diff options
Diffstat (limited to 'src/s3v_dac.c')
| -rw-r--r-- | src/s3v_dac.c | 125 |
1 files changed, 125 insertions, 0 deletions
diff --git a/src/s3v_dac.c b/src/s3v_dac.c new file mode 100644 index 0000000..180b7f4 --- /dev/null +++ b/src/s3v_dac.c @@ -0,0 +1,125 @@ +/* $XFree86: xc/programs/Xserver/hw/xfree86/drivers/s3virge/s3v_dac.c,v 1.4 2003/02/04 02:20:50 dawes Exp $ */ + +/* +Copyright (C) 1994-1998 The XFree86 Project, Inc. All Rights Reserved. + +Permission is hereby granted, free of charge, to any person obtaining a copy of +this software and associated documentation files (the "Software"), to deal in +the Software without restriction, including without limitation the rights to +use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies +of the Software, and to permit persons to whom the Software is furnished to do +so, subject to the following conditions: + +The above copyright notice and this permission notice shall be included in all +copies or substantial portions of the Software. + +THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR +IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FIT- +NESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE +XFREE86 PROJECT BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN +AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION +WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. + +Except as contained in this notice, the name of the XFree86 Project shall not +be used in advertising or otherwise to promote the sale, use or other dealings +in this Software without prior written authorization from the XFree86 Project. +*/ + +/* + * s3v_dac.c + * Port to 4.0 design level + * + * S3 ViRGE driver + * + * + * s3vcommonCalcClock from S3gendac.c in pre 4.0 tree. + * + */ + +#ifdef HAVE_CONFIG_H +#include "config.h" +#endif + +#include "s3v.h" + + +#define BASE_FREQ 14.31818 /* MHz */ + + + /* function */ +void +S3VCommonCalcClock(ScrnInfoPtr pScrn, DisplayModePtr mode, + long freq, int min_m, int min_n1, + int max_n1, int min_n2, int max_n2, + long freq_min, long freq_max, + unsigned char * mdiv, unsigned char * ndiv) +{ + double ffreq, ffreq_min, ffreq_max, ffreq_min_warn; + double div, diff, best_diff; + unsigned int m; + unsigned char n1, n2; + unsigned char best_n1=16+2, best_n2=2, best_m=125+2; + + ffreq = freq / 1000.0 / BASE_FREQ; + ffreq_min = freq_min / 1000.0 / BASE_FREQ; + ffreq_max = freq_max / 1000.0 / BASE_FREQ; + + /* Doublescan modes can run at half the min frequency */ + /* But only use that value for warning and changing */ + /* ffreq, don't change the actual min used for clock calcs below. */ + if(mode->Flags & V_DBLSCAN && ffreq_min) + ffreq_min_warn = ffreq_min / 2; + else + ffreq_min_warn = ffreq_min; + + if (ffreq < ffreq_min_warn / (1<<max_n2)) { + xf86DrvMsg(pScrn->scrnIndex, X_ERROR, + "invalid frequency %1.3f MHz [freq <= %1.3f MHz]\n", + ffreq*BASE_FREQ, ffreq_min_warn*BASE_FREQ / (1<<max_n2)); + ffreq = ffreq_min_warn / (1<<max_n2); + } + if (ffreq > ffreq_max / (1<<min_n2)) { + xf86DrvMsg(pScrn->scrnIndex, X_ERROR, + "invalid frequency %1.3f MHz [freq >= %1.3f MHz]\n", + ffreq*BASE_FREQ, ffreq_max*BASE_FREQ / (1<<min_n2)); + ffreq = ffreq_max / (1<<min_n2); + } + + /* work out suitable timings */ + + best_diff = ffreq; + + for (n2=min_n2; n2<=max_n2; n2++) { + for (n1 = min_n1+2; n1 <= max_n1+2; n1++) { + m = (int)(ffreq * n1 * (1<<n2) + 0.5) ; + if (m < min_m+2 || m > 127+2) + continue; + div = (double)(m) / (double)(n1); + if ((div >= ffreq_min) && + (div <= ffreq_max)) { + diff = ffreq - div / (1<<n2); + if (diff < 0.0) + diff = -diff; + if (diff < best_diff) { + best_diff = diff; + best_m = m; + best_n1 = n1; + best_n2 = n2; + } + } + } + } + +#ifdef EXTENDED_DEBUG + ErrorF("Clock parameters for %1.6f MHz: m=%d, n1=%d, n2=%d\n", + ((double)(best_m) / (double)(best_n1) / (1 << best_n2)) * BASE_FREQ, + best_m-2, best_n1-2, best_n2); +#endif + + if (max_n1 == 63) + *ndiv = (best_n1 - 2) | (best_n2 << 6); + else + *ndiv = (best_n1 - 2) | (best_n2 << 5); + *mdiv = best_m - 2; +} + |