/* * miscellaneous helper functions * * Copyright (c) Clemens Ladisch * Licensed under the terms of the GNU General Public License, version 2. */ #include #include #include #include #include #include "lib.h" #define ERROR_RETRY_DELAY_MS 20 /** * snd_fw_transaction - send a request and wait for its completion * @unit: the driver's unit on the target device * @tcode: the transaction code * @offset: the address in the target's address space * @buffer: input/output data * @length: length of @buffer * @flags: use %FW_FIXED_GENERATION and add the generation value to attempt the * request only in that generation; use %FW_QUIET to suppress error * messages * * Submits an asynchronous request to the target device, and waits for the * response. The node ID and the current generation are derived from @unit. * On a bus reset or an error, the transaction is retried a few times. * Returns zero on success, or a negative error code. */ int snd_fw_transaction(struct fw_unit *unit, int tcode, u64 offset, void *buffer, size_t length, unsigned int flags) { struct fw_device *device = fw_parent_device(unit); int generation, rcode, tries = 0; generation = flags & FW_GENERATION_MASK; for (;;) { if (!(flags & FW_FIXED_GENERATION)) { generation = device->generation; smp_rmb(); /* node_id vs. generation */ } rcode = fw_run_transaction(device->card, tcode, device->node_id, generation, device->max_speed, offset, buffer, length); if (rcode == RCODE_COMPLETE) return 0; if (rcode == RCODE_GENERATION && (flags & FW_FIXED_GENERATION)) return -EAGAIN; if (rcode_is_permanent_error(rcode) || ++tries >= 3) { if (!(flags & FW_QUIET)) dev_err(&unit->device, "transaction failed: %s\n", fw_rcode_string(rcode)); return -EIO; } msleep(ERROR_RETRY_DELAY_MS); } } EXPORT_SYMBOL(snd_fw_transaction); static void async_midi_port_callback(struct fw_card *card, int rcode, void *data, size_t length, void *callback_data) { struct snd_fw_async_midi_port *port = callback_data; struct snd_rawmidi_substream *substream = ACCESS_ONCE(port->substream); /* This port is closed. */ if (substream == NULL) return; if (rcode == RCODE_COMPLETE) snd_rawmidi_transmit_ack(substream, port->consume_bytes); else if (!rcode_is_permanent_error(rcode)) /* To start next transaction immediately for recovery. */ port->next_ktime = ktime_set(0, 0); else /* Don't continue processing. */ port->error = true; port->idling = true; if (!snd_rawmidi_transmit_empty(substream)) schedule_work(&port->work); } static void midi_port_work(struct work_struct *work) { struct snd_fw_async_midi_port *port = container_of(work, struct snd_fw_async_midi_port, work); struct snd_rawmidi_substream *substream = ACCESS_ONCE(port->substream); int generation; int type; /* Under transacting or error state. */ if (!port->idling || port->error) return; /* Nothing to do. */ if (substream == NULL || snd_rawmidi_transmit_empty(substream)) return; /* Do it in next chance. */ if (ktime_after(port->next_ktime, ktime_get())) { schedule_work(&port->work); return; } /* * Fill the buffer. The callee must use snd_rawmidi_transmit_peek(). * Later, snd_rawmidi_transmit_ack() is called. */ memset(port->buf, 0, port->len); port->consume_bytes = port->fill(substream, port->buf); if (port->consume_bytes <= 0) { /* Do it in next chance, immediately. */ if (port->consume_bytes == 0) { port->next_ktime = ktime_set(0, 0); schedule_work(&port->work); } else { /* Fatal error. */ port->error = true; } return; } /* Calculate type of transaction. */ if (port->len == 4) type = TCODE_WRITE_QUADLET_REQUEST; else type = TCODE_WRITE_BLOCK_REQUEST; /* Set interval to next transaction. */ port->next_ktime = ktime_add_ns(ktime_get(), port->consume_bytes * 8 * NSEC_PER_SEC / 31250); /* Start this transaction. */ port->idling = false; /* * In Linux FireWire core, when generation is updated with memory * barrier, node id has already been updated. In this module, After * this smp_rmb(), load/store instructions to memory are completed. * Thus, both of generation and node id are available with recent * values. This is a light-serialization solution to handle bus reset * events on IEEE 1394 bus. */ generation = port->parent->generation; smp_rmb(); fw_send_request(port->parent->card, &port->transaction, type, port->parent->node_id, generation, port->parent->max_speed, port->addr, port->buf, port->len, async_midi_port_callback, port); } /** * snd_fw_async_midi_port_init - initialize asynchronous MIDI port structure * @port: the asynchronous MIDI port to initialize * @unit: the target of the asynchronous transaction * @addr: the address to which transactions are transferred * @len: the length of transaction * @fill: the callback function to fill given buffer, and returns the * number of consumed bytes for MIDI message. * */ int snd_fw_async_midi_port_init(struct snd_fw_async_midi_port *port, struct fw_unit *unit, u64 addr, unsigned int len, snd_fw_async_midi_port_fill fill) { port->len = DIV_ROUND_UP(len, 4) * 4; port->buf = kzalloc(port->len, GFP_KERNEL); if (port->buf == NULL) return -ENOMEM; port->parent = fw_parent_device(unit); port->addr = addr; port->fill = fill; port->idling = true; port->next_ktime = ktime_set(0, 0); port->error = false; INIT_WORK(&port->work, midi_port_work); return 0; } EXPORT_SYMBOL(snd_fw_async_midi_port_init); /** * snd_fw_async_midi_port_destroy - free asynchronous MIDI port structure * @port: the asynchronous MIDI port structure */ void snd_fw_async_midi_port_destroy(struct snd_fw_async_midi_port *port) { snd_fw_async_midi_port_finish(port); cancel_work_sync(&port->work); kfree(port->buf); } EXPORT_SYMBOL(snd_fw_async_midi_port_destroy); MODULE_DESCRIPTION("FireWire audio helper functions"); MODULE_AUTHOR("Clemens Ladisch "); MODULE_LICENSE("GPL v2");