Subversion Repositories or1k

/*

 * 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 "hosts.h"

#include "dma.h"

/* 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;

};

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

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 */

        /* 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;

        /* 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) */

/* allocate the buffer and DMA context */

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*));

/* note: if channel = -1, multi-channel receive is enabled */

struct hpsb_iso* hpsb_iso_recv_init(struct hpsb_host *host,

                                    unsigned int data_buf_size,

                                    unsigned int buf_packets,

                                    int channel,

                                    int irq_interval,

                                    void (*callback)(struct hpsb_iso*));

/* multi-channel only */

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);

/* start/stop DMA */

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);

/* deallocate buffer and DMA context */

void hpsb_iso_shutdown(struct hpsb_iso *iso);

/* queue a packet for transmission. 'offset' is relative to the beginning of the

   DMA buffer, where the packet's data payload should already have been placed */

int hpsb_iso_xmit_queue_packet(struct hpsb_iso *iso, u32 offset, u16 len, u8 tag, u8 sy);

/* wait until all queued packets have been transmitted to the bus */

int hpsb_iso_xmit_sync(struct hpsb_iso *iso);

/* N packets have been read out of the buffer, re-use the buffer space */

int  hpsb_iso_recv_release_packets(struct hpsb_iso *recv, unsigned int n_packets);

/* check for arrival of new packets immediately (even if irq_interval

   has not yet been reached) */

int hpsb_iso_recv_flush(struct hpsb_iso *iso);

/* returns # of packets ready to send or receive */

int hpsb_iso_n_ready(struct hpsb_iso *iso);

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

/* call after a packet has been transmitted to the bus (interrupt context is OK)

   'cycle' is the _exact_ cycle the packet was sent on

   'error' should be non-zero if some sort of error occurred when sending the packet

*/

void hpsb_iso_packet_sent(struct hpsb_iso *iso, int cycle, int error);

/* call after a packet has been received (interrupt context OK) */

void hpsb_iso_packet_received(struct hpsb_iso *iso, u32 offset, u16 len,

                              u16 cycle, u8 channel, u8 tag, u8 sy);

/* call to wake waiting processes after buffer space has opened up. */

void hpsb_iso_wake(struct hpsb_iso *iso);

#endif /* IEEE1394_ISO_H */