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 --- include/linux/firewire-cdev.h | 281 +++++++++++++++++++++++++++++------------- 1 file changed, 195 insertions(+), 86 deletions(-) (limited to 'include/linux/firewire-cdev.h') diff --git a/include/linux/firewire-cdev.h b/include/linux/firewire-cdev.h index 14831119ff71..bc5c26fc1c64 100644 --- a/include/linux/firewire-cdev.h +++ b/include/linux/firewire-cdev.h @@ -25,17 +25,18 @@ #include #include -#define FW_CDEV_EVENT_BUS_RESET 0x00 -#define FW_CDEV_EVENT_RESPONSE 0x01 -#define FW_CDEV_EVENT_REQUEST 0x02 -#define FW_CDEV_EVENT_ISO_INTERRUPT 0x03 -#define FW_CDEV_EVENT_ISO_RESOURCE_ALLOCATED 0x04 -#define FW_CDEV_EVENT_ISO_RESOURCE_DEALLOCATED 0x05 +#define FW_CDEV_EVENT_BUS_RESET 0x00 +#define FW_CDEV_EVENT_RESPONSE 0x01 +#define FW_CDEV_EVENT_REQUEST 0x02 +#define FW_CDEV_EVENT_ISO_INTERRUPT 0x03 +#define FW_CDEV_EVENT_ISO_RESOURCE_ALLOCATED 0x04 +#define FW_CDEV_EVENT_ISO_RESOURCE_DEALLOCATED 0x05 /* available since kernel version 2.6.36 */ -#define FW_CDEV_EVENT_REQUEST2 0x06 -#define FW_CDEV_EVENT_PHY_PACKET_SENT 0x07 -#define FW_CDEV_EVENT_PHY_PACKET_RECEIVED 0x08 +#define FW_CDEV_EVENT_REQUEST2 0x06 +#define FW_CDEV_EVENT_PHY_PACKET_SENT 0x07 +#define FW_CDEV_EVENT_PHY_PACKET_RECEIVED 0x08 +#define FW_CDEV_EVENT_ISO_INTERRUPT_MULTICHANNEL 0x09 /** * struct fw_cdev_event_common - Common part of all fw_cdev_event_ types @@ -218,35 +219,41 @@ struct fw_cdev_event_request2 { * This event is sent when the controller has completed an &fw_cdev_iso_packet * with the %FW_CDEV_ISO_INTERRUPT bit set. * - * Isochronous transmit events: + * Isochronous transmit events (context type %FW_CDEV_ISO_CONTEXT_TRANSMIT): * - * In version 1 of the ABI, &header_length is 0. In version 3 and some - * implementations of version 2 of the ABI, &header_length is a multiple of 4 - * and &header contains timestamps of all packets up until the interrupt packet. - * The format of the timestamps is as described below for isochronous reception. + * In version 3 and some implementations of version 2 of the ABI, &header_length + * is a multiple of 4 and &header contains timestamps of all packets up until + * the interrupt packet. The format of the timestamps is as described below for + * isochronous reception. In version 1 of the ABI, &header_length was 0. * - * Isochronous receive events: + * Isochronous receive events (context type %FW_CDEV_ISO_CONTEXT_RECEIVE): * * The headers stripped of all packets up until and including the interrupt * packet are returned in the @header field. The amount of header data per * packet is as specified at iso context creation by * &fw_cdev_create_iso_context.header_size. * - * In version 1 of this ABI, header data consisted of the 1394 isochronous - * packet header, followed by quadlets from the packet payload if - * &fw_cdev_create_iso_context.header_size > 4. + * Hence, _interrupt.header_length / _context.header_size is the number of + * packets received in this interrupt event. The client can now iterate + * through the mmap()'ed DMA buffer according to this number of packets and + * to the buffer sizes as the client specified in &fw_cdev_queue_iso. * - * In version 2 of this ABI, header data consist of the 1394 isochronous - * packet header, followed by a timestamp quadlet if - * &fw_cdev_create_iso_context.header_size > 4, followed by quadlets from the - * packet payload if &fw_cdev_create_iso_context.header_size > 8. + * Since version 2 of this ABI, the portion for each packet in _interrupt.header + * consists of the 1394 isochronous packet header, followed by a timestamp + * quadlet if &fw_cdev_create_iso_context.header_size > 4, followed by quadlets + * from the packet payload if &fw_cdev_create_iso_context.header_size > 8. * - * Behaviour of ver. 1 of this ABI is no longer available since ABI ver. 2. + * Format of 1394 iso packet header: 16 bits data_length, 2 bits tag, 6 bits + * channel, 4 bits tcode, 4 bits sy, in big endian byte order. + * data_length is the actual received size of the packet without the four + * 1394 iso packet header bytes. + * + * Format of timestamp: 16 bits invalid, 3 bits cycleSeconds, 13 bits + * cycleCount, in big endian byte order. * - * Format of 1394 iso packet header: 16 bits len, 2 bits tag, 6 bits channel, - * 4 bits tcode, 4 bits sy, in big endian byte order. Format of timestamp: - * 16 bits invalid, 3 bits cycleSeconds, 13 bits cycleCount, in big endian byte - * order. + * In version 1 of the ABI, no timestamp quadlet was inserted; instead, payload + * data followed directly after the 1394 is header if header_size > 4. + * Behaviour of ver. 1 of this ABI is no longer available since ABI ver. 2. */ struct fw_cdev_event_iso_interrupt { __u64 closure; @@ -256,6 +263,43 @@ struct fw_cdev_event_iso_interrupt { __u32 header[0]; }; +/** + * struct fw_cdev_event_iso_interrupt_mc - An iso buffer chunk was completed + * @closure: See &fw_cdev_event_common; + * set by %FW_CDEV_CREATE_ISO_CONTEXT ioctl + * @type: %FW_CDEV_EVENT_ISO_INTERRUPT_MULTICHANNEL + * @completed: Offset into the receive buffer; data before this offest is valid + * + * This event is sent in multichannel contexts (context type + * %FW_CDEV_ISO_CONTEXT_RECEIVE_MULTICHANNEL) for &fw_cdev_iso_packet buffer + * chunks that have the %FW_CDEV_ISO_INTERRUPT bit set. Whether this happens + * when a packet is completed and/or when a buffer chunk is completed depends + * on the hardware implementation. + * + * The buffer is continuously filled with the following data, per packet: + * - the 1394 iso packet header as described at &fw_cdev_event_iso_interrupt, + * but in little endian byte order, + * - packet payload (as many bytes as specified in the data_length field of + * the 1394 iso packet header) in big endian byte order, + * - 0...3 padding bytes as needed to align the following trailer quadlet, + * - trailer quadlet, containing the reception timestamp as described at + * &fw_cdev_event_iso_interrupt, but in little endian byte order. + * + * Hence the per-packet size is data_length (rounded up to a multiple of 4) + 8. + * When processing the data, stop before a packet that would cross the + * @completed offset. + * + * A packet near the end of a buffer chunk will typically spill over into the + * next queued buffer chunk. It is the responsibility of the client to check + * for this condition, assemble a broken-up packet from its parts, and not to + * re-queue any buffer chunks in which as yet unread packet parts reside. + */ +struct fw_cdev_event_iso_interrupt_mc { + __u64 closure; + __u32 type; + __u32 completed; +}; + /** * struct fw_cdev_event_iso_resource - Iso resources were allocated or freed * @closure: See &fw_cdev_event_common; @@ -311,16 +355,18 @@ struct fw_cdev_event_phy_packet { /** * union fw_cdev_event - Convenience union of fw_cdev_event_ types - * @common: Valid for all types - * @bus_reset: Valid if @common.type == %FW_CDEV_EVENT_BUS_RESET - * @response: Valid if @common.type == %FW_CDEV_EVENT_RESPONSE - * @request: Valid if @common.type == %FW_CDEV_EVENT_REQUEST - * @request2: Valid if @common.type == %FW_CDEV_EVENT_REQUEST2 - * @iso_interrupt: Valid if @common.type == %FW_CDEV_EVENT_ISO_INTERRUPT - * @iso_resource: Valid if @common.type == + * @common: Valid for all types + * @bus_reset: Valid if @common.type == %FW_CDEV_EVENT_BUS_RESET + * @response: Valid if @common.type == %FW_CDEV_EVENT_RESPONSE + * @request: Valid if @common.type == %FW_CDEV_EVENT_REQUEST + * @request2: Valid if @common.type == %FW_CDEV_EVENT_REQUEST2 + * @iso_interrupt: Valid if @common.type == %FW_CDEV_EVENT_ISO_INTERRUPT + * @iso_interrupt_mc: Valid if @common.type == + * %FW_CDEV_EVENT_ISO_INTERRUPT_MULTICHANNEL + * @iso_resource: Valid if @common.type == * %FW_CDEV_EVENT_ISO_RESOURCE_ALLOCATED or * %FW_CDEV_EVENT_ISO_RESOURCE_DEALLOCATED - * @phy_packet: Valid if @common.type == + * @phy_packet: Valid if @common.type == * %FW_CDEV_EVENT_PHY_PACKET_SENT or * %FW_CDEV_EVENT_PHY_PACKET_RECEIVED * @@ -337,10 +383,11 @@ union fw_cdev_event { struct fw_cdev_event_bus_reset bus_reset; struct fw_cdev_event_response response; struct fw_cdev_event_request request; - struct fw_cdev_event_request2 request2; /* added in 2.6.36 */ + struct fw_cdev_event_request2 request2; /* added in 2.6.36 */ struct fw_cdev_event_iso_interrupt iso_interrupt; - struct