[alsa-devel] Help requested: new HSS1394 MIDI back-end
Clemens Ladisch
clemens at ladisch.de
Sun May 27 15:50:27 CEST 2012
Sean M. Pappalardo - D.J. Pegasus wrote:
> where can I find documentation on writing a new MIDI driver for ALSA?
See the document "Writing an ALSA Driver", and look at the source code
of other MIDI drivers, such as, for example, sound/usb/midi.c or the
(untested) patch below.
BTW: What is the output of "lsfirewire -v" for these devices?
Regards,
Clemens
--- a/sound/firewire/Kconfig
+++ b/sound/firewire/Kconfig
@@ -33,4 +33,17 @@ config SND_ISIGHT
To compile this driver as a module, choose M here: the module
will be called snd-isight.
+config SND_SCS1X
+ tristate "Stanton Control System 1 MIDI"
+ select SND_PCM
+ select SND_RAWMIDI
+ select SND_FIREWIRE_LIB
+ help
+ Say Y here to include support for the MIDI ports of the Stanton
+ SCS.1d/SCS.1m DJ controllers. (SCS.1m audio is still handled
+ by FFADO.)
+
+ To compile this driver as a module, choose M here: the module
+ will be called snd-scs1x.
+
endif # SND_FIREWIRE
--- a/sound/firewire/Makefile
+++ b/sound/firewire/Makefile
@@ -2,7 +2,9 @@ snd-firewire-lib-objs := lib.o iso-resources.o packets-buffer.o \
fcp.o cmp.o amdtp.o
snd-firewire-speakers-objs := speakers.o
snd-isight-objs := isight.o
+snd-scs1x-objs := scs1x.o
obj-$(CONFIG_SND_FIREWIRE_LIB) += snd-firewire-lib.o
obj-$(CONFIG_SND_FIREWIRE_SPEAKERS) += snd-firewire-speakers.o
obj-$(CONFIG_SND_ISIGHT) += snd-isight.o
+obj-$(CONFIG_SND_SCS1X) += snd-scs1x.o
--- /dev/null
+++ b/sound/firewire/scs1x.c
@@ -0,0 +1,447 @@
+/*
+ * Stanton Control System 1 MIDI driver
+ *
+ * Copyright (c) Clemens Ladisch <clemens at ladisch.de>
+ * Licensed under the terms of the GNU General Public License, version 2.
+ */
+
+#include <linux/device.h>
+#include <linux/firewire.h>
+#include <linux/firewire-constants.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/mod_devicetable.h>
+#include <linux/slab.h>
+#include <linux/wait.h>
+#include <sound/core.h>
+#include <sound/initval.h>
+#include <sound/rawmidi.h>
+#include "lib.h"
+
+#define OUI_STANTON 0x001260
+#define MODEL_SCS_1M 0x001000
+
+#define HSS1394_ADDRESS 0xc007dedadadaULL
+#define HSS1394_MAX_PACKET_SIZE 64
+
+#define HSS1394_TAG_USER_DATA 0x00
+#define HSS1394_TAG_CHANGE_ADDRESS 0xf1
+#define HSS1394_TAG_PING_RESPONSE 0xf3
+
+struct scs {
+ struct snd_card *card;
+ struct fw_unit *unit;
+ struct fw_address_handler hss_handler;
+ struct fw_transaction transaction;
+ bool transaction_running;
+ bool output_idle;
+ u8 midi_status;
+ u8 midi_bytes;
+ struct snd_rawmidi_substream *output;
+ struct snd_rawmidi_substream *input;
+ struct tasklet_struct tasklet;
+ wait_queue_head_t idle_wait;
+ u8 *buffer;
+};
+
+static int scs_output_open(struct snd_rawmidi_substream *stream)
+{
+ struct scs *scs = stream->rmidi->private_data;
+
+ scs->midi_status = 0;
+ scs->midi_bytes = 0;
+
+ return 0;
+}
+
+static int scs_output_close(struct snd_rawmidi_substream *stream)
+{
+ return 0;
+}
+
