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 enum hpsb_iso_type { HPSB_ISO_RECV = 0, HPSB_ISO_XMIT = 1 }; 53 54 struct hpsb_iso { 55 enum hpsb_iso_type type; 56 57 /* pointer to low-level driver and its private data */ 58 struct hpsb_host *host; 59 void *hostdata; 60 61 /* a function to be called (from interrupt context) after 62 outgoing packets have been sent, or incoming packets have 63 arrived */ 64 void (*callback)(struct hpsb_iso*); 65 66 /* wait for buffer space */ 67 wait_queue_head_t waitq; 68 69 int speed; /* IEEE1394_SPEED_100, 200, or 400 */ 70 int channel; /* -1 if multichannel */ 71 72 /* greatest # of packets between interrupts - controls 73 the maximum latency of the buffer */ 74 int irq_interval; 75 76 /* the buffer for packet data payloads */ 77 struct dma_region data_buf; 78 79 /* size of data_buf, in bytes (always a multiple of PAGE_SIZE) */ 80 unsigned int buf_size; 81 82 /* # of packets in the ringbuffer */ 83 unsigned int buf_packets; 84 85 /* protects packet cursors */ 86 spinlock_t lock; 87 88 /* the index of the next packet that will be produced 89 or consumed by the user */ 90 int first_packet; 91 92 /* the index of the next packet that will be transmitted 93 or received by the 1394 hardware */ 94 int pkt_dma; 95 96 /* how many packets, starting at first_packet: 97 (transmit) are ready to be filled with data 98 (receive) contain received data */ 99 int n_ready_packets; 100 101 /* how many times the buffer has overflowed or underflowed */ 102 atomic_t overflows; 103 104 /* private flags to track initialization progress */ 105 #define HPSB_ISO_DRIVER_INIT (1<<0) 106 #define HPSB_ISO_DRIVER_STARTED (1<<1) 107 unsigned int flags; 108 109 /* # of packets left to prebuffer (xmit only) */ 110 int prebuffer; 111 112 /* starting cycle for DMA (xmit only) */ 113 int start_cycle; 114 115 /* cycle at which next packet will be transmitted, 116 -1 if not known */ 117 int xmit_cycle; 118 119 /* ringbuffer of packet descriptors in regular kernel memory 120 * XXX Keep this last, since we use over-allocated memory from 121 * this entry to fill this field. */ 122 struct hpsb_iso_packet_info *infos; 123 }; 124 125 /* functions available to high-level drivers (e.g. raw1394) */ 126 127 /* allocate the buffer and DMA context */ 128 129 struct hpsb_iso* hpsb_iso_xmit_init(struct hpsb_host *host, 130 unsigned int data_buf_size, 131 unsigned int buf_packets, 132 int channel, 133 int speed, 134 int irq_interval, 135 void (*callback)(struct hpsb_iso*)); 136 137 /* note: if channel = -1, multi-channel receive is enabled */ 138 struct hpsb_iso* hpsb_iso_recv_init(struct hpsb_host *host, 139 unsigned int data_buf_size, 140 unsigned int buf_packets, 141 int channel, 142 int irq_interval, 143 void (*callback)(struct hpsb_iso*)); 144 145 /* multi-channel only */ 146 int hpsb_iso_recv_listen_channel(struct hpsb_iso *iso, unsigned char channel); 147 int hpsb_iso_recv_unlisten_channel(struct hpsb_iso *iso, unsigned char channel); 148 int hpsb_iso_recv_set_channel_mask(struct hpsb_iso *iso, u64 mask); 149 150 /* start/stop DMA */ 151 int hpsb_iso_xmit_start(struct hpsb_iso *iso, int start_on_cycle, int prebuffer); 152 int hpsb_iso_recv_start(struct hpsb_iso *iso, int start_on_cycle, int tag_mask, int sync); 153 void hpsb_iso_stop(struct hpsb_iso *iso); 154 155 /* deallocate buffer and DMA context */ 156 void hpsb_iso_shutdown(struct hpsb_iso *iso); 157 158 /* queue a packet for transmission. 'offset' is relative to the beginning of the 159 DMA buffer, where the packet's data payload should already have been placed */ 160 int hpsb_iso_xmit_queue_packet(struct hpsb_iso *iso, u32 offset, u16 len, u8 tag, u8 sy); 161 162 /* wait until all queued packets have been transmitted to the bus */ 163 int hpsb_iso_xmit_sync(struct hpsb_iso *iso); 164 165 /* N packets have been read out of the buffer, re-use the buffer space */ 166 int hpsb_iso_recv_release_packets(struct hpsb_iso *recv, unsigned int n_packets); 167 168 /* check for arrival of new packets immediately (even if irq_interval 169 has not yet been reached) */ 170 int hpsb_iso_recv_flush(struct hpsb_iso *iso); 171 172 /* returns # of packets ready to send or receive */ 173 int hpsb_iso_n_ready(struct hpsb_iso *iso); 174 175 /* the following are callbacks available to low-level drivers */ 176 177 /* call after a packet has been transmitted to the bus (interrupt context is OK) 178 'cycle' is the _exact_ cycle the packet was sent on 179 'error' should be non-zero if some sort of error occurred when sending the packet 180 */ 181 void hpsb_iso_packet_sent(struct hpsb_iso *iso, int cycle, int error); 182 183 /* call after a packet has been received (interrupt context OK) */ 184 void hpsb_iso_packet_received(struct hpsb_iso *iso, u32 offset, u16 len, 185 u16 cycle, u8 channel, u8 tag, u8 sy); 186 187 /* call to wake waiting processes after buffer space has opened up. */ 188 void hpsb_iso_wake(struct hpsb_iso *iso); 189 190 #endif /* IEEE1394_ISO_H */ 191