1 files changed, 416 insertions, 0 deletions
diff --git a/arch/powerpc/cpu/mpc8xx/speed.c b/arch/powerpc/cpu/mpc8xx/speed.c
new file mode 100644
index 0000000..f309f29
--- /dev/null
+++ b/arch/powerpc/cpu/mpc8xx/speed.c
@@ -0,0 +1,416 @@
+/*
+ * (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(CONFIG_SYS_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 *) CONFIG_SYS_IMMR;
+	volatile cpmtimer8xx_t *timerp = &immr->im_cpmtimer;
+	ulong timer2_val;
+	ulong msr_val;
+
+#ifdef CONFIG_SYS_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 = CONFIG_SYS_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(CONFIG_SYS_8XX_XIN)
+	/* not using OSCM, using XIN, so scale appropriately */
+	return (((timer2_val + 2) / 4) * (CONFIG_SYS_8XX_XIN/512))/8192 * 100000L;
+#else
+	return ((timer2_val + 2) / 4) * 100000L;	/* convert to Hz	*/
+#endif
+}
+
+#endif
+
+void get_brgclk(uint sccr)
+{
+	uint divider = 0;
+
+	switch((sccr&SCCR_DFBRG11)>>11){
+		case 0:
+			divider = 1;
+			break;
+		case 1:
+			divider = 4;
+			break;
+		case 2:
+			divider = 16;
+			break;
+		case 3:
+			divider = 64;
+			break;
+	}
+	gd->brg_clk = gd->cpu_clk/divider;
+}
+
+#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;
+	}
+
+	get_brgclk(sccr);
+
+	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 *) CONFIG_SYS_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 ((CONFIG_SYS_8xx_CPUCLK_MIN > cpuclk) || (CONFIG_SYS_8xx_CPUCLK_MAX < cpuclk))
+		cpuclk = CONFIG_8xx_CPUCLK_DEFAULT;
+
+	gd->cpu_clk = init_pll_866 (cpuclk);
+#if defined(CONFIG_SYS_MEASURE_CPUCLK)
+	gd->cpu_clk = measure_gclk ();
+#endif
+
+	get_brgclk(immr->im_clkrst.car_sccr);
+
+	/* 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 *) CONFIG_SYS_IMMR;
+	long		  mamr;
+
+	mamr = immr->im_memctl.memc_mamr;
+	mamr &= ~MAMR_PTA_MSK;
+	mamr |= ((gd->cpu_clk / CONFIG_SYS_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 *) CONFIG_SYS_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) \
+    && !defined(CONFIG_TQM885D)
+/*
+ * 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 *) CONFIG_SYS_IMMR;
+	long		  mamr;
+	long              sccr;
+
+	mamr = immr->im_memctl.memc_mamr;
+	mamr &= ~MAMR_PTA_MSK;
+	mamr |= ((gd->cpu_clk / CONFIG_SYS_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, !TQM885D */
+
+/* ------------------------------------------------------------------------- */