ce8939a97e
Timing generator for a pixel-based display. The timing generator is intended for display processors driving a standard rasterized display. The simplest possible display processor needs to derive from this class and override the nextPixel() method to feed the display with pixel data. Pixels are ordered relative to the top left corner of the display. Scan lines appear in the following order: * Vertical Sync (starting at line 0) * Vertical back porch * Visible lines * Vertical front porch Pixel order within a scan line: * Horizontal Sync * Horizontal Back Porch * Visible pixels * Horizontal Front Porch All events in the timing generator are automatically suspended on a drain() request and restarted on drainResume(). This is conceptually equivalent to clock gating when the pixel clock while the system is draining. By gating the pixel clock, we prevent display controllers from disturbing a memory system that is about to drain.
306 lines
8.7 KiB
C++
306 lines
8.7 KiB
C++
/*
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* Copyright (c) 2015 ARM Limited
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* All rights reserved
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*
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* The license below extends only to copyright in the software and shall
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* not be construed as granting a license to any other intellectual
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* property including but not limited to intellectual property relating
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* to a hardware implementation of the functionality of the software
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* licensed hereunder. You may use the software subject to the license
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* terms below provided that you ensure that this notice is replicated
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* unmodified and in its entirety in all distributions of the software,
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* modified or unmodified, in source code or in binary form.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are
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* met: redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer;
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* redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution;
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* neither the name of the copyright holders nor the names of its
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* contributors may be used to endorse or promote products derived from
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* this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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* Authors: Andreas Sandberg
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*/
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#include "dev/pixelpump.hh"
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const DisplayTimings DisplayTimings::vga(
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640, 480,
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48, 96, 16,
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33, 2, 10);
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DisplayTimings::DisplayTimings(unsigned _width, unsigned _height,
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unsigned hbp, unsigned h_sync, unsigned hfp,
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unsigned vbp, unsigned v_sync, unsigned vfp)
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: width(_width), height(_height),
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hBackPorch(hbp), hFrontPorch(hfp), hSync(h_sync),
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vBackPorch(vbp), vFrontPorch(vfp), vSync(v_sync)
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{
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}
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void
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DisplayTimings::serialize(CheckpointOut &cp) const
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{
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SERIALIZE_SCALAR(width);
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SERIALIZE_SCALAR(height);
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SERIALIZE_SCALAR(hBackPorch);
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SERIALIZE_SCALAR(hFrontPorch);
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SERIALIZE_SCALAR(hSync);
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SERIALIZE_SCALAR(vBackPorch);
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SERIALIZE_SCALAR(vFrontPorch);
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SERIALIZE_SCALAR(vSync);
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}
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void
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DisplayTimings::unserialize(CheckpointIn &cp)
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{
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UNSERIALIZE_SCALAR(width);
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UNSERIALIZE_SCALAR(height);
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UNSERIALIZE_SCALAR(hBackPorch);
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UNSERIALIZE_SCALAR(hFrontPorch);
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UNSERIALIZE_SCALAR(hSync);
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UNSERIALIZE_SCALAR(vBackPorch);
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UNSERIALIZE_SCALAR(vFrontPorch);
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UNSERIALIZE_SCALAR(vSync);
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}
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BasePixelPump::BasePixelPump(EventManager &em, ClockDomain &pxl_clk,
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unsigned pixel_chunk)
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: EventManager(em), Clocked(pxl_clk), Serializable(),
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pixelChunk(pixel_chunk),
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pixelEvents(),
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evVSyncBegin("evVSyncBegin", this, &BasePixelPump::onVSyncBegin),
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evVSyncEnd("evVSyncEnd", this, &BasePixelPump::onVSyncEnd),
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evHSyncBegin("evHSyncBegin", this, &BasePixelPump::onHSyncBegin),
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evHSyncEnd("evHSyncEnd", this, &BasePixelPump::onHSyncEnd),
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evBeginLine("evBeginLine", this, &BasePixelPump::beginLine),
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evRenderPixels("evRenderPixels", this, &BasePixelPump::renderPixels),
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_timings(DisplayTimings::vga),
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line(0), _posX(0), _underrun(false)
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{
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}
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BasePixelPump::~BasePixelPump()
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{
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}
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void
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BasePixelPump::serialize(CheckpointOut &cp) const
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{
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SERIALIZE_SCALAR(line);
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SERIALIZE_SCALAR(_posX);
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SERIALIZE_SCALAR(_underrun);
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SERIALIZE_OBJ(_timings);
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SERIALIZE_OBJ(fb);
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for (PixelEvent *event : pixelEvents)
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event->serializeSection(cp, event->name());
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}
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void
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BasePixelPump::unserialize(CheckpointIn &cp)
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{
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UNSERIALIZE_SCALAR(line);
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UNSERIALIZE_SCALAR(_posX);
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UNSERIALIZE_SCALAR(_underrun);
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UNSERIALIZE_OBJ(_timings);
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UNSERIALIZE_OBJ(fb);
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// We don't need to reschedule the event here since the event was
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// suspended by PixelEvent::drain() and will be rescheduled by
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// PixelEvent::drainResume().
