sound blaster code doesn't work yet

[bootcensus] / src / au_sb.c

diff --git a/src/au_sb.c b/src/au_sb.c
index f3184ae..b42a603 100644 (file)
--- a/src/au_sb.c
+++ b/src/au_sb.c
@@ -19,6 +19,8 @@ along with this program.  If not, see <https://www.gnu.org/licenses/>.
 #include "audio.h"
 #include "au_sb.h"
 #include "asmops.h"
+#include "intr.h"
+#include "dma.h"
 
 #define REG_MIXPORT            (base_port + 0x4)
 #define REG_MIXDATA            (base_port + 0x5)
@@ -33,20 +35,49 @@ along with this program.  If not, see <https://www.gnu.org/licenses/>.
 #define WSTAT_BUSY             0x80
 #define RSTAT_RDY              0x80
 
-#define CMD_SET_RATE   0x41
-#define CMD_PLAY_PCM   0xa6
-#define CMD_STOP_PCM   0xd9
-#define CMD_GET_VER            0xe1
+#define CMD_RATE                       0x40
+#define CMD_SB16_OUT_RATE      0x41
+#define CMD_SB16_IN_RATE       0x42
+#define CMD_GET_VER                    0xe1
+
+/* start DMA playback/recording. combine with fifo/auto/input flags */
+#define CMD_START_DMA8         0xc0
+#define CMD_START_DMA16                0xb0
+#define CMD_FIFO                       0x02
+#define CMD_AUTO                       0x04
+#define CMD_INPUT                      0x08
+
+/* immediately pause/continue */
+#define CMD_PAUSE_DMA8         0xd0
+#define CMD_CONT_DMA8          0xd4
+#define CMD_PAUSE_DMA16                0xd5
+#define CMD_CONT_DMA16         0xd6
+
+/* end the playback at the end of the current buffer */
+#define CMD_END_DMA16          0xd9
+#define CMD_END_DMA8           0xda
+
+/* transfer mode commands */
+#define CMD_MODE_SIGNED                0x10
+#define CMD_MODE_STEREO                0x20
 
 #define VER_MAJOR(x)   ((x) >> 8)
 #define VER_MINOR(x)   ((x) & 0xff)
 
+static void intr_handler();
+static void start_dma_transfer(uint32_t addr, int size);
 static void write_dsp(unsigned char val);
 static unsigned char read_dsp(void);
 static int get_dsp_version(void);
 static const char *sbname(int ver);
 
+extern unsigned char low_mem_buffer[];
+
 static int base_port;
+static int irq, dma_chan;
+static int sb16;
+static void *buffer;
+static int xfer_mode;
 
 int sb_detect(void)
 {
@@ -56,12 +87,17 @@ int sb_detect(void)
                base_port = 0x200 + ((i + 1) << 4);
                if(sb_reset_dsp() == 0) {
                        ver = get_dsp_version();
+                       sb16 = VER_MAJOR(ver) >= 4;
                        printf("sb_detect: found %s (DSP v%d.%02d) at port %xh\n", sbname(ver),
                                        VER_MAJOR(ver), VER_MINOR(ver), base_port);
                        return 1;
                }
        }
 
+       /* TODO: detect these somehow? */
+       irq = 5;
+       dma_chan = 1;
+
        return 0;
 }
 
@@ -84,6 +120,101 @@ int sb_reset_dsp(void)
        return -1;
 }
 
+void sb_set_output_rate(int rate)
+{
+       if(sb16) {
+               write_dsp(CMD_SB16_OUT_RATE);
+               write_dsp(rate >> 8);
+               write_dsp(rate & 0xff);
+       } else {
+               int tcon = 256 - 1000000 / rate;
+               write_dsp(CMD_RATE);
+               write_dsp(tcon);
+       }
+}
+
+void *sb_buffer(int *size)
+{
+       *size = 65536;
+       return buffer;
+}
+
+void sb_start(int rate, int nchan)
+{
+       uint32_t addr;
+       int size;
+
+       /* for now just use the are after boot2. it's only used by the second stage
+        * loader and the VBE init code, none of which should overlap with audio playback.
+        * It's not necessary to use low memory. We can use up to the first 16mb for this,
+        * so if this becomes an issue, I'll make a DMA buffer allocator over 1mb.
+        * start the buffer from the next 64k boundary.
+        */
+       addr = ((uint32_t)low_mem_buffer + 0xffff) & 0xffff0000;
+       buffer = (void*)addr;
+
+       xfer_mode = CMD_MODE_SIGNED;
+       if(nchan > 1) {
+               xfer_mode |= CMD_MODE_STEREO;
+       }
+
+       if(!(size = audio_callback(buffer, 65536))) {
+               return;
+       }
+
+       interrupt(IRQ_TO_INTR(irq), intr_handler);
+
+       start_dma_transfer(addr, size);
+}
+
+void sb_pause(void)
+{
+       write_dsp(CMD_PAUSE_DMA8);
+}
+
+void sb_continue(void)
+{
+       write_dsp(CMD_CONT_DMA8);
+}
+
+void sb_stop(void)
+{
+       write_dsp(CMD_END_DMA8);
+}
+
+void sb_volume(int vol)
+{
+       /* TODO */
+}
+
+static void intr_handler()
+{
+       int size;
+
+       /* ask for more data */
+       if(!(size = audio_callback(buffer, 65536))) {
+               sb_stop();
+               return;
+       }
+       start_dma_transfer((uint32_t)buffer, size);
+
+       /* acknowledge the interrupt */
+       inb(REG_INTACK);
+}
+
+static void start_dma_transfer(uint32_t addr, int size)
+{
+       /* set up the next DMA transfer */
+       dma_out(dma_chan, addr, size, DMA_SINGLE);
+
+       /* program the DSP to accept the DMA transfer */
+       write_dsp(CMD_START_DMA8 | CMD_FIFO);
+       write_dsp(xfer_mode);
+       size--;
+       write_dsp(size & 0xff);
+       write_dsp((size >> 8) & 0xff);
+}
+
 static void write_dsp(unsigned char val)
 {
        while(inb(REG_WSTAT) & WSTAT_BUSY);