Detect hw and wire active console and TTY

src/gopheros/device/driver.go

@@ -13,3 +13,7 @@ type Driver interface {
 	// DriverInit initializes the device driver.
 	DriverInit() *kernel.Error
 }
+
+// ProbeFn is a function that scans for the presence of a particular
+// piece of hardware and returns a driver for it.
+type ProbeFn func() Driver

src/gopheros/device/tty/device.go

@@ -5,6 +5,14 @@ import (
 	"io"
 )
 
+const (
+	// DefaultScrollback defines the terminal scrollback in lines.
+	DefaultScrollback = 80
+
+	// DefaultTabWidth defines the number of spaces that tabs expand to.
+	DefaultTabWidth = 4
+)
+
 // State defines the supported terminal state values.
 type State uint8
 

src/gopheros/device/tty/probe.go

@@ -0,0 +1,11 @@
+package tty
+
+import "gopheros/device"
+
+// HWProbes returns a slice of device.ProbeFn that can be used by the hal
+// package to probe for TTY device hardware.
+func HWProbes() []device.ProbeFn {
+	return []device.ProbeFn{
+		probeForVT,
+	}
+}

src/gopheros/device/tty/vt.go

@@ -1,6 +1,7 @@
 package tty
 
 import (
+	"gopheros/device"
 	"gopheros/device/video/console"
 	"gopheros/kernel"
 	"io"
@@ -258,3 +259,7 @@ func (t *VT) DriverVersion() (uint16, uint16, uint16) {
 
 // DriverInit initializes this driver.
 func (t *VT) DriverInit() *kernel.Error { return nil }
+
+func probeForVT() device.Driver {
+	return NewVT(DefaultTabWidth, DefaultScrollback)
+}

src/gopheros/device/tty/vt_test.go

@@ -5,6 +5,7 @@ import (
 	"gopheros/device/video/console"
 	"image/color"
 	"io"
+	"reflect"
 	"testing"
 )
 
@@ -337,6 +338,28 @@ func TestVTDriverInterface(t *testing.T) {
 	}
 }
 
+func TestVTProbe(t *testing.T) {
+	var (
+		expProbePtr = reflect.ValueOf(probeForVT).Pointer()
+		foundProbe  bool
+	)
+
+	for _, probeFn := range HWProbes() {
+		if reflect.ValueOf(probeFn).Pointer() == expProbePtr {
+			foundProbe = true
+			break
+		}
+	}
+
+	if !foundProbe {
+		t.Fatal("expected probeForVT to be part of the probes returned by HWProbes")
+	}
+
+	if drv := probeForVT(); drv == nil {
+		t.Fatal("expected probeForVT to return a driver")
+	}
+}
+
 type mockConsole struct {
 	width, height   uint16
 	fg, bg          uint8

src/gopheros/device/video/console/probe.go

@@ -0,0 +1,16 @@
+package console
+
+import "gopheros/device"
+import "gopheros/kernel/hal/multiboot"
+
+var (
+	getFramebufferInfoFn = multiboot.GetFramebufferInfo
+)
+
+// HWProbes returns a slice of device.ProbeFn that can be used by the hal
+// package to probe for console device hardware.
+func HWProbes() []device.ProbeFn {
+	return []device.ProbeFn{
+		probeForVgaTextConsole,
+	}
+}

src/gopheros/device/video/console/vga_text.go

@@ -1,8 +1,10 @@
 package console
 
 import (
+	"gopheros/device"
 	"gopheros/kernel"
 	"gopheros/kernel/cpu"
+	"gopheros/kernel/hal/multiboot"
 	"image/color"
 	"reflect"
 	"unsafe"
@@ -196,3 +198,15 @@ func (cons *VgaTextConsole) DriverVersion() (uint16, uint16, uint16) {
 
 // DriverInit initializes this driver.
 func (cons *VgaTextConsole) DriverInit() *kernel.Error { return nil }
+
+// probeForVgaTextConsole checks for the presence of a vga text console.
+func probeForVgaTextConsole() device.Driver {
+	var drv device.Driver
+
+	fbInfo := getFramebufferInfoFn()
+	if fbInfo.Type == multiboot.FramebufferTypeEGA {
+		drv = NewVgaTextConsole(uint16(fbInfo.Width), uint16(fbInfo.Height), uintptr(fbInfo.PhysAddr))
+	}
+
+	return drv
+}

src/gopheros/device/video/console/vga_text_test.go

@@ -3,7 +3,9 @@ package console
 import (
 	"gopheros/device"
 	"gopheros/kernel/cpu"
+	"gopheros/kernel/hal/multiboot"
 	"image/color"
+	"reflect"
 	"testing"
 	"unsafe"
 )
@@ -318,3 +320,39 @@ func TestVgaTextDriverInterface(t *testing.T) {
 		t.Fatal("DriverVersion() returned an invalid version number")
 	}
 }
+
+func TestVgaTextProbe(t *testing.T) {
+	defer func() {
+		getFramebufferInfoFn = multiboot.GetFramebufferInfo
+	}()
+
+	var (
+		expProbePtr = reflect.ValueOf(probeForVgaTextConsole).Pointer()
+		foundProbe  bool
+	)
+
+	for _, probeFn := range HWProbes() {
+		if reflect.ValueOf(probeFn).Pointer() == expProbePtr {
+			foundProbe = true
+			break
+		}
+	}
+
+	if !foundProbe {
+		t.Fatal("expected probeForVgaTextConsole to be part of the probes returned by HWProbes")
+	}
+
+	getFramebufferInfoFn = func() *multiboot.FramebufferInfo {
+		return &multiboot.FramebufferInfo{
+			Width:    80,
+			Height:   25,
+			Pitch:    160,
+			PhysAddr: 0xb80000,
+			Type:     multiboot.FramebufferTypeEGA,
+		}
+	}
+
+	if drv := probeForVgaTextConsole(); drv == nil {
+		t.Fatal("expected probeForVgaTextConsole to return a driver")
+	}
+}