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Kernel: Check i8042 existence before trying to use it

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If we don't do so, we just hang forever because we assume there's i8042
controller in the system, which is not a valid assumption for modern PC
hardware.
This commit is contained in:
Liav A 2022-02-10 10:19:28 +02:00 • committed by Idan Horowitz
parent f1f0770d68
commit dc41a0b830
2 changed files with 39 additions and 0 deletions
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34
Kernel/Devices/HID/I8042Controller.cpp
View file

@ -31,8 +31,30 @@ UNMAP_AFTER_INIT I8042Controller::I8042Controller()
{
}
UNMAP_AFTER_INIT bool I8042Controller::check_existence()
{
{
SpinlockLocker lock(m_lock);
// Note: Perform controller self-test before touching the controller
// Try to probe the controller for 5 times and give up if nothing
// responded.
for (int attempt = 0; attempt < 5; attempt++) {
do_write(I8042Port::Command, I8042Command::TestPS2Controller);
if (do_read(I8042Port::Buffer) == I8042Response::ControllerTestPassed)
return true;
// Note: Wait 50 microseconds in case the controller couldn't respond
IO::delay(50);
}
dbgln("I8042: Trying to probe for existence of controller failed");
return false;
}
}
UNMAP_AFTER_INIT void I8042Controller::detect_devices()
{
if (!check_existence())
return;
u8 configuration;
{
SpinlockLocker lock(m_lock);
@ -255,6 +277,18 @@ void I8042Controller::prepare_for_output()
}
}
UNMAP_AFTER_INIT void I8042Controller::do_write(u8 port, u8 data)
{
VERIFY(m_lock.is_locked());
IO::out8(port, data);
}
UNMAP_AFTER_INIT u8 I8042Controller::do_read(u8 port)
{
VERIFY(m_lock.is_locked());
return IO::in8(port);
}
void I8042Controller::do_wait_then_write(u8 port, u8 data)
{
VERIFY(m_lock.is_locked());

5
Kernel/Devices/HID/I8042Controller.h
View file

@ -144,6 +144,11 @@ private:
u8 do_wait_then_read(u8 port);
void drain_output_buffer();
// Note: These functions exist only for the initialization process of the controller
void do_write(u8 port, u8 data);
u8 do_read(u8 port);
bool check_existence();
Spinlock m_lock;
bool m_first_port_available { false };
bool m_second_port_available { false };