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iso.h

/*
 * IEEE 1394 for Linux
 *
 * kernel ISO transmission/reception
 *
 * Copyright (C) 2002 Maas Digital LLC
 *
 * This code is licensed under the GPL.  See the file COPYING in the root
 * directory of the kernel sources for details.
 */

#ifndef IEEE1394_ISO_H
#define IEEE1394_ISO_H

#include <linux/spinlock_types.h>
#include <asm/atomic.h>
#include <asm/types.h>

#include "dma.h"

struct hpsb_host;

/* high-level ISO interface */

/*
 * This API sends and receives isochronous packets on a large,
 * virtually-contiguous kernel memory buffer. The buffer may be mapped
 * into a user-space process for zero-copy transmission and reception.
 *
 * There are no explicit boundaries between packets in the buffer. A
 * packet may be transmitted or received at any location. However,
 * low-level drivers may impose certain restrictions on alignment or
 * size of packets. (e.g. in OHCI no packet may cross a page boundary,
 * and packets should be quadlet-aligned)
 */

/* Packet descriptor - the API maintains a ring buffer of these packet
 * descriptors in kernel memory (hpsb_iso.infos[]).  */
struct hpsb_iso_packet_info {
      /* offset of data payload relative to the first byte of the buffer */
      __u32 offset;

      /* length of the data payload, in bytes (not including the isochronous
       * header) */
      __u16 len;

      /* (recv only) the cycle number (mod 8000) on which the packet was
       * received */
      __u16 cycle;

      /* (recv only) channel on which the packet was received */
      __u8 channel;

      /* 2-bit 'tag' and 4-bit 'sy' fields of the isochronous header */
      __u8 tag;
      __u8 sy;

      /* length in bytes of the packet including header/trailer.
       * MUST be at structure end, since the first part of this structure is
       * also defined in raw1394.h (i.e. struct raw1394_iso_packet_info), is
       * copied to userspace and is accessed there through libraw1394. */
      __u16 total_len;
};

enum hpsb_iso_type { HPSB_ISO_RECV = 0, HPSB_ISO_XMIT = 1 };

/* The mode of the dma when receiving iso data. Must be supported by chip */
enum raw1394_iso_dma_recv_mode {
      HPSB_ISO_DMA_DEFAULT = -1,
      HPSB_ISO_DMA_OLD_ABI = 0,
      HPSB_ISO_DMA_BUFFERFILL = 1,
      HPSB_ISO_DMA_PACKET_PER_BUFFER = 2
};

struct hpsb_iso {
      enum hpsb_iso_type type;

      /* pointer to low-level driver and its private data */
      struct hpsb_host *host;
      void *hostdata;

      /* a function to be called (from interrupt context) after
       * outgoing packets have been sent, or incoming packets have
       * arrived */
      void (*callback)(struct hpsb_iso*);

      /* wait for buffer space */
      wait_queue_head_t waitq;

      int speed; /* IEEE1394_SPEED_100, 200, or 400 */
      int channel; /* -1 if multichannel */
      int dma_mode; /* dma receive mode */


      /* greatest # of packets between interrupts - controls
       * the maximum latency of the buffer */
      int irq_interval;

      /* the buffer for packet data payloads */
      struct dma_region data_buf;

      /* size of data_buf, in bytes (always a multiple of PAGE_SIZE) */
      unsigned int buf_size;

      /* # of packets in the ringbuffer */
      unsigned int buf_packets;

      /* protects packet cursors */
      spinlock_t lock;

      /* the index of the next packet that will be produced
         or consumed by the user */
      int first_packet;

      /* the index of the next packet that will be transmitted
         or received by the 1394 hardware */
      int pkt_dma;

      /* how many packets, starting at first_packet:
       * (transmit) are ready to be filled with data
       * (receive)  contain received data */
      int n_ready_packets;

      /* how many times the buffer has overflowed or underflowed */
      atomic_t overflows;

      /* Current number of bytes lost in discarded packets */
      int bytes_discarded;

      /* private flags to track initialization progress */
#define HPSB_ISO_DRIVER_INIT     (1<<0)
#define HPSB_ISO_DRIVER_STARTED  (1<<1)
      unsigned int flags;

      /* # of packets left to prebuffer (xmit only) */
      int prebuffer;

      /* starting cycle for DMA (xmit only) */
      int start_cycle;

      /* cycle at which next packet will be transmitted,
       * -1 if not known */
      int xmit_cycle;

      /* ringbuffer of packet descriptors in regular kernel memory
       * XXX Keep this last, since we use over-allocated memory from
       * this entry to fill this field. */
      struct hpsb_iso_packet_info *infos;
};

/* functions available to high-level drivers (e.g. raw1394) */

struct hpsb_iso* hpsb_iso_xmit_init(struct hpsb_host *host,
                            unsigned int data_buf_size,
                            unsigned int buf_packets,
                            int channel,
                            int speed,
                            int irq_interval,
                            void (*callback)(struct hpsb_iso*));
struct hpsb_iso* hpsb_iso_recv_init(struct hpsb_host *host,
                            unsigned int data_buf_size,
                            unsigned int buf_packets,
                            int channel,
                            int dma_mode,
                            int irq_interval,
                            void (*callback)(struct hpsb_iso*));
int hpsb_iso_recv_listen_channel(struct hpsb_iso *iso, unsigned char channel);
int hpsb_iso_recv_unlisten_channel(struct hpsb_iso *iso, unsigned char channel);
int hpsb_iso_recv_set_channel_mask(struct hpsb_iso *iso, u64 mask);
int hpsb_iso_xmit_start(struct hpsb_iso *iso, int start_on_cycle,
                  int prebuffer);
int hpsb_iso_recv_start(struct hpsb_iso *iso, int start_on_cycle,
                  int tag_mask, int sync);
void hpsb_iso_stop(struct hpsb_iso *iso);
void hpsb_iso_shutdown(struct hpsb_iso *iso);
int hpsb_iso_xmit_queue_packet(struct hpsb_iso *iso, u32 offset, u16 len,
                         u8 tag, u8 sy);
int hpsb_iso_xmit_sync(struct hpsb_iso *iso);
int hpsb_iso_recv_release_packets(struct hpsb_iso *recv,
                          unsigned int n_packets);
int hpsb_iso_recv_flush(struct hpsb_iso *iso);
int hpsb_iso_n_ready(struct hpsb_iso *iso);

/* the following are callbacks available to low-level drivers */

void hpsb_iso_packet_sent(struct hpsb_iso *iso, int cycle, int error);
void hpsb_iso_packet_received(struct hpsb_iso *iso, u32 offset, u16 len,
                        u16 total_len, u16 cycle, u8 channel, u8 tag,
                        u8 sy);
void hpsb_iso_wake(struct hpsb_iso *iso);

#endif /* IEEE1394_ISO_H */

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