many changes have happned

- updates to panic() interface
- genericized timer interface
- (yet unused) additions to task management

1 files changed, 56 insertions, 19 deletions

diff --git a/kc/core/pit8253.c b/kc/core/pit8253.c
index 0cf5232..4728020 100644
--- a/kc/core/pit8253.c
+++ b/kc/core/pit8253.c
@@ -3,6 +3,8 @@
 #include "port.h"
 #include "kprint.h"
 
+#include <stdatomic.h>
+
 #define PIT8253_DATA0 0x40
 #define PIT8253_CMD 0x43
 
@@ -13,51 +15,86 @@
 
 #define CONFIG_CHANNEL_0 (SEL_CHANNEL0|ACC_LOHI|MODE_RATE|BIN_COUNT)
 
+#define PIT_IRQ 0
 #define PIT_HZ 1193182U
+#define PIT_HZ_MIN (PIT_HZ/0xffff)
+
+static void pit8253_set_divisor(uint16_t divisor);
 
-static uint64_t count = 0;
+static atomic_uint_fast64_t count = 0;
+static uint16_t divisor = 0;
+
+const struct timer_source pit8253_timer_source =
+{
+    "pit8253",
+    pit8253_init,
+    pit8253_start,
+    pit8253_stop,
+
+    pit8253_set_frequency,
+    pit8253_get_frequency,
+
+    pit8253_nanoseconds_elapsed,
+    pit8253_nanoseconds_delta
+};
 
 int pit8253_callback(uint8_t irq)
 {
     (void)irq;
     count++;
 
-    if (!(count % (185)))
-    {
-        kprintf("it's been about %lu seconds since starting\n", count / 18);
-    }
-
     return 0;
 }
 
 void pit8253_init(void)
 {
-    kprintf(
-            "initializing timer to an approximate frequency of %uHz\n",
-            PIT_HZ / 0xffff);
-    outb(PIT8253_CMD, CONFIG_CHANNEL_0);
-    outb(PIT8253_DATA0, 0xff);
-    outb(PIT8253_DATA0, 0xff);
-
-    pic8259_irq_install(0, pit8253_callback);
-    pic8259_irq_unmask(0);
+    pic8259_irq_install(PIT_IRQ, pit8253_callback);
 }
 
 void pit8253_start(void)
 {
+    pic8259_irq_unmask(PIT_IRQ);
 }
 
 void pit8253_stop(void)
 {
+    pic8259_irq_mask(PIT_IRQ);
 }
 
-uint64_t pit8253_count(void)
+void pit8253_set_frequency(uint32_t frequency)
 {
-    return count;
+    uint32_t d = PIT_HZ / frequency;
+
+    if (d > UINT16_MAX)
+    {
+        kprintf("warning: %uHz is too slow for 8253 pit\n", PIT_HZ/d);
+        d = UINT16_MAX;
+        kprintf("warning: set timer to minimum frequency\n");
+    }
+
+    pit8253_set_divisor(d);
+}
+
+uint32_t pit8253_get_frequency(void)
+{
+    return PIT_HZ/divisor;
+}
+
+uint64_t pit8253_nanoseconds_elapsed(void)
+{
+    return pit8253_nanoseconds_delta() * count;
+}
+
+uint64_t pit8253_nanoseconds_delta(void)
+{
+    return (TIMER_NANOSECOND * divisor)/PIT_HZ;
 }
 
-void pit8253_set_hz(uint16_t hz)
+static void pit8253_set_divisor(uint16_t d)
 {
-    (void)hz;
+    outb(PIT8253_CMD, CONFIG_CHANNEL_0);
+    outb(PIT8253_DATA0, (uint8_t)d);
+    outb(PIT8253_DATA0, (uint8_t)(d >> 8));
+    divisor = d;
 }