/*
 *
 * (C) Copyright 2000-2003
 * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
 *
 * Copyright (C) 2004-2008 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 */

#ifdef CONFIG_MCF5301x
#define FREF            20000   /* KHz */
#define MAX_MFD         63      /* Multiplier */
#define MIN_MFD         0       /* Multiplier */
#define USBDIV          8

/* Low Power Divider specifications */
#define MIN_LPD         (0)     /* Divider (not encoded) */
#define MAX_LPD         (15)    /* Divider (not encoded) */
#define DEFAULT_LPD     (0)     /* Divider (not encoded) */
#endif

#ifdef CONFIG_MCF532x
#define FREF            16000   /* KHz */
#define MAX_MFD         135     /* Multiplier */
#define MIN_MFD         88      /* Multiplier */

/* 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) */
#endif

#define BUSDIV          6       /* Divider */

/* Get the value of the current system clock */
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);
#ifdef CONFIG_MCF5301x
                return (FREF / (3 * (1 << divider)));
#endif
#ifdef CONFIG_MCF532x
                return (FREF / (2 << divider));
#endif
        } else {
#ifdef CONFIG_MCF5301x
                u32 pfdr = (pll->pcr & 0x3F) + 1;
                u32 refdiv = (1 << ((pll->pcr & PLL_PCR_REFDIV(7)) >> 8));
                u32 busdiv = ((pll->pdr & 0x00F0) >> 4) + 1;

                return (((FREF * pfdr) / refdiv) / busdiv);
#endif
#ifdef CONFIG_MCF532x
                return ((FREF * pll->pfdr) / (BUSDIV * 4));
#endif
        }
}

/*
 * 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(0xFF));

        /* 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 */
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)
{
#ifdef CONFIG_MCF532x
        volatile u32 *sdram_workaround = (volatile u32 *)(MMAP_SDRAM + 0x80);
#endif
        volatile sdram_t *sdram = (volatile sdram_t *)(MMAP_SDRAM);
        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 */
#ifdef CONFIG_MCF5301x
                u32 busdiv = ((pll->pdr >> 4) & 0x0F) + 1;
                mfd = (pll->pcr & 0x3F) + 1;

                return (fref * mfd) / busdiv;
#endif
#ifdef CONFIG_MCF532x
                mfd = pll->pfdr;

                return (fref * mfd / (BUSDIV * 4));
#endif
        }

        /* 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;
#ifdef CONFIG_MCF5301x
        mfd = (BUSDIV * temp) / 100;

        /* Determine the output frequency for selected values */
        fout = ((fref * mfd) / BUSDIV);
#endif
#ifdef CONFIG_MCF532x
        mfd = (4 * BUSDIV * temp) / 100;

        /* Determine the output frequency for selected values */
        fout = ((fref * mfd) / (BUSDIV * 4));
#endif

        /*
         * 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.
         */
        if (sdram->ctrl & SDRAMC_SDCR_REF)
                sdram->ctrl &= ~SDRAMC_SDCR_CKE;

        /*
         * 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);

#ifdef CONFIG_MCF5301x
        pll->pdr =
            PLL_PDR_OUTDIV1((BUSDIV / 3) - 1)   |
            PLL_PDR_OUTDIV2(BUSDIV - 1) |
            PLL_PDR_OUTDIV3((BUSDIV / 2) - 1)   |
            PLL_PDR_OUTDIV4(USBDIV - 1);

        pll->pcr &= PLL_PCR_FBDIV_MASK;
        pll->pcr |= PLL_PCR_FBDIV(mfd - 1);
#endif
#ifdef CONFIG_MCF532x
        /* Reprogram PLL for desired fsys */
        pll->podr = (PLL_PODR_CPUDIV(BUSDIV / 3) | PLL_PODR_BUSDIV(BUSDIV));

        pll->pfdr = mfd;
#endif

        /* Exit LIMP mode */
        clock_exit_limp();

        /* Return the SDRAM to normal operation if it is in use. */
        if (sdram->ctrl & SDRAMC_SDCR_REF)
                sdram->ctrl |= SDRAMC_SDCR_CKE;

#ifdef CONFIG_MCF532x
        /*
         * software workaround for SDRAM opeartion after exiting LIMP
         * mode errata
         */
        *sdram_workaround = CONFIG_SYS_SDRAM_BASE;
#endif

        /* 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(CONFIG_SYS_CLK / 1000, 0) * 1000;
        gd->cpu_clk = (gd->bus_clk * 3);

#ifdef CONFIG_FSL_I2C
        gd->i2c1_clk = gd->bus_clk;
#endif

        return (0);
}