Kernel: HPET is now used in legacy mode when PIC is forced

kernel/include/kernel/Timer/HPET.h

@@ -8,14 +8,14 @@ namespace Kernel
 	class HPET final : public Timer
 	{
 	public:
-		static BAN::ErrorOr<BAN::UniqPtr<HPET>> create();
+		static BAN::ErrorOr<BAN::UniqPtr<HPET>> create(bool force_pic);
 
 		virtual uint64_t ms_since_boot() const override;
 		virtual timespec time_since_boot() const override;
 
 	private:
 		HPET() = default;
-		BAN::ErrorOr<void> initialize();
+		BAN::ErrorOr<void> initialize(bool force_pic);
 
 		void write_register(ptrdiff_t reg, uint64_t value) const;
 		uint64_t read_register(ptrdiff_t reg) const;

kernel/include/kernel/Timer/Timer.h

@@ -18,7 +18,7 @@ namespace Kernel
 	class SystemTimer : public Timer
 	{
 	public:
-		static void initialize();
+		static void initialize(bool force_pic);
 		static SystemTimer& get();
 		static bool is_initialized();
 
@@ -32,7 +32,7 @@ namespace Kernel
 	private:
 		SystemTimer() = default;
 
-		void initialize_timers();
+		void initialize_timers(bool force_pic);
 
 	private:
 		uint64_t m_boot_time { 0 };

kernel/kernel/Timer/HPET.cpp

@@ -31,12 +31,12 @@
 namespace Kernel
 {
 
-	BAN::ErrorOr<BAN::UniqPtr<HPET>> HPET::create()
+	BAN::ErrorOr<BAN::UniqPtr<HPET>> HPET::create(bool force_pic)
 	{
 		HPET* hpet = new HPET();
 		if (hpet == nullptr)
 			return BAN::Error::from_errno(ENOMEM);
-		if (auto ret = hpet->initialize(); ret.is_error())
+		if (auto ret = hpet->initialize(force_pic); ret.is_error())
 		{
 			delete hpet;
 			return ret.release_error();
@@ -44,7 +44,7 @@ namespace Kernel
 		return BAN::UniqPtr<HPET>::adopt(hpet);
 	}
 
-	BAN::ErrorOr<void> HPET::initialize()
+	BAN::ErrorOr<void> HPET::initialize(bool force_pic)
 	{
 		auto* header = (ACPI::HPET*)ACPI::get().get_header("HPET");
 		if (header == nullptr)
@@ -53,7 +53,7 @@ namespace Kernel
 		if (header->hardware_rev_id == 0)
 			return BAN::Error::from_errno(EINVAL);
 
-		if (!header->legacy_replacement_irq_routing_cable)
+		if (force_pic && !header->legacy_replacement_irq_routing_cable)
 		{
 			dwarnln("HPET doesn't support legacy mapping");
 			return BAN::Error::from_errno(ENOTSUP);
@@ -92,26 +92,38 @@ namespace Kernel
 			return BAN::Error::from_errno(ENOTSUP);
 		}
 
-		uint32_t irq_cap = timer0_config >> 32;
-		
-		if (irq_cap == 0)
-		{
-			dwarnln("HPET doesn't have any interrupts available");
-			return BAN::Error::from_errno(EINVAL);
-		}
-		
 		int irq = 0;
-		for (; irq < 32; irq++)
+		if (!force_pic)
-			if (irq_cap & (1 << irq))
+		{
-				break;
+			uint32_t irq_cap = timer0_config >> 32;
+			if (irq_cap == 0)
+			{
+				dwarnln("HPET doesn't have any interrupts available");
+				return BAN::Error::from_errno(EINVAL);
+			}
+			for (irq = 0; irq < 32; irq++)
+				if (irq_cap & (1 << irq))
+					break;
+		}
 
 		unmapper.disable();
 
+		uint64_t main_flags = HPET_CONFIG_ENABLE;
+		if (force_pic)
+			main_flags |= HPET_CONFIG_LEG_RT;
+
 		// Enable main counter
-		write_register(HPET_REG_CONFIG, read_register(HPET_REG_CONFIG) | HPET_CONFIG_ENABLE);
+		write_register(HPET_REG_CONFIG, read_register(HPET_REG_CONFIG) | main_flags);
+
+		uint64_t timer0_flags = 0;
+		timer0_flags |= HPET_Tn_INT_ENB_CNF;
+		timer0_flags |= HPET_Tn_TYPE_CNF;
+		timer0_flags |= HPET_Tn_VAL_SET_CNF;
+		if (!force_pic)
+			timer0_flags |= irq << HPET_Tn_INT_ROUTE_CNF_SHIFT;
 
 		// Enable timer 0 as 1 ms periodic
-		write_register(HPET_REG_TIMER_CONFIG(0), HPET_Tn_INT_ENB_CNF | HPET_Tn_TYPE_CNF | HPET_Tn_VAL_SET_CNF | (irq << HPET_Tn_INT_ROUTE_CNF_SHIFT));
+		write_register(HPET_REG_TIMER_CONFIG(0), timer0_flags);
 		write_register(HPET_REG_TIMER_COMPARATOR(0), read_register(HPET_REG_COUNTER) + ticks_per_ms);
 		write_register(HPET_REG_TIMER_COMPARATOR(0), ticks_per_ms);
 

kernel/kernel/Timer/Timer.cpp

@@ -8,12 +8,12 @@ namespace Kernel
 
 	static SystemTimer* s_instance = nullptr;
 
-	void SystemTimer::initialize()
+	void SystemTimer::initialize(bool force_pic)
 	{
 		ASSERT(s_instance == nullptr);
 		auto* temp = new SystemTimer;
 		ASSERT(temp);
-		temp->initialize_timers();
+		temp->initialize_timers(force_pic);
 		s_instance = temp;
 	}
 
@@ -28,12 +28,12 @@ namespace Kernel
 		return !!s_instance;
 	}
 
-	void SystemTimer::initialize_timers()
+	void SystemTimer::initialize_timers(bool force_pic)
 	{
 		m_rtc = MUST(BAN::UniqPtr<RTC>::create());
 		m_boot_time = BAN::to_unix_time(m_rtc->get_current_time());
 
-		if (auto res = HPET::create(); res.is_error())
+		if (auto res = HPET::create(force_pic); res.is_error())
 			dwarnln("HPET: {}", res.error());
 		else
 		{

kernel/kernel/kernel.cpp

@@ -141,10 +141,13 @@ extern "C" void kernel_main()
 	MUST(ACPI::initialize());
 	dprintln("ACPI initialized");
 
+	parse_command_line();
+	dprintln("command line parsed, root='{}'", cmdline.root);
+
 	InterruptController::initialize(cmdline.force_pic);
 	dprintln("Interrupt controller initialized");
 
-	SystemTimer::initialize();
+	SystemTimer::initialize(cmdline.force_pic);
 	dprintln("Timers initialized");
 
 	DevFileSystem::initialize();
@@ -154,9 +157,6 @@ extern "C" void kernel_main()
 	ASSERT(tty1);
 	dprintln("TTY initialized");
 
-	parse_command_line();
-	dprintln("command line parsed, root='{}'", cmdline.root);
-
 	MUST(Scheduler::initialize());
 	dprintln("Scheduler initialized");