added mtd driver

[linux-2.4.git] / drivers / ieee1394 / amdtp.c

/* -*- c-basic-offset: 8 -*-
 *
 * amdtp.c - Audio and Music Data Transmission Protocol Driver
 * Copyright (C) 2001 Kristian Høgsberg
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */

/* OVERVIEW
 * --------
 *
 * The AMDTP driver is designed to expose the IEEE1394 bus as a
 * regular OSS soundcard, i.e. you can link /dev/dsp to /dev/amdtp and
 * then your favourite MP3 player, game or whatever sound program will
 * output to an IEEE1394 isochronous channel.  The signal destination
 * could be a set of IEEE1394 loudspeakers (if and when such things
 * become available) or an amplifier with IEEE1394 input (like the
 * Sony STR-LSA1).  The driver only handles the actual streaming, some
 * connection management is also required for this to actually work.
 * That is outside the scope of this driver, and furthermore it is not
 * really standardized yet.
 *
 * The Audio and Music Data Tranmission Protocol is available at
 *
 *     http://www.1394ta.org/Download/Technology/Specifications/2001/AM20Final-jf2.pdf
 *
 *
 * TODO
 * ----
 *
 * - We should be able to change input sample format between LE/BE, as
 *   we already shift the bytes around when we construct the iso
 *   packets.
 *
 * - Fix DMA stop after bus reset!
 *
 * - Clean up iso context handling in ohci1394.
 *
 *
 * MAYBE TODO
 * ----------
 *
 * - Receive data for local playback or recording.  Playback requires
 *   soft syncing with the sound card.
 *
 * - Signal processing, i.e. receive packets, do some processing, and
 *   transmit them again using the same packet structure and timestamps
 *   offset by processing time.
 *
 * - Maybe make an ALSA interface, that is, create a file_ops
 *   implementation that recognizes ALSA ioctls and uses defaults for
 *   things that can't be controlled through ALSA (iso channel).
 *
 *   Changes:
 *
 * - Audit copy_from_user in amdtp_write.
 *                           Daniele Bellucci <bellucda@tiscali.it>
 *
 */

#include <linux/module.h>
#include <linux/list.h>
#include <linux/sched.h>
#include <linux/types.h>
#include <linux/fs.h>
#include <linux/ioctl.h>
#include <linux/wait.h>
#include <linux/pci.h>
#include <linux/interrupt.h>
#include <linux/poll.h>
#include <asm/uaccess.h>
#include <asm/atomic.h>

#include "hosts.h"
#include "highlevel.h"
#include "ieee1394.h"
#include "ieee1394_core.h"
#include "ohci1394.h"

#include "amdtp.h"
#include "cmp.h"

#define FMT_AMDTP 0x10
#define FDF_AM824 0x00
#define FDF_SFC_32KHZ   0x00
#define FDF_SFC_44K1HZ  0x01
#define FDF_SFC_48KHZ   0x02
#define FDF_SFC_88K2HZ  0x03
#define FDF_SFC_96KHZ   0x04
#define FDF_SFC_176K4HZ 0x05
#define FDF_SFC_192KHZ  0x06

struct descriptor_block {
        struct output_more_immediate {
                u32 control;
                u32 pad0;
                u32 skip;
                u32 pad1;
                u32 header[4];
        } header_desc;

        struct output_last {
                u32 control;
                u32 data_address;
                u32 branch;
                u32 status;
        } payload_desc;
};

struct packet {
        struct descriptor_block *db;
        dma_addr_t db_bus;
        struct iso_packet *payload;
        dma_addr_t payload_bus;
};

#include <asm/byteorder.h>

#if defined __BIG_ENDIAN_BITFIELD

struct iso_packet {
        /* First quadlet */
        unsigned int dbs      : 8;
        unsigned int eoh0     : 2;
        unsigned int sid      : 6;

        unsigned int dbc      : 8;
        unsigned int fn       : 2;
        unsigned int qpc      : 3;
        unsigned int sph      : 1;
        unsigned int reserved : 2;

        /* Second quadlet */
        unsigned int fdf      : 8;
        unsigned int eoh1     : 2;
        unsigned int fmt      : 6;

        unsigned int syt      : 16;

        quadlet_t data[0];
};

#elif defined __LITTLE_ENDIAN_BITFIELD

struct iso_packet {
        /* First quadlet */
        unsigned int sid      : 6;
        unsigned int eoh0     : 2;
        unsigned int dbs      : 8;

        unsigned int reserved : 2;
        unsigned int sph      : 1;
        unsigned int qpc      : 3;
        unsigned int fn       : 2;
        unsigned int dbc      : 8;

        /* Second quadlet */
        unsigned int fmt      : 6;
        unsigned int eoh1     : 2;
        unsigned int fdf      : 8;

        unsigned int syt      : 16;

        quadlet_t data[0];
};

#else

#error Unknown bitfield type

#endif

struct fraction {
        int integer;
        int numerator;
        int denominator;
};

#define PACKET_LIST_SIZE 256
#define MAX_PACKET_LISTS 4

struct packet_list {
        struct list_head link;
        int last_cycle_count;
        struct packet packets[PACKET_LIST_SIZE];
};

