kernel/ATA: Route interrupts to the correct drive

kernel/src/arch/x86_64/CPU.cpp

@@ -180,7 +180,7 @@ extern "C" void arch_interrupt_entry(Registers* regs)
     if (regs->isr < 32) handle_x86_exception(regs);
     else if (regs->isr >= 32 && regs->isr < 48) // IRQ from the PIC
     {
-        u64 irq = regs->error;
+        u64 irq = regs->irq;
         auto handler = irq_handlers[irq];
         if (!handler.function)
         {

kernel/src/arch/x86_64/CPU.h

@@ -5,7 +5,11 @@ struct Registers // Saved CPU registers for x86-64
 {
     u64 r15, r14, r13, r12, r11, r10, r9, r8;
     u64 rbp, rdi, rsi, rdx, rcx, rbx, rax;
-    u64 isr, error;
+    u64 isr;
+    union {
+        u64 error;
+        u64 irq;
+    };
     u64 rip, cs, rflags, rsp, ss;
 };
 

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

@@ -14,7 +14,7 @@ SharedPtr<ATA::Controller> g_controller;
 
 static void irq_handler(Registers* regs, void* ctx)
 {
-    ((ATA::Channel*)ctx)->irq_handler(regs);
+    ((ATA::Controller*)ctx)->irq_handler(regs);
 }
 
 static usize copy_ata_string(char* out, u16* in, usize size)
@@ -70,6 +70,12 @@ namespace ATA
         return m_secondary_channel.initialize();
     }
 
+    void Controller::irq_handler(Registers* regs)
+    {
+        if (regs->irq == m_primary_channel.irq_line()) m_primary_channel.irq_handler(regs);
+        if (regs->irq == m_secondary_channel.irq_line()) m_secondary_channel.irq_handler(regs);
+    }
+
     Controller::Controller(const PCI::Device& device)
         : m_device(device), m_primary_channel(this, 0, {}), m_secondary_channel(this, 1, {})
     {
@@ -150,7 +156,7 @@ namespace ATA
 
     void Channel::irq_handler(Registers*)
     {
-        // FIXME: Read the Busmaster register to make sure the IRQ is for this channel.
+        if (!(read_bm(BusmasterRegister::Status) & BMS_IRQPending)) return;
 
         if (m_current_drive < 2 && m_drives[m_current_drive]) m_drives[m_current_drive]->irq_handler();
 
@@ -314,13 +320,7 @@ namespace ATA
             }
         }
 
-        bool ok = CPU::register_interrupt(m_interrupt_line, ::irq_handler, this);
-        if (!ok)
-        {
-            kerrorln("ata: Failed to register IRQ handler for ATA channel %d (IRQ %d)", m_channel_index,
-                     m_interrupt_line);
-            return false;
-        }
+        CPU::register_interrupt(m_interrupt_line, ::irq_handler, m_controller);
 
         for (u8 drive = 0; drive < 2; drive++)
         {

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

@@ -231,6 +231,11 @@ namespace ATA
         bool wait_for_irq_or_timeout(u64 timeout);
         void irq_handler(Registers*);
 
+        u8 irq_line()
+        {
+            return m_interrupt_line;
+        }
+
         void select(u8 drive);
 
         bool initialize();
@@ -269,6 +274,8 @@ namespace ATA
 
         bool initialize();
 
+        void irq_handler(Registers*);
+
       private:
         Controller(const PCI::Device& device);
         PCI::Device m_device;

kernel/src/arch/x86_64/init/PIC.cpp

@@ -58,5 +58,5 @@ void pic_eoi(unsigned char irq)
 
 void pic_eoi(Registers* regs)
 {
-    pic_eoi((unsigned char)(regs->error)); // On IRQs, the error code is the IRQ number
+    pic_eoi((unsigned char)(regs->irq));
 }