sergiotarxz/nuttx
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity
7554eedf9a
nuttx/video/videomode/vesagtf.c
Xiang Xiao 68951e8d72 Remove exra whitespace from files (#189) 
* Remove multiple newlines at the end of files
* Remove the whitespace from the end of lines
2020-01-31 09:24:49 -06:00

506 lines
17 KiB
C
Raw Blame History

/****************************************************************************
* video/videomode/vesagtf.c
*
* Copyright (C) 2019 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* Derives from logic in FreeBSD which has an equivalent 3-clause BSD
* license:
*
* Copyright (c) 2006 Itronix Inc. All rights reserved.
* Written by Garrett D'Amore for Itronix Inc.
*
* That version, in turn, derived from a userland GTF program supplied by
* Nvidia which was also released under a compatible 3-clause BSD license:
*
* Copyright (c) 2001, Andy Ritger <aritger@nvidia.com>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of Itronix Inc. may not be used to endorse
* or promote products derived from this software without specific
* prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY ITRONIX INC. ``AS IS'' AND ANY EXPRESS
* OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL ITRONIX INC. BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
* GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
****************************************************************************/
/* The logic in this file program was based on the Generalized Timing
* Formula(GTF TM) Standard Version: 1.0, Revision: 1.0
*
* NOTES:
*
* The GTF allows for computation of "margins" (the visible border
* surrounding the addressable video); on most non-overscan type
* systems, the margin period is zero. I've implemented the margin
* computations but not enabled it because 1) I don't really have
* any experience with this, and 2) neither XFree86 modelines nor
* fbset fb.modes provide an obvious way for margin timings to be
* included in their mode descriptions (needs more investigation).
*
* The GTF provides for computation of interlaced mode timings;
* I've implemented the computations but not enabled them, yet.
* I should probably enable and test this at some point.
*
* TODO:
*
* o Add support for interlaced modes.
*
* o Implement the other portions of the GTF: compute mode timings
* given either the desired pixel clock or the desired horizontal
* frequency.
*
* o It would be nice if this were more general purpose to do things
* outside the scope of the GTF: like generate double scan mode
* timings, for example.
*
* o Printing digits to the right of the decimal point when the
* digits are 0 annoys me.
*
* o Error checking.
*/
/****************************************************************************
* Included Files
****************************************************************************/
#include <sys/types.h>
#include <nuttx/video/videomode.h>
#include <nuttx/video/vesagtf.h>
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
#define CELL_GRAN 8 /* Assumed character cell granularity */
/* c' and m' are part of the Blanking Duty Cycle computation
*
* #define C_PRIME (((c - j) * k/256.0) + j)
* #define M_PRIME (k/256.0 * m)
*/
/* c' and m' multiplied by 256 to give integer math. Make sure to
* scale results using these back down, appropriately.
*/
#define C_PRIME256(p) (((p->c - p->j) * p->k) + (p->j * 256))
#define M_PRIME256(p) (p->k * p->m)
#define DIVIDE(x,y) (((x) + ((y) / 2)) / (y))
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: vesagtf_mode_params
*
* Description:
* vesagtf_mode_params() - as defined by the GTF Timing Standard, compute
* the Stage 1 Parameters using the vertical refresh frequency. In other
* words: input a desired resolution and desired refresh rate, and
* output the GTF mode timings.
*
****************************************************************************/
void vesagtf_mode_params(unsigned int x, unsigned int y,
unsigned int refresh,
FAR struct vesagtf_params *params,
unsigned int flags,
FAR struct videomode_s *videomode)
{
uint64_t h_period_est;
uint64_t v_field_est;
uint64_t h_period;
uint64_t ideal_duty_cycle;
unsigned int v_field_rqd;
unsigned int top_margin;
unsigned int bottom_margin;
unsigned int interlace;
unsigned int vsync_plus_bp;
unsigned total_v_lines;
unsigned int left_margin;
unsigned int right_margin;
unsigned int total_active_pixels;
unsigned int h_blank;
unsigned int h_pixels;
unsigned int v_lines;
unsigned int total_pixels;
unsigned int pixel_freq;
unsigned int h_sync;
unsigned int h_front_porch;
unsigned int v_odd_front_porch_lines;
#if 0 /* Unused, not needed */
unsigned int v_field_rate;
unsigned int v_back_porch;
unsigned int v_frame_rate;
unsigned int h_freq;
#endif
/* 1. In order to give correct results, the number of horizontal
* pixels requested is first processed to ensure that it is divisible
* by the character size, by rounding it to the nearest character
* cell boundary:
*
* [H PIXELS RND] = ((ROUND([H PIXELS]/[CELL GRAN RND],0))*[CELLGRAN RND])
*/
h_pixels = DIVIDE(x, CELL_GRAN) * CELL_GRAN;
/* 2. If interlace is requested, the number of vertical lines assumed
* by the calculation must be halved, as the computation calculates
* the number of vertical lines per field. In either case, the
* number of lines is rounded to the nearest integer.