fw_cdev_event_iso_resource iso_resource; /* added in 2.6.30 */ - struct fw_cdev_event_phy_packet phy_packet; /* added in 2.6.36 */ + struct fw_cdev_event_iso_interrupt_mc iso_interrupt_mc; /* added in 2.6.36 */ + struct fw_cdev_event_iso_resource iso_resource; /* added in 2.6.30 */ + struct fw_cdev_event_phy_packet phy_packet; /* added in 2.6.36 */ }; /* available since kernel version 2.6.22 */ @@ -375,6 +422,7 @@ union fw_cdev_event { /* available since kernel version 2.6.36 */ #define FW_CDEV_IOC_SEND_PHY_PACKET _IOWR('#', 0x15, struct fw_cdev_send_phy_packet) #define FW_CDEV_IOC_RECEIVE_PHY_PACKETS _IOW('#', 0x16, struct fw_cdev_receive_phy_packets) +#define FW_CDEV_IOC_SET_ISO_CHANNELS _IOW('#', 0x17, struct fw_cdev_set_iso_channels) /* * ABI version history @@ -391,10 +439,13 @@ union fw_cdev_event { * - shared use and auto-response for FCP registers * 3 (2.6.34) - made &fw_cdev_get_cycle_timer reliable * - added %FW_CDEV_IOC_GET_CYCLE_TIMER2 - * 4 (2.6.36) - added %FW_CDEV_EVENT_REQUEST2, %FW_CDEV_EVENT_PHY_PACKET_* + * 4 (2.6.36) - added %FW_CDEV_EVENT_REQUEST2, %FW_CDEV_EVENT_PHY_PACKET_*, + * and &fw_cdev_allocate.region_end * - implemented &fw_cdev_event_bus_reset.bm_node_id * - added %FW_CDEV_IOC_SEND_PHY_PACKET, _RECEIVE_PHY_PACKETS - * - added &fw_cdev_allocate.region_end + * - added %FW_CDEV_EVENT_ISO_INTERRUPT_MULTICHANNEL, + * %FW_CDEV_ISO_CONTEXT_RECEIVE_MULTICHANNEL, and + * %FW_CDEV_IOC_SET_ISO_CHANNELS */ #define FW_CDEV_VERSION 3 /* Meaningless; don't use this macro. */ @@ -597,34 +648,43 @@ struct fw_cdev_remove_descriptor { __u32 handle; }; -#define FW_CDEV_ISO_CONTEXT_TRANSMIT 0 -#define FW_CDEV_ISO_CONTEXT_RECEIVE 1 +#define FW_CDEV_ISO_CONTEXT_TRANSMIT 0 +#define FW_CDEV_ISO_CONTEXT_RECEIVE 1 +#define FW_CDEV_ISO_CONTEXT_RECEIVE_MULTICHANNEL 2 /* added in 2.6.36 */ /** - * struct fw_cdev_create_iso_context - Create a context for isochronous IO - * @type: %FW_CDEV_ISO_CONTEXT_TRANSMIT or %FW_CDEV_ISO_CONTEXT_RECEIVE - * @header_size: Header size to strip for receive contexts - * @channel: Channel to bind to - * @speed: Speed for transmit contexts - * @closure: To be returned in &fw_cdev_event_iso_interrupt + * struct fw_cdev_create_iso_context - Create a context for isochronous I/O + * @type: %FW_CDEV_ISO_CONTEXT_TRANSMIT or %FW_CDEV_ISO_CONTEXT_RECEIVE or + * %FW_CDEV_ISO_CONTEXT_RECEIVE_MULTICHANNEL + * @header_size: Header size to strip in single-channel reception + * @channel: Channel to bind to in single-channel reception or transmission + * @speed: Transmission speed + * @closure: To be returned in &fw_cdev_event_iso_interrupt or + * &fw_cdev_event_iso_interrupt_multichannel * @handle: Handle to context, written back by kernel * * Prior to sending or receiving isochronous I/O, a context must be created. * The context records information about the transmit or receive configuration * and typically maps to an underlying hardware resource. A context is set up * for either sending or receiving. It is bound to a specific isochronous - * channel. + * @channel. * - * If a context was successfully created, the kernel writes back a handle to the - * context, which must be passed in for subsequent operations on that context. + * In case of multichannel reception, @header_size and @channel are ignored + * and the channels are selected by %FW_CDEV_IOC_SET_ISO_CHANNELS. + * + * For %FW_CDEV_ISO_CONTEXT_RECEIVE contexts, @header_size must be at least 4 + * and must be a multiple of 4. It is ignored in other context types. * - * For receive contexts, @header_size must be at least 4 and must be a multiple - * of 4. + * @speed is ignored in receive context types. * - * Note that the effect of a @header_size > 4 depends on - * &fw_cdev_get_info.version, as documented at &fw_cdev_event_iso_interrupt. + * If a context was successfully created, the kernel writes back a handle to the + * context, which must be passed in for subsequent operations on that context. * + * Limitations: * No more than one iso context can be created per fd. + * The total number of contexts that all userspace and kernelspace drivers can + * create on a card at a time is a hardware limit, typically 4 or 8 contexts per + * direction, and of them at most one multichannel receive context. */ struct fw_cdev_create_iso_context { __u32 type; @@ -635,6 +695,22 @@ struct fw_cdev_create_iso_context { __u32 handle; }; +/** + * struct fw_cdev_set_iso_channels - Select channels in multichannel reception + * @channels: Bitmask of channels to listen to + * @handle: Handle of the mutichannel receive context + * + * @channels is the bitwise or of 1ULL << n for each channel n to listen to. + * + * The ioctl fails with errno %EBUSY if there is already another receive context + * on a channel in @channels. In that case, the bitmask of all unoccupied + * channels is returned in @channels. + */ +struct fw_cdev_set_iso_channels { + __u64 channels; + __u32 handle; +}; + #define FW_CDEV_ISO_PAYLOAD_LENGTH(v) (v) #define FW_CDEV_ISO_INTERRUPT (1 << 16) #define FW_CDEV_ISO_SKIP (1 << 17) @@ -645,42 +721,72 @@ struct fw_cdev_create_iso_context { /** * struct fw_cdev_iso_packet - Isochronous packet - * @control: Contains the header length (8 uppermost bits), the sy field - * (4 bits), the tag field (2 bits), a sync flag (1 bit), - * a skip flag (1 bit), an interrupt flag (1 bit), and the + * @control: Contains the header length (8 uppermost bits), + * the sy field (4 bits), the tag field (2 bits), a sync flag + * or a skip flag (1 bit), an interrupt flag (1 bit), and the * payload length (16 lowermost bits) - * @header: Header and payload + * @header: Header and payload in case of a transmit context. * * &struct fw_cdev_iso_packet is used to describe isochronous packet queues. - * * Use the FW_CDEV_ISO_ macros to fill in @control. + * The @header array is empty in case of receive contexts. + * + * Context type %FW_CDEV_ISO_CONTEXT_TRANSMIT: + * + * @control.HEADER_LENGTH must be a multiple of 4. It specifies the numbers of + * bytes in @header that will be prepended to the packet's payload. These bytes + * are copied into the kernel and will not be accessed after the ioctl has + * returned. + * + * The @control.SY and TAG fields are copied to the iso packet header. These + * fields are specified by IEEE 1394a and IEC 61883-1. + * + * The @control.SKIP flag specifies that no packet is to be sent in a frame. + * When using this, all other fields except @control.INTERRUPT must be zero. + * + * When a packet with the @control.INTERRUPT flag set has been completed, an + * &fw_cdev_event_iso_interrupt event will be sent. + * + * Context type %FW_CDEV_ISO_CONTEXT_RECEIVE: * - * For transmit packets, the header length must be a multiple of 4 and specifies - * the numbers of bytes in @header that will be prepended to the packet's - * payload; these bytes are copied into the kernel and will not be accessed - * after the ioctl has returned. The sy and tag fields are copied to the iso - * packet header (these fields are specified by IEEE 1394a and IEC 61883-1). - * The skip flag specifies that no packet is to be sent in a frame; when using - * this, all other fields except the interrupt flag must be zero. - * - * For receive packets, the header length must be a multiple of the context's - * header size; if the header length is larger than the context's header size, - * multiple packets are queued for this entry. The sy and tag fields are - * ignored. If the sync flag is set, the context drops all packets until - * a packet with a matching sy field is received (the sync value to wait for is - * specified in the &fw_cdev_start_iso structure). The payload length defines - * how many payload bytes can be received for one packet (in addition to payload - * quadlets that have been defined as headers and are stripped and returned in - * the &fw_cdev_event_iso_interrupt structure). If more bytes are received, the - * additional bytes are dropped. If less bytes are received, the remaining - * bytes in this part of the payload buffer will not be written to, not even by - * the next packet, i.e., packets received in consecutive frames will not - * necessarily be consecutive in memory. If an entry has queued multiple - * packets, the payload length is divided equally among them. - * - * When a packet with the interrupt flag set has been completed, the + * @control.HEