9369b42a65
Most tools used for compliance and SBOM generation use SPDX identifiers This change brings us a step closer to an easy SBOM generation. Signed-off-by: Alin Jerpelea <alin.jerpelea@sony.com>
483 lines
16 KiB
C
483 lines
16 KiB
C
/****************************************************************************
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* video/videomode/vesagtf.c
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*
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* SPDX-License-Identifier: Apache-2.0
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*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership. The
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* ASF licenses this file to you under the Apache License, Version 2.0 (the
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* "License"); you may not use this file except in compliance with the
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* License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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*
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****************************************************************************/
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/* The logic in this file program was based on the Generalized Timing
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* Formula(GTF TM) Standard Version: 1.0, Revision: 1.0
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*
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* NOTES:
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*
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* The GTF allows for computation of "margins" (the visible border
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* surrounding the addressable video); on most non-overscan type
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* systems, the margin period is zero. I've implemented the margin
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* computations but not enabled it because 1) I don't really have
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* any experience with this, and 2) neither XFree86 modelines nor
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* fbset fb.modes provide an obvious way for margin timings to be
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* included in their mode descriptions (needs more investigation).
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*
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* The GTF provides for computation of interlaced mode timings;
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* I've implemented the computations but not enabled them, yet.
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* I should probably enable and test this at some point.
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*
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* TODO:
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*
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* o Add support for interlaced modes.
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*
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* o Implement the other portions of the GTF: compute mode timings
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* given either the desired pixel clock or the desired horizontal
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* frequency.
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*
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* o It would be nice if this were more general purpose to do things
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* outside the scope of the GTF: like generate double scan mode
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* timings, for example.
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*
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* o Printing digits to the right of the decimal point when the
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* digits are 0 annoys me.
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*
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* o Error checking.
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*/
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <sys/types.h>
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#include <nuttx/video/videomode.h>
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#include <nuttx/video/vesagtf.h>
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/****************************************************************************
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* Pre-processor Definitions
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****************************************************************************/
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#define CELL_GRAN 8 /* Assumed character cell granularity */
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/* c' and m' are part of the Blanking Duty Cycle computation
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*
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* #define C_PRIME (((c - j) * k/256.0) + j)
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* #define M_PRIME (k/256.0 * m)
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*/
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/* c' and m' multiplied by 256 to give integer math. Make sure to
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* scale results using these back down, appropriately.
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*/
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#define C_PRIME256(p) (((p->c - p->j) * p->k) + (p->j * 256))
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#define M_PRIME256(p) (p->k * p->m)
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#define DIVIDE(x,y) (((x) + ((y) / 2)) / (y))
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: vesagtf_mode_params
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*
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* Description:
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* vesagtf_mode_params() - as defined by the GTF Timing Standard, compute
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* the Stage 1 Parameters using the vertical refresh frequency. In other
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* words: input a desired resolution and desired refresh rate, and
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* output the GTF mode timings.
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*
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****************************************************************************/
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void vesagtf_mode_params(unsigned int x, unsigned int y,
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unsigned int refresh,
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FAR struct vesagtf_params *params,
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unsigned int flags,
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FAR struct videomode_s *videomode)
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{
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uint64_t h_period_est;
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uint64_t v_field_est;
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uint64_t h_period;
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uint64_t ideal_duty_cycle;
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unsigned int v_field_rqd;
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unsigned int top_margin;
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unsigned int bottom_margin;
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unsigned int interlace;
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unsigned int vsync_plus_bp;
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unsigned total_v_lines;
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unsigned int left_margin;
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unsigned int right_margin;
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unsigned int total_active_pixels;
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unsigned int h_blank;
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unsigned int h_pixels;
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unsigned int v_lines;
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unsigned int total_pixels;
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unsigned int pixel_freq;
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unsigned int h_sync;
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unsigned int h_front_porch;
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unsigned int v_odd_front_porch_lines;
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#if 0 /* Unused, not needed */
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unsigned int v_field_rate;
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unsigned int v_back_porch;
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unsigned int v_frame_rate;
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unsigned int h_freq;
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#endif
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/* 1. In order to give correct results, the number of horizontal
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* pixels requested is first processed to ensure that it is divisible
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* by the character size, by rounding it to the nearest character
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* cell boundary:
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*
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* [H PIXELS RND] = ((ROUND([H PIXELS]/[CELL GRAN RND],0))*[CELLGRAN RND])
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*/
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h_pixels = DIVIDE(x, CELL_GRAN) * CELL_GRAN;
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/* 2. If interlace is requested, the number of vertical lines assumed
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* by the calculation must be halved, as the computation calculates
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* the number of vertical lines per field. In either case, the
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* number of lines is rounded to the nearest integer.
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*
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* [V LINES RND] = IF([INT RQD?]="y", ROUND([V LINES]/2,0),
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* ROUND([V LINES],0))
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*/
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v_lines = (flags & VESAGTF_FLAG_ILACE) ? DIVIDE(y, 2) : y;
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/* 3. Find the frame rate required:
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*
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* [V FIELD RATE RQD] = IF([INT RQD?]="y", [I/P FREQ RQD]*2,
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* [I/P FREQ RQD])
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*/
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v_field_rqd = (flags & VESAGTF_FLAG_ILACE) ? (refresh * 2) : (refresh);
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/* 4. Find number of lines in Top margin:
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* 5. Find number of lines in Bottom margin:
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*
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* [TOP MARGIN (LINES)] = IF([MARGINS RQD?]="Y",
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* ROUND(([MARGIN%]/100*[V LINES RND]),0),
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* 0)
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*
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* Ditto for bottom margin. Note that instead of %, we use PPT, which
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* is parts per thousand. This helps us with integer math.
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*/
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top_margin = (flags & VESAGTF_FLAG_MARGINS) ?
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DIVIDE(v_lines * params->margin_ppt, 1000) : 0;
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bottom_margin = top_margin;
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/* 6. If interlace is required, then set variable [INTERLACE]=0.5:
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*
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* [INTERLACE]=(IF([INT RQD?]="y",0.5,0))
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*
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* To make this integer friendly, we use some special hacks in step
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* 7 below. Please read those comments to understand why I am using
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* a whole number of 1.0 instead of 0.5 here.
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*/
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interlace = (flags & VESAGTF_FLAG_ILACE) ? 1 : 0;
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/* 7. Estimate the Horizontal period
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*
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* [H PERIOD EST] = ((1/[V FIELD RATE RQD]) - [MIN VSYNC+BP]/1000000) /
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* ([V LINES RND] + (2*[TOP MARGIN (LINES)]) +
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* [MIN PORCH RND]+[INTERLACE]) * 1000000
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*
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* To make it integer friendly, we pre-multiply the 1000000 to get to
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* usec. This gives us:
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*
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* [H PERIOD EST] = ((1000000/[V FIELD RATE RQD]) - [MIN VSYNC+BP]) /
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* ([V LINES RND] + (2 * [TOP MARGIN (LINES)]) +
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* [MIN PORCH RND]+[INTERLACE])
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*
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* The other problem is that the interlace value is wrong. To get
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* the interlace to a whole number, we multiply both the numerator and
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* divisor by 2, so we can use a value of either 1 or 0 for the interlace
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* factor.
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*
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* This gives us:
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*
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* [H PERIOD EST] = ((2*((1000000/[V FIELD RATE RQD]) - [MIN VSYNC+BP])) /
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* (2*([V LINES RND] + (2*[TOP MARGIN (LINES)]) +
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* [MIN PORCH RND]) + [2*INTERLACE]))
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*
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* Finally we multiply by another 1000, to get value in picosec.
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* Why picosec? To minimize rounding errors. Gotta love integer
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* math and error propagation.
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*/
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h_period_est = DIVIDE(((DIVIDE(2000000000000ULL, v_field_rqd)) -
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(2000000 * params->min_vsbp)),
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((2 * (v_lines +
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(2 * top_margin) + params->min_porch)) +
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interlace));
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/* 8. Find the number of lines in V sync + back porch:
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*
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* [V SYNC+BP] = ROUND(([MIN VSYNC+BP]/[H PERIOD EST]),0)
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*
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* But recall that h_period_est is in psec. So multiply by 1000000.
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*/
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vsync_plus_bp = DIVIDE(params->min_vsbp * 1000000, h_period_est);
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#if 0 /* Not needed */
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/* 9. Find the number of lines in V back porch alone:
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*
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* [V BACK PORCH] = [V SYNC+BP] - [V SYNC RND]
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*
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* XXX is "[V SYNC RND]" a typo? should be [V SYNC RQD]?
