/* $XConsortium: I2061Acal.c,v 1.1 95/01/26 15:27:33 kaleb Exp $ */ /* $XFree86: xc/programs/Xserver/hw/xfree86/accel/p9000/I2061Acal.c,v 3.2 1995/01/28 15:54:34 dawes Exp $ */ /* Id: ICD2061Acal.c,v 4.0 1994/05/28 01:24:17 nygren Exp */ /* Based on the number 9 Inc code */ /* Copyright (c) 1992, Number Nine Computer Corp. All Rights Reserved. * * Permission to use, copy, modify, distribute, and sell this software and its * documentation for any purpose is hereby granted without fee, provided that * the above copyright notice appear in all copies and that both that * copyright notice and this permission notice appear in supporting * documentation, and that the name of Number Nine Computer Corp not be used * in advertising or publicity pertaining to distribution of the software * without specific, written prior permission. Number Nine Computer Corp * makes no representations about the suitability of this software for any * purpose. It is provided "as is" without express or implied warranty. * * NUMBER NINE COMPUTER CORP DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS * SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, * IN NO EVENT SHALL NUMBER NINE COMPUTER CORP BE LIABLE FOR ANY SPECIAL, * INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING * FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, * NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION * WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. * * Modifications - Copyright (c) 1994, Harry Langenbacher,All Rights Reserved. * HARRY LANGENBACHER DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS * SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, * IN NO EVENT SHALL HARRY LANGENBACHER BE LIABLE FOR ANY SPECIAL, * INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING * FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, * NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION * WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. * Permission to use, copy, modify, distribute, and sell this software and its * documentation for any purpose is hereby granted without fee, provided that * the above copyright notice appear in all copies and that both that * copyright notice and this permission notice appear in supporting * documentation. Harry Langenbacher * makes no representations about the suitability of this software for any * purpose. It is provided "as is" without express or implied warranty. */ #include "X.h" #include "input.h" #include "xf86_OSlib.h" #include "xf86.h" #include "ICD2061A.h" #undef MIN #define MIN(a, b) (((a) < (b)) ? (a) : (b)) #undef MAX #define MAX(a, b) (((a) > (b)) ? (a) : (b)) #define MAX_NUMERATOR 130 #define MAX_DENOMINATOR MIN(129, CRYSTAL_FREQUENCY / 400000) #define MIN_DENOMINATOR MAX(3, CRYSTAL_FREQUENCY / 2000000) /* Index register frequency ranges for ICD2061A chip */ /* "The Index Field is used to preset the VCO to an appropriate range." pg. 13 */ static long vclk_range[14] = { 51000000, 53200000, 58500000, 60700000, 64400000, 66800000, 73500000, 75600000, 80900000, 83200000, 91500000, 100000000, 120000000, 135000000 /* BE WARNED THIS COULD BE VERY VERY BAD (i.e. , I'm guessing)!!!!!!! */ } ; unsigned long ICD2061ACalcClock ( long frequency , int chipreg ) /* frequency in Hz */ /* chipreg - select one of 3 registers in icd2061a to be selected to hold new frequency parameters */ { int Q_Divider ; int P_Divider ; int Mux ; /* divider after vco */ register int index; unsigned long temp; int Best_Qdivider, Best_Pdivider; long min_diff; long diff; min_diff = 0xFFFFFFF; Best_Pdivider = 1; Best_Qdivider = 1; #ifdef DEBUG ErrorF ( "Buiding clock control word for freq=%d, chipreg=%d\n" , frequency , chipreg ) ; #endif /* Calculate 17 bit ( 7 + 3 + 7 ) frequency control field */ /* find what post VCO divider we need */ Mux = 0; if (frequency < MIN_VCO_FREQUENCY) Mux = 1; if (frequency < MIN_VCO_FREQUENCY / 2) Mux = 2; if (frequency < MIN_VCO_FREQUENCY / 4) Mux = 3; /* boy, this is a really low frequency (50Mhz/4?)