#define BUFFER_SIZE 128

/* This implements a circular buffer for incoming samples. */

struct buffer {
        size_t head, tail, length, size;
        unsigned char data[0];
};

struct stream {
        int iso_channel;
        int format;
        int rate;
        int dimension;
        int fdf;
        int mode;
        int sample_format;
        struct cmp_pcr *opcr;

        /* Input samples are copied here. */
        struct buffer *input;

        /* ISO Packer state */
        unsigned char dbc;
        struct packet_list *current_packet_list;
        int current_packet;
        struct fraction ready_samples, samples_per_cycle;

        /* We use these to generate control bits when we are packing
         * iec958 data.
         */
        int iec958_frame_count;
        int iec958_rate_code;

        /* The cycle_count and cycle_offset fields are used for the
         * synchronization timestamps (syt) in the cip header.  They
         * are incremented by at least a cycle every time we put a
         * time stamp in a packet.  As we don't time stamp all
         * packages, cycle_count isn't updated in every cycle, and
         * sometimes it's incremented by 2.  Thus, we have
         * cycle_count2, which is simply incremented by one with each
         * packet, so we can compare it to the transmission time
         * written back in the dma programs.
         */
        atomic_t cycle_count, cycle_count2;
        struct fraction cycle_offset, ticks_per_syt_offset;
        int syt_interval;
        int stale_count;

        /* Theses fields control the sample output to the DMA engine.
         * The dma_packet_lists list holds packet lists currently
         * queued for dma; the head of the list is currently being
         * processed.  The last program in a packet list generates an
         * interrupt, which removes the head from dma_packet_lists and
         * puts it back on the free list.
         */
        struct list_head dma_packet_lists;
        struct list_head free_packet_lists;
        wait_queue_head_t packet_list_wait;
        spinlock_t packet_list_lock;
        struct ohci1394_iso_tasklet iso_tasklet;
        struct pci_pool *descriptor_pool, *packet_pool;

        /* Streams at a host controller are chained through this field. */
        struct list_head link;
        struct amdtp_host *host;
};

struct amdtp_host {
        struct hpsb_host *host;
        struct ti_ohci *ohci;
        struct list_head stream_list;
        devfs_handle_t devfs;
        spinlock_t stream_list_lock;
};

static devfs_handle_t devfs_handle;

static struct hpsb_highlevel amdtp_highlevel;

/* FIXME: This doesn't belong here... */

#define OHCI1394_CONTEXT_CYCLE_MATCH 0x80000000
#define OHCI1394_CONTEXT_RUN         0x00008000
#define OHCI1394_CONTEXT_WAKE        0x00001000
#define OHCI1394_CONTEXT_DEAD        0x00000800
#define OHCI1394_CONTEXT_ACTIVE      0x00000400

void ohci1394_start_it_ctx(struct ti_ohci *ohci, int ctx,
                           dma_addr_t first_cmd, int z, int cycle_match)
{
        reg_write(ohci, OHCI1394_IsoXmitIntMaskSet, 1 << ctx);
        reg_write(ohci, OHCI1394_IsoXmitCommandPtr + ctx * 16, first_cmd | z);
        reg_write(ohci, OHCI1394_IsoXmitContextControlClear + ctx * 16, ~0);
        wmb();
        reg_write(ohci, OHCI1394_IsoXmitContextControlSet + ctx * 16,
                  OHCI1394_CONTEXT_CYCLE_MATCH | (cycle_match << 16) |
                  OHCI1394_CONTEXT_RUN);
}

void ohci1394_wake_it_ctx(struct ti_ohci *ohci, int ctx)
{
        reg_write(ohci, OHCI1394_IsoXmitContextControlSet + ctx * 16,
                  OHCI1394_CONTEXT_WAKE);
}

void ohci1394_stop_it_ctx(struct ti_ohci *ohci, int ctx, int synchronous)
{
        u32 control;
        int wait;

        reg_write(ohci, OHCI1394_IsoXmitIntMaskClear, 1 << ctx);
        reg_write(ohci, OHCI1394_IsoXmitContextControlClear + ctx * 16,
                  OHCI1394_CONTEXT_RUN);
        wmb();

        if (synchronous) {
                for (wait = 0; wait < 5; wait++) {
                        control = reg_read(ohci, OHCI1394_IsoXmitContextControlSet + ctx * 16);
                        if ((control & OHCI1394_CONTEXT_ACTIVE) == 0)
                                break;
                        
                        set_current_state(TASK_INTERRUPTIBLE);
                        schedule_timeout(1);
                }
        }
}

/* Note: we can test if free_packet_lists is empty without aquiring
 * the packet_list_lock.  The interrupt handler only adds to the free
 * list, there is no race condition between testing the list non-empty
 * and acquiring the lock.
 */

static struct packet_list *stream_get_free_packet_list(struct stream *s)
{
        struct packet_list *pl;
        unsigned long flags;

        if (list_empty(&s->free_packet_lists))
                return NULL;

        spin_lock_irqsave(&s->packet_list_lock, flags);
        pl = list_entry(s->free_packet_lists.next, struct packet_list, link);
        list_del(&pl->link);
        spin_unlock_irqrestore(&s->packet_list_lock, flags);

        return pl;
}

static void stream_start_dma(struct stream *s, struct packet_list *pl)
{
        u32 syt_cycle, cycle_count, start_cycle;

        cycle_count = reg_read(s->host->ohci,
                               OHCI1394_IsochronousCycleTimer) >> 12;
        syt_cycle = (pl->last_cycle_count - PACKET_LIST_SIZE + 1) & 0x0f;

