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")
+	}
+}

src/gopheros/kernel/hal/hal.go

@@ -1,23 +1,67 @@
 package hal
 
 import (
-	"gopheros/kernel/driver/tty"
-	"gopheros/kernel/driver/video/console"
-	"gopheros/kernel/hal/multiboot"
+	"gopheros/device"
+	"gopheros/device/tty"
+	"gopheros/device/video/console"
+	"gopheros/kernel/kfmt"
 )
 
-var (
-	egaConsole = &console.Ega{}
-
-	// ActiveTerminal points to the currently active terminal.
-	ActiveTerminal = &tty.Vt{}
-)
-
-// InitTerminal provides a basic terminal to allow the kernel to emit some output
-// till everything is properly setup
-func InitTerminal() {
-	fbInfo := multiboot.GetFramebufferInfo()
-
-	egaConsole.Init(uint16(fbInfo.Width), uint16(fbInfo.Height), uintptr(fbInfo.PhysAddr))
-	ActiveTerminal.AttachTo(egaConsole)
+// managedDevices contains the devices discovered by the HAL.
+type managedDevices struct {
+	activeConsole console.Device
+	activeTTY     tty.Device
+}
+
+var devices managedDevices
+
+// ActiveTTY returns the currently active TTY
+func ActiveTTY() tty.Device {
+	return devices.activeTTY
+}
+
+// DetectHardware probes for hardware devices and initializes the appropriate
+// drivers.
+func DetectHardware() {
+	consoles := probe(console.HWProbes())
+	if len(consoles) != 0 {
+		devices.activeConsole = consoles[0].(console.Device)
+	}
+
+	ttys := probe(tty.HWProbes())
+	if len(ttys) != 0 {
+		devices.activeTTY = ttys[0].(tty.Device)
+		devices.activeTTY.AttachTo(devices.activeConsole)
+		kfmt.SetOutputSink(devices.activeTTY)
+
+		// Sync terminal contents with console
+		devices.activeTTY.SetState(tty.StateActive)
+	}
+}
+
+// probe executes the supplied hw probe functions and attempts to initialize
+// each detected device. The function returns a list of device drivers that
+// were successfully initialized.
+func probe(hwProbeFns []device.ProbeFn) []device.Driver {
+	var drivers []device.Driver
+
+	for _, probeFn := range hwProbeFns {
+		drv := probeFn()
+		if drv == nil {
+			continue
+		}
+
+		major, minor, patch := drv.DriverVersion()
+
+		kfmt.Printf("[hal] %s(%d.%d.%d): ", drv.DriverName(), major, minor, patch)
+		if err := drv.DriverInit(); err != nil {
+			kfmt.Printf("init failed: %s\n", err.Message)
+			continue
+		}
+
+		drivers = append(drivers, drv)
+		kfmt.Printf("initialized\n")
+	}
+
+	return drivers
 }

src/gopheros/kernel/kmain/kmain.go

@@ -5,6 +5,7 @@ import (
 	"gopheros/kernel/goruntime"
 	"gopheros/kernel/hal"
 	"gopheros/kernel/hal/multiboot"
+	"gopheros/kernel/kfmt"
 	"gopheros/kernel/mem/pmm/allocator"
 	"gopheros/kernel/mem/vmm"
 )
@@ -27,9 +28,6 @@ var (
 func Kmain(multibootInfoPtr, kernelStart, kernelEnd uintptr) {
 	multiboot.SetInfoPtr(multibootInfoPtr)
 
-	hal.InitTerminal()
-	hal.ActiveTerminal.Clear()
-
 	var err *kernel.Error
 	if err = allocator.Init(kernelStart, kernelEnd); err != nil {
 		panic(err)
@@ -39,7 +37,10 @@ func Kmain(multibootInfoPtr, kernelStart, kernelEnd uintptr) {
 		panic(err)
 	}
 
-	// Use kernel.Panic instead of panic to prevent the compiler from
+	// Detect and initialize hardware
+	hal.DetectHardware()
+
+	// Use kfmt.Panic instead of panic to prevent the compiler from
 	// treating kernel.Panic as dead-code and eliminating it.
-	kernel.Panic(errKmainReturned)
+	kfmt.Panic(errKmainReturned)
 }