*/ frequency <<= Mux ; /* make frequency = the VCO frequency we have to get */ for (P_Divider = 4; P_Divider <= MAX_NUMERATOR; P_Divider++) { index = CRYSTAL_FREQUENCY / (frequency / P_Divider); if (index > MAX_DENOMINATOR) index = MAX_DENOMINATOR; if (index < MIN_DENOMINATOR) index = MIN_DENOMINATOR; for (Q_Divider = index - 3; Q_Divider < index + 4; Q_Divider++) if (Q_Divider >= MIN_DENOMINATOR && Q_Divider <= MAX_DENOMINATOR) { diff = (CRYSTAL_FREQUENCY / Q_Divider) * P_Divider - frequency; if (diff < 0) diff = -diff; if ( Best_Qdivider * ICD2061AGCD(Q_Divider, P_Divider) / ICD2061AGCD(Best_Qdivider, Best_Pdivider) == Q_Divider && Best_Pdivider * ICD2061AGCD(Q_Divider, P_Divider) / ICD2061AGCD(Best_Qdivider, Best_Pdivider) == P_Divider ) { if (diff > min_diff) diff = min_diff; } if (diff <= min_diff) { min_diff = diff; Best_Qdivider = Q_Divider; Best_Pdivider = P_Divider; } } } Q_Divider = Best_Qdivider; P_Divider = Best_Pdivider; /* Calculate the resultant VCO frequency */ temp = CalcVCOfreq ( Q_Divider , P_Divider ) ; /* look up the index field value appropriate for this vco freq */ index = 0 ; while ( ( vclk_range [ index ] < temp ) && ( index < 14 ) ) index ++ ; if ( index == 14 ) /* vco freq too high */ { ErrorF ("\a\aProgram error - vco freq too high !\n" ) ; } /* Pack the control word for the frequency snthesizer , packed into bits 0-23, not 1-24 like before */ temp = ( (long) chipreg << 21 ) | ( (long) index << 17 ) | ( (long) ( P_Divider - 3 ) << 10 ) | ( (long) Mux << 7 ) | ( Q_Divider - 2 ) ; #ifdef DEBUG ErrorF ("Clock Control Word is 0x%06X\n" , temp ) ; #endif return temp; } /* Number theoretic function - GCD (Greatest Common Divisor) */ int ICD2061AGCD ( int number1 , int number2 ) { register int remainder = number1 % number2 ; while ( remainder ) { number1 = number2 ; number2 = remainder ; remainder = number1 % number2 ; } return number2 ; } unsigned int ICD2061AGetClock ( unsigned long control_word ) /* value now in bits 0-23 ( not 1-24 like before ) */ { unsigned int Q_Divider ; unsigned int Feedback_Divider_P ; unsigned int Post_VCO_Divider_M ; unsigned int FinalFreq ; unsigned int VCOFreq ; unsigned int Index ; unsigned int select ; /* Unpack the clock value */ select = ( control_word >> 21 ) & 7 ; Index = ( ( control_word >> 17 ) & 0x0F) ; /* P */ Feedback_Divider_P = ( ( control_word >> 10 ) & 0x7F) + 3 ; /* P */ Post_VCO_Divider_M = ( ( control_word >> 7 ) & 0x07) ; /* M */ Q_Divider = ( ( control_word ) & 0x7F) + 2 ; /* Q */ /* f(VCO) = Prescale * f(ref) * P / Q */ /* where Prescale is determined by a bit in the control reg, and will be 2 or 4 , default 2 */ /* then the VCO output is divided by 2^^M */ VCOFreq = CalcVCOfreq ( Q_Divider , Feedback_Divider_P ) ; FinalFreq = VCOFreq >> Post_VCO_Divider_M ; /* (2*f(ref)*P/Q)/2^^Post_VCO_Divider_M */ #ifdef DEBUG ErrorF ("\ register select=%d\n\ Index Field =%d=0x%X\n\ Feedback_Divider_P=%d=0x%X\n\ Post_VCO_Divider_M=%d\n\ Q_Divider=%d=0x%X\n\ VCOFreq=%d Hz, FinalFreq=%d Hz\n" , select , Index , Index , Feedback_Divider_P , Feedback_Divider_P , Post_VCO_Divider_M , Q_Divider , Q_Divider , VCOFreq , FinalFreq ) ; #endif return FinalFreq ; } unsigned long CalcVCOfreq ( unsigned int Q_Divider , unsigned int Feedback_Divider_P ) { unsigned long VCO_Freq ; /* f(VCO) = Prescale * f(ref) * P / Q */ /* where Prescale is determined by a bit in the control reg, and will be 2 or 4 , default 2 */ /* assume a (standard?) 14.318180 Mhz Crystal */ VCO_Freq = ( 2 * 14318180 * Feedback_Divider_P ) / Q_Divider ; return VCO_Freq ; }