        /* We program the DMA controller to start transmission at
         * least 17 cycles from now - this happens when the lower four
         * bits of cycle_count is 0x0f and syt_cycle is 0, in this
         * case the start cycle is cycle_count - 15 + 32. */
        start_cycle = (cycle_count & ~0x0f) + 32 + syt_cycle;
        if ((start_cycle & 0x1fff) >= 8000)
                start_cycle = start_cycle - 8000 + 0x2000;

        ohci1394_start_it_ctx(s->host->ohci, s->iso_tasklet.context,
                              pl->packets[0].db_bus, 3,
                              start_cycle & 0x7fff);
}

static void stream_put_dma_packet_list(struct stream *s,
                                       struct packet_list *pl)
{
        unsigned long flags;
        struct packet_list *prev;

        /* Remember the cycle_count used for timestamping the last packet. */
        pl->last_cycle_count = atomic_read(&s->cycle_count2) - 1;
        pl->packets[PACKET_LIST_SIZE - 1].db->payload_desc.branch = 0;

        spin_lock_irqsave(&s->packet_list_lock, flags);
        list_add_tail(&pl->link, &s->dma_packet_lists);
        spin_unlock_irqrestore(&s->packet_list_lock, flags);

        prev = list_entry(pl->link.prev, struct packet_list, link);
        if (pl->link.prev != &s->dma_packet_lists) {
                struct packet *last = &prev->packets[PACKET_LIST_SIZE - 1];
                last->db->payload_desc.branch = pl->packets[0].db_bus | 3;
                last->db->header_desc.skip = pl->packets[0].db_bus | 3;
                ohci1394_wake_it_ctx(s->host->ohci, s->iso_tasklet.context);
        }
        else
                stream_start_dma(s, pl);
}

static void stream_shift_packet_lists(unsigned long l)
{
        struct stream *s = (struct stream *) l;
        struct packet_list *pl;
        struct packet *last;
        int diff;

        if (list_empty(&s->dma_packet_lists)) {
                HPSB_ERR("empty dma_packet_lists in %s", __FUNCTION__);
                return;
        }

        /* Now that we know the list is non-empty, we can get the head
         * of the list without locking, because the process context
         * only adds to the tail.  
         */
        pl = list_entry(s->dma_packet_lists.next, struct packet_list, link);
        last = &pl->packets[PACKET_LIST_SIZE - 1];

        /* This is weird... if we stop dma processing in the middle of
         * a packet list, the dma context immediately generates an
         * interrupt if we enable it again later.  This only happens
         * when amdtp_release is interrupted while waiting for dma to
         * complete, though.  Anyway, we detect this by seeing that
         * the status of the dma descriptor that we expected an
         * interrupt from is still 0.
         */
        if (last->db->payload_desc.status == 0) {
                HPSB_INFO("weird interrupt...");
                return;
        }               

        /* If the last descriptor block does not specify a branch
         * address, we have a sample underflow.
         */
        if (last->db->payload_desc.branch == 0)
                HPSB_INFO("FIXME: sample underflow...");

        /* Here we check when (which cycle) the last packet was sent
         * and compare it to what the iso packer was using at the
         * time.  If there is a mismatch, we adjust the cycle count in
         * the iso packer.  However, there are still up to
         * MAX_PACKET_LISTS packet lists queued with bad time stamps,
         * so we disable time stamp monitoring for the next
         * MAX_PACKET_LISTS packet lists.
         */
        diff = (last->db->payload_desc.status - pl->last_cycle_count) & 0xf;
        if (diff > 0 && s->stale_count == 0) {
                atomic_add(diff, &s->cycle_count);
                atomic_add(diff, &s->cycle_count2);
                s->stale_count = MAX_PACKET_LISTS;
        }

        if (s->stale_count > 0)
                s->stale_count--;

        /* Finally, we move the packet list that was just processed
         * back to the free list, and notify any waiters.
         */
        spin_lock(&s->packet_list_lock);
        list_del(&pl->link);
        list_add_tail(&pl->link, &s->free_packet_lists);
        spin_unlock(&s->packet_list_lock);

        wake_up_interruptible(&s->packet_list_wait);
}

static struct packet *stream_current_packet(struct stream *s)
{
        if (s->current_packet_list == NULL &&
            (s->current_packet_list = stream_get_free_packet_list(s)) == NULL)
                return NULL;

        return &s->current_packet_list->packets[s->current_packet];
}
        
static void stream_queue_packet(struct stream *s)
{
        s->current_packet++;
        if (s->current_packet == PACKET_LIST_SIZE) {
                stream_put_dma_packet_list(s, s->current_packet_list);
                s->current_packet_list = NULL;
                s->current_packet = 0;
        }
}

