stos/amd64: isa: Add legacy i8254 driver

Signed-off-by: Chloe M. <chloe@mensia.org>
2026-06-27 05:18:33 -05:00
parent ef72c9d6d5
commit 354cf87a16
2 changed files with 78 additions and 0 deletions
@@ -0,0 +1,36 @@
+/*
+ * Copyright (c) 2026, Chloe M.
+ * Provided under the BSD-3 clause.
+ *
+ * Description:  i8254 timer driver
+ * Author:       Chloe M.
+ */
+
+#ifndef _MACHINE_I8254_H_
+#define _MACHINE_I8254_H_ 1
+
+#include <stdef.h>
+
+#define I8254_COMMAND     0x43
+#define I8254_CHANNEL_0   0x40
+#define I8254_CHANNEL_2   0x42
+#define I8254_DIVIDEND    1193182ULL
+
+/*
+ * Obtain the current counter value
+ */
+USHORT MdPitGetCount(VOID);
+
+/*
+ * Set a new counter value
+ */
+VOID MdPitSetCount(USHORT Value);
+
+/*
+ * Set the PIT counter to match a frequency in Hz
+ *
+ * @Frequency: Frequency in HZ to set
+ */
+VOID MdPitSetFrequency(UQUAD Frequency);
+
+#endif  /* !_MACHINE_I8254_H_ */