base: Redesign internal frame buffer handling

Currently, frame buffer handling in gem5 is quite ad hoc. In practice,
we pass around naked pointers to raw pixel data and expect consumers
to convert frame buffers using the (broken) VideoConverter.

This changeset completely redesigns the way we handle frame buffers
internally. In summary, it fixes several color conversion bugs, adds
support for more color formats (e.g., big endian), and makes the code
base easier to follow.

In the new world, gem5 always represents pixel data using the Pixel
struct when pixels need to be passed between different classes (e.g.,
a display controller and the VNC server). Producers of entire frames
(e.g., display controllers) should use the FrameBuffer class to
represent a frame.

Frame producers are expected to create one instance of the FrameBuffer
class in their constructors and register it with its consumers
once. Consumers are expected to check the dimensions of the frame
buffer when they consume it.

Conversion between the external representation and the internal
representation is supported for all common "true color" RGB formats of
up to 32-bit color depth. The external pixel representation is
expected to be between 1 and 4 bytes in either big endian or little
endian. Color channels are assumed to be contiguous ranges of bits
within each pixel word. The external pixel value is scaled to an 8-bit
internal representation using a floating multiplication to map it to
the entire 8-bit range.

1 files changed, 43 insertions, 81 deletions

diff --git a/src/dev/arm/hdlcd.cc b/src/dev/arm/hdlcd.cc
index 37569b22b..b1c1c450b 100644
--- a/src/dev/arm/hdlcd.cc
+++ b/src/dev/arm/hdlcd.cc
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2010-2013 ARM Limited
+ * Copyright (c) 2010-2013, 2015 ARM Limited
  * All rights reserved
  *
  * The license below extends only to copyright in the software and shall
@@ -37,15 +37,15 @@
  * Authors: Chris Emmons
  */
 
+#include "dev/arm/hdlcd.hh"
+
 #include "base/vnc/vncinput.hh"
-#include "base/bitmap.hh"
 #include "base/output.hh"
 #include "base/trace.hh"
 #include "debug/HDLcd.hh"
 #include "debug/Uart.hh"
 #include "dev/arm/amba_device.hh"
 #include "dev/arm/base_gic.hh"
-#include "dev/arm/hdlcd.hh"
 #include "mem/packet.hh"
 #include "mem/packet_access.hh"
 #include "sim/system.hh"
@@ -63,10 +63,11 @@ HDLcd::HDLcd(const Params *p)
       h_sync(0), h_back_porch(0), h_data(0), h_front_porch(0),
       polarities(0), command(0), pixel_format(0),
       red_select(0), green_select(0), blue_select(0),
-      pixelClock(p->pixel_clock), vnc(p->vnc), bmp(NULL), pic(NULL),
+      pixelClock(p->pixel_clock),
+      fb(0, 0), vnc(p->vnc), bmp(&fb), pic(NULL),
       frameReadStartTime(0),
       dmaStartAddr(0), dmaCurAddr(0), dmaMaxAddr(0), dmaPendingNum(0),
-      frameUnderrun(false), virtualDisplayBuffer(NULL), pixelBufferSize(0),
+      frameUnderrun(false), pixelBufferSize(0),
       pixelIndex(0), doUpdateParams(false), frameUnderway(false),
       dmaBytesInFlight(0),
       startFrameEvent(this), endFrameEvent(this), renderPixelEvent(this),
@@ -81,13 +82,11 @@ HDLcd::HDLcd(const Params *p)
         dmaDoneEventFree[i] = &dmaDoneEventAll[i];
 
     if (vnc)
-        vnc->setFramebufferAddr(NULL);
+        vnc->setFrameBuffer(&fb);
 }
 
 HDLcd::~HDLcd()
 {
-    if (virtualDisplayBuffer)
-        delete [] virtualDisplayBuffer;
 }
 
 // read registers and frame buffer
@@ -315,8 +314,14 @@ HDLcd::write(PacketPtr pkt)
 void
 HDLcd::updateVideoParams(bool unserializing = false)
 {
-    const uint16_t bpp = bytesPerPixel() << 3;
-    const size_t buffer_size = bytesPerPixel() * width() * height();
+    const uint16_t bpp M5_VAR_USED = bytesPerPixel() << 3;
+
+    // Workaround configuration bugs where multiple display
+    // controllers are attached to the same VNC server by reattaching
+    // enabled devices. This isn't ideal, but works as long as only
+    // one display controller is active at a time.
+    if (command.enable && vnc)
+        vnc->setFrameBuffer(&fb);
 