/* Integer fractional math.  When we transmit a 44k1Hz signal we must
 * send 5 41/80 samples per isochronous cycle, as these occur 8000
 * times a second.  Of course, we must send an integral number of
 * samples in a packet, so we use the integer math to alternate
 * between sending 5 and 6 samples per packet.
 */

static void fraction_init(struct fraction *f, int numerator, int denominator)
{
        f->integer = numerator / denominator;
        f->numerator = numerator % denominator;
        f->denominator = denominator;
}

static __inline__ void fraction_add(struct fraction *dst,
                                    struct fraction *src1,
                                    struct fraction *src2)
{
        /* assert: src1->denominator == src2->denominator */

        int sum, denom;

        /* We use these two local variables to allow gcc to optimize
         * the division and the modulo into only one division. */

        sum = src1->numerator + src2->numerator;
        denom = src1->denominator;
        dst->integer = src1->integer + src2->integer + sum / denom;
        dst->numerator = sum % denom;
        dst->denominator = denom;
}

static __inline__ void fraction_sub_int(struct fraction *dst,
                                        struct fraction *src, int integer)
{
        dst->integer = src->integer - integer;
        dst->numerator = src->numerator;
        dst->denominator = src->denominator;
}

static __inline__ int fraction_floor(struct fraction *frac)
{
        return frac->integer;
}

static __inline__ int fraction_ceil(struct fraction *frac)
{
        return frac->integer + (frac->numerator > 0 ? 1 : 0);
}

void packet_initialize(struct packet *p, struct packet *next)
{
        /* Here we initialize the dma descriptor block for
         * transferring one iso packet.  We use two descriptors per
         * packet: an OUTPUT_MORE_IMMMEDIATE descriptor for the
         * IEEE1394 iso packet header and an OUTPUT_LAST descriptor
         * for the payload.
         */

        p->db->header_desc.control =
                DMA_CTL_OUTPUT_MORE | DMA_CTL_IMMEDIATE | 8;

        if (next) {
                p->db->payload_desc.control = 
                        DMA_CTL_OUTPUT_LAST | DMA_CTL_BRANCH;
                p->db->payload_desc.branch = next->db_bus | 3;
                p->db->header_desc.skip = next->db_bus | 3;
        }
        else {
                p->db->payload_desc.control = 
                        DMA_CTL_OUTPUT_LAST | DMA_CTL_BRANCH |
                        DMA_CTL_UPDATE | DMA_CTL_IRQ;
                p->db->payload_desc.branch = 0;
                p->db->header_desc.skip = 0;
        }
        p->db->payload_desc.data_address = p->payload_bus;
        p->db->payload_desc.status = 0;
}

struct packet_list *packet_list_alloc(struct stream *s)
{
        int i;
        struct packet_list *pl;
        struct packet *next;

        pl = kmalloc(sizeof *pl, SLAB_KERNEL);
        if (pl == NULL)
                return NULL;

        for (i = 0; i < PACKET_LIST_SIZE; i++) {
                struct packet *p = &pl->packets[i];
                p->db = pci_pool_alloc(s->descriptor_pool, SLAB_KERNEL,
                                       &p->db_bus);
                p->payload = pci_pool_alloc(s->packet_pool, SLAB_KERNEL,
                                            &p->payload_bus);
        }

        for (i = 0; i < PACKET_LIST_SIZE; i++) {
                if (i < PACKET_LIST_SIZE - 1)
                        next = &pl->packets[i + 1];
                else 
                        next = NULL;
                packet_initialize(&pl->packets[i], next);
        }

        return pl;
}

void packet_list_free(struct packet_list *pl, struct stream *s)
{
        int i;

        for (i = 0; i < PACKET_LIST_SIZE; i++) {
                struct packet *p = &pl->packets[i];
                pci_pool_free(s->descriptor_pool, p->db, p->db_bus);
                pci_pool_free(s->packet_pool, p->payload, p->payload_bus);
        }
        kfree(pl);
}

static struct buffer *buffer_alloc(int size)
{
        struct buffer *b;

        b = kmalloc(sizeof *b + size, SLAB_KERNEL);
        if (b == NULL)
                return NULL;
        b->head = 0;
        b->tail = 0;
        b->length = 0;
        b->size = size;

        return b;
}

static unsigned char *buffer_get_bytes(struct buffer *buffer, int size)
{
        unsigned char *p;

        if (buffer->head + size > buffer->size)
                BUG();

        p = &buffer->data[buffer->head];
        buffer->head += size;
        if (buffer->head == buffer->size)
                buffer->head = 0;
        buffer->length -= size;

        return p;
}

static unsigned char *buffer_put_bytes(struct buffer *buffer,
                                       size_t max, size_t *actual)
{
        size_t length;
        unsigned char *p;

        p = &buffer->data[buffer->tail];
        length = min(buffer->size - buffer->length, max);
        if (buffer->tail + length < buffer->size) {
                *actual = length;
                buffer->tail += length;
        }
        else {
                *actual = buffer->size - buffer->tail;
                 buffer->tail = 0;
        }

        buffer->length += *actual;
        return p;
}

static u32 get_iec958_header_bits(struct stream *s, int sub_frame, u32 sample)
{
        int csi, parity, shift;
        int block_start;
        u32 bits;

        switch (s->iec958_frame_count) {
        case 1:
                csi = s->format == AMDTP_FORMAT_IEC958_AC3;
                break;
        case 2:
        case 9:
                csi = 1;
                break;
        case 24 ... 27:
                csi = (s->iec958_rate_code >> (27 - s->iec958_frame_count)) & 0x01;
                break;
        default:
                csi = 0;
                break;
        }

        block_start = (s->iec958_frame_count == 0 && sub_frame == 0);

