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2012-02-17i8254: Factor out pit_get_channel_infoJan Kiszka
Instead of providing 4 individual query functions for mode, gate, output and initial counter state, introduce a service that queries all information at once. This comes with tiny additional costs for pcspk_callback but with a much cleaner interface. Also, it will simplify the implementation of the KVM in-kernel PIT model. Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2012-02-17i8254: Rework & fix interaction with HPET in legacy modeJan Kiszka
When the HPET enters legacy mode, the IRQ output of the PIT is suppressed and replaced by the HPET timer 0. But the current code to emulate this was broken in many ways. It reset the PIT state after re-enabling, it worked against a stale static PIT structure, and it did not properly saved/restored the IRQ output mask in the PIT vmstate. This patch solves the PIT IRQ control in a different way. On x86, it both redirects the PIT IRQ to the HPET, just like the RTC. But it also keeps the control line from the HPET to the PIT. This allows to disable the PIT QEMU timer when it is not needed. The PIT's view on the control line state is now saved in the same format that qemu-kvm is already using. Note that, in contrast to the suppressed RTC IRQ line, we do not need to save/restore the PIT line state in the HPET. As we trigger a PIT IRQ update via the control line, the line state is reconstructed on mode switch. Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2012-02-17i8254: Pass alternative IRQ output object on initializationJan Kiszka
HPET legacy emulation will require control over the PIT IRQ output. To enable this, add support for an alternative IRQ output object to the PIT factory function. If the isa_irq number is < 0, this object will be used. This also removes the IRQ number property from the PIT class as we now use a generic GPIO output pin that is connected by the factory function. Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2012-02-17i8254: Factor out interface headerJan Kiszka
Move the public interface of the PIT into its own header file and update all users. Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>