drivers/ieee1394/iso.h

   1 /*
   2  * IEEE 1394 for Linux
   3  *
   4  * kernel ISO transmission/reception
   5  *
   6  * Copyright (C) 2002 Maas Digital LLC
   7  *
   8  * This code is licensed under the GPL.  See the file COPYING in the root
   9  * directory of the kernel sources for details.
  10  */
  11
  12 #ifndef IEEE1394_ISO_H
  13 #define IEEE1394_ISO_H
  14
  15 #include <linux/spinlock_types.h>
  16 #include <asm/atomic.h>
  17 #include <asm/types.h>
  18
  19 #include "dma.h"
  20
  21 struct hpsb_host;
  22
  23 /* high-level ISO interface */
  24
  25 /*
  26  * This API sends and receives isochronous packets on a large,
  27  * virtually-contiguous kernel memory buffer. The buffer may be mapped
  28  * into a user-space process for zero-copy transmission and reception.
  29  *
  30  * There are no explicit boundaries between packets in the buffer. A
  31  * packet may be transmitted or received at any location. However,
  32  * low-level drivers may impose certain restrictions on alignment or
  33  * size of packets. (e.g. in OHCI no packet may cross a page boundary,
  34  * and packets should be quadlet-aligned)
  35  */
  36
  37 /* Packet descriptor - the API maintains a ring buffer of these packet
  38  * descriptors in kernel memory (hpsb_iso.infos[]).  */
  39 struct hpsb_iso_packet_info {
  40         /* offset of data payload relative to the first byte of the buffer */
  41         __u32 offset;
  42
  43         /* length of the data payload, in bytes (not including the isochronous
  44          * header) */
  45         __u16 len;
  46
  47         /* (recv only) the cycle number (mod 8000) on which the packet was
  48          * received */
  49         __u16 cycle;
  50
  51         /* (recv only) channel on which the packet was received */
  52         __u8 channel;
  53
  54         /* 2-bit 'tag' and 4-bit 'sy' fields of the isochronous header */
  55         __u8 tag;
  56         __u8 sy;
  57
  58         /* length in bytes of the packet including header/trailer.
  59          * MUST be at structure end, since the first part of this structure is
  60          * also defined in raw1394.h (i.e. struct raw1394_iso_packet_info), is
  61          * copied to userspace and is accessed there through libraw1394. */
  62         __u16 total_len;
  63 };
  64
  65 enum hpsb_iso_type { HPSB_ISO_RECV = 0, HPSB_ISO_XMIT = 1 };
  66
  67 /* The mode of the dma when receiving iso data. Must be supported by chip */
  68 enum raw1394_iso_dma_recv_mode {
  69         HPSB_ISO_DMA_DEFAULT = -1,
  70         HPSB_ISO_DMA_OLD_ABI = 0,
  71         HPSB_ISO_DMA_BUFFERFILL = 1,
  72         HPSB_ISO_DMA_PACKET_PER_BUFFER = 2
  73 };
  74
  75 struct hpsb_iso {
  76         enum hpsb_iso_type type;
  77
  78         /* pointer to low-level driver and its private data */
  79         struct hpsb_host *host;
  80         void *hostdata;
  81
  82         /* a function to be called (from interrupt context) after
  83          * outgoing packets have been sent, or incoming packets have
  84          * arrived */
  85         void (*callback)(struct hpsb_iso*);
  86
  87         /* wait for buffer space */
  88         wait_queue_head_t waitq;
  89
  90         int speed; /* IEEE1394_SPEED_100, 200, or 400 */
  91         int channel; /* -1 if multichannel */
  92         int dma_mode; /* dma receive mode */
  93
  94
  95         /* greatest # of packets between interrupts - controls
  96          * the maximum latency of the buffer */
  97         int irq_interval;
  98
  99         /* the buffer for packet data payloads */
 100         struct dma_region data_buf;
 101
 102         /* size of data_buf, in bytes (always a multiple of PAGE_SIZE) */
 103         unsigned int buf_size;
 104
 105         /* # of packets in the ringbuffer */
 106         unsigned int buf_packets;
 107
 108         /* protects packet cursors */
 109         spinlock_t lock;
 110
