cpmt_tgcr |= TGCR_RST2; /* enable timer 2 */ 103 104 /* 105 * PIT setup: 106 * 107 * We want to time for SPEED_PITC_COUNTS counts (of 8192 Hz), 108 * so the count value would be SPEED_PITC_COUNTS - 1. 109 * But there would be an uncertainty in the start time of 1/4 110 * count since when we enable the PIT the count is not 111 * synchronized to the 32768 Hz oscillator. The trick here is 112 * to start the count higher and wait until the PIT count 113 * changes to the required value before starting timer 2. 114 * 115 * One count high should be enough, but occasionally the start 116 * is off by 1 or 2 counts of 32768 Hz. With the start value 117 * set two counts high it seems very reliable. 118 */ 119 120 immr->im_sitk.sitk_pitck = KAPWR_KEY; /* PIT initialization */ 121 immr->im_sit.sit_pitc = SPEED_PITC_INIT; 122 123 immr->im_sitk.sitk_piscrk = KAPWR_KEY; 124 immr->im_sit.sit_piscr = CONFIG_SYS_PISCR; 125 126 /* 127 * Start measurement - disable interrupts, just in case 128 */ 129 msr_val = get_msr (); 130 set_msr (msr_val & ~MSR_EE); 131 132 immr->im_sit.sit_piscr |= PISCR_PTE; 133 134 /* spin until get exact count when we want to start */ 135 while (immr->im_sit.sit_pitr > SPEED_PITC); 136 137 timerp->cpmt_tgcr &= ~TGCR_STP2; /* Start Timer 2 */ 138 while ((immr->im_sit.sit_piscr & PISCR_PS) == 0); 139 timerp->cpmt_tgcr |= TGCR_STP2; /* Stop Timer 2 */ 140 141 /* re-enable external interrupts if they were on */ 142 set_msr (msr_val); 143 144 /* Disable timer and PIT 145 */ 146 timer2_val = timerp->cpmt_tcn2; /* save before reset timer */ 147 148 timerp->cpmt_tgcr &= ~(TGCR_RST2 | TGCR_FRZ2 | TGCR_STP2); 149 immr->im_sit.sit_piscr &= ~PISCR_PTE; 150 151 #if defined(CONFIG_SYS_8XX_XIN) 152 /* not using OSCM, using XIN, so scale appropriately */ 153 return (((timer2_val + 2) / 4) * (CONFIG_SYS_8XX_XIN/512))/8192 * 100000L; 154 #else 155 return ((timer2_val + 2) / 4) * 100000L; /* convert to Hz */ 156 #endif 157 } 158 159 #endif 160 161 void get_brgclk(uint sccr) 162 { 163 uint divider = 0; 164 165 switch((sccr&SCCR_DFBRG11)>>11){ 166 case 0: 167 divider = 1; 168 break; 169 case 1: 170 divider = 4; 171 break; 172 case 2: 173 divider = 16; 174 break; 175 case 3: 176 divider = 64; 177 break; 178 } 179 gd->arch.brg_clk = gd->cpu_clk/divider; 180 } 181 182 #if !defined(CONFIG_8xx_CPUCLK_DEFAULT) 183 184 /* 185 * get_clocks() fills in gd->cpu_clock depending on CONFIG_8xx_GCLK_FREQ 186 * or (if it is not defined) measure_gclk() (which uses the ref clock) 187 * from above. 188 */ 189 int get_clocks (void) 190 { 191 uint immr = get_immr (0); /* Return full IMMR contents */ 192 volatile immap_t *immap = (immap_t *) (immr & 0xFFFF0000); 193 uint sccr = immap->im_clkrst.car_sccr; 194 /* 195 * If for some reason measuring the gclk frequency won't 196 * work, we return the hardwired value. 