include/i8254.hpp

   1 #ifndef I8254_HPP
   2 #define I8254_HPP
   3
   4 #include "device.hpp"
   5 #include "io.hpp"
   6 #include "marshal.hpp"
   7 #include "timer.hpp"
   8
   9 #define PIT_FREQ 1193182
  10
  11 enum DriftMode
  12 {
  13     DRIFT_DROP,
  14     DRIFT_REINJECT_GRADUAL,
  15     DRIFT_REINJECT_FAST,
  16 };
  17
  18 class PITChannel : public Device
  19 {
  20 public:
  21     PITChannel(void);
  22
  23     void write_back_command(uint8_t val);
  24     void write_control(uint8_t val);
  25     void write_counter(uint8_t val);
  26     uint8_t read(void);
  27
  28     void marshal(Marshaller *m, const char *name);
  29     void reset(int gate);
  30
  31     void set_drift_mode(DriftMode mode);
  32
  33     OutputPin irq;
  34
  35 private:
  36     int64_t get_next_transition_time(uint64_t current_time);
  37     void irq_timer_update(uint64_t current_time);
  38     void on_irq_timer(void);
  39     int get_out1(int64_t current_time);
  40     void load_count(int val);
  41     void latch_count(void);
  42     uint16_t get_count(void);
  43     void update_irq(uint64_t current_time);
  44
  45     uint32_t count; /* can be 65536 */
  46     uint16_t latched_count;
  47     uint8_t count_latched;
  48     uint8_t status_latched;
  49     uint8_t status;
  50     uint8_t read_state;
  51     uint8_t write_state;
  52     uint8_t write_latch;
  53     uint8_t rw_mode;
  54     uint8_t mode;
  55     uint8_t bcd; /* not supported */
  56     uint8_t gate; /* timer start */
  57     int64_t count_load_time;
  58     /* irq handling */
  59     int64_t next_transition_time;
  60     Timer irq_timer;
  61     int64_t missed_ticks;
  62
  63     DriftMode drift_mode;
  64 };
  65
  66 class PIT : public Device
  67 {
  68 public:
  69     PIT(DriftMode mode = DRIFT_DROP);
  70
  71     void marshal(Marshaller *m, const char *name);
  72
  73     void write(uint8_t addr, uint8_t val);
  74     uint8_t read(uint8_t addr);
  75
  76     OutputPin &get_irq(void);
  77
  78     void reset(void);
  79
  80 private:
  81     PITChannel channels[3];
  82 };
  83
  84 static inline void marshal(Marshaller *m, const char *name, DriftMode *mode)
  85 {
  86     uint32_t val = (int)*mode;
  87     marshal(m, name, &val);
  88     *mode = (DriftMode)val;
  89 }
  90
  91 #endif