Implement READ PMA command.

src/cdrom/cdrom.c

@@ -2149,6 +2149,21 @@ cdrom_get_current_subcodeq_playstatus(cdrom_t *dev, uint8_t *b)
     return ret;
 }
 
+int
+cdrom_read_pma(const cdrom_t *dev, uint8_t *b, const int max_len)
+{
+    if (max_len < 4)
+        return -1;
+
+    // This is exactly what a blank CD-R returns, no PMA, seems only CD-RWs have PMA?
+    b[0] = 0x00; /* PMA Data Length (MSB) */
+    b[1] = 0x02; /* PMA Data Length (LSB) */
+    b[2] = 0x00; /* Reserved */
+    b[3] = 0x00; /* Reserved */
+
+    return 4;
+}
+
 int
 cdrom_read_toc(const cdrom_t *dev, uint8_t *b, const int type,
                const uint8_t start_track, const int msf, const int max_len)

src/include/86box/cdrom.h

@@ -446,6 +446,7 @@ extern void            cdrom_get_current_subcodeq(cdrom_t *dev, uint8_t *b);
 extern uint8_t         cdrom_get_current_subcodeq_playstatus(cdrom_t *dev, uint8_t *b);
 extern int             cdrom_read_toc(const cdrom_t *dev, uint8_t *b, const int type,
                                       const uint8_t start_track, const int msf, const int max_len);
+extern int             cdrom_read_pma(const cdrom_t *dev, uint8_t *b, const int max_len);
 extern int             cdrom_read_toc_sony(const cdrom_t *dev, uint8_t *b, const uint8_t start_track,
                                            const int msf, const int max_len);
 #ifdef USE_CDROM_MITSUMI

src/scsi/scsi_cdrom.c

@@ -2658,6 +2658,11 @@ scsi_cdrom_command(scsi_common_t *sc, const uint8_t *cdb)
                     scsi_cdrom_set_buf_len(dev, BufLen, &len);
                     scsi_cdrom_data_command_finish(dev, len, len, len, 0);
                 }
+            } else if (toc_format == 3 && dev->drv->cd_status == CD_STATUS_BLANK_CDR) {
+                len = cdrom_read_pma(dev->drv, dev->buffer, max_len);
+
+                scsi_cdrom_set_buf_len(dev, BufLen, &len);
+                scsi_cdrom_data_command_finish(dev, len, len, len, 0);
             } else
                 scsi_cdrom_invalid_field(dev, toc_format);
             break;