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hw_x86_64_muen: Implement paravirt timer driver

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The driver uses the timer page containing a vector and timer value to
implement the start_one_shot() and value() functions. The timer value
designates the absolute tick count of the next event.

The address of the time page is acquired using the get_memregion_info
Sinfo API function.
This commit is contained in:
Reto Buerki 2015-04-23 15:17:24 +02:00 committed by Stefan Kalkowski
parent 4a51f933ce
commit fa26805fd7
1 changed files with 67 additions and 6 deletions
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73
repos/base-hw/src/core/include/spec/x86_64_muen/timer.h
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@ -14,7 +14,11 @@
#ifndef _TIMER_H_
#define _TIMER_H_
#include <base/stdint.h>
#include <base/printf.h>
/* core includes */
#include <board.h>
#include <sinfo.h>
namespace Genode
{
@ -26,18 +30,75 @@ namespace Genode
class Genode::Timer
{
private:
enum {
TIMER_DISABLED = ~0ULL,
};
uint64_t _tics_per_ms;
struct Subject_timer
{
uint64_t value;
uint8_t vector;
} __attribute__((packed));
struct Subject_timer * _timer_page;
inline uint64_t rdtsc()
{
uint32_t lo, hi;
asm volatile("rdtsc" : "=a" (lo), "=d" (hi));
return (uint64_t)hi << 32 | lo;
}
class Invalid_region {};
public:
Timer() { }
Timer() : _tics_per_ms(Sinfo::get_tsc_khz())
{
struct Sinfo::Memregion_info region;
if (!Sinfo::get_memregion_info("timer", &region)) {
PERR("muen-timer: Unable to retrieve time memory region");
throw Invalid_region();
}
static unsigned interrupt_id(int) { return 0; }
_timer_page = (Subject_timer *)region.address;
_timer_page->vector = Board::TIMER_VECTOR_KERNEL;
PINF("muen-timer: page @0x%llx, frequency %llu kHz, vector %u",
region.address, _tics_per_ms, _timer_page->vector);
}
inline void start_one_shot(uint32_t const tics, unsigned) { }
static unsigned interrupt_id(int)
{
return Board::TIMER_VECTOR_KERNEL;
}
uint32_t ms_to_tics(unsigned const ms) { return 1000; }
inline void start_one_shot(uint32_t const tics, unsigned)
{
_timer_page->value = rdtsc() + tics;
}
unsigned value(unsigned) { return 0; }
uint32_t ms_to_tics(unsigned const ms)
{
return ms * _tics_per_ms;
}
unsigned value(unsigned)
{
const uint64_t now = rdtsc();
if (_timer_page->value != TIMER_DISABLED
&& _timer_page->value > now) {
return _timer_page->value - now;
}
return 0;
}
/*
* Dummies
*/
static void disable_pit(void) { }
};