kernel/ATA: Start reading/writing registers and detecting drives

kernel/src/arch/x86_64/disk/ATA.cpp

@@ -45,30 +45,88 @@ namespace ATA
     {
     }
 
+    u8 Channel::read_register(Register reg)
+    {
+        return IO::inb(m_io_base + (u16)reg);
+    }
+
+    void Channel::write_register(Register reg, u8 value)
+    {
+        IO::outb(m_io_base + (u16)reg, value);
+    }
+
+    u8 Channel::read_control(ControlRegister reg)
+    {
+        return IO::inb(m_control_base + (u16)reg);
+    }
+
+    void Channel::write_control(ControlRegister reg, u8 value)
+    {
+        IO::outb(m_control_base + (u16)reg, value);
+    }
+
+    void Channel::delay_400ns()
+    {
+        read_control(ControlRegister::AltStatus);
+        read_control(ControlRegister::AltStatus);
+        read_control(ControlRegister::AltStatus);
+        read_control(ControlRegister::AltStatus);
+    }
+
+    void Channel::select(u8 drive)
+    {
+        if (drive == m_current_drive) return;
+
+        u8 value = (drive << 4) | 0xa0;
+        write_register(Register::DriveSelect, value);
+
+        delay_400ns();
+
+        m_current_drive = drive;
+    }
+
     bool Channel::initialize()
     {
         int offset = m_channel_index ? 2 : 0;
         m_is_pci_native_mode = m_controller->device().type.prog_if & (1 << offset);
-        kinfoln("ata: Channel %d is %sin PCI native mode", m_channel_index, m_is_pci_native_mode ? "" : "not ");
+
+        u32 control_port_base_address;
+        u32 io_base_address;
 
         if (m_is_pci_native_mode)
         {
-            m_base_address = PCI::read32(m_controller->device().address, m_channel_index ? PCI::BAR2 : PCI::BAR0);
-            m_control_port_base_address =
+            // FIXME: Properly decode BARs.
+            io_base_address = PCI::read32(m_controller->device().address, m_channel_index ? PCI::BAR2 : PCI::BAR0);
+            control_port_base_address =
                 PCI::read32(m_controller->device().address, m_channel_index ? PCI::BAR3 : PCI::BAR1);
         }
         else
         {
-            m_base_address = m_channel_index ? 0x170 : 0x1f0;
-            m_control_port_base_address = m_channel_index ? 0x376 : 0x3f6;
+            io_base_address = m_channel_index ? 0x170 : 0x1f0;
+            control_port_base_address = m_channel_index ? 0x376 : 0x3f6;
         }
 
-        u8 interrupt_line;
-        if (m_is_pci_native_mode) interrupt_line = PCI::read8(m_controller->device().address, PCI::InterruptLine);
-        else
-            interrupt_line = m_channel_index ? 15 : 14;
+        m_io_base = (u16)io_base_address;
+        m_control_base = (u16)control_port_base_address + 2;
 
-        kinfoln("ata: Channel %d uses IRQ %hhu", m_channel_index, interrupt_line);
+        if (m_is_pci_native_mode) m_interrupt_line = PCI::read8(m_controller->device().address, PCI::InterruptLine);
+        else
+            m_interrupt_line = m_channel_index ? 15 : 14;
+
+        for (u8 drive = 0; drive < 2; drive++)
+        {
+            ScopedKMutexLock<100> lock(m_lock);
+
+            select(drive);
+
+            if (read_register(Register::Status) == 0)
+            {
+                // No drive on this slot.
+                continue;
+            }
+
+            kinfoln("ata: Channel %d has a drive on slot %d!", m_channel_index, drive);
+        }
 
         return true;
     }

kernel/src/arch/x86_64/disk/ATA.h

@@ -7,12 +7,53 @@
 
 namespace ATA
 {
+    enum class Register : u16
+    {
+        Data = 0,
+        Error = 1,
+        Features = 1,
+        SectorCount = 2,
+        SectorNumber = 3,
+        LBALow = 3,
+        CylinderLow = 4,
+        LBAMiddle = 4,
+        CylinderHigh = 5,
+        LBAHigh = 5,
+        DriveSelect = 6,
+        Status = 7,
+        Command = 8,
+    };
+
+    enum class ControlRegister : u16
+    {
+        AltStatus = 0,
+        DeviceControl = 0,
+        DriveAddress = 1,
+    };
+
     class Controller;
+    class Channel;
+
+    class Drive
+    {
+      private:
+        Channel* m_channel;
+    };
+
     class Channel
     {
       public:
         Channel(Controller* controller, u8 channel_index, Badge<Controller>);
 
+        u8 read_register(Register reg);
+        void write_register(Register reg, u8 value);
+        u8 read_control(ControlRegister reg);
+        void write_control(ControlRegister reg, u8 value);
+
+        void delay_400ns();
+
+        void select(u8 drive);
+
         bool initialize();
 
       private:
@@ -20,8 +61,14 @@ namespace ATA
         u8 m_channel_index;
         bool m_is_pci_native_mode;
 
-        u32 m_base_address;
-        u32 m_control_port_base_address;
+        u8 m_interrupt_line;
+
+        KMutex<100> m_lock {};
+
+        u16 m_io_base;
+        u16 m_control_base;
+
+        u8 m_current_drive = (u8)-1;
     };
 
     class Controller
@@ -41,8 +88,6 @@ namespace ATA
         PCI::Device m_device;
         Channel m_primary_channel;
         Channel m_secondary_channel;
-
-        KMutex<100> m_lock;
     };
 
 }

kernel/src/lib/KMutex.h

@@ -52,9 +52,8 @@ template <usize ConcurrentThreads> class KMutex
 template <usize ConcurrentThreads> class ScopedKMutexLock
 {
   public:
-    ScopedKMutexLock(KMutex<ConcurrentThreads>& lock)
+    ScopedKMutexLock(KMutex<ConcurrentThreads>& lock) : m_lock(lock)
     {
-        m_lock = lock;
         m_lock.lock();
     }