*
* [V LINES RND] = IF([INT RQD?]="y", ROUND([V LINES]/2,0),
* ROUND([V LINES],0))
*/
v_lines = (flags & VESAGTF_FLAG_ILACE) ? DIVIDE(y, 2) : y;
/* 3. Find the frame rate required:
*
* [V FIELD RATE RQD] = IF([INT RQD?]="y", [I/P FREQ RQD]*2,
* [I/P FREQ RQD])
*/
v_field_rqd = (flags & VESAGTF_FLAG_ILACE) ? (refresh * 2) : (refresh);
/* 4. Find number of lines in Top margin:
* 5. Find number of lines in Bottom margin:
*
* [TOP MARGIN (LINES)] = IF([MARGINS RQD?]="Y",
* ROUND(([MARGIN%]/100*[V LINES RND]),0),
* 0)
*
* Ditto for bottom margin. Note that instead of %, we use PPT, which
* is parts per thousand. This helps us with integer math.
*/
top_margin = (flags & VESAGTF_FLAG_MARGINS) ?
DIVIDE(v_lines * params->margin_ppt, 1000) : 0;
bottom_margin = top_margin;
/* 6. If interlace is required, then set variable [INTERLACE]=0.5:
*
* [INTERLACE]=(IF([INT RQD?]="y",0.5,0))
*
* To make this integer friendly, we use some special hacks in step
* 7 below. Please read those comments to understand why I am using
* a whole number of 1.0 instead of 0.5 here.
*/
interlace = (flags & VESAGTF_FLAG_ILACE) ? 1 : 0;
/* 7. Estimate the Horizontal period
*
* [H PERIOD EST] = ((1/[V FIELD RATE RQD]) - [MIN VSYNC+BP]/1000000) /
* ([V LINES RND] + (2*[TOP MARGIN (LINES)]) +
* [MIN PORCH RND]+[INTERLACE]) * 1000000
*
* To make it integer friendly, we pre-multiply the 1000000 to get to
* usec. This gives us:
*
* [H PERIOD EST] = ((1000000/[V FIELD RATE RQD]) - [MIN VSYNC+BP]) /
* ([V LINES RND] + (2 * [TOP MARGIN (LINES)]) +
* [MIN PORCH RND]+[INTERLACE])
*
* The other problem is that the interlace value is wrong. To get
* the interlace to a whole number, we multiply both the numerator and
* divisor by 2, so we can use a value of either 1 or 0 for the interlace
* factor.
*
* This gives us:
*
* [H PERIOD EST] = ((2*((1000000/[V FIELD RATE RQD]) - [MIN VSYNC+BP])) /
* (2*([V LINES RND] + (2*[TOP MARGIN (LINES)]) +
* [MIN PORCH RND]) + [2*INTERLACE]))
*
* Finally we multiply by another 1000, to get value in picosec.
* Why picosec? To minimize rounding errors. Gotta love integer
* math and error propagation.
*/
h_period_est = DIVIDE(((DIVIDE(2000000000000ULL, v_field_rqd)) -
(2000000 * params->min_vsbp)),
((2 * (v_lines +
(2 * top_margin) + params->min_porch)) +
interlace));
/* 8. Find the number of lines in V sync + back porch:
*
* [V SYNC+BP] = ROUND(([MIN VSYNC+BP]/[H PERIOD EST]),0)
*
* But recall that h_period_est is in psec. So multiply by 1000000.
*/
vsync_plus_bp = DIVIDE(params->min_vsbp * 1000000, h_period_est);
#if 0 /* Not needed */
/* 9. Find the number of lines in V back porch alone:
*
* [V BACK PORCH] = [V SYNC+BP] - [V SYNC RND]
*
* XXX is "[V SYNC RND]" a typo? should be [V SYNC RQD]?