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for (PixelEvent *event : pixelEvents)
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event->unserializeSection(cp, event->name());
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}
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void
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BasePixelPump::start(const DisplayTimings &timings)
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{
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_timings = timings;
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// Resize the frame buffer if needed
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if (_timings.width != fb.width() || _timings.height != fb.height())
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fb.resize(timings.width, timings.height);
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// Set the current line past the last line in the frame. This
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// triggers the new frame logic in beginLine().
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line = _timings.linesPerFrame();
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schedule(evBeginLine, clockEdge());
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}
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void
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BasePixelPump::stop()
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{
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if (evVSyncEnd.scheduled())
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deschedule(evVSyncEnd);
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if (evHSyncBegin.scheduled())
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deschedule(evHSyncBegin);
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if (evHSyncEnd.scheduled())
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deschedule(evHSyncEnd);
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if (evBeginLine.scheduled())
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deschedule(evBeginLine);
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if (evRenderPixels.scheduled())
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deschedule(evRenderPixels);
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}
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void
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BasePixelPump::beginLine()
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{
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_posX = 0;
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line++;
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if (line >= _timings.linesPerFrame()) {
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_underrun = false;
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line = 0;
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}
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if (line == _timings.lineVSyncStart()) {
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onVSyncBegin();
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} else if (line == _timings.lineVBackPorchStart()) {
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onVSyncEnd();
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}
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const Cycles h_sync_begin(0);
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schedule(evHSyncBegin, clockEdge(h_sync_begin));
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const Cycles h_sync_end(h_sync_begin + _timings.hSync);
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schedule(evHSyncEnd, clockEdge(h_sync_end));
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// Visible area
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if (line >= _timings.lineFirstVisible() &&
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line < _timings.lineFrontPorchStart()) {
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const Cycles h_first_visible(h_sync_end + _timings.hBackPorch);
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schedule(evRenderPixels, clockEdge(h_first_visible));
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}
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schedule(evBeginLine, clockEdge(_timings.cyclesPerLine()));
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}
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void
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BasePixelPump::renderPixels()
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{
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// Try to handle multiple pixels at a time; doing so reduces the
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// accuracy of the underrun detection but lowers simulation
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// overhead
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const unsigned x_end(std::min(_posX + pixelChunk, _timings.width));
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const unsigned pxl_count(x_end - _posX);
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const unsigned pos_y(posY());
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Pixel pixel(0, 0, 0);
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const Pixel underrun_pixel(0, 0, 0);
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for (; _posX < x_end && !_underrun; ++_posX) {
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if (!nextPixel(pixel)) {
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warn("Input buffer underrun in BasePixelPump (%u, %u)\n",
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_posX, pos_y);
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_underrun = true;
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onUnderrun(_posX, pos_y);
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pixel = underrun_pixel;
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}
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fb.pixel(_posX, pos_y) = pixel;
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}
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// Fill remaining pixels with a dummy pixel value if we ran out of
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// data
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for (; _posX < x_end; ++_posX)
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fb.pixel(_posX, pos_y) = underrun_pixel;
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// Schedule a new event to handle the next block of pixels
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if (_posX < _timings.width) {
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schedule(evRenderPixels, clockEdge(Cycles(pxl_count)));
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} else {
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if (pos_y == _timings.height - 1)
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onFrameDone();
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}
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}
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BasePixelPump::PixelEvent::PixelEvent(
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const char *name, BasePixelPump *_parent, CallbackType _func)
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: Event(), Drainable(),
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_name(name), parent(*_parent), func(_func),
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suspended(false),
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relativeTick(0)
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{
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parent.pixelEvents.push_back(this);
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}
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DrainState
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BasePixelPump::PixelEvent::drain()
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{
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if (scheduled())
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suspend();
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return DrainState::Drained;
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}
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void
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BasePixelPump::PixelEvent::drainResume()
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{
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if (suspended)
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resume();
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}
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void
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BasePixelPump::PixelEvent::serialize(CheckpointOut &cp) const
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{
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assert(!scheduled());
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Event::serialize(cp);
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SERIALIZE_SCALAR(suspended);
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SERIALIZE_SCALAR(relativeTick);
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}
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void
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BasePixelPump::PixelEvent::unserialize(CheckpointIn &cp)
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{
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Event::unserialize(cp);
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UNSERIALIZE_SCALAR(suspended);
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UNSERIALIZE_SCALAR(relativeTick);
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assert(!scheduled());
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}
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void
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BasePixelPump::PixelEvent::suspend()
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{
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assert(scheduled());
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assert(!suspended);
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suspended = true;
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relativeTick = when() - curTick();
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parent.deschedule(this);
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}
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void
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BasePixelPump::PixelEvent::resume()
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{
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assert(!scheduled());
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assert(suspended);
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parent.schedule(this, relativeTick + curTick());
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suspended = false;
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relativeTick = 0;
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}
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