+static void scs_output_trigger(struct snd_rawmidi_substream *stream, int up)
+{
+ struct scs *scs = stream->rmidi->private_data;
+
+ ACCESS_ONCE(scs->output) = up ? stream : NULL;
+ if (up) {
+ scs->output_idle = false;
+ tasklet_schedule(&scs->tasklet);
+ }
+}
+
+static void scs_write_callback(struct fw_card *card, int rcode,
+ void *data, size_t length, void *callback_data)
+{
+ struct scs *scs = callback_data;
+
+ if (rcode == RCODE_GENERATION) {
+ /* TODO: retry this packet */
+ }
+
+ scs->transaction_running = false;
+ tasklet_schedule(&scs->tasklet);
+}
+
+static bool is_valid_running_status(u8 status)
+{
+ return status >= 0x80 && status <= 0xef;
+}
+
+static bool is_one_byte_cmd(u8 status)
+{
+ return status == 0xf6 ||
+ status >= 0xf8;
+}
+
+static bool is_two_bytes_cmd(u8 status)
+{
+ return (status >= 0xc0 && status <= 0xdf) ||
+ status == 0xf1 ||
+ status == 0xf3;
+}
+
+static bool is_three_bytes_cmd(u8 status)
+{
+ return (status >= 0x80 && status <= 0xbf) ||
+ (status >= 0xe0 && status <= 0xef) ||
+ status == 0xf2;
+}
+
+static bool is_invalid_cmd(u8 status)
+{
+ return status == 0xf4 || status == 0xf5;
+}
+
+static void scs_output_tasklet(unsigned long data)
+{
+ struct scs *scs = (void *)data;
+ struct snd_rawmidi_substream *stream;
+ unsigned int i;
+ u8 byte;
+ struct fw_device *dev;
+ int generation;
+
+ if (scs->transaction_running)
+ return;
+
+ stream = ACCESS_ONCE(scs->output);
+ if (!stream) {
+ scs->output_idle = true;
+ wake_up(&scs->idle_wait);
+ return;
+ }
+
+ i = scs->midi_bytes;
+ for (;;) {
+ if (snd_rawmidi_transmit(stream, &byte, 1) != 1) {
+ scs->midi_bytes = i;
+ scs->output_idle = true;
+ wake_up(&scs->idle_wait);
+ return;
+ }
+ /*
+ * Convert from real MIDI to what the device expects (no
+ * running status, one command per packet).
+ */
+ if (byte < 0x80) {
+ if (i == 0) {
+ if (!is_valid_running_status(scs->midi_status))
+ continue;
+ scs->buffer[++i] = scs->midi_status;
+ }
+ scs->buffer[++i] = byte;
+ if ((i == 2 && is_two_bytes_cmd(scs->midi_status)) ||
+ (i == 3 && is_three_bytes_cmd(scs->midi_status)))
+ break;
+ if (i >= HSS1394_MAX_PACKET_SIZE - 1)
+ i = 0;
+ } else if (byte == 0xf7) {
+ if (i > 0 && scs->midi_status == 0xf0) {
+ scs->buffer[++i] = 0xf7;
+ break;
+ }
+ } else if (!is_invalid_cmd(byte) &&
+ byte < 0xf8) {
+ i = 0;
+ scs->buffer[++i] = byte;
+ scs->midi_status = byte;
+ if (is_one_byte_cmd(byte))
+ break;
+ }
+ }
+ scs->midi_bytes = 0;
+
+ scs->transaction_running = true;
+ dev = fw_parent_device(scs->unit);
+ generation = dev->generation;
+ smp_rmb(); /* node_id vs. generation */
+ fw_send_request(dev->card, &scs->transaction, TCODE_WRITE_BLOCK_REQUEST,
+ dev->node_id, generation, dev->max_speed,
+ HSS1394_ADDRESS, scs->buffer, 1 + i,
+ scs_write_callback, scs);
+}
+
+static void scs_output_drain(struct snd_rawmidi_substream *stream)
+{
+ struct scs *scs = stream->rmidi->private_data;
+
+ wait_event(scs->idle_wait, scs->output_idle);
+}
+
+static struct snd_rawmidi_ops output_ops = {
+ .open = scs_output_open,
+ .close = scs_output_close,