     // updating these parameters while LCD is enabled is not supported
     if (frameUnderway && !unserializing)
@@ -328,18 +333,14 @@ HDLcd::updateVideoParams(bool unserializing = false)
     // there must be no outstanding DMA transactions for this to work
     if (!unserializing) {
         assert(dmaPendingNum == 0);
-        if (virtualDisplayBuffer)
-            delete [] virtualDisplayBuffer;
-        virtualDisplayBuffer = new uint8_t[buffer_size];
-        memset(virtualDisplayBuffer, 0, buffer_size);
-    }
 
-    assert(virtualDisplayBuffer);
-    if (vnc)
-        vnc->setFramebufferAddr(virtualDisplayBuffer);
+        virtualDisplayBuffer.resize(bytesPerPixel() * area());
+        fb.resize(width(), height());
+        fb.clear();
 
-    if (bmp)
-        delete bmp;
+        std::fill(virtualDisplayBuffer.begin(), virtualDisplayBuffer.end(),
+                  0);
+    }
 
     DPRINTF(HDLcd, "bpp = %d\n", bpp);
     DPRINTF(HDLcd, "display size = %d x %d\n", width(), height());
@@ -354,61 +355,11 @@ HDLcd::updateVideoParams(bool unserializing = false)
     DPRINTF(HDLcd, "simulated refresh rate ~ %.1ffps generating ~ %.1fMB/s "
             "traffic ([%.1fMHz, T=%d sim clocks] pclk, %d bpp => %.1fMB/s peak requirement)\n",
             fps,
-            fps * buffer_size / 1024 / 1024,
+            fps * virtualDisplayBuffer.size() / 1024 / 1024,
             (double)SimClock::Frequency / pixelClock / 1000000.0,
             pixelClock,
             bpp,
             (double)(SimClock::Frequency / pixelClock * (bpp / 8)) / 1024 / 1024);
-
-    if (pixel_format.big_endian)
-        panic("Big Endian pixel format not implemented by HDLcd controller");
-
-    if (vnc) {
-        if ((bpp == 24) &&
-                (red_select.size == 8) &&
-                (blue_select.size == 8) &&
-                (green_select.size == 8) &&
-                (green_select.offset == 8)) {
-            if ((blue_select.offset == 0) &&
-                    (red_select.offset == 16)) {
-                vnc->setFrameBufferParams(VideoConvert::rgb8888, width(),
-                        height());
-                bmp = new Bitmap(VideoConvert::rgb8888, width(), height(),
-                        virtualDisplayBuffer);
-                DPRINTF(HDLcd, "color mode:  rgb888\n");
-            } else if ((red_select.offset == 0) &&
-                    (blue_select.offset == 16)) {
-                vnc->setFrameBufferParams(VideoConvert::bgr8888, width(),
-                        height());
-                bmp = new Bitmap(VideoConvert::bgr8888, width(), height(),
-                        virtualDisplayBuffer);
-                DPRINTF(HDLcd, "color mode:  bgr888\n");
-            }
-        } else if ((bpp == 16) &&
-                (red_select.size == 5) &&
-                (blue_select.size == 5) &&
-                (green_select.size == 6) &&
-                (green_select.offset == 5)) {
-            if ((blue_select.offset == 0) &&
-                    (red_select.offset == 11)) {
-                vnc->setFrameBufferParams(VideoConvert::rgb565, width(),
-                        height());
-                bmp = new Bitmap(VideoConvert::rgb565, width(), height(),
-                        virtualDisplayBuffer);
-                DPRINTF(HDLcd, "color mode:  rgb565\n");
-            } else if ((red_select.offset == 0) &&
-                    (blue_select.offset == 11)) {
-                vnc->setFrameBufferParams(VideoConvert::bgr565, width(),
-                        height());
-                bmp = new Bitmap(VideoConvert::bgr565, width(), height(),
-                        virtualDisplayBuffer);
-                DPRINTF(HDLcd, "color mode:  bgr565\n");
-            }
-        } else {
-            DPRINTF(HDLcd, "color mode:  undefined\n");
-            panic("Unimplemented video mode\n");
-        }
-    }
 }
 
