1 files changed, 216 insertions, 0 deletions
diff --git a/cpu/mcf532x/speed.c b/cpu/mcf532x/speed.c
new file mode 100644
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--- /dev/null
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@@ -0,0 +1,216 @@
+/*
+ *
+ * (C) Copyright 2000-2003
+ * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
+ *
+ * Copyright (C) 2004-2007 Freescale Semiconductor, Inc.
+ * TsiChung Liew (Tsi-Chung.Liew@freescale.com)
+ *
+ * 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 <asm/processor.h>
+
+#include <asm/immap.h>
+
+/* PLL min/max specifications */
+#define MAX_FVCO	500000	/* KHz */
+#define MAX_FSYS	80000	/* KHz */
+#define MIN_FSYS	58333	/* KHz */
+#define FREF		16000	/* KHz */
+#define MAX_MFD		135	/* Multiplier */
+#define MIN_MFD		88	/* Multiplier */
+#define BUSDIV		6	/* Divider */
+/*
+ * Low Power Divider specifications
+ */
+#define MIN_LPD		(1 << 0)	/* Divider (not encoded) */
+#define MAX_LPD		(1 << 15)	/* Divider (not encoded) */
+#define DEFAULT_LPD	(1 << 1)	/* Divider (not encoded) */
+
+/*
+ * Get the value of the current system clock
+ *
+ * Parameters:
+ *  none
+ *
+ * Return Value:
+ *  The current output system frequency
+ */
+int get_sys_clock(void)
+{
+	volatile ccm_t *ccm = (volatile ccm_t *)(MMAP_CCM);
+	volatile pll_t *pll = (volatile pll_t *)(MMAP_PLL);
+	int divider;
+
+	/* Test to see if device is in LIMP mode */
+	if (ccm->misccr & CCM_MISCCR_LIMP) {
+		divider = ccm->cdr & CCM_CDR_LPDIV(0xF);
+		return (FREF / (2 << divider));
+	} else {
+		return ((FREF * pll->pfdr) / (BUSDIV * 4));
+	}
+}
+
+/*
+ * Initialize the Low Power Divider circuit
+ *
+ * Parameters:
+ *  div     Desired system frequency divider
+ *
+ * Return Value:
+ *  The resulting output system frequency
+ */
+int clock_limp(int div)
+{
+	volatile ccm_t *ccm = (volatile ccm_t *)(MMAP_CCM);
+	u32 temp;
+
+	/* Check bounds of divider */
+	if (div < MIN_LPD)
+		div = MIN_LPD;
+	if (div > MAX_LPD)
+		div = MAX_LPD;
+
+	/* Save of the current value of the SSIDIV so we don't overwrite the value */
+	temp = (ccm->cdr & CCM_CDR_SSIDIV(0xF));
+
+	/* Apply the divider to the system clock */
+	ccm->cdr = (CCM_CDR_LPDIV(div) | CCM_CDR_SSIDIV(temp));
+
+	ccm->misccr |= CCM_MISCCR_LIMP;
+
+	return (FREF / (3 * (1 << div)));
+}
+
+/*
+ * Exit low power LIMP mode
+ *
+ * Parameters:
+ *  div     Desired system frequency divider
+ *
+ * Return Value:
+ *  The resulting output system frequency
+ */
+int clock_exit_limp(void)
+{
+	volatile ccm_t *ccm = (volatile ccm_t *)(MMAP_CCM);
+	int fout;
+
+	/* Exit LIMP mode */
+	ccm->misccr &= (~CCM_MISCCR_LIMP);
+
+	/* Wait for PLL to lock */
+	while (!(ccm->misccr & CCM_MISCCR_PLL_LOCK)) ;
+
+	fout = get_sys_clock();
+
+	return fout;
+}
+
+/* Initialize the PLL
+ *
+ * Parameters:
+ *  fref    PLL reference clock frequency in KHz
+ *  fsys    Desired PLL output frequency in KHz
+ *  flags   Operating parameters
+ *
+ * Return Value:
+ *  The resulting output system frequency
+ */
+int clock_pll(int fsys, int flags)
+{
+	volatile u32 *sdram_workaround = (volatile u32 *)(MMAP_SDRAM + 0x80);
+	volatile pll_t *pll = (volatile pll_t *)(MMAP_PLL);
+	int fref, temp, fout, mfd;
+	u32 i;
+
+	fref = FREF;
+
+	if (fsys == 0) {
+		/* Return current PLL output */
+		mfd = pll->pfdr;
+
+		return (fref * mfd / (BUSDIV * 4));
+	}
+
+	/* Check bounds of requested system clock */
+	if (fsys > MAX_FSYS)
+		fsys = MAX_FSYS;
+
+	if (fsys < MIN_FSYS)
+		fsys = MIN_FSYS;
+
+	/* Multiplying by 100 when calculating the temp value,
+	   and then dividing by 100 to calculate the mfd allows
+	   for exact values without needing to include floating
+	   point libraries. */
+	temp = (100 * fsys) / fref;
+	mfd = (4 * BUSDIV * temp) / 100;
+
+	/* Determine the output frequency for selected values */
+	fout = ((fref * mfd) / (BUSDIV * 4));
+
+	/*
+	 * Check to see if the SDRAM has already been initialized.
+	 * If it has then the SDRAM needs to be put into self refresh
+	 * mode before reprogramming the PLL.
+	 */
+
+	/*
+	 * Initialize the PLL to generate the new system clock frequency.
+	 * The device must be put into LIMP mode to reprogram the PLL.
+	 */
+
+	/* Enter LIMP mode */
+	clock_limp(DEFAULT_LPD);
+
+	/* Reprogram PLL for desired fsys */
+	pll->podr = (PLL_PODR_CPUDIV(BUSDIV / 3) | PLL_PODR_BUSDIV(BUSDIV));
+
+	pll->pfdr = mfd;
+
+	/* Exit LIMP mode */
+	clock_exit_limp();
+
+	/*
+	 * Return the SDRAM to normal operation if it is in use.
+	 */
+
+	/* software workaround for SDRAM opeartion after exiting LIMP mode errata */
+	*sdram_workaround = CFG_SDRAM_BASE;
+
+	/* wait for DQS logic to relock */
+	for (i = 0; i < 0x200; i++) ;
+
+	return fout;
+}
+
+/*
+ * get_clocks() fills in gd->cpu_clock and gd->bus_clk
+ */
+int get_clocks(void)
+{
+	DECLARE_GLOBAL_DATA_PTR;
+
+	gd->bus_clk = clock_pll(CFG_CLK / 1000, 0) * 1000;
+	gd->cpu_clk = (gd->bus_clk * 3);
+	return (0);
+}