mirror of
https://github.com/qemu/qemu.git
synced 2025-08-02 12:45:00 +00:00
ce967e2f33
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>
54 lines
1.9 KiB
C
54 lines
1.9 KiB
C
/*
|
|
* QEMU 8253/8254 interval timer emulation
|
|
*
|
|
* Copyright (c) 2003-2004 Fabrice Bellard
|
|
*
|
|
* Permission is hereby granted, free of charge, to any person obtaining a copy
|
|
* of this software and associated documentation files (the "Software"), to deal
|
|
* in the Software without restriction, including without limitation the rights
|
|
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
|
|
* copies of the Software, and to permit persons to whom the Software is
|
|
* furnished to do so, subject to the following conditions:
|
|
*
|
|
* The above copyright notice and this permission notice shall be included in
|
|
* all copies or substantial portions of the Software.
|
|
*
|
|
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
|
|
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
|
|
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
|
|
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
|
|
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
|
|
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
|
|
* THE SOFTWARE.
|
|
*/
|
|
|
|
#ifndef HW_I8254_H
|
|
#define HW_I8254_H
|
|
|
|
#include "hw.h"
|
|
#include "isa.h"
|
|
|
|
#define PIT_FREQ 1193182
|
|
|
|
static inline ISADevice *pit_init(ISABus *bus, int base, int isa_irq,
|
|
qemu_irq alt_irq)
|
|
{
|
|
ISADevice *dev;
|
|
|
|
dev = isa_create(bus, "isa-pit");
|
|
qdev_prop_set_uint32(&dev->qdev, "iobase", base);
|
|
qdev_init_nofail(&dev->qdev);
|
|
qdev_connect_gpio_out(&dev->qdev, 0,
|
|
isa_irq >= 0 ? isa_get_irq(dev, isa_irq) : alt_irq);
|
|
|
|
return dev;
|
|
}
|
|
|
|
void pit_set_gate(ISADevice *dev, int channel, int val);
|
|
int pit_get_gate(ISADevice *dev, int channel);
|
|
int pit_get_initial_count(ISADevice *dev, int channel);
|
|
int pit_get_mode(ISADevice *dev, int channel);
|
|
int pit_get_out(ISADevice *dev, int channel, int64_t current_time);
|
|
|
|
#endif /* !HW_I8254_H */
|