197 * (For example, the cogent CMA286-60 CPU module has no 198 * separate oscillator for PITRTCLK) 199 */ 200 #if defined(CONFIG_8xx_GCLK_FREQ) 201 gd->cpu_clk = CONFIG_8xx_GCLK_FREQ; 202 #elif defined(CONFIG_8xx_OSCLK) 203 #define PLPRCR_val(a) ((pll & PLPRCR_ ## a ## _MSK) >> PLPRCR_ ## a ## _SHIFT) 204 uint pll = immap->im_clkrst.car_plprcr; 205 uint clk; 206 207 if ((immr & 0x0FFF) >= MPC8xx_NEW_CLK) { /* MPC866/87x/88x series */ 208 clk = ((CONFIG_8xx_OSCLK / (PLPRCR_val(PDF)+1)) * 209 (PLPRCR_val(MFI) + PLPRCR_val(MFN) / (PLPRCR_val(MFD)+1))) / 210 (1<<PLPRCR_val(S)); 211 } else { 212 clk = CONFIG_8xx_OSCLK * (PLPRCR_val(MF)+1); 213 } 214 if (pll & PLPRCR_CSRC) { /* Low frequency division factor is used */ 215 gd->cpu_clk = clk / (2 << ((sccr >> 8) & 7)); 216 } else { /* High frequency division factor is used */ 217 gd->cpu_clk = clk / (1 << ((sccr >> 5) & 7)); 218 } 219 #else 220 gd->cpu_clk = measure_gclk(); 221 #endif /* CONFIG_8xx_GCLK_FREQ */ 222 223 if ((sccr & SCCR_EBDF11) == 0) { 224 /* No Bus Divider active */ 225 gd->bus_clk = gd->cpu_clk; 226 } else { 227 /* The MPC8xx has only one BDF: half clock speed */ 228 gd->bus_clk = gd->cpu_clk / 2; 229 } 230 231 get_brgclk(sccr); 232 233 return (0); 234 } 235 236 #else /* CONFIG_8xx_CPUCLK_DEFAULT defined, use dynamic clock setting */ 237 238 static long init_pll_866 (long clk); 239 240 /* Adjust sdram refresh rate to actual CPU clock. 241 */ 242 static int sdram_adjust_866(void) 243 { 244 volatile immap_t *immr = (immap_t *)CONFIG_SYS_IMMR; 245 long mamr; 246 247 mamr = immr->im_memctl.memc_mamr; 248 mamr &= ~MAMR_PTA_MSK; 249 mamr |= ((gd->cpu_clk / CONFIG_SYS_PTA_PER_CLK) << MAMR_PTA_SHIFT); 250 immr->im_memctl.memc_mamr = mamr; 251 252 return 0; 253 } 254 255 /* 256 * Adjust sdram refresh rate to actual CPU clock 257 * and set timebase source according to actual CPU clock 258 */ 259 static int adjust_sdram_tbs_8xx(void) 260 { 261 #if defined(CONFIG_TQM8xxL) && !defined(CONFIG_TQM866M) && \ 262 !defined(CONFIG_TQM885D) 263 volatile immap_t *immr = (immap_t *)CONFIG_SYS_IMMR; 264 long mamr; 265 long sccr; 266 267 mamr = immr->im_memctl.memc_mamr; 268 mamr &= ~MAMR_PTA_MSK; 269 mamr |= ((gd->cpu_clk / CONFIG_SYS_PTA_PER_CLK) << MAMR_PTA_SHIFT); 270 immr->im_memctl.memc_mamr = mamr; 271 272 if (gd->cpu_clk < 67000000) { 273 sccr = immr->im_clkrst.car_sccr; 274 sccr |= SCCR_TBS; 275 immr->im_clkrst.car_sccr = sccr; 276 } 277 #endif /* CONFIG_TQM8xxL/M, !TQM866M, !TQM885D */ 278 279 return 0; 280 } 281 282 /* This function sets up PLL (init_pll_866() is called) and 283 * fills gd->cpu_clk and gd->bus_clk according to the environment 284 * variable 'cpuclk' or to CONFIG_8xx_CPUCLK_DEFAULT (if 'cpuclk' 285 * contains invalid value). 