ALSA: firewire: add Stanton SCS.1d/1m driver

Add a MIDI driver for the Stanton FireWire DJ controllers.

Tested-by: Sean M. Pappalardo - D.J. Pegasus <spappalardo@mixxx.org>
Signed-off-by: Clemens Ladisch <clemens@ladisch.de>

3 files changed, 542 insertions, 0 deletions

diff --git a/sound/firewire/Kconfig b/sound/firewire/Kconfig
index 26071489970b..ea063e1f8722 100644
--- 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
diff --git a/sound/firewire/Makefile b/sound/firewire/Makefile
index d71ed8935f76..460179df5bb5 100644
--- 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
diff --git a/sound/firewire/scs1x.c b/sound/firewire/scs1x.c
new file mode 100644
index 000000000000..844a555c3b1e
--- /dev/null
+++ b/sound/firewire/scs1x.c
@@ -0,0 +1,527 @@
+/*
+ * Stanton Control System 1 MIDI driver
+ *
+ * Copyright (c) Clemens Ladisch <clemens@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/string.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 MODEL_SCS_1D    0x002000
+
+#define HSS1394_ADDRESS                 0xc007dedadadaULL
+#define HSS1394_MAX_PACKET_SIZE         64
+
+#define HSS1394_TAG_USER_DATA           0x00
+#define HSS1394_TAG_CHANGE_ADDRESS      0xf1
+
+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 output_status;
+        u8 output_bytes;
+        bool output_escaped;
+        bool output_escape_high_nibble;
+        u8 input_escape_count;
+        struct snd_rawmidi_substream *output;
+        struct snd_rawmidi_substream *input;
+        struct tasklet_struct tasklet;
+        wait_queue_head_t idle_wait;
+        u8 *buffer;
+};
+
+static const u8 sysex_escape_prefix[] = {
+        0xf0,                   /* SysEx begin */
+        0x00, 0x01, 0x60,       /* Stanton DJ */
+        0x48, 0x53, 0x53,       /* "HSS" */
+};
+
+static int scs_output_open(struct snd_rawmidi_substream *stream)
+{
+        struct scs *scs = stream->rmidi->private_data;
+
+        scs->output_status = 0;
+        scs->output_bytes = 1;
+        scs->output_escaped = false;
+
+        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 ||
+               status == 0xf9 ||
+               status == 0xfd;
+}
+
+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->output_bytes;
+        for (;;) {
+                if (snd_rawmidi_transmit(stream, &byte, 1) != 1) {
+                        scs->output_bytes = i;
+                        scs->output_idle = true;
+                        wake_up(&scs->idle_wait);
+                        return;
+                }
+                /*
+                 * Convert from real MIDI to what I think the device expects (no
+                 * running status, one command per packet, unescaped SysExs).
+                 */
+                if (scs->output_escaped && byte < 0x80) {
+                        if (scs->output_escape_high_nibble) {
+                                if (i < HSS1394_MAX_PACKET_SIZE) {
+                                        scs->buffer[i] = byte << 4;
+                                        scs->output_escape_high_nibble = false;
+                                }
+                        } else {
+                                scs->buffer[i++] |= byte & 0x0f;
+                                scs->output_escape_high_nibble = true;
+                        }
+                } else if (byte < 0x80) {
+                        if (i == 1) {
+                                if (!is_valid_running_status(scs->output_status))
+                                        continue;
+                                scs->buffer[0] = HSS1394_TAG_USER_DATA;
+                                scs->buffer[i++] = scs->output_status;
+                        }
+                        scs->buffer[i++] = byte;
+                        if ((i == 3 && is_two_bytes_cmd(scs->output_status)) ||
+                            (i == 4 && is_three_bytes_cmd(scs->output_status)))
+                                break;
+                        if (i == 1 + ARRAY_SIZE(sysex_escape_prefix) &&
+                            !memcmp(scs->buffer + 1, sysex_escape_prefix,
+                                    ARRAY_SIZE(sysex_escape_prefix))) {
+                                scs->output_escaped = true;
+                                scs->output_escape_high_nibble = true;
+                                i = 0;
+                        }
+                        if (i >= HSS1394_MAX_PACKET_SIZE)
+                                i = 1;
+                } else if (byte == 0xf7) {
+                        if (scs->output_escaped) {
+                                if (i >= 1 && scs->output_escape_high_nibble &&
