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531f471834
In Linux kernel 4.4, firewire-lib got a feature called as 'async midi port' for transmission of MIDI message via IEEE 1394 asynchronous communication, however actual consumer of this feature is ALSA driver for TASCAM FireWire series only. When adding this feature, I assumed that ALSA driver for Digi00x might also be a consumer, actually it's not. This commit moves the feature from firewire-lib to firewire-tascam module. Two minor kernel APIs are removed. Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp> Signed-off-by: Takashi Iwai <tiwai@suse.de>
105 lines
3.1 KiB
C
105 lines
3.1 KiB
C
/*
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* miscellaneous helper functions
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*
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* Copyright (c) Clemens Ladisch <clemens@ladisch.de>
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* Licensed under the terms of the GNU General Public License, version 2.
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*/
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#include <linux/delay.h>
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#include <linux/device.h>
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#include <linux/firewire.h>
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#include <linux/module.h>
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#include <linux/slab.h>
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#include "lib.h"
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#define ERROR_RETRY_DELAY_MS 20
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/**
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* snd_fw_transaction - send a request and wait for its completion
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* @unit: the driver's unit on the target device
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* @tcode: the transaction code
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* @offset: the address in the target's address space
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* @buffer: input/output data
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* @length: length of @buffer
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* @flags: use %FW_FIXED_GENERATION and add the generation value to attempt the
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* request only in that generation; use %FW_QUIET to suppress error
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* messages
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*
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* Submits an asynchronous request to the target device, and waits for the
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* response. The node ID and the current generation are derived from @unit.
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* On a bus reset or an error, the transaction is retried a few times.
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* Returns zero on success, or a negative error code.
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*/
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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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{
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struct fw_device *device = fw_parent_device(unit);
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int generation, rcode, tries = 0;
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generation = flags & FW_GENERATION_MASK;
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for (;;) {
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if (!(flags & FW_FIXED_GENERATION)) {
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generation = device->generation;
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smp_rmb(); /* node_id vs. generation */
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}
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rcode = fw_run_transaction(device->card, tcode,
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device->node_id, generation,
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device->max_speed, offset,
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buffer, length);
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if (rcode == RCODE_COMPLETE)
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return 0;
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if (rcode == RCODE_GENERATION && (flags & FW_FIXED_GENERATION))
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return -EAGAIN;
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if (rcode_is_permanent_error(rcode) || ++tries >= 3) {
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if (!(flags & FW_QUIET))
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dev_err(&unit->device,
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"transaction failed: %s\n",
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fw_rcode_string(rcode));
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return -EIO;
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}
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msleep(ERROR_RETRY_DELAY_MS);
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}
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}
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EXPORT_SYMBOL(snd_fw_transaction);
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#define PROBE_DELAY_MS (2 * MSEC_PER_SEC)
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/**
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* snd_fw_schedule_registration - schedule work for sound card registration
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* @unit: an instance for unit on IEEE 1394 bus
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* @dwork: delayed work with callback function
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*
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* This function is not designed for general purposes. When new unit is
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* connected to IEEE 1394 bus, the bus is under bus-reset state because of
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* topological change. In this state, units tend to fail both of asynchronous
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* and isochronous communication. To avoid this problem, this function is used
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* to postpone sound card registration after the state. The callers must
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* set up instance of delayed work in advance.
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*/
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void snd_fw_schedule_registration(struct fw_unit *unit,
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struct delayed_work *dwork)
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{
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u64 now, delay;
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now = get_jiffies_64();
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delay = fw_parent_device(unit)->card->reset_jiffies
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+ msecs_to_jiffies(PROBE_DELAY_MS);
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if (time_after64(delay, now))
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delay -= now;
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else
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delay = 0;
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mod_delayed_work(system_wq, dwork, delay);
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}
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EXPORT_SYMBOL(snd_fw_schedule_registration);
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MODULE_DESCRIPTION("FireWire audio helper functions");
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MODULE_AUTHOR("Clemens Ladisch <clemens@ladisch.de>");
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MODULE_LICENSE("GPL v2");
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