diff options
Diffstat (limited to 'arch/m68k/cpu/mcf532x/speed.c')
| -rw-r--r-- | arch/m68k/cpu/mcf532x/speed.c | 275 |
1 files changed, 275 insertions, 0 deletions
diff --git a/arch/m68k/cpu/mcf532x/speed.c b/arch/m68k/cpu/mcf532x/speed.c new file mode 100644 index 0000000..5a29e25 --- /dev/null +++ b/arch/m68k/cpu/mcf532x/speed.c @@ -0,0 +1,275 @@ +/* + * + * (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 + +/* must not tamper with SDRAMC if running from SDRAM */ +#if !defined(CONFIG_MONITOR_IS_IN_RAM) + /* + * 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_UNMASK; + 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++) ; +#endif /* !defined(CONFIG_MONITOR_IS_IN_RAM) */ + + 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); +} |