+                                    scs->buffer[0] != HSS1394_TAG_CHANGE_ADDRESS)
+                                        break;
+                        } else {
+                                if (i > 1 && scs->output_status == 0xf0) {
+                                        scs->buffer[i++] = 0xf7;
+                                        break;
+                                }
+                        }
+                        i = 1;
+                        scs->output_escaped = false;
+                } else if (!is_invalid_cmd(byte) &&
+                           byte < 0xf8) {
+                        i = 1;
+                        scs->buffer[0] = HSS1394_TAG_USER_DATA;
+                        scs->buffer[i++] = byte;
+                        scs->output_status = byte;
+                        scs->output_escaped = false;
+                        if (is_one_byte_cmd(byte))
+                                break;
+                }
+        }
+        scs->output_bytes = 1;
+        scs->output_escaped = false;
+
+        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, 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)
+{
+        struct scs *scs = stream->rmidi->private_data;
+
+        scs->input_escape_count = 0;
+
+        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 void scs_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 scs_input_midi_byte(struct scs *scs,
+                                struct snd_rawmidi_substream *stream,
+                                u8 byte)
+{
+        if (scs->input_escape_count > 0) {
+                scs_input_escaped_byte(stream, byte);
+                scs->input_escape_count--;
+                if (scs->input_escape_count == 0)
+                        snd_rawmidi_receive(stream, (const u8[]) { 0xf7 }, 1);
+        } else if (byte == 0xf9) {
+                snd_rawmidi_receive(stream, sysex_escape_prefix,
+                                    ARRAY_SIZE(sysex_escape_prefix));
+                scs_input_escaped_byte(stream, 0x00);
+                scs_input_escaped_byte(stream, 0xf9);
+                scs->input_escape_count = 3;
+        } else {
+                snd_rawmidi_receive(stream, &byte, 1);
+        }
+}
+
+static void scs_input_packet(struct scs *scs,
+                             struct snd_rawmidi_substream *stream,
+                             const u8 *data, unsigned int bytes)
+{
+        unsigned int i;
+
+        if (data[0] == HSS1394_TAG_USER_DATA) {
+                for (i = 1; i < bytes; ++i)
+                        scs_input_midi_byte(scs, stream, data[i]);
+        } else {
+                snd_rawmidi_receive(stream, sysex_escape_prefix,
+                                    ARRAY_SIZE(sysex_escape_prefix));
+                for (i = 0; i < bytes; ++i)
+                        scs_input_escaped_byte(stream, data[i]);
+                snd_rawmidi_receive(stream, (const u8[]) { 0xf7 }, 1);
+        }
+}
+
+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) {
+                stream = ACCESS_ONCE(scs->input);
+                if (stream)
+                        scs_input_packet(scs, stream, data, length);
+        }
+
+        fw_send_response(card, request, RCODE_COMPLETE);
+}
+
+static int scs_init_hss_address(struct scs *scs)
+{
+        __be64 data;
+        int err;
+
+        data = cpu_to_be64(((u64)HSS1394_TAG_CHANGE_ADDRESS << 56) |
+                           scs->hss_handler.offset);
+        err = snd_fw_transaction(scs->unit, TCODE_WRITE_BLOCK_REQUEST,
+                                 HSS1394_ADDRESS, &data, 8);
+        if (err < 0)
+                dev_err(&scs->unit->device, "HSS1394 communication failed\n");
+
+        return err;
+}
+
+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->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 DJ %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);
+        __be64 data;
+
+        data = cpu_to_be64(((u64)HSS1394_TAG_CHANGE_ADDRESS << 56) |
+                           scs->hss_handler.offset);
+        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,
+        },
+        {
+                .match_flags = IEEE1394_MATCH_VENDOR_ID |
+                               IEEE1394_MATCH_MODEL_ID,
+                .vendor_id   = OUI_STANTON,
+                .model_id    = MODEL_SCS_1D,
+        },
+        {}
+};
+MODULE_DEVICE_TABLE(ieee1394, scs_id_table);
+
+MODULE_DESCRIPTION("SCS.1x MIDI driver");
+MODULE_AUTHOR("Clemens Ladisch <clemens@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);