Draw the RAK4631's SSD1306 under Renode

CHANGELOG.md

@@ -23,6 +23,12 @@ had changed in them - which is the gap this file exists to close.
 
 ### Added
 
+- **The RAK4631's display is drawn under Renode.** Its SSD1306 is on I2C,
+  and the TWIM model answered every address with a NACK. The TWIM now carries
+  devices registered at an address and moves each transfer's bytes through
+  EasyDMA, and a new SSD1306 model sends the controller's memory to the board
+  view. An address nobody claims is still a NACK. The published v1.17.1
+  repeater draws its own boot screen.
 - **Script input at an instant of simulated time.** `console.type`,
   `console.cli` and the `companion.*` verbs that write to a node take `at_ms`:
   the call is held and runs when the run reaches that instant, so a script

internal/firmware/emulated/renode.go

@@ -52,8 +52,14 @@ lora: Radio.VirtualSX1262 @ radiospi
     %d -> lora@0
 `, renode.EasyDMASPI(e.SPIBase), e.SPIBase, engineHost, enginePort, e.IrqPort,
 		e.IrqPin, e.NssPort, e.NssPin)
-	wiring += renode.Panel(e.SPIBase, e.PanelPort, e.PanelWidth, e.PanelHgt,
-		e.PanelCS, e.PanelDC, e.NssPort)
+	// A colour panel has a select line of its own; an I2C display has an
+	// address instead.
+	if e.PanelCS != 0 {
+		wiring += renode.Panel(e.SPIBase, e.PanelPort, e.PanelWidth, e.PanelHgt,
+			e.PanelCS, e.PanelDC, e.NssPort)
+	} else {
+		wiring += renode.Oled(e.PanelPort, e.PanelAddr, e.PanelWidth, e.PanelHgt, e.PanelOffset)
+	}
 	wiring += renode.Inputs(e.ButtonPort, e.HasMeter)
 	if err := os.WriteFile(repl, []byte(wiring), 0o644); err != nil {
 		return "", err
@@ -80,6 +86,7 @@ i @%[1]s/peripherals/VirtualSX1262Engine.cs
 i @%[1]s/peripherals/VirtualSX1262.cs
 i @%[1]s/peripherals/MeshBenchInputs.cs
 i @%[1]s/peripherals/MeshBenchPanel.cs
+i @%[1]s/peripherals/MeshBenchOled.cs
 i @%[1]s/peripherals/NRF52840_Temp.cs
 i @%[1]s/peripherals/NRF52840_Clock.cs
 i @%[1]s/peripherals/NRF52840_SAADC.cs

internal/firmware/emulated/renode/oled_test.go

@@ -0,0 +1,20 @@
+package renode
+
+import (
+	"strings"
+	"testing"
+)
+
+// An I2C display hangs off the first TWIM at its own address, told its glass
+// and where its columns start (#602).
+func TestAnI2CDisplayIsRegisteredAtItsAddress(t *testing.T) {
+	got := Oled(4242, 0x3C, 128, 64, 0)
+	for _, want := range []string{"Video.MeshBenchOled @ twi0 0x3C", "port: 4242", "width: 128", "height: 64", "columnOffset: 0"} {
+		if !strings.Contains(got, want) {
+			t.Errorf("missing %q in:\n%s", want, got)
+		}
+	}
+	if Oled(0, 0x3C, 128, 64, 0) != "" || Oled(4242, 0, 128, 64, 0) != "" {
+		t.Error("a display with no channel or no address was wired anyway")
+	}
+}

internal/firmware/emulated/renode/script.go

@@ -64,6 +64,20 @@ func Panel(radioBase uint32, port, width, height, cs, dc int, dcPort string) str
 `, stockSPIName, port, width, height, cs, dc, dcPort, cs, cs, dc, dc)
 }
 
+// Oled is an I2C display on the first TWIM, at its address. offset is where
+// the glass starts in the controller's columns: 2 for an SH1106.
+func Oled(port int, addr uint8, width, height, offset int) string {
+	if port == 0 || addr == 0 || width <= 0 || height <= 0 {
+		return ""
+	}
+	return fmt.Sprintf(`oled: Video.MeshBenchOled @ twi0 0x%X
+    port: %d
+    width: %d
+    height: %d
+    columnOffset: %d
+`, addr, port, width, height, offset)
+}
+
 func UnregisterStockSPI() string {
 	return "sysbus Unregister sysbus." + stockSPIName + "\n"
 }

internal/sim/engine/boardsettings_test.go

@@ -160,3 +160,15 @@ func shortNodeFS(t *testing.T) string {
 	t.Cleanup(func() { _ = os.RemoveAll(dir) })
 	return dir
 }
+
+// The RAK4631's SSD1306 is drawn under Renode now, so the window must say so
+// rather than say the gap is ours (#602).
+func TestTheRAK4631DisplayIsModelled(t *testing.T) {
+	b, err := hw.BoardByName("RAK_4631")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !ScreenModelled(b) {
+		t.Error("the RAK4631's I2C display reads as not modelled")
+	}
+}