*/
v_back_porch = vsync_plus_bp - params->vsync_rqd;
#endif
/* 10. Find the total number of lines in Vertical field period:
*
* [TOTAL V LINES] = [V LINES RND] + [TOP MARGIN (LINES)] +
* [BOT MARGIN (LINES)] + [V SYNC+BP] + [INTERLACE] +
* [MIN PORCH RND]
*/
total_v_lines = v_lines + top_margin + bottom_margin + vsync_plus_bp +
interlace + params->min_porch;
/* 11. Estimate the Vertical field frequency:
*
* [V FIELD RATE EST] = 1 / [H PERIOD EST] / [TOTAL V LINES] * 1000000
*
* Again, we want to pre multiply by 10^9 to convert for nsec, thereby
* making it usable in integer math.
*
* So we get:
*
* [V FIELD RATE EST] = 1000000000 / [H PERIOD EST] / [TOTAL V LINES]
*
* This is all scaled to get the result in uHz. Again, we're trying to
* minimize error propagation.
*/
v_field_est = DIVIDE(DIVIDE(1000000000000000ULL, h_period_est),
total_v_lines);
/* 12. Find the actual horizontal period:
*
* [H PERIOD] = [H PERIOD EST] / ([V FIELD RATE RQD] / [V FIELD RATE EST])
*/
h_period = DIVIDE(h_period_est * v_field_est, v_field_rqd * 1000);
#if 0 /* Not needed */
/* 13. Find the actual Vertical field frequency:
*
* [V FIELD RATE] = 1 / [H PERIOD] / [TOTAL V LINES] * 1000000
*
* And again, we convert to nsec ahead of time, giving us:
*
* [V FIELD RATE] = 1000000 / [H PERIOD] / [TOTAL V LINES]
*
* And another rescaling back to mHz. Gotta love it.
*/
v_field_rate = DIVIDE(1000000000000ULL, h_period * total_v_lines);
/* 14. Find the Vertical frame frequency:
*
* [V FRAME RATE] = (IF([INT RQD?]="y", [V FIELD RATE]/2, [V FIELD RATE]))
*
* N.B. that the result here is in mHz.
*/
v_frame_rate = (flags & VESAGTF_FLAG_ILACE) ?
v_field_rate / 2 : v_field_rate;
#endif
/* 15. Find number of pixels in left margin:
* 16. Find number of pixels in right margin:
*
* [LEFT MARGIN (PIXELS)] = (IF( [MARGINS RQD?]="Y",
* (ROUND( ([H PIXELS RND] * [MARGIN%] / 100 /
* [CELL GRAN RND]),0)) * [CELL GRAN RND],
* 0))
*
* Again, we deal with margin percentages as PPT (parts per thousand).
* And the calculations for left and right are the same.
*/
left_margin = right_margin = (flags & VESAGTF_FLAG_MARGINS) ?
DIVIDE(DIVIDE(h_pixels * params->margin_ppt, 1000),
CELL_GRAN) * CELL_GRAN : 0;
/* 17. Find total number of active pixels in image and left and right
* margins:
*
* [TOTAL ACTIVE PIXELS] = [H PIXELS RND] + [LEFT MARGIN (PIXELS)] +
* [RIGHT MARGIN (PIXELS)]
*/
total_active_pixels = h_pixels + left_margin + right_margin;
/* 18. Find the ideal blanking duty cycle from the blanking duty cycle
* equation:
*
* [IDEAL DUTY CYCLE] = [c'] - ([m']*[H PERIOD]/1000)
*
* However, we have modified values for [c'] as [256*c'] and
* [m'] as [256*m']. Again the idea here is to get good scaling.
* We use 256 as the factor to make the math fast.
*
* Note that this means that we have to scale it appropriately in
* later calculations.
*
* The ending result is that our ideal_duty_cycle is 256000x larger
* than the duty cycle used by VESA. But again, this reduces error
* propagation.
*/
ideal_duty_cycle =
((C_PRIME256(params) * 1000) -
(M_PRIME256(params) * h_period / 1000000));
/* 19. Find the number of pixels in the blanking time to the nearest
* double character cell:
*
* [H BLANK (PIXELS)] = (ROUND(([TOTAL ACTIVE PIXELS] *
* [IDEAL DUTY CYCLE] /
* (100-[IDEAL DUTY CYCLE]) /
* (2*[CELL GRAN RND])), 0))
* * (2*[CELL GRAN RND])
*
* Of course, we adjust to make this rounding work in integer math.
