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ALSA: oxfw: copy handlers of asynchronous transaction for MIDI capture

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This commit copies some functions of asynchronous transactions for MIDI
capture, to merge scs1x module. The features of payload in asynchronous
transaction are:

 * System exclusive messages for SCS.1 are encoded without ID data. In
   this encoding scheme, 4 bits in LSB are available. The bits are squashed
   in payload byte. Thus, one payload byte transfers two MIDI messages.
 * The first byte of payload byte means:
  * 0x00: depending on second payload byte
   * 0xf9: including escaped system exclusive messages for SCS.1, up to
     3 byte (= 6 MIDI messages)
   * the others: including MIDI 1.0 messages
  * the others: including escaped system exclusive messages for SCS.1, up
    to 64 bytes

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
This commit is contained in:
Takashi Sakamoto 2015-12-22 09:15:41 +09:00 committed by Takashi Iwai
parent e3315b439c
commit 13b8b78c7f
1 changed files with 82 additions and 1 deletions
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83
sound/firewire/oxfw/oxfw-scs1x.c
View File

@ -11,18 +11,99 @@
#define HSS1394_ADDRESS 0xc007dedadadaULL
#define HSS1394_MAX_PACKET_SIZE 64
#define HSS1394_TAG_USER_DATA 0x00
#define HSS1394_TAG_CHANGE_ADDRESS 0xf1
struct fw_scs1x {
struct fw_address_handler hss_handler;
u8 input_escape_count;
struct snd_rawmidi_substream *input;
};
static const u8 sysex_escape_prefix[] = {
0xf0, /* SysEx begin */
0x00, 0x01, 0x60, /* Stanton DJ */
0x48, 0x53, 0x53, /* "HSS" */
};
static void midi_input_escaped_byte(struct snd_rawmidi_substream *stream,
u8 byte)
{
u8 nibbles[2];
nibbles[0] = byte >> 4;
nibbles[1] = byte & 0x0f;
snd_rawmidi_receive(stream, nibbles, 2);
}
static void midi_input_byte(struct fw_scs1x *scs,
struct snd_rawmidi_substream *stream, u8 byte)
{
const u8 eox = 0xf7;
if (scs->input_escape_count > 0) {
midi_input_escaped_byte(stream, byte);
scs->input_escape_count--;
if (scs->input_escape_count == 0)
snd_rawmidi_receive(stream, &eox, sizeof(eox));
} else if (byte == 0xf9) {
snd_rawmidi_receive(stream, sysex_escape_prefix,
ARRAY_SIZE(sysex_escape_prefix));
midi_input_escaped_byte(stream, 0x00);
midi_input_escaped_byte(stream, 0xf9);
scs->input_escape_count = 3;
} else {
snd_rawmidi_receive(stream, &byte, 1);
}
}
static void midi_input_packet(struct fw_scs1x *scs,
struct snd_rawmidi_substream *stream,
const u8 *data, unsigned int bytes)
{
unsigned int i;
const u8 eox = 0xf7;
if (data[0] == HSS1394_TAG_USER_DATA) {
for (i = 1; i < bytes; ++i)
midi_input_byte(scs, stream, data[i]);
} else {
snd_rawmidi_receive(stream, sysex_escape_prefix,
ARRAY_SIZE(sysex_escape_prefix));
for (i = 0; i < bytes; ++i)
midi_input_escaped_byte(stream, data[i]);
snd_rawmidi_receive(stream, &eox, sizeof(eox));
}
}
static void handle_hss(struct fw_card *card, struct fw_request *request,
int tcode, int destination, int source, int generation,
unsigned long long offset, void *data, size_t length,
void *callback_data)
{
fw_send_response(card, request, RCODE_COMPLETE);
struct fw_scs1x *scs = callback_data;
struct snd_rawmidi_substream *stream;
int rcode;
if (offset != scs->hss_handler.offset) {
rcode = RCODE_ADDRESS_ERROR;
goto end;
}
if (tcode != TCODE_WRITE_QUADLET_REQUEST &&
tcode != TCODE_WRITE_BLOCK_REQUEST) {
rcode = RCODE_TYPE_ERROR;
goto end;
}
if (length >= 1) {
stream = ACCESS_ONCE(scs->input);
if (stream)
midi_input_packet(scs, stream, data, length);
}
rcode = RCODE_COMPLETE;
end:
fw_send_response(card, request, rcode);
}
static int register_address(struct snd_oxfw *oxfw)