        /* The parity bit is the xor of the sample bits and the
         * channel status info bit. */
        for (shift = 16, parity = sample ^ csi; shift > 0; shift >>= 1)
                parity ^= (parity >> shift);

        bits =  (block_start << 5) |            /* Block start bit */
                ((sub_frame == 0) << 4) |       /* Subframe bit */
                ((parity & 1) << 3) |           /* Parity bit */
                (csi << 2);                     /* Channel status info bit */

        return bits;
}

static u32 get_header_bits(struct stream *s, int sub_frame, u32 sample)
{
        switch (s->format) {
        case AMDTP_FORMAT_IEC958_PCM:
        case AMDTP_FORMAT_IEC958_AC3:
                return get_iec958_header_bits(s, sub_frame, sample);
                
        case AMDTP_FORMAT_RAW:
                return 0x40;

        default:
                return 0;
        }
}

static void fill_payload_le16(struct stream *s, quadlet_t *data, int nevents)
{
        quadlet_t *event, sample, bits;
        unsigned char *p;
        int i, j;

        for (i = 0, event = data; i < nevents; i++) {

                for (j = 0; j < s->dimension; j++) {
                        p = buffer_get_bytes(s->input, 2);
                        sample = (p[1] << 16) | (p[0] << 8);
                        bits = get_header_bits(s, j, sample);
                        event[j] = cpu_to_be32((bits << 24) | sample);
                }

                event += s->dimension;
                if (++s->iec958_frame_count == 192)
                        s->iec958_frame_count = 0;
        }
}

static void fill_packet(struct stream *s, struct packet *packet, int nevents)
{
        int syt_index, syt, size;
        u32 control;

        size = (nevents * s->dimension + 2) * sizeof(quadlet_t);

        /* Update DMA descriptors */
        packet->db->payload_desc.status = 0;
        control = packet->db->payload_desc.control & 0xffff0000;
        packet->db->payload_desc.control = control | size;

        /* Fill IEEE1394 headers */
        packet->db->header_desc.header[0] =
                (IEEE1394_SPEED_100 << 16) | (0x01 << 14) | 
                (s->iso_channel << 8) | (TCODE_ISO_DATA << 4);
        packet->db->header_desc.header[1] = size << 16;
        
        /* Calculate synchronization timestamp (syt). First we
         * determine syt_index, that is, the index in the packet of
         * the sample for which the timestamp is valid. */
        syt_index = (s->syt_interval - s->dbc) & (s->syt_interval - 1);
        if (syt_index < nevents) {
                syt = ((atomic_read(&s->cycle_count) << 12) | 
                       s->cycle_offset.integer) & 0xffff;
                fraction_add(&s->cycle_offset, 
                             &s->cycle_offset, &s->ticks_per_syt_offset);

                /* This next addition should be modulo 8000 (0x1f40),
                 * but we only use the lower 4 bits of cycle_count, so
                 * we don't need the modulo. */
                atomic_add(s->cycle_offset.integer / 3072, &s->cycle_count);
                s->cycle_offset.integer %= 3072;
        }
        else
                syt = 0xffff;

        atomic_inc(&s->cycle_count2);
        
        /* Fill cip header */
        packet->payload->eoh0 = 0;
        packet->payload->sid = s->host->host->node_id & 0x3f;
        packet->payload->dbs = s->dimension;
        packet->payload->fn = 0;
        packet->payload->qpc = 0;
        packet->payload->sph = 0;
        packet->payload->reserved = 0;
        packet->payload->dbc = s->dbc;
        packet->payload->eoh1 = 2;
        packet->payload->fmt = FMT_AMDTP;
        packet->payload->fdf = s->fdf;
        packet->payload->syt = cpu_to_be16(syt);

        switch (s->sample_format) {
        case AMDTP_INPUT_LE16:
                fill_payload_le16(s, packet->payload->data, nevents);
                break;
        }

        s->dbc += nevents;
}

static void stream_flush(struct stream *s)
{
        struct packet *p;
        int nevents;
        struct fraction next;

