/* * (C) Copyright 2000-2004 * Wolfgang Denk, DENX Software Engineering, wd@denx.de. * * See file CREDITS for list of people who contributed to this * project. * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License as * published by the Free Software Foundation; either version 2 of * the License, or (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, * MA 02111-1307 USA */ #include <common.h> #include <mpc8xx.h> #include <asm/processor.h> DECLARE_GLOBAL_DATA_PTR; #if !defined(CONFIG_8xx_CPUCLK_DEFAULT) || defined(CFG_MEASURE_CPUCLK) || defined(DEBUG) #define PITC_SHIFT 16 #define PITR_SHIFT 16 /* pitc values to time for 58/8192 seconds (about 70.8 milliseconds) */ #define SPEED_PIT_COUNTS 58 #define SPEED_PITC ((SPEED_PIT_COUNTS - 1) << PITC_SHIFT) #define SPEED_PITC_INIT ((SPEED_PIT_COUNTS + 1) << PITC_SHIFT) /* Access functions for the Machine State Register */ static __inline__ unsigned long get_msr(void) { unsigned long msr; asm volatile("mfmsr %0" : "=r" (msr) :); return msr; } static __inline__ void set_msr(unsigned long msr) { asm volatile("mtmsr %0" : : "r" (msr)); } /* ------------------------------------------------------------------------- */ /* * Measure CPU clock speed (core clock GCLK1, GCLK2), * also determine bus clock speed (checking bus divider factor) * * (Approx. GCLK frequency in Hz) * * Initializes timer 2 and PIT, but disables them before return. * [Use timer 2, because MPC823 CPUs mask 0.x do not have timers 3 and 4] * * When measuring the CPU clock against the PIT, we count cpu clocks * for 58/8192 seconds with a prescale divide by 177 for the cpu clock. * These strange values for the timing interval and prescaling are used * because the formula for the CPU clock is: * * CPU clock = count * (177 * (8192 / 58)) * * = count * 24999.7241 * * which is very close to * * = count * 25000 * * Since the count gives the CPU clock divided by 25000, we can get * the CPU clock rounded to the nearest 0.1 MHz by * * CPU clock = ((count + 2) / 4) * 100000; * * The rounding is important since the measurement is sometimes going * to be high or low by 0.025 MHz, depending on exactly how the clocks * and counters interact. By rounding we get the exact answer for any * CPU clock that is an even multiple of 0.1 MHz. */ unsigned long measure_gclk(void) { volatile immap_t *immr = (immap_t *) CFG_IMMR; volatile cpmtimer8xx_t *timerp = &immr->im_cpmtimer; ulong timer2_val; ulong msr_val; #ifdef CFG_8XX_XIN /* dont use OSCM, only use EXTCLK/512 */ immr->im_clkrst.car_sccr |= SCCR_RTSEL | SCCR_RTDIV; #else immr->im_clkrst.car_sccr &= ~(SCCR_RTSEL | SCCR_RTDIV); #endif /* Reset + Stop Timer 2, no cascading */ timerp->cpmt_tgcr &= ~(TGCR_CAS2 | TGCR_RST2); /* Keep stopped, halt in debug mode */ timerp->cpmt_tgcr |= (TGCR_FRZ2 | TGCR_STP2); /* Timer 2 setup: * Output ref. interrupt disable, int. clock * Prescale by 177. Note that prescaler divides by value + 1 * so we must subtract 1 here. */ timerp->cpmt_tmr2 = ((177 - 1) << TMR_PS_SHIFT) | TMR_ICLK_IN_GEN; timerp->cpmt_tcn2 = 0; /* reset state */ timerp->cpmt_tgcr |= TGCR_RST2; /* enable timer 2 */ /* * PIT setup: * * We want to time for SPEED_PITC_COUNTS counts (of 8192 Hz), * so the count value would be SPEED_PITC_COUNTS - 1. * But there would be an uncertainty in the start time of 1/4 * count since when we enable the PIT the count is not * synchronized to the 32768 Hz oscillator. The trick here is * to start the count higher and wait until the PIT count * changes to the required value before starting timer 2. * * One count high should be enough, but occasionally the start * is off by 1 or 2 counts of 32768 Hz. With the start value * set two counts high it seems very reliable. */ immr->im_sitk.sitk_pitck = KAPWR_KEY; /* PIT initialization */ immr->im_sit.sit_pitc = SPEED_PITC_INIT; immr->im_sitk.sitk_piscrk = KAPWR_KEY; immr->im_sit.sit_piscr = CFG_PISCR; /* * Start measurement - disable interrupts, just in case */ msr_val = get_msr (); set_msr (msr_val & ~MSR_EE); immr->im_sit.sit_piscr |= PISCR_PTE; /* spin until get exact count when we want to start */ while (immr->im_sit.sit_pitr > SPEED_PITC); timerp->cpmt_tgcr &= ~TGCR_STP2; /* Start Timer 2 */ while ((immr->im_sit.sit_piscr & PISCR_PS) == 0); timerp->cpmt_tgcr |= TGCR_STP2; /* Stop Timer 2 */ /* re-enable external interrupts if they were on */ set_msr (msr_val); /* Disable timer and PIT */ timer2_val = timerp->cpmt_tcn2; /* save before reset timer */ timerp->cpmt_tgcr &= ~(TGCR_RST2 | TGCR_FRZ2 | TGCR_STP2); immr->im_sit.sit_piscr &= ~PISCR_PTE; #if defined(CFG_8XX_XIN) /* not using OSCM, using XIN, so scale appropriately */ return (((timer2_val + 2) / 4) * (CFG_8XX_XIN/512))/8192 * 100000L; #else return ((timer2_val + 2) / 4) * 100000L; /* convert to Hz */ #endif } #endif #if !defined(CONFIG_8xx_CPUCLK_DEFAULT) /* * get_clocks() fills in gd->cpu_clock depending on CONFIG_8xx_GCLK_FREQ * or (if it is not defined) measure_gclk() (which uses the ref clock) * from above. */ int get_clocks (void) { uint immr = get_immr (0); /* Return full IMMR contents */ volatile immap_t *immap = (immap_t *) (immr & 0xFFFF0000); uint sccr = immap->im_clkrst.car_sccr; /* * If for some reason measuring the gclk frequency won't * work, we return the hardwired value. * (For example, the cogent CMA286-60 CPU module has no * separate oscillator for PITRTCLK) */ #if defined(CONFIG_8xx_GCLK_FREQ) gd->cpu_clk = CONFIG_8xx_GCLK_FREQ; #elif defined(CONFIG_8xx_OSCLK) #define PLPRCR_val(a) ((pll & PLPRCR_ ## a ## _MSK) >> PLPRCR_ ## a ## _SHIFT) uint pll = immap->im_clkrst.car_plprcr; uint clk; if ((immr & 0x0FFF) >= MPC8xx_NEW_CLK) { /* MPC866/87x/88x series */ clk = ((CONFIG_8xx_OSCLK / (PLPRCR_val(PDF)+1)) * (PLPRCR_val(MFI) + PLPRCR_val(MFN) / (PLPRCR_val(MFD)+1))) / (1<<PLPRCR_val(S)); } else { clk = CONFIG_8xx_OSCLK * (PLPRCR_val(MF)+1); } if (pll & PLPRCR_CSRC) { /* Low frequency division factor is used */ gd->cpu_clk = clk / (2 << ((sccr >> 8) & 7)); } else { /* High frequency division factor is used */ gd->cpu_clk = clk / (1 << ((sccr >> 5) & 7)); } #else gd->cpu_clk = measure_gclk(); #endif /* CONFIG_8xx_GCLK_FREQ */ if ((sccr & SCCR_EBDF11) == 0) { /* No Bus Divider active */ gd->bus_clk = gd->cpu_clk; } else { /* The MPC8xx has only one BDF: half clock speed */ gd->bus_clk = gd->cpu_clk / 2; } return (0); } #else /* CONFIG_8xx_CPUCLK_DEFAULT defined, use dynamic clock setting */ static long init_pll_866 (long clk); /* This function sets up PLL (init_pll_866() is called) and * fills gd->cpu_clk and gd->bus_clk according to the environment * variable 'cpuclk' or to CONFIG_8xx_CPUCLK_DEFAULT (if 'cpuclk' * contains invalid value). * This functions requires an MPC866 or newer series CPU. */ int get_clocks_866 (void) { volatile immap_t *immr = (immap_t *) CFG_IMMR; char tmp[64]; long cpuclk = 0; long sccr_reg; if (getenv_r ("cpuclk", tmp, sizeof (tmp)) > 0) cpuclk = simple_strtoul (tmp, NULL, 10) * 1000000; if ((CFG_8xx_CPUCLK_MIN > cpuclk) || (CFG_8xx_CPUCLK_MAX < cpuclk)) cpuclk = CONFIG_8xx_CPUCLK_DEFAULT; gd->cpu_clk = init_pll_866 (cpuclk); #if defined(CFG_MEASURE_CPUCLK) gd->cpu_clk = measure_gclk (); #endif /* if cpu clock <= 66 MHz then set bus division factor to 1, * otherwise set it to 2 */ sccr_reg = immr->im_clkrst.car_sccr; sccr_reg &= ~SCCR_EBDF11; if (gd->cpu_clk <= 66000000) { sccr_reg |= SCCR_EBDF00; /* bus division factor = 1 */ gd->bus_clk = gd->cpu_clk; } else { sccr_reg |= SCCR_EBDF01; /* bus division factor = 2 */ gd->bus_clk = gd->cpu_clk / 2; } immr->im_clkrst.car_sccr = sccr_reg; return (0); } /* Adjust sdram refresh rate to actual CPU clock. */ int sdram_adjust_866 (void) { volatile immap_t *immr = (immap_t *) CFG_IMMR; long mamr; mamr = immr->im_memctl.memc_mamr; mamr &= ~MAMR_PTA_MSK; mamr |= ((gd->cpu_clk / CFG_PTA_PER_CLK) << MAMR_PTA_SHIFT); immr->im_memctl.memc_mamr = mamr; return (0); } /* Configure PLL for MPC866/859/885 CPU series * PLL multiplication factor is set to the value nearest to the desired clk, * assuming a oscclk of 10 MHz. */ static long init_pll_866 (long clk) { extern void plprcr_write_866 (long); volatile immap_t *immr = (immap_t *) CFG_IMMR; long n, plprcr; char mfi, mfn, mfd, s, pdf; long step_mfi, step_mfn; if (clk < 20000000) { clk *= 2; pdf = 1; } else { pdf = 0; } if (clk < 40000000) { s = 2; step_mfi = CONFIG_8xx_OSCLK / 4; mfd = 7; step_mfn = CONFIG_8xx_OSCLK / 30; } else if (clk < 80000000) { s = 1; step_mfi = CONFIG_8xx_OSCLK / 2; mfd = 14; step_mfn = CONFIG_8xx_OSCLK / 30; } else { s = 0; step_mfi = CONFIG_8xx_OSCLK; mfd = 29; step_mfn = CONFIG_8xx_OSCLK / 30; } /* Calculate integer part of multiplication factor */ n = clk / step_mfi; mfi = (char)n; /* Calculate numerator of fractional part of multiplication factor */ n = clk - (n * step_mfi); mfn = (char)(n / step_mfn); /* Calculate effective clk */ n = ((mfi * step_mfi) + (mfn * step_mfn)) / (pdf + 1); immr->im_clkrstk.cark_plprcrk = KAPWR_KEY; plprcr = (immr->im_clkrst.car_plprcr & ~(PLPRCR_MFN_MSK | PLPRCR_MFD_MSK | PLPRCR_S_MSK | PLPRCR_MFI_MSK | PLPRCR_DBRMO | PLPRCR_PDF_MSK)) | (mfn << PLPRCR_MFN_SHIFT) | (mfd << PLPRCR_MFD_SHIFT) | (s << PLPRCR_S_SHIFT) | (mfi << PLPRCR_MFI_SHIFT) | (pdf << PLPRCR_PDF_SHIFT); if( (mfn > 0) && ((mfd / mfn) > 10) ) plprcr |= PLPRCR_DBRMO; plprcr_write_866 (plprcr); /* set value using SIU4/9 workaround */ immr->im_clkrstk.cark_plprcrk = 0x00000000; return (n); } #endif /* CONFIG_8xx_CPUCLK_DEFAULT */ #if defined(CONFIG_TQM8xxL) && !defined(CONFIG_TQM866M) /* * Adjust sdram refresh rate to actual CPU clock * and set timebase source according to actual CPU clock */ int adjust_sdram_tbs_8xx (void) { volatile immap_t *immr = (immap_t *) CFG_IMMR; long mamr; long sccr; mamr = immr->im_memctl.memc_mamr; mamr &= ~MAMR_PTA_MSK; mamr |= ((gd->cpu_clk / CFG_PTA_PER_CLK) << MAMR_PTA_SHIFT); immr->im_memctl.memc_mamr = mamr; if (gd->cpu_clk < 67000000) { sccr = immr->im_clkrst.car_sccr; sccr |= SCCR_TBS; immr->im_clkrst.car_sccr = sccr; } return (0); } #endif /* CONFIG_TQM8xxL/M, !TQM866M */ /* ------------------------------------------------------------------------- */