rockbox/firmware/target/arm/as3525/clock-target.h

/***************************************************************************
 *             __________               __   ___.
 *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
 *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
 *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
 *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
 *                     \/            \/     \/    \/            \/
 * $Id$
 *
 * Copyright © 2008 Rafaël Carré
 *
 * 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 software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
 * KIND, either express or implied.
 *
 ****************************************************************************/
#ifndef CLOCK_TARGET_H
#define CLOCK_TARGET_H

/* returns clock divider, given maximal target frequency and clock reference */
#define CLK_DIV(ref, target) ((ref + target - 1) / target)


/*  Frequency and Bus Settings
 *  These bus settings work on the assumption that unboosted performance will be
 *  based on fastbus mode(FCLK == PCLK) at a frequency configured with this file.
 *  Boosted performance defaults to synchronous bus but will be changed to
 *  asynchronous bus if FCLK is not an integer multiple of PCLK.
 *  The player starts up in fastbus mode and synchronous or asynchronous mode is
 *  implemented in the set_cpu_frequency() function in system-as3525.c.  There
 *  are limitations on both frequencies and frequency relationships listed in 7.3.14
 *  of the as3525 datasheet that need to be observed.  If you are determined to
 *  use a frequency that is not "legal" you can do that. There are no checks for
 *  legal frequency values, only some validity checks to make sure the divider
 *  value fits into the number of bits allotted to it.
 *
 *  The CLOCK_DIV macro does a pretty good job at selecting divider values but
 *  you can always overide it by choosing your own value and commenting out the
 *  macro.  If you are going to use AS3525_FCLK_PREDIV or AS3525_PCLK_DIV1 you
 *  will have to do a manual calculation.  I have included USB & PLLB for future
 *  use but commented them out for now.
 */

/* Clock Sources  */
#define AS3525_CLK_MAIN           0
#define AS3525_CLK_PLLA           1
//#define AS3525_CLK_PLLB           2
#define AS3525_CLK_FCLK           3         /* for synchronous bus only  */

/* PLL  frequencies and settings*/

#define AS3525_PLLA_FREQ        248000000   /*124,82.7,62,49.6,41.3,35.4 */
       /* FCLK_PREDIV->  *7/8 = 217MHz      108.5 ,72.3, 54.25, 43.4, 36.17 */
                      /* *6/8 = 186MHz      93, 62, 46.5, 37.2 */
                      /* *5/8 = 155MHz      77.5, 51.67, 38.75 */
#define AS3525_PLLA_SETTING     0x261F

//#define AS3525_PLLA_FREQ        384000000 /*192,128,96,76.8,64,54.9,48,42.7,38.4*/
       /* FCLK_PREDIV->  *7/8 = 336MHz      168, 112, 84, 67.2, 56, 48, 42, 37.3*/
                      /* *6/8 = 288MHz      144, 96, 72, 57.6, 48, 41.1, */
                      /* *5/8 = 240MHz      120, 80, 60, 48, 40  */
//#define AS3525_PLLA_SETTING     0x2630

/*  PLLB not used at this time! */
//#define AS3525_PLLB_FREQ
//#define AS3525_PLLB_SETTING

/** ************ Change these to reconfigure clocking scheme *******************/

#define AS3525_FCLK_FREQ         248000000          /* Boosted FCLK frequency  */
#define AS3525_PCLK_FREQ         62000000           /* Initial PCLK frequency  */
#define AS3525_DBOP_FREQ         AS3525_PCLK_FREQ   /* Initial DBOP frequency  */

/** ****************************************************************************/

/* Figure out if we need to use asynchronous bus */
#if (AS3525_FCLK_FREQ % AS3525_PCLK_FREQ)
#define ASYNCHRONOUS_BUS                          /* Boosted mode asynchronous */
#endif

/* Tell the software what frequencies we're running */
#define CPUFREQ_MAX              AS3525_FCLK_FREQ
#define CPUFREQ_DEFAULT          AS3525_PCLK_FREQ
#define CPUFREQ_NORMAL           AS3525_PCLK_FREQ

/* FCLK */
#define AS3525_FCLK_SEL          AS3525_CLK_PLLA
#define AS3525_FCLK_PREDIV       0   /* div = (8-n)/8 acts strange when used!*/
#define AS3525_FCLK_POSTDIV      (CLK_DIV(AS3525_PLLA_FREQ, AS3525_FCLK_FREQ) - 1) /*div=1/(n+1)*/

/* PCLK */
#ifdef ASYNCHRONOUS_BUS
#define AS3525_PCLK_SEL          AS3525_CLK_PLLA    /* PLLA input for asynchronous */
#define AS3525_PCLK_DIV0         (CLK_DIV(AS3525_PLLA_FREQ, AS3525_PCLK_FREQ) - 1)/*div=1/(n+1)*/
#else
#define AS3525_PCLK_SEL          AS3525_CLK_FCLK    /* Fclk input for synchronous */
#define AS3525_PCLK_DIV0         (CLK_DIV(AS3525_FCLK_FREQ, AS3525_PCLK_FREQ) - 1) /*div=1/(n+1)*/
#endif
#define AS3525_PCLK_DIV1         0 /* div = 1/(n+1) unable to use successfuly so far*/

   /* PCLK as Source */
  #define AS3525_DBOP_DIV        (CLK_DIV(AS3525_PCLK_FREQ, AS3525_DBOP_FREQ) - 1) /*div=1/(n+1)*/
  #define AS3525_I2C_PRESCALER   CLK_DIV(AS3525_PCLK_FREQ, AS3525_I2C_FREQ)
  #define AS3525_I2C_FREQ        400000
  #define AS3525_SD_IDENT_DIV    ((CLK_DIV(AS3525_PCLK_FREQ, AS3525_SD_IDENT_FREQ) / 2) - 1)
  #define AS3525_SD_IDENT_FREQ   400000      /* must be between 100 & 400 kHz */

#define AS3525_IDE_SEL           AS3525_CLK_PLLA           /* Input Source   */
#define AS3525_IDE_DIV           (CLK_DIV(AS3525_PLLA_FREQ, AS3525_IDE_FREQ) - 1)/*div=1/(n+1)*/
#define AS3525_IDE_FREQ          90000000    /* The OF uses 66MHz maximal freq
                                               but sd transfers fail on some
                                               players with this limit */

//#define AS3525_USB_SEL           AS3525_CLK_PLLA            /* Input Source   */
//#define AS3525_USB_DIV           /* div = 1/(n=0?1:2n)*/


/* Validity Checks */

/* AS3525_PCLK_FREQ  */
#if (CLK_DIV(AS3525_PLLA_FREQ, AS3525_PCLK_FREQ) - 1) >= (1<<4) /* 4 bits */
#error PCLK frequency is too low : clock divider will not fit !
#endif
/*  AS3525_DBOP_FREQ */
#if (CLK_DIV(AS3525_PCLK_FREQ, AS3525_DBOP_FREQ) - 1) >= (1<<3) /* 3 bits */
#error DBOP frequency is too low : clock divider will not fit !
#endif
/* AS3525_IDE_FREQ */
#if (CLK_DIV(AS3525_PLLA_FREQ, AS3525_IDE_FREQ) - 1) >= (1<<4) /* 4 bits */
#error IDE frequency is too low : clock divider will not fit !
#endif
/* AS3525_I2C_FREQ */
#if (CLK_DIV(AS3525_PCLK_FREQ, AS3525_I2C_FREQ)) >= (1<<10) /* 2+8 bits */
#error I2C frequency is too low : clock divider will not fit !
#endif
/* AS3525_SD_IDENT_FREQ */
#if ((CLK_DIV(AS3525_PCLK_FREQ, AS3525_SD_IDENT_FREQ) / 2) - 1) >= (1<<8) /* 8 bits */
#error SD IDENTIFICATION frequency is too low : clock divider will not fit !
#endif

#endif /* CLOCK_TARGET_H */