From 872e330e38806d835bd6c311c93ab998e2fb9058 Mon Sep 17 00:00:00 2001 From: Stefan Richter Date: Thu, 29 Jul 2010 18:19:22 +0200 Subject: 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 --- drivers/firewire/core-iso.c | 32 +++++++++++++++++++++++++------- 1 file changed, 25 insertions(+), 7 deletions(-) (limited to 'drivers/firewire/core-iso.c') diff --git a/drivers/firewire/core-iso.c b/drivers/firewire/core-iso.c index 4fe932e60fb8..0c8e662a5daf 100644 --- a/drivers/firewire/core-iso.c +++ b/drivers/firewire/core-iso.c @@ -117,6 +117,23 @@ void fw_iso_buffer_destroy(struct fw_iso_buffer *buffer, } EXPORT_SYMBOL(fw_iso_buffer_destroy); +/* Convert DMA address to offset into virtually contiguous buffer. */ +size_t fw_iso_buffer_lookup(struct fw_iso_buffer *buffer, dma_addr_t completed) +{ + int i; + dma_addr_t address; + ssize_t offset; + + for (i = 0; i < buffer->page_count; i++) { + address = page_private(buffer->pages[i]); + offset = (ssize_t)completed - (ssize_t)address; + if (offset > 0 && offset <= PAGE_SIZE) + return (i << PAGE_SHIFT) + offset; + } + + return 0; +} + 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) @@ -133,7 +150,7 @@ struct fw_iso_context *fw_iso_context_create(struct fw_card *card, ctx->channel = channel; ctx->speed = speed; ctx->header_size = header_size; - ctx->callback = callback; + ctx->callback.sc = callback; ctx->callback_data = callback_data; return ctx; @@ -142,9 +159,7 @@ EXPORT_SYMBOL(fw_iso_context_create); void fw_iso_context_destroy(struct fw_iso_context *ctx) { - struct fw_card *card = ctx->card; - - card->driver->free_iso_context(ctx); + ctx->card->driver->free_iso_context(ctx); } EXPORT_SYMBOL(fw_iso_context_destroy); @@ -155,14 +170,17 @@ int fw_iso_context_start(struct fw_iso_context *ctx, } EXPORT_SYMBOL(fw_iso_context_start); +int fw_iso_context_set_channels(struct fw_iso_context *ctx, u64 *channels) +{ + return ctx->card->driver->set_iso_channels(ctx, channels); +} + int fw_iso_context_queue(struct fw_iso_context *ctx, struct fw_iso_packet *packet, struct fw_iso_buffer *buffer, unsigned long payload) { - struct fw_card *card = ctx->card; - - return card->driver->queue_iso(ctx, packet, buffer, payload); + return ctx->card->driver->queue_iso(ctx, packet, buffer, payload); } EXPORT_SYMBOL(fw_iso_context_queue); -- cgit v1.2.3