        /* The AMDTP specifies two transmission modes: blocking and
         * non-blocking.  In blocking mode you always transfer
         * syt_interval or zero samples, whereas in non-blocking mode
         * you send as many samples as you have available at transfer
         * time.
         *
         * The fraction samples_per_cycle specifies the number of
         * samples that become available per cycle.  We add this to
         * the fraction ready_samples, which specifies the number of
         * leftover samples from the previous transmission.  The sum,
         * stored in the fraction next, specifies the number of
         * samples available for transmission, and from this we
         * determine the number of samples to actually transmit.
         */

        while (1) {
                fraction_add(&next, &s->ready_samples, &s->samples_per_cycle);
                if (s->mode == AMDTP_MODE_BLOCKING) {
                        if (fraction_floor(&next) >= s->syt_interval)
                                nevents = s->syt_interval;
                        else
                                nevents = 0;
                }
                else
                        nevents = fraction_floor(&next);

                p = stream_current_packet(s);
                if (s->input->length < nevents * s->dimension * 2 || p == NULL)
                        break;

                fill_packet(s, p, nevents);
                stream_queue_packet(s);

                /* Now that we have successfully queued the packet for
                 * transmission, we update the fraction ready_samples. */
                fraction_sub_int(&s->ready_samples, &next, nevents);
        }
}

static int stream_alloc_packet_lists(struct stream *s)
{
        int max_nevents, max_packet_size, i;

        if (s->mode == AMDTP_MODE_BLOCKING)
                max_nevents = s->syt_interval;
        else
                max_nevents = fraction_ceil(&s->samples_per_cycle);

        max_packet_size = max_nevents * s->dimension * 4 + 8;
        s->packet_pool = pci_pool_create("packet pool", s->host->ohci->dev,
                                         max_packet_size, 0, 0 ,SLAB_KERNEL);

        if (s->packet_pool == NULL)
                return -1;

        INIT_LIST_HEAD(&s->free_packet_lists);
        INIT_LIST_HEAD(&s->dma_packet_lists);
        for (i = 0; i < MAX_PACKET_LISTS; i++) {
                struct packet_list *pl = packet_list_alloc(s);
                if (pl == NULL)
                        break;
                list_add_tail(&pl->link, &s->free_packet_lists);
        }

        return i < MAX_PACKET_LISTS ? -1 : 0;
}

static void stream_free_packet_lists(struct stream *s)
{
        struct list_head *lh, *next;

        if (s->current_packet_list != NULL)
                packet_list_free(s->current_packet_list, s);
        list_for_each_safe(lh, next, &s->dma_packet_lists)
                packet_list_free(list_entry(lh, struct packet_list, link), s);
        list_for_each_safe(lh, next, &s->free_packet_lists)
                packet_list_free(list_entry(lh, struct packet_list, link), s);
        if (s->packet_pool != NULL)
                pci_pool_destroy(s->packet_pool);

        s->current_packet_list = NULL;
        INIT_LIST_HEAD(&s->free_packet_lists);
        INIT_LIST_HEAD(&s->dma_packet_lists);
        s->packet_pool = NULL;
}

static void plug_update(struct cmp_pcr *plug, void *data)
{
        struct stream *s = data;

        HPSB_INFO("plug update: p2p_count=%d, channel=%d",
                  plug->p2p_count, plug->channel);
        s->iso_channel = plug->channel;
        if (plug->p2p_count > 0) {
                struct packet_list *pl;

                pl = list_entry(s->dma_packet_lists.next, struct packet_list, link);
                stream_start_dma(s, pl);
        }
        else {
                ohci1394_stop_it_ctx(s->host->ohci, s->iso_tasklet.context, 0);
        }
}

static int stream_configure(struct stream *s, int cmd, struct amdtp_ioctl *cfg)
{
        const int transfer_delay = 9000;

        if (cfg->format <= AMDTP_FORMAT_IEC958_AC3)
                s->format = cfg->format;
        else
                return -EINVAL;

        switch (cfg->rate) {
        case 32000:
                s->syt_interval = 8;
                s->fdf = FDF_SFC_32KHZ;
                s->iec958_rate_code = 0x0c;
                break;
        case 44100:
                s->syt_interval = 8;
                s->fdf = FDF_SFC_44K1HZ;
                s->iec958_rate_code = 0x00;
                break;
        case 48000:
                s->syt_interval = 8;
                s->fdf = FDF_SFC_48KHZ;
                s->iec958_rate_code = 0x04;
                break;
        case 88200:
                s->syt_interval = 16;
                s->fdf = FDF_SFC_88K2HZ;
                s->iec958_rate_code = 0x00;
                break;
        case 96000:
                s->syt_interval = 16;
                s->fdf = FDF_SFC_96KHZ;
                s->iec958_rate_code = 0x00;
                break;
        case 176400:
                s->syt_interval = 32;
                s->fdf = FDF_SFC_176K4HZ;
                s->iec958_rate_code = 0x00;
                break;
        case 192000:
                s->syt_interval = 32;
                s->fdf = FDF_SFC_192KHZ;
                s->iec958_rate_code = 0x00;
                break;

        default:
                return -EINVAL;
        }

        s->rate = cfg->rate;
        fraction_init(&s->samples_per_cycle, s->rate, 8000);
        fraction_init(&s->ready_samples, 0, 8000);

        /* The ticks_per_syt_offset is initialized to the number of
         * ticks between syt_interval events.  The number of ticks per
         * second is 24.576e6, so the number of ticks between
         * syt_interval events is 24.576e6 * syt_interval / rate.
         */
        fraction_init(&s->ticks_per_syt_offset,
                      24576000 * s->syt_interval, s->rate);
        fraction_init(&s->cycle_offset, (transfer_delay % 3072) * s->rate, s->rate);
        atomic_set(&s->cycle_count, transfer_delay / 3072);
        atomic_set(&s->cycle_count2, 0);

        s->mode = cfg->mode;
        s->sample_format = AMDTP_INPUT_LE16;

