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 "hosts.h"
  16 #include "dma.h"
  17
  18 /* high-level ISO interface */
  19
  20 /* This API sends and receives isochronous packets on a large,
  21    virtually-contiguous kernel memory buffer. The buffer may be mapped
  22    into a user-space process for zero-copy transmission and reception.
  23
  24    There are no explicit boundaries between packets in the buffer. A
  25    packet may be transmitted or received at any location. However,
  26    low-level drivers may impose certain restrictions on alignment or
  27    size of packets. (e.g. in OHCI no packet may cross a page boundary,
  28    and packets should be quadlet-aligned)
  29 */
  30
  31 /* Packet descriptor - the API maintains a ring buffer of these packet
  32    descriptors in kernel memory (hpsb_iso.infos[]).  */
  33
  34 struct hpsb_iso_packet_info {
  35         /* offset of data payload relative to the first byte of the buffer */
  36         __u32 offset;
  37
  38         /* length of the data payload, in bytes (not including the isochronous header) */
  39         __u16 len;
  40
  41         /* (recv only) the cycle number (mod 8000) on which the packet was received */
  42         __u16 cycle;
  43
  44         /* (recv only) channel on which the packet was received */
  45         __u8 channel;
  46
  47         /* 2-bit 'tag' and 4-bit 'sy' fields of the isochronous header */
  48         __u8 tag;
  49         __u8 sy;
  50
  51         /*
  52          * length in bytes of the packet including header/trailer.
  53          * MUST be at structure end, since the first part of this structure is also
  54          * defined in raw1394.h (i.e. struct raw1394_iso_packet_info), is copied to
  55          * userspace and is accessed there through libraw1394.
  56          */
  57         __u16 total_len;
  58 };
  59
  60 enum hpsb_iso_type { HPSB_ISO_RECV = 0, HPSB_ISO_XMIT = 1 };
  61
  62 /* The mode of the dma when receiving iso data. Must be supported by chip */
  63 enum raw1394_iso_dma_recv_mode {
  64         HPSB_ISO_DMA_DEFAULT = -1,
  65         HPSB_ISO_DMA_OLD_ABI = 0,
  66         HPSB_ISO_DMA_BUFFERFILL = 1,
  67         HPSB_ISO_DMA_PACKET_PER_BUFFER = 2
  68 };
  69
  70 struct hpsb_iso {
  71         enum hpsb_iso_type type;
  72
  73         /* pointer to low-level driver and its private data */
  74         struct hpsb_host *host;
  75         void *hostdata;
  76
  77         /* a function to be called (from interrupt context) after
  78            outgoing packets have been sent, or incoming packets have
  79            arrived */
  80         void (*callback)(struct hpsb_iso*);
  81
  82         /* wait for buffer space */
  83         wait_queue_head_t waitq;
  84
  85         int speed; /* IEEE1394_SPEED_100, 200, or 400 */
  86         int channel; /* -1 if multichannel */
  87         int dma_mode; /* dma receive mode */
  88
  89
  90         /* greatest # of packets between interrupts - controls
  91            the maximum latency of the buffer */
  92         int irq_interval;
  93
  94         /* the buffer for packet data payloads */
  95         struct dma_region data_buf;
  96
  97         /* size of data_buf, in bytes (always a multiple of PAGE_SIZE) */
  98         unsigned int buf_size;
  99
 100         /* # of packets in the ringbuffer */
 101         unsigned int buf_packets;
 102
 103         /* protects packet cursors */
 104         spinlock_t lock;
 105
 106         /* the index of the next packet that will be produced
 107            or consumed by the user */
 108         int first_packet;
 109
 110         /* the index of the next packet that will be transmitted
 111            or received by the 1394 hardware */
 112         int pkt_dma;
 113
 114         /* how many packets, starting at first_packet:
 115            (transmit) are ready to be filled with data
 116            (receive)  contain received data */
 117         int n_ready_packets;
 118
 119         /* how many times the buffer has overflowed or underflowed */
 120         atomic_t overflows;
 121
 122         /* Current number of bytes lost in discarded packets */