 void
@@ -424,7 +375,7 @@ HDLcd::startFrame()
         doUpdateParams = false;
     }
     frameUnderway = true;
-    assert(virtualDisplayBuffer);
+    assert(!virtualDisplayBuffer.empty());
     assert(pixelBufferSize == 0);
     assert(dmaBytesInFlight == 0);
     assert(dmaPendingNum == 0);
@@ -484,10 +435,11 @@ HDLcd::fillPixelBuffer()
         // will be uncacheable as well. If we have uncacheable and cacheable
         // requests in the memory system for the same address it won't be
         // pleased
+        uint8_t *const dma_dst(
+            virtualDisplayBuffer.data() + dmaCurAddr - dmaStartAddr);
         event->setTransactionSize(transaction_size);
         dmaPort.dmaAction(MemCmd::ReadReq, dmaCurAddr, transaction_size, event,
-                          virtualDisplayBuffer + dmaCurAddr - dmaStartAddr,
-                          0, Request::UNCACHEABLE);
+                          dma_dst, 0, Request::UNCACHEABLE);
         dmaCurAddr += transaction_size;
         dmaBytesInFlight += transaction_size;
     }
@@ -549,6 +501,16 @@ HDLcd::renderPixel()
     schedule(renderPixelEvent, nextEventTick);
 }
 
+PixelConverter
+HDLcd::pixelConverter() const
+{
+    return PixelConverter(
+        bytesPerPixel(),
+        red_select.offset, green_select.offset, blue_select.offset,
+        red_select.size, green_select.size, blue_select.size,
+        pixel_format.big_endian ? BigEndianByteOrder : LittleEndianByteOrder);
+}
+
 void
 HDLcd::endFrame() {
     assert(pixelBufferSize == 0);
@@ -556,6 +518,8 @@ HDLcd::endFrame() {
     assert(dmaBytesInFlight == 0);
     assert(dmaDoneEventFree.size() == dmaDoneEventAll.size());
 
+    fb.copyIn(virtualDisplayBuffer, pixelConverter());
+
     if (vnc)
         vnc->setDirty();
 
@@ -563,10 +527,9 @@ HDLcd::endFrame() {
         if (!pic)
             pic = simout.create(csprintf("%s.framebuffer.bmp", sys->name()), true);
 
-        assert(bmp);
         assert(pic);
         pic->seekp(0);
-        bmp->write(pic);
+        bmp.write(*pic);
     }
 
     // start the next frame
@@ -664,8 +627,7 @@ HDLcd::serialize(std::ostream &os)
     SERIALIZE_SCALAR(dmaPendingNum);
     SERIALIZE_SCALAR(frameUnderrun);
 
-    const size_t buffer_size = bytesPerPixel() * width() * height();
-    SERIALIZE_ARRAY(virtualDisplayBuffer, buffer_size);
+    arrayParamOut(os, "virtualDisplayBuffer", virtualDisplayBuffer);
 
     SERIALIZE_SCALAR(pixelBufferSize);
     SERIALIZE_SCALAR(pixelIndex);
@@ -777,9 +739,7 @@ HDLcd::unserialize(Checkpoint *cp, const std::string &section)
     UNSERIALIZE_SCALAR(frameUnderrun);
     UNSERIALIZE_SCALAR(dmaBytesInFlight);
 
-    const size_t buffer_size = bytesPerPixel() * width() * height();
-    virtualDisplayBuffer = new uint8_t[buffer_size];
-    UNSERIALIZE_ARRAY(virtualDisplayBuffer, buffer_size);
+    arrayParamIn(cp, section, "virtualDisplayBuffer", virtualDisplayBuffer);
 
     UNSERIALIZE_SCALAR(pixelBufferSize);
     UNSERIALIZE_SCALAR(pixelIndex);
@@ -823,6 +783,8 @@ HDLcd::unserialize(Checkpoint *cp, const std::string &section)
 
     if (frameUnderway) {
         updateVideoParams(true);
+        fb.resize(width(), height());
+        fb.copyIn(virtualDisplayBuffer, pixelConverter());
         if (vnc)
             vnc->setDirty();
     }