        /* When using the AM824 raw subformat we can stream signals of
         * any dimension.  The IEC958 subformat, however, only
         * supports 2 channels.
         */
        if (s->format == AMDTP_FORMAT_RAW || cfg->dimension == 2)
                s->dimension = cfg->dimension;
        else
                return -EINVAL;

        if (s->opcr != NULL) {
                cmp_unregister_opcr(s->host->host, s->opcr);
                s->opcr = NULL;
        }

        switch(cmd) {
        case AMDTP_IOC_PLUG:
                s->opcr = cmp_register_opcr(s->host->host, cfg->u.plug,
                                           /*payload*/ 12, plug_update, s);
                if (s->opcr == NULL)
                        return -EINVAL;
                s->iso_channel = s->opcr->channel;
                break;

        case AMDTP_IOC_CHANNEL:
                if (cfg->u.channel >= 0 && cfg->u.channel < 64)
                        s->iso_channel = cfg->u.channel;
                else
                        return -EINVAL;
                break;
        }

        /* The ioctl settings were all valid, so we realloc the packet
         * lists to make sure the packet size is big enough.
         */
        if (s->packet_pool != NULL)
                stream_free_packet_lists(s);

        if (stream_alloc_packet_lists(s) < 0) {
                stream_free_packet_lists(s);
                return -ENOMEM;
        }

        return 0;
}

struct stream *stream_alloc(struct amdtp_host *host)
{
        struct stream *s;
        unsigned long flags;

        s = kmalloc(sizeof(struct stream), SLAB_KERNEL);
        if (s == NULL)
                return NULL;

        memset(s, 0, sizeof(struct stream));
        s->host = host;

        s->input = buffer_alloc(BUFFER_SIZE);
        if (s->input == NULL) {
                kfree(s);
                return NULL;
        }

        s->descriptor_pool = pci_pool_create("descriptor pool", host->ohci->dev,
                                             sizeof(struct descriptor_block),
                                             16, 0, SLAB_KERNEL);

        if (s->descriptor_pool == NULL) {
                kfree(s->input);
                kfree(s);
                return NULL;
        }

        INIT_LIST_HEAD(&s->free_packet_lists);
        INIT_LIST_HEAD(&s->dma_packet_lists);

        init_waitqueue_head(&s->packet_list_wait);
        spin_lock_init(&s->packet_list_lock);

        ohci1394_init_iso_tasklet(&s->iso_tasklet, OHCI_ISO_TRANSMIT,
                                  stream_shift_packet_lists,
                                  (unsigned long) s);

        if (ohci1394_register_iso_tasklet(host->ohci, &s->iso_tasklet) < 0) {
                pci_pool_destroy(s->descriptor_pool);
                kfree(s->input);
                kfree(s);
                return NULL;
        }

        spin_lock_irqsave(&host->stream_list_lock, flags);
        list_add_tail(&s->link, &host->stream_list);
        spin_unlock_irqrestore(&host->stream_list_lock, flags);

        return s;
}

void stream_free(struct stream *s)
{
        unsigned long flags;

        /* Stop the DMA.  We wait for the dma packet list to become
         * empty and let the dma controller run out of programs.  This
         * seems to be more reliable than stopping it directly, since
         * that sometimes generates an it transmit interrupt if we
         * later re-enable the context.
         */
        wait_event_interruptible(s->packet_list_wait, 
                                 list_empty(&s->dma_packet_lists));

        ohci1394_stop_it_ctx(s->host->ohci, s->iso_tasklet.context, 1);
        ohci1394_unregister_iso_tasklet(s->host->ohci, &s->iso_tasklet);

        if (s->opcr != NULL)
                cmp_unregister_opcr(s->host->host, s->opcr);

        spin_lock_irqsave(&s->host->stream_list_lock, flags);
        list_del(&s->link);
        spin_unlock_irqrestore(&s->host->stream_list_lock, flags);

        kfree(s->input);

        stream_free_packet_lists(s);
        pci_pool_destroy(s->descriptor_pool);

        kfree(s);
}

/* File operations */

static ssize_t amdtp_write(struct file *file, const char *buffer, size_t count,
                           loff_t *offset_is_ignored)
{
        struct stream *s = file->private_data;
        unsigned char *p;
        int i;
        size_t length;
        
        if (s->packet_pool == NULL)
                return -EBADFD;