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*/
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v_back_porch = vsync_plus_bp - params->vsync_rqd;
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#endif
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/* 10. Find the total number of lines in Vertical field period:
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*
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* [TOTAL V LINES] = [V LINES RND] + [TOP MARGIN (LINES)] +
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* [BOT MARGIN (LINES)] + [V SYNC+BP] + [INTERLACE] +
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* [MIN PORCH RND]
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*/
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total_v_lines = v_lines + top_margin + bottom_margin + vsync_plus_bp +
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interlace + params->min_porch;
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/* 11. Estimate the Vertical field frequency:
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*
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* [V FIELD RATE EST] = 1 / [H PERIOD EST] / [TOTAL V LINES] * 1000000
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*
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* Again, we want to pre multiply by 10^9 to convert for nsec, thereby
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* making it usable in integer math.
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*
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* So we get:
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*
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* [V FIELD RATE EST] = 1000000000 / [H PERIOD EST] / [TOTAL V LINES]
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*
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* This is all scaled to get the result in uHz. Again, we're trying to
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* minimize error propagation.
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*/
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v_field_est = DIVIDE(DIVIDE(1000000000000000ULL, h_period_est),
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total_v_lines);
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/* 12. Find the actual horizontal period:
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*
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* [H PERIOD] = [H PERIOD EST] / ([V FIELD RATE RQD] / [V FIELD RATE EST])
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*/
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h_period = DIVIDE(h_period_est * v_field_est, v_field_rqd * 1000);
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#if 0 /* Not needed */
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/* 13. Find the actual Vertical field frequency:
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*
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* [V FIELD RATE] = 1 / [H PERIOD] / [TOTAL V LINES] * 1000000
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*
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* And again, we convert to nsec ahead of time, giving us:
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*
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* [V FIELD RATE] = 1000000 / [H PERIOD] / [TOTAL V LINES]
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*
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* And another rescaling back to mHz. Gotta love it.
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*/
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v_field_rate = DIVIDE(1000000000000ULL, h_period * total_v_lines);
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/* 14. Find the Vertical frame frequency:
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*
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* [V FRAME RATE] = (IF([INT RQD?]="y", [V FIELD RATE]/2, [V FIELD RATE]))
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*
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* N.B. that the result here is in mHz.
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*/
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v_frame_rate = (flags & VESAGTF_FLAG_ILACE) ?
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v_field_rate / 2 : v_field_rate;
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#endif
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/* 15. Find number of pixels in left margin:
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* 16. Find number of pixels in right margin:
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*
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* [LEFT MARGIN (PIXELS)] = (IF( [MARGINS RQD?]="Y",
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* (ROUND( ([H PIXELS RND] * [MARGIN%] / 100 /
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* [CELL GRAN RND]),0)) * [CELL GRAN RND],
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* 0))
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*
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* Again, we deal with margin percentages as PPT (parts per thousand).
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* And the calculations for left and right are the same.
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*/
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left_margin = right_margin = (flags & VESAGTF_FLAG_MARGINS) ?
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DIVIDE(DIVIDE(h_pixels * params->margin_ppt, 1000),
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CELL_GRAN) * CELL_GRAN : 0;
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/* 17. Find total number of active pixels in image and left and right
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* margins:
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*
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* [TOTAL ACTIVE PIXELS] = [H PIXELS RND] + [LEFT MARGIN (PIXELS)] +
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* [RIGHT MARGIN (PIXELS)]
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*/
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total_active_pixels = h_pixels + left_margin + right_margin;
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/* 18. Find the ideal blanking duty cycle from the blanking duty cycle
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* equation:
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*
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* [IDEAL DUTY CYCLE] = [c'] - ([m']*[H PERIOD]/1000)
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*
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* However, we have modified values for [c'] as [256*c'] and
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* [m'] as [256*m']. Again the idea here is to get good scaling.
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* We use 256 as the factor to make the math fast.
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*
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* Note that this means that we have to scale it appropriately in
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* later calculations.
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*
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* The ending result is that our ideal_duty_cycle is 256000x larger
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* than the duty cycle used by VESA. But again, this reduces error
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* propagation.
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*/
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ideal_duty_cycle =
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((C_PRIME256(params) * 1000) -
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(M_PRIME256(params) * h_period / 1000000));
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/* 19. Find the number of pixels in the blanking time to the nearest
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* double character cell:
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*
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* [H BLANK (PIXELS)] = (ROUND(([TOTAL ACTIVE PIXELS] *
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* [IDEAL DUTY CYCLE] /
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* (100-[IDEAL DUTY CYCLE]) /
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* (2*[CELL GRAN RND])), 0))
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* * (2*[CELL GRAN RND])
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*
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* Of course, we adjust to make this rounding work in integer math.