*/
h_blank = DIVIDE(DIVIDE(total_active_pixels * ideal_duty_cycle,
(256000 * 100ULL) - ideal_duty_cycle),
2 * CELL_GRAN) * (2 * CELL_GRAN);
/* 20. Find total number of pixels:
*
* [TOTAL PIXELS] = [TOTAL ACTIVE PIXELS] + [H BLANK (PIXELS)]
*/
total_pixels = total_active_pixels + h_blank;
/* 21. Find pixel clock frequency:
*
* [PIXEL FREQ] = [TOTAL PIXELS] / [H PERIOD]
*
* We calculate this in Hz rather than MHz, to get a value that
* is usable with integer math. Recall that the [H PERIOD] is in
* nsec.
*/
pixel_freq = DIVIDE(total_pixels * 1000000, DIVIDE(h_period, 1000));
#if 0 /* Not needed */
/* 22. Find horizontal frequency:
*
* [H FREQ] = 1000 / [H PERIOD]
*
* We calculate this in Hz rather than kHz, to avoid rounding
* errors. Recall that the [H PERIOD] is in usec.
*/
h_freq = 1000000000 / h_period;
#endif
/* Stage 1 computations are now complete; I should really pass
* the results to another function and do the Stage 2
* computations, but I only need a few more values so I'll just
* append the computations here for now.
*/
/* 17. Find the number of pixels in the horizontal sync period:
*
* [H SYNC (PIXELS)] =(ROUND(([H SYNC%] / 100 * [TOTAL PIXELS] /
* [CELL GRAN RND]),0))*[CELL GRAN RND]
*
* Rewriting for integer math:
*
* [H SYNC (PIXELS)]=(ROUND((H SYNC%] * [TOTAL PIXELS] / 100 /
* [CELL GRAN RND),0))*[CELL GRAN RND]
*/
h_sync = DIVIDE(((params->hsync_pct * total_pixels) / 100), CELL_GRAN) *
CELL_GRAN;
/* 18. Find the number of pixels in the horizontal front porch period:
*
* [H FRONT PORCH (PIXELS)] = ([H BLANK (PIXELS)]/2)-[H SYNC (PIXELS)]
*
* Note that h_blank is always an even number of characters (i.e.
* h_blank % (CELL_GRAN * 2) == 0)
*/
h_front_porch = (h_blank / 2) - h_sync;
/* 36. Find the number of lines in the odd front porch period:
*
* [V ODD FRONT PORCH(LINES)]=([MIN PORCH RND]+[INTERLACE])
*
* Adjusting for the fact that the interlace is scaled:
*
* [V ODD FRONT PORCH(LINES)]=(([MIN PORCH RND] * 2) + [2*INTERLACE]) / 2
*/
v_odd_front_porch_lines = ((2 * params->min_porch) + interlace) / 2;
/* finally, pack the results in the mode struct */
videomode->hsync_start = h_pixels + h_front_porch;
videomode->hsync_end = videomode->hsync_start + h_sync;
videomode->htotal = total_pixels;
videomode->hdisplay = h_pixels;
videomode->vsync_start = v_lines + v_odd_front_porch_lines;
videomode->vsync_end = videomode->vsync_start + params->vsync_rqd;
videomode->vtotal = total_v_lines;
videomode->vdisplay = v_lines;
videomode->dotclock = pixel_freq;
}
/****************************************************************************
* Name: vesagtf_mode
*
* Description:
* Use VESA GTF formula to generate monitor timings. Assumes default
* GTF parameters, non-interlaced, and no margins.
*
****************************************************************************/
void vesagtf_mode(unsigned int x, unsigned int y, unsigned int refresh,
FAR struct videomode_s *videomode)
{
struct vesagtf_params params;
params.margin_ppt = VESAGTF_MARGIN_PPT;
params.min_porch = VESAGTF_MIN_PORCH;
params.vsync_rqd = VESAGTF_VSYNC_RQD;
params.hsync_pct = VESAGTF_HSYNC_PCT;
params.min_vsbp = VESAGTF_MIN_VSBP;
params.m = VESAGTF_M;
params.c = VESAGTF_C;
params.k = VESAGTF_K;
params.j = VESAGTF_J;
vesagtf_mode_params(x, y, refresh, &params, 0, videomode);
}
Reference in New Issue View Git Blame Copy Permalink