585d7cba5e
Some models receive MIDI messages via IEEE 1394 asynchronous transactions. In this case, MIDI messages are transferred in fixed-length payload. It's nice that firewire-lib module has common helper functions. This commit implements this idea. Each driver adds 'struct snd_fw_async_midi_port' in its instance structure. In probing, it should call snd_fw_async_midi_port_init() to initialize the structure with some parameters such as target address, the length of payload in a transaction and a pointer for callback function to fill the payload buffer. At 'struct snd_rawmidi_ops.trigger()' callback, it should call 'snd_fw_async_midi_port_run()' to start transactions. Each driver should ensure that the lifetime of MIDI substream continues till calling 'snd_fw_async_midi_port_finish()'. The helper functions support retries to transferring MIDI messages when transmission errors occur. When transactions are successful, the helper functions call 'snd_rawmidi_transmit_ack()' internally to consume MIDI bytes in the buffer. Therefore, Each driver is expected to use 'snd_rawmidi_transmit_peek()' to tell the number of bytes to transfer to return value of 'fill' callback. Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp> Signed-off-by: Takashi Iwai <tiwai@suse.de>
74 lines
1.8 KiB
C
74 lines
1.8 KiB
C
#ifndef SOUND_FIREWIRE_LIB_H_INCLUDED
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#define SOUND_FIREWIRE_LIB_H_INCLUDED
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#include <linux/firewire-constants.h>
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#include <linux/types.h>
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#include <linux/sched.h>
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#include <sound/rawmidi.h>
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struct fw_unit;
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#define FW_GENERATION_MASK 0x00ff
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#define FW_FIXED_GENERATION 0x0100
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#define FW_QUIET 0x0200
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int snd_fw_transaction(struct fw_unit *unit, int tcode,
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u64 offset, void *buffer, size_t length,
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unsigned int flags);
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/* returns true if retrying the transaction would not make sense */
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static inline bool rcode_is_permanent_error(int rcode)
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{
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return rcode == RCODE_TYPE_ERROR || rcode == RCODE_ADDRESS_ERROR;
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}
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struct snd_fw_async_midi_port;
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typedef int (*snd_fw_async_midi_port_fill)(
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struct snd_rawmidi_substream *substream,
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u8 *buf);
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struct snd_fw_async_midi_port {
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struct fw_device *parent;
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struct work_struct work;
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u64 addr;
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struct fw_transaction transaction;
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u8 *buf;
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unsigned int len;
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struct snd_rawmidi_substream *substream;
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snd_fw_async_midi_port_fill fill;
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unsigned int consume_bytes;
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};
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int snd_fw_async_midi_port_init(struct snd_fw_async_midi_port *port,
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struct fw_unit *unit, u64 addr, unsigned int len,
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snd_fw_async_midi_port_fill fill);
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void snd_fw_async_midi_port_destroy(struct snd_fw_async_midi_port *port);
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/**
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* snd_fw_async_midi_port_run - run transactions for the async MIDI port
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* @port: the asynchronous MIDI port
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* @substream: the MIDI substream
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*/
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static inline void
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snd_fw_async_midi_port_run(struct snd_fw_async_midi_port *port,
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struct snd_rawmidi_substream *substream)
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{
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port->substream = substream;
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schedule_work(&port->work);
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}
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/**
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* snd_fw_async_midi_port_finish - finish the asynchronous MIDI port
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* @port: the asynchronous MIDI port
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*/
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static inline void
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snd_fw_async_midi_port_finish(struct snd_fw_async_midi_port *port)
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{
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port->substream = NULL;
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}
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#endif
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