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*/
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h_blank = DIVIDE(DIVIDE(total_active_pixels * ideal_duty_cycle,
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(256000 * 100ULL) - ideal_duty_cycle),
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2 * CELL_GRAN) * (2 * CELL_GRAN);
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/* 20. Find total number of pixels:
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*
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* [TOTAL PIXELS] = [TOTAL ACTIVE PIXELS] + [H BLANK (PIXELS)]
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*/
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total_pixels = total_active_pixels + h_blank;
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/* 21. Find pixel clock frequency:
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*
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* [PIXEL FREQ] = [TOTAL PIXELS] / [H PERIOD]
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*
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* We calculate this in Hz rather than MHz, to get a value that
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* is usable with integer math. Recall that the [H PERIOD] is in
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* nsec.
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*/
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pixel_freq = DIVIDE(total_pixels * 1000000, DIVIDE(h_period, 1000));
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#if 0 /* Not needed */
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/* 22. Find horizontal frequency:
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*
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* [H FREQ] = 1000 / [H PERIOD]
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*
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* We calculate this in Hz rather than kHz, to avoid rounding
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* errors. Recall that the [H PERIOD] is in usec.
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*/
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h_freq = 1000000000 / h_period;
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#endif
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/* Stage 1 computations are now complete; I should really pass
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* the results to another function and do the Stage 2
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* computations, but I only need a few more values so I'll just
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* append the computations here for now.
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*/
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/* 17. Find the number of pixels in the horizontal sync period:
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*
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* [H SYNC (PIXELS)] =(ROUND(([H SYNC%] / 100 * [TOTAL PIXELS] /
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* [CELL GRAN RND]),0))*[CELL GRAN RND]
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*
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* Rewriting for integer math:
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*
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* [H SYNC (PIXELS)]=(ROUND((H SYNC%] * [TOTAL PIXELS] / 100 /
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* [CELL GRAN RND),0))*[CELL GRAN RND]
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*/
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h_sync = DIVIDE(((params->hsync_pct * total_pixels) / 100), CELL_GRAN) *
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CELL_GRAN;
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/* 18. Find the number of pixels in the horizontal front porch period:
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*
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* [H FRONT PORCH (PIXELS)] = ([H BLANK (PIXELS)]/2)-[H SYNC (PIXELS)]
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*
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* Note that h_blank is always an even number of characters (i.e.
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* h_blank % (CELL_GRAN * 2) == 0)
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*/
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h_front_porch = (h_blank / 2) - h_sync;
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/* 36. Find the number of lines in the odd front porch period:
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*
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* [V ODD FRONT PORCH(LINES)]=([MIN PORCH RND]+[INTERLACE])
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*
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* Adjusting for the fact that the interlace is scaled:
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*
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* [V ODD FRONT PORCH(LINES)]=(([MIN PORCH RND] * 2) + [2*INTERLACE]) / 2
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*/
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v_odd_front_porch_lines = ((2 * params->min_porch) + interlace) / 2;
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/* finally, pack the results in the mode struct */
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videomode->hsync_start = h_pixels + h_front_porch;
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videomode->hsync_end = videomode->hsync_start + h_sync;
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videomode->htotal = total_pixels;
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videomode->hdisplay = h_pixels;
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videomode->vsync_start = v_lines + v_odd_front_porch_lines;
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videomode->vsync_end = videomode->vsync_start + params->vsync_rqd;
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videomode->vtotal = total_v_lines;
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videomode->vdisplay = v_lines;
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videomode->dotclock = pixel_freq;
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}
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/****************************************************************************
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* Name: vesagtf_mode
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*
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* Description:
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* Use VESA GTF formula to generate monitor timings. Assumes default
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* GTF parameters, non-interlaced, and no margins.
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*
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****************************************************************************/
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void vesagtf_mode(unsigned int x, unsigned int y, unsigned int refresh,
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FAR struct videomode_s *videomode)
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{
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struct vesagtf_params params;
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params.margin_ppt = VESAGTF_MARGIN_PPT;
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params.min_porch = VESAGTF_MIN_PORCH;
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params.vsync_rqd = VESAGTF_VSYNC_RQD;
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params.hsync_pct = VESAGTF_HSYNC_PCT;
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params.min_vsbp = VESAGTF_MIN_VSBP;
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params.m = VESAGTF_M;
|
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params.c = VESAGTF_C;
|
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params.k = VESAGTF_K;
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params.j = VESAGTF_J;
|
|
|
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vesagtf_mode_params(x, y, refresh, ¶ms, 0, videomode);
|
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}
|