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+/*
+ *
+ * (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>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+/* 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)
+{
+ gd->bus_clk = clock_pll(CFG_CLK / 1000, 0) * 1000;
+ gd->cpu_clk = (gd->bus_clk * 3);
+ return (0);
+}