+ .trigger = scs_output_trigger,
+ .drain = scs_output_drain,
+};
+
+static int scs_input_open(struct snd_rawmidi_substream *stream)
+{
+ return 0;
+}
+
+static int scs_input_close(struct snd_rawmidi_substream *stream)
+{
+ return 0;
+}
+
+static void scs_input_trigger(struct snd_rawmidi_substream *stream, int up)
+{
+ struct scs *scs = stream->rmidi->private_data;
+
+ ACCESS_ONCE(scs->input) = up ? stream : NULL;
+}
+
+static struct snd_rawmidi_ops input_ops = {
+ .open = scs_input_open,
+ .close = scs_input_close,
+ .trigger = scs_input_trigger,
+};
+
+static int scs_create_midi(struct scs *scs)
+{
+ struct snd_rawmidi *rmidi;
+ int err;
+
+ err = snd_rawmidi_new(scs->card, "SCS.1x", 0, 1, 1, &rmidi);
+ if (err < 0)
+ return err;
+ snprintf(rmidi->name, sizeof(rmidi->name),
+ "%s MIDI", scs->card->shortname);
+ rmidi->info_flags = SNDRV_RAWMIDI_INFO_OUTPUT |
+ SNDRV_RAWMIDI_INFO_INPUT |
+ SNDRV_RAWMIDI_INFO_DUPLEX;
+ rmidi->private_data = scs;
+ snd_rawmidi_set_ops(rmidi, SNDRV_RAWMIDI_STREAM_OUTPUT, &output_ops);
+ snd_rawmidi_set_ops(rmidi, SNDRV_RAWMIDI_STREAM_INPUT, &input_ops);
+
+ return 0;
+}
+
+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)
+{
+ struct scs *scs = callback_data;
+ struct snd_rawmidi_substream *stream;
+
+ if (offset != scs->hss_handler.offset) {
+ fw_send_response(card, request, RCODE_ADDRESS_ERROR);
+ return;
+ }
+ if (tcode != TCODE_WRITE_QUADLET_REQUEST &&
+ tcode != TCODE_WRITE_BLOCK_REQUEST) {
+ fw_send_response(card, request, RCODE_TYPE_ERROR);
+ return;
+ }
+
+ if (length >= 1 && ((const u8 *)data)[0] == HSS1394_TAG_USER_DATA) {
+ stream = ACCESS_ONCE(scs->input);
+ if (stream)
+ snd_rawmidi_receive(stream, data + 1, length - 1);
+ }
+
+ fw_send_response(card, request, RCODE_COMPLETE);
+}
+
+static int scs_check_version(struct scs *scs)
+{
+ u8 data[4];
+ int err;
+
+ err = snd_fw_transaction(scs->unit, TCODE_READ_BLOCK_REQUEST,
+ HSS1394_ADDRESS, data, 4);
+ if (err < 0)
+ return err;
+
+ if (data[0] != HSS1394_TAG_PING_RESPONSE) {
+ dev_err(&scs->unit->device,
+ "wrong ping response: expected %#02x, got %#02x\n",
+ HSS1394_TAG_PING_RESPONSE, data[0]);
+ return -ENXIO;
+ }
+
+ return 0;
+}
+
+static int scs_init_hss_address(struct scs *scs)
+{
+ u8 data[8];
+
+ *(__be64 *)data = cpu_to_be64(scs->hss_handler.offset);
+ data[0] = HSS1394_TAG_CHANGE_ADDRESS;
+ return snd_fw_transaction(scs->unit, TCODE_WRITE_BLOCK_REQUEST,
+ HSS1394_ADDRESS, data, 8);
+}
+
+static void scs_card_free(struct snd_card *card)
+{
+ struct scs *scs = card->private_data;
+
+ fw_core_remove_address_handler(&scs->hss_handler);
+ kfree(scs->buffer);
+}
+
+static int scs_probe(struct device *unit_dev)
+{
+ struct fw_unit *unit = fw_unit(unit_dev);
+ struct fw_device *fw_dev = fw_parent_device(unit);
+ struct snd_card *card;
+ struct scs *scs;
+ int err;
+
+ err = snd_card_create(-16, NULL, THIS_MODULE, sizeof(*scs), &card);
+ if (err < 0)
+ return err;
+ snd_card_set_dev(card, unit_dev);
+
+ scs = card->private_data;
+ scs->card = card;