 111         /* the index of the next packet that will be produced
 112            or consumed by the user */
 113         int first_packet;
 114
 115         /* the index of the next packet that will be transmitted
 116            or received by the 1394 hardware */
 117         int pkt_dma;
 118
 119         /* how many packets, starting at first_packet:
 120          * (transmit) are ready to be filled with data
 121          * (receive)  contain received data */
 122         int n_ready_packets;
 123
 124         /* how many times the buffer has overflowed or underflowed */
 125         atomic_t overflows;
 126         /* how many cycles were skipped for a given context */
 127         atomic_t skips;
 128
 129         /* Current number of bytes lost in discarded packets */
 130         int bytes_discarded;
 131
 132         /* private flags to track initialization progress */
 133 #define HPSB_ISO_DRIVER_INIT     (1<<0)
 134 #define HPSB_ISO_DRIVER_STARTED  (1<<1)
 135         unsigned int flags;
 136
 137         /* # of packets left to prebuffer (xmit only) */
 138         int prebuffer;
 139
 140         /* starting cycle for DMA (xmit only) */
 141         int start_cycle;
 142
 143         /* cycle at which next packet will be transmitted,
 144          * -1 if not known */
 145         int xmit_cycle;
 146
 147         /* ringbuffer of packet descriptors in regular kernel memory
 148          * XXX Keep this last, since we use over-allocated memory from
 149          * this entry to fill this field. */
 150         struct hpsb_iso_packet_info *infos;
 151 };
 152
 153 /* functions available to high-level drivers (e.g. raw1394) */
 154
 155 struct hpsb_iso* hpsb_iso_xmit_init(struct hpsb_host *host,
 156                                     unsigned int data_buf_size,
 157                                     unsigned int buf_packets,
 158                                     int channel,
 159                                     int speed,
 160                                     int irq_interval,
 161                                     void (*callback)(struct hpsb_iso*));
 162 struct hpsb_iso* hpsb_iso_recv_init(struct hpsb_host *host,
 163                                     unsigned int data_buf_size,
 164                                     unsigned int buf_packets,
 165                                     int channel,
 166                                     int dma_mode,
 167                                     int irq_interval,
 168                                     void (*callback)(struct hpsb_iso*));
 169 int hpsb_iso_recv_listen_channel(struct hpsb_iso *iso, unsigned char channel);
 170 int hpsb_iso_recv_unlisten_channel(struct hpsb_iso *iso, unsigned char channel);
 171 int hpsb_iso_recv_set_channel_mask(struct hpsb_iso *iso, u64 mask);
 172 int hpsb_iso_xmit_start(struct hpsb_iso *iso, int start_on_cycle,
 173                         int prebuffer);
 174 int hpsb_iso_recv_start(struct hpsb_iso *iso, int start_on_cycle,
 175                         int tag_mask, int sync);
 176 void hpsb_iso_stop(struct hpsb_iso *iso);
 177 void hpsb_iso_shutdown(struct hpsb_iso *iso);
 178 int hpsb_iso_xmit_queue_packet(struct hpsb_iso *iso, u32 offset, u16 len,
 179                                u8 tag, u8 sy);
 180 int hpsb_iso_xmit_sync(struct hpsb_iso *iso);
 181 int hpsb_iso_recv_release_packets(struct hpsb_iso *recv,
 182                                   unsigned int n_packets);
 183 int hpsb_iso_recv_flush(struct hpsb_iso *iso);
 184 int hpsb_iso_n_ready(struct hpsb_iso *iso);
 185
 186 /* the following are callbacks available to low-level drivers */
 187
 188 void hpsb_iso_packet_sent(struct hpsb_iso *iso, int cycle, int error);
 189 void hpsb_iso_packet_received(struct hpsb_iso *iso, u32 offset, u16 len,
 190                               u16 total_len, u16 cycle, u8 channel, u8 tag,
 191                               u8 sy);
 192 void hpsb_iso_wake(struct hpsb_iso *iso);
 193
 194 #endif /* IEEE1394_ISO_H */