 123         int bytes_discarded;
 124
 125         /* private flags to track initialization progress */
 126 #define HPSB_ISO_DRIVER_INIT     (1<<0)
 127 #define HPSB_ISO_DRIVER_STARTED  (1<<1)
 128         unsigned int flags;
 129
 130         /* # of packets left to prebuffer (xmit only) */
 131         int prebuffer;
 132
 133         /* starting cycle for DMA (xmit only) */
 134         int start_cycle;
 135
 136         /* cycle at which next packet will be transmitted,
 137            -1 if not known */
 138         int xmit_cycle;
 139
 140         /* ringbuffer of packet descriptors in regular kernel memory
 141          * XXX Keep this last, since we use over-allocated memory from
 142          * this entry to fill this field. */
 143         struct hpsb_iso_packet_info *infos;
 144 };
 145
 146 /* functions available to high-level drivers (e.g. raw1394) */
 147
 148 /* allocate the buffer and DMA context */
 149
 150 struct hpsb_iso* hpsb_iso_xmit_init(struct hpsb_host *host,
 151                                     unsigned int data_buf_size,
 152                                     unsigned int buf_packets,
 153                                     int channel,
 154                                     int speed,
 155                                     int irq_interval,
 156                                     void (*callback)(struct hpsb_iso*));
 157
 158 /* note: if channel = -1, multi-channel receive is enabled */
 159 struct hpsb_iso* hpsb_iso_recv_init(struct hpsb_host *host,
 160                                     unsigned int data_buf_size,
 161                                     unsigned int buf_packets,
 162                                     int channel,
 163                                     int dma_mode,
 164                                     int irq_interval,
 165                                     void (*callback)(struct hpsb_iso*));
 166
 167 /* multi-channel only */
 168 int hpsb_iso_recv_listen_channel(struct hpsb_iso *iso, unsigned char channel);
 169 int hpsb_iso_recv_unlisten_channel(struct hpsb_iso *iso, unsigned char channel);
 170 int hpsb_iso_recv_set_channel_mask(struct hpsb_iso *iso, u64 mask);
 171
 172 /* start/stop DMA */
 173 int hpsb_iso_xmit_start(struct hpsb_iso *iso, int start_on_cycle, int prebuffer);
 174 int hpsb_iso_recv_start(struct hpsb_iso *iso, int start_on_cycle, int tag_mask, int sync);
 175 void hpsb_iso_stop(struct hpsb_iso *iso);
 176
 177 /* deallocate buffer and DMA context */
 178 void hpsb_iso_shutdown(struct hpsb_iso *iso);
 179
 180 /* queue a packet for transmission. 'offset' is relative to the beginning of the
 181    DMA buffer, where the packet's data payload should already have been placed */
 182 int hpsb_iso_xmit_queue_packet(struct hpsb_iso *iso, u32 offset, u16 len, u8 tag, u8 sy);
 183
 184 /* wait until all queued packets have been transmitted to the bus */
 185 int hpsb_iso_xmit_sync(struct hpsb_iso *iso);
 186
 187 /* N packets have been read out of the buffer, re-use the buffer space */
 188 int  hpsb_iso_recv_release_packets(struct hpsb_iso *recv, unsigned int n_packets);
 189
 190 /* check for arrival of new packets immediately (even if irq_interval
 191    has not yet been reached) */
 192 int hpsb_iso_recv_flush(struct hpsb_iso *iso);
 193
 194 /* returns # of packets ready to send or receive */
 195 int hpsb_iso_n_ready(struct hpsb_iso *iso);
 196
 197 /* the following are callbacks available to low-level drivers */
 198
 199 /* call after a packet has been transmitted to the bus (interrupt context is OK)
 200    'cycle' is the _exact_ cycle the packet was sent on
 201    'error' should be non-zero if some sort of error occurred when sending the packet
 202 */
 203 void hpsb_iso_packet_sent(struct hpsb_iso *iso, int cycle, int error);
 204
 205 /* call after a packet has been received (interrupt context OK) */
 206 void hpsb_iso_packet_received(struct hpsb_iso *iso, u32 offset, u16 len,
 207                               u16 total_len, u16 cycle, u8 channel, u8 tag, u8 sy);
 208
 209 /* call to wake waiting processes after buffer space has opened up. */
 210 void hpsb_iso_wake(struct hpsb_iso *iso);
 211
 212 #endif /* IEEE1394_ISO_H */