+ scs->unit = unit;
+ tasklet_init(&scs->tasklet, scs_output_tasklet, (unsigned long)scs);
+ init_waitqueue_head(&scs->idle_wait);
+ scs->output_idle = true;
+
+ scs->buffer = kmalloc(HSS1394_MAX_PACKET_SIZE, GFP_KERNEL);
+ if (!scs->buffer)
+ goto err_card;
+ scs->buffer[0] = HSS1394_TAG_USER_DATA;
+
+ err = scs_check_version(scs);
+ if (err < 0)
+ goto err_buffer;
+
+ scs->hss_handler.length = HSS1394_MAX_PACKET_SIZE;
+ scs->hss_handler.address_callback = handle_hss;
+ scs->hss_handler.callback_data = scs;
+ err = fw_core_add_address_handler(&scs->hss_handler,
+ &fw_high_memory_region);
+ if (err < 0)
+ goto err_buffer;
+
+ card->private_free = scs_card_free;
+
+ strcpy(card->driver, "SCS.1x");
+ strcpy(card->shortname, "SCS.1x");
+ fw_csr_string(unit->directory, CSR_MODEL,
+ card->shortname, sizeof(card->shortname));
+ snprintf(card->longname, sizeof(card->longname),
+ "Stanton %s (GUID %08x%08x) at %s, S%d",
+ card->shortname, fw_dev->config_rom[3], fw_dev->config_rom[4],
+ dev_name(&unit->device), 100 << fw_dev->max_speed);
+ strcpy(card->mixername, card->shortname);
+
+ err = scs_init_hss_address(scs);
+ if (err < 0)
+ goto err_card;
+
+ err = scs_create_midi(scs);
+ if (err < 0)
+ goto err_card;
+
+ err = snd_card_register(card);
+ if (err < 0)
+ goto err_card;
+
+ dev_set_drvdata(unit_dev, scs);
+
+ return 0;
+
+err_buffer:
+ kfree(scs->buffer);
+err_card:
+ snd_card_free(card);
+ return err;
+}
+
+static int scs_remove(struct device *dev)
+{
+ struct scs *scs = dev_get_drvdata(dev);
+
+ snd_card_disconnect(scs->card);
+
+ ACCESS_ONCE(scs->output) = NULL;
+ ACCESS_ONCE(scs->input) = NULL;
+
+ wait_event(scs->idle_wait, scs->output_idle);
+
+ tasklet_kill(&scs->tasklet);
+
+ snd_card_free_when_closed(scs->card);
+
+ return 0;
+}
+
+static void scs_update(struct fw_unit *unit)
+{
+ struct scs *scs = dev_get_drvdata(&unit->device);
+ u8 data[8];
+
+ *(__be64 *)data = cpu_to_be64(scs->hss_handler.offset);
+ data[0] = HSS1394_TAG_CHANGE_ADDRESS;
+ snd_fw_transaction(scs->unit, TCODE_WRITE_BLOCK_REQUEST,
+ HSS1394_ADDRESS, data, 8);
+}
+
+static const struct ieee1394_device_id scs_id_table[] = {
+ {
+ .match_flags = IEEE1394_MATCH_VENDOR_ID |
+ IEEE1394_MATCH_MODEL_ID,
+ .vendor_id = OUI_STANTON,
+ .model_id = MODEL_SCS_1M,
+ },
+ /* TODO: add ID for SCS.1d */
+ {}
+};
+MODULE_DEVICE_TABLE(ieee1394, scs_id_table);
+
+MODULE_DESCRIPTION("SCS.1x MIDI driver");
+MODULE_AUTHOR("Clemens Ladisch <clemens at ladisch.de>");
+MODULE_LICENSE("GPL v2");
+
+static struct fw_driver scs_driver = {
+ .driver = {
+ .owner = THIS_MODULE,
+ .name = KBUILD_MODNAME,
+ .bus = &fw_bus_type,
+ .probe = scs_probe,
+ .remove = scs_remove,
+ },
+ .update = scs_update,
+ .id_table = scs_id_table,
+};
+
+static int __init alsa_scs1x_init(void)
+{
+ return driver_register(&scs_driver.driver);
+}
+
+static void __exit alsa_scs1x_exit(void)
+{
+ driver_unregister(&scs_driver.driver);
+}
+
+module_init(alsa_scs1x_init);
+module_exit(alsa_scs1x_exit);
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