        /* Fill the circular buffer from the input buffer and call the
         * iso packer when the buffer is full.  The iso packer may
         * leave bytes in the buffer for two reasons: either the
         * remaining bytes wasn't enough to build a new packet, or
         * there were no free packet lists.  In the first case we
         * re-fill the buffer and call the iso packer again or return
         * if we used all the data from userspace.  In the second
         * case, the wait_event_interruptible will block until the irq
         * handler frees a packet list.
         */

        for (i = 0; i < count; i += length) {
                p = buffer_put_bytes(s->input, count - i, &length);
                if (copy_from_user(p, buffer + i, length))
                        return -EFAULT;
                if (s->input->length < s->input->size)
                        continue;
                
                stream_flush(s);
                
                if (s->current_packet_list != NULL)
                        continue;

                if (file->f_flags & O_NONBLOCK)
                        return i + length > 0 ? i + length : -EAGAIN;

                if (wait_event_interruptible(s->packet_list_wait, 
                                             !list_empty(&s->free_packet_lists)))
                        return -EINTR;
        }

        return count;
}

static int amdtp_ioctl(struct inode *inode, struct file *file,
                           unsigned int cmd, unsigned long arg)
{
        struct stream *s = file->private_data;
        struct amdtp_ioctl cfg;

        switch(cmd)
        {
        case AMDTP_IOC_PLUG:
        case AMDTP_IOC_CHANNEL:
                if (copy_from_user(&cfg, (struct amdtp_ioctl *) arg, sizeof cfg))
                        return -EFAULT;
                else 
                        return stream_configure(s, cmd, &cfg);

        default:
                return -EINVAL;
        }
}

static unsigned int amdtp_poll(struct file *file, poll_table *pt)
{
        struct stream *s = file->private_data;

        poll_wait(file, &s->packet_list_wait, pt);

        if (!list_empty(&s->free_packet_lists))
                return POLLOUT | POLLWRNORM;
        else
                return 0;
}

static int amdtp_open(struct inode *inode, struct file *file)
{
        struct amdtp_host *host;
        int i = ieee1394_file_to_instance(file);

        host = hpsb_get_hostinfo_bykey(&amdtp_highlevel, i);
        if (host == NULL)
                return -ENODEV;

        file->private_data = stream_alloc(host);
        if (file->private_data == NULL)
                return -ENOMEM;

        return 0;
}

static int amdtp_release(struct inode *inode, struct file *file)
{
        struct stream *s = file->private_data;

        stream_free(s);

        return 0;
}

static struct file_operations amdtp_fops =
{
        .owner =        THIS_MODULE,
        .write =        amdtp_write,
        .poll =         amdtp_poll,
        .ioctl =        amdtp_ioctl,
        .open =         amdtp_open,
        .release =      amdtp_release
};

/* IEEE1394 Subsystem functions */

static void amdtp_add_host(struct hpsb_host *host)
{
        struct amdtp_host *ah;
        int minor;
        char name[16];

        if (strcmp(host->driver->name, OHCI1394_DRIVER_NAME) != 0)
                return;

        ah = hpsb_create_hostinfo(&amdtp_highlevel, host, sizeof(*ah));
        if (!ah) {
                HPSB_ERR("amdtp: Unable able to alloc hostinfo");
                return;
        }

        ah->host = host;
        ah->ohci = host->hostdata;

        hpsb_set_hostinfo_key(&amdtp_highlevel, host, ah->ohci->id);

        minor = IEEE1394_MINOR_BLOCK_AMDTP * 16 + ah->ohci->id;

        sprintf(name, "%d", ah->ohci->id);

        INIT_LIST_HEAD(&ah->stream_list);
        spin_lock_init(&ah->stream_list_lock);

        ah->devfs = devfs_register(devfs_handle, name,
                                   DEVFS_FL_AUTO_OWNER,
                                   IEEE1394_MAJOR, minor,
                                   S_IFCHR | S_IRUSR | S_IWUSR,
                                   &amdtp_fops, NULL);
}

static void amdtp_remove_host(struct hpsb_host *host)
{
        struct amdtp_host *ah = hpsb_get_hostinfo(&amdtp_highlevel, host);

        if (ah)
                devfs_unregister(ah->devfs);

        return;
}

static struct hpsb_highlevel amdtp_highlevel = {
        .name =         "amdtp",
        .add_host =     amdtp_add_host,
        .remove_host =  amdtp_remove_host,
};

/* Module interface */

MODULE_AUTHOR("Kristian Hogsberg <hogsberg@users.sf.net>");
MODULE_DESCRIPTION("Driver for Audio & Music Data Transmission Protocol "
                   "on OHCI boards.");
MODULE_SUPPORTED_DEVICE("amdtp");
MODULE_LICENSE("GPL");

static int __init amdtp_init_module (void)
{
        if (ieee1394_register_chardev(IEEE1394_MINOR_BLOCK_AMDTP,
                                      THIS_MODULE, &amdtp_fops)) {
                HPSB_ERR("amdtp: unable to get minor device block");
                return -EIO;
        }

        devfs_handle = devfs_mk_dir(NULL, "amdtp", NULL);

        hpsb_register_highlevel(&amdtp_highlevel);

        HPSB_INFO("Loaded AMDTP driver");

        return 0;
}

static void __exit amdtp_exit_module (void)
{
        hpsb_unregister_highlevel(&amdtp_highlevel);
        devfs_unregister(devfs_handle);
        ieee1394_unregister_chardev(IEEE1394_MINOR_BLOCK_AMDTP);

        HPSB_INFO("Unloaded AMDTP driver");
}

module_init(amdtp_init_module);
module_exit(amdtp_exit_module);