path: root/include/linux/firewire.h
diff options
authorStefan Richter <stefanr@s5r6.in-berlin.de>2010-07-29 18:19:22 +0200
committerStefan Richter <stefanr@s5r6.in-berlin.de>2010-07-29 23:09:18 +0200
commit872e330e38806d835bd6c311c93ab998e2fb9058 (patch)
tree92497ce79b1157761b1aebdb63b8d74f68d42c15 /include/linux/firewire.h
parentae2a97661482c1d0f1aa41b837da95054d0e9a1b (diff)
firewire: add isochronous multichannel reception
This adds the DMA context programming and userspace ABI for multichannel reception, i.e. for listening on multiple channel numbers by means of a single DMA context. The use case is reception of more streams than there are IR DMA units offered by the link layer. This is already implemented by the older ohci1394 + ieee1394 + raw1394 stack. And as discussed recently on linux1394-devel, this feature is occasionally used in practice. The big drawbacks of this mode are that buffer layout and interrupt generation necessarily differ from single-channel reception: Headers and trailers are not stripped from packets, packets are not aligned with buffer chunks, interrupts are per buffer chunk, not per packet. These drawbacks also cause a rather hefty code footprint to support this rarely used OHCI-1394 feature. (367 lines added, among them 94 lines of added userspace ABI documentation.) This implementation enforces that a multichannel reception context may only listen to channels to which no single-channel context on the same link layer is presently listening to. OHCI-1394 would allow to overlay single-channel contexts by the multi-channel context, but this would be a departure from the present first-come-first-served policy of IR context creation. The implementation is heavily based on an earlier one by Jay Fenlason. Thanks Jay. Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Diffstat (limited to 'include/linux/firewire.h')
1 files changed, 19 insertions, 10 deletions
diff --git a/include/linux/firewire.h b/include/linux/firewire.h
index d974aa4a24c9..1cd637ef62d2 100644
--- a/include/linux/firewire.h
+++ b/include/linux/firewire.h
@@ -372,17 +372,19 @@ void fw_core_remove_descriptor(struct fw_descriptor *desc);
* scatter-gather streaming (e.g. assembling video frame automatically).
struct fw_iso_packet {
- u16 payload_length; /* Length of indirect payload. */
- u32 interrupt:1; /* Generate interrupt on this packet */
- u32 skip:1; /* Set to not send packet at all. */
- u32 tag:2;
- u32 sy:4;
- u32 header_length:8; /* Length of immediate header. */
- u32 header[0];
+ u16 payload_length; /* Length of indirect payload */
+ u32 interrupt:1; /* Generate interrupt on this packet */
+ u32 skip:1; /* tx: Set to not send packet at all */
+ /* rx: Sync bit, wait for matching sy */
+ u32 tag:2; /* tx: Tag in packet header */
+ u32 sy:4; /* tx: Sy in packet header */
+ u32 header_length:8; /* Length of immediate header */
+ u32 header[0]; /* tx: Top of 1394 isoch. data_block */
@@ -406,24 +408,31 @@ struct fw_iso_buffer {
int fw_iso_buffer_init(struct fw_iso_buffer *buffer, struct fw_card *card,
int page_count, enum dma_data_direction direction);
void fw_iso_buffer_destroy(struct fw_iso_buffer *buffer, struct fw_card *card);
+size_t fw_iso_buffer_lookup(struct fw_iso_buffer *buffer, dma_addr_t completed);
struct fw_iso_context;
typedef void (*fw_iso_callback_t)(struct fw_iso_context *context,
u32 cycle, size_t header_length,
void *header, void *data);
+typedef void (*fw_iso_mc_callback_t)(struct fw_iso_context *context,
+ dma_addr_t completed, void *data);
struct fw_iso_context {
struct fw_card *card;
int type;
int channel;
int speed;
size_t header_size;
- fw_iso_callback_t callback;
+ union {
+ fw_iso_callback_t sc;
+ fw_iso_mc_callback_t mc;
+ } callback;
void *callback_data;
struct fw_iso_context *fw_iso_context_create(struct fw_card *card,
int type, int channel, int speed, size_t header_size,
fw_iso_callback_t callback, void *callback_data);
+int fw_iso_context_set_channels(struct fw_iso_context *ctx, u64 *channels);
int fw_iso_context_queue(struct fw_iso_context *ctx,
struct fw_iso_packet *packet,
struct fw_iso_buffer *buffer,

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