major refactorings

Signed-off-by: kaguya3311 <kaguya3311@national.shitposting.agency>

oldsrc/audio/pcm.h

@@ -0,0 +1,53 @@
+#pragma once
+#include <stdint.h>
+#include <stdbool.h>
+#include "hda.h"
+
+/*
+ * Minimal WAV (RIFF/WAVE) header types.
+ * pcm_play_file() autodetects RIFF/WAVE and falls back to raw PCM if the
+ * magic bytes aren't present.
+ */
+
+typedef struct __attribute__((packed)) {
+    char     chunk_id[4];    /* "RIFF"                                        */
+    uint32_t chunk_size;     /* file size − 8                                 */
+    char     format[4];      /* "WAVE"                                        */
+} wav_riff_t;
+
+typedef struct __attribute__((packed)) {
+    char     chunk_id[4];    /* "fmt "                                        */
+    uint32_t chunk_size;     /* 16 for PCM                                    */
+    uint16_t audio_format;   /* 1 = PCM (linear)                              */
+    uint16_t channels;
+    uint32_t sample_rate;
+    uint32_t byte_rate;      /* sample_rate * channels * bits_per_sample / 8  */
+    uint16_t block_align;
+    uint16_t bits_per_sample;
+} wav_fmt_chunk_t;
+
+/*
+ * pcm_play_file - read a file from the ext2 root directory and play it via HDA.
+ *
+ * Supports:
+ *   • WAV  – any PCM WAV (no compression): sample rate / channels / bit depth
+ *            are read from the "fmt " chunk automatically.
+ *   • Raw  – no RIFF header; audio is assumed to be 48 000 Hz, 16-bit, stereo.
+ *            Override with pcm_play_raw() if file has a different format.
+ *
+ * The function allocates a physically-contiguous DMA buffer, reads the file,
+ * starts playback, blocks until complete, then frees the buffer.
+ *
+ * @filename : name of the file in the ext2 root directory (e.g. "music.wav").
+ * Returns   : true on success.
+ */
+bool pcm_play_file(const char *filename);
+
+/*
+ * pcm_play_raw - same as pcm_play_file but forces the given format instead of
+ * auto-detecting from a WAV header.  Useful for headerless .pcm files.
+ *
+ * @filename : file in ext2 root.
+ * @fmt      : sample rate / channels / bit depth.
+ */
+bool pcm_play_raw(const char *filename, hda_format_t fmt);