286 * This functions requires an MPC866 or newer series CPU. 287 */ 288 int get_clocks(void) 289 { 290 volatile immap_t *immr = (immap_t *) CONFIG_SYS_IMMR; 291 char tmp[64]; 292 long cpuclk = 0; 293 long sccr_reg; 294 int ret; 295 296 if (getenv_f("cpuclk", tmp, sizeof (tmp)) > 0) 297 cpuclk = simple_strtoul (tmp, NULL, 10) * 1000000; 298 299 if ((CONFIG_SYS_8xx_CPUCLK_MIN > cpuclk) || (CONFIG_SYS_8xx_CPUCLK_MAX < cpuclk)) 300 cpuclk = CONFIG_8xx_CPUCLK_DEFAULT; 301 302 gd->cpu_clk = init_pll_866 (cpuclk); 303 #if defined(CONFIG_SYS_MEASURE_CPUCLK) 304 gd->cpu_clk = measure_gclk (); 305 #endif 306 307 get_brgclk(immr->im_clkrst.car_sccr); 308 309 /* if cpu clock <= 66 MHz then set bus division factor to 1, 310 * otherwise set it to 2 311 */ 312 sccr_reg = immr->im_clkrst.car_sccr; 313 sccr_reg &= ~SCCR_EBDF11; 314 315 if (gd->cpu_clk <= 66000000) { 316 sccr_reg |= SCCR_EBDF00; /* bus division factor = 1 */ 317 gd->bus_clk = gd->cpu_clk; 318 } else { 319 sccr_reg |= SCCR_EBDF01; /* bus division factor = 2 */ 320 gd->bus_clk = gd->cpu_clk / 2; 321 } 322 immr->im_clkrst.car_sccr = sccr_reg; 323 324 ret = sdram_adjust_866(); 325 if (ret) 326 return ret; 327 328 return adjust_sdram_tbs_8xx(); 329 } 330 331 /* Configure PLL for MPC866/859/885 CPU series 332 * PLL multiplication factor is set to the value nearest to the desired clk, 333 * assuming a oscclk of 10 MHz. 334 */ 335 static long init_pll_866 (long clk) 336 { 337 extern void plprcr_write_866 (long); 338 339 volatile immap_t *immr = (immap_t *) CONFIG_SYS_IMMR; 340 long n, plprcr; 341 char mfi, mfn, mfd, s, pdf; 342 long step_mfi, step_mfn; 343 344 if (clk < 20000000) { 345 clk *= 2; 346 pdf = 1; 347 } else { 348 pdf = 0; 349 } 350 351 if (clk < 40000000) { 352 s = 2; 353 step_mfi = CONFIG_8xx_OSCLK / 4; 354 mfd = 7; 355 step_mfn = CONFIG_8xx_OSCLK / 30; 356 } else if (clk < 80000000) { 357 s = 1; 358 step_mfi = CONFIG_8xx_OSCLK / 2; 359 mfd = 14; 360 step_mfn = CONFIG_8xx_OSCLK / 30; 361 } else { 362 s = 0; 363 step_mfi = CONFIG_8xx_OSCLK; 364 mfd = 29; 365 step_mfn = CONFIG_8xx_OSCLK / 30; 366 } 367 368 /* Calculate integer part of multiplication factor 369 */ 370 n = clk / step_mfi; 371 mfi = (char)n; 372 373 /* Calculate numerator of fractional part of multiplication factor 374 */ 375 n = clk - (n * step_mfi); 376 mfn = (char)(n / step_mfn); 377 378 /* Calculate effective clk 379 */ 380 n = ((mfi * step_mfi) + (mfn * step_mfn)) / (pdf + 1); 381 382 immr->im_clkrstk.cark_plprcrk = KAPWR_KEY; 383 384 plprcr = (immr->im_clkrst.car_plprcr & ~(PLPRCR_MFN_MSK 385 | PLPRCR_MFD_MSK | PLPRCR_S_MSK 386 | PLPRCR_MFI_MSK | PLPRCR_DBRMO 387 | PLPRCR_PDF_MSK)) 388 | (mfn << PLPRCR_MFN_SHIFT) 389 | (mfd << PLPRCR_MFD_SHIFT) 390 | (s << PLPRCR_S_SHIFT) 391 | (mfi << PLPRCR_MFI_SHIFT) 392 | (pdf << PLPRCR_PDF_SHIFT); 393 394 if( (mfn > 0) && ((mfd / mfn) > 10) ) 395 plprcr |= PLPRCR_DBRMO; 396 397 plprcr_write_866 (plprcr); /* set value using SIU4/9 workaround */ 398 immr->im_clkrstk.cark_plprcrk = 0x00000000; 399 400 return (n); 401 } 402 403 #endif /* CONFIG_8xx_CPUCLK_DEFAULT */ 404