internal/sim/engine/nodeparts.go

@@ -149,6 +149,11 @@ func withParts(node *emulated.EmulatedNode, board hw.Board, spec scenario.Node,
 			node.PanelCS, node.PanelDC = p.Screen.CS, p.Screen.DC
 			node.PanelWidth, node.PanelHgt = p.Screen.WidthPx, p.Screen.HeightPx
 		}
+		// Renode's I2C display model is told its glass too; QEMU's takes it
+		// from the controller it emulates.
+		if p.Screen.Bus == hw.BusI2C && board.Renode != nil {
+			node.PanelWidth, node.PanelHgt = p.Screen.WidthPx, p.Screen.HeightPx
+		}
 	}
 	return node, nil
 }
@@ -162,11 +167,10 @@ func withParts(node *emulated.EmulatedNode, board hw.Board, spec scenario.Node,
 // nothing draws must read as "no display modelled" and never as "silent", which
 // says the firmware chose not to draw.
 //
-// QEMU has both buses. Renode has the SPI panels - an ST7789 and an ST7735,
-// sharing the radio's controller and told apart by chip select, which is how
-// they are wired in copper - and not the I2C one: its TWIM model answers an
-// address with a NACK because until now no board under it had anything on that
-// bus to answer.
+// QEMU has both buses. So does Renode: the SPI panels - an ST7789 and an
+// ST7735, sharing the radio's controller and told apart by chip select, which
+// is how they are wired in copper - and an SSD1306 on I2C, registered on the
+// TWIM at its address.
 func ScreenModelled(board hw.Board) bool {
 	p := board.Hardware
 	if p == nil || p.Screen == nil {
@@ -178,6 +182,11 @@ func ScreenModelled(board hw.Board) bool {
 		// other port would be wired wrong rather than unsupported. Both boards
 		// that carry one have it on the radio's port; this is the check that
 		// says so rather than a comment claiming it.
+		// An I2C display hangs off the first TWIM at its address, where
+		// MeshBenchOled answers for an SSD1306 or an SH1106 (#602).
+		if p.Screen.Bus == hw.BusI2C {
+			return p.Screen.Controller == "SSD1306" || p.Screen.Controller == "SH1106"
+		}
 		return p.Screen.Bus == hw.BusSPI &&
 			p.Screen.CS != 0 && p.Screen.DC != 0 &&
 			onSamePort(p.Screen.CS, board.Renode.NssPort) &&

internal/ui/workbench/boardview/rows_test.go

@@ -232,9 +232,9 @@ func TestABoardWithNoRecordedPanelStillHasARadio(t *testing.T) {
 // reporting that as silence sends somebody looking for a fault in a firmware
 // that is behaving perfectly.
 //
-// The RAK4631 is the one left. Its display is on I2C, and Renode's TWIM model
-// answers an address with a NACK, so there is nowhere to put an SSD1306 yet -
-// where the two SPI panels beside it are drawn.
+// Every Renode board in the catalogue has its panel drawn now (the RAK4631's
+// SSD1306 was the last, #602), so the case is made by hand: the same board
+// with a controller nothing models, an e-paper one.
 func TestAnUndrawablePanelBlamesUsRatherThanTheFirmware(t *testing.T) {
 	b, err := hw.BoardByName("RAK_4631")
 	if err != nil {
@@ -243,24 +243,29 @@ func TestAnUndrawablePanelBlamesUsRatherThanTheFirmware(t *testing.T) {
 	if b.Renode == nil || b.Hardware == nil || b.Hardware.Screen == nil {
 		t.Fatal("this test needs a Renode board that declares a screen")
 	}
+	panel := *b.Hardware
+	screen := *panel.Screen
+	screen.Controller = "UC8151"
+	panel.Screen = &screen
+	b.Hardware = &panel
 	running := &state.NodeStat{Name: "n", Board: b.Name, Running: true}
-	var screen *Row
+	var row *Row
 	rows := wiringRows(b, running)
 	for i := range rows {
 		if rows[i].Group == "Display" {
-			screen = &rows[i]
+			row = &rows[i]
 			break
 		}
 	}
-	if screen == nil {
+	if row == nil {
 		t.Fatal("a board that declares a screen produced no display row")
 	}
-	if screen.Verdict == Silent {
+	if row.Verdict == Silent {
 		t.Errorf("a panel with no model behind it read as %v, which says the "+
 			"firmware chose not to draw", Silent)
 	}
-	if screen.Verdict != NotModelled {
-		t.Errorf("read %v (%q), want %v", screen.Verdict, screen.Observed, NotModelled)
+	if row.Verdict != NotModelled {
+		t.Errorf("read %v (%q), want %v", row.Verdict, row.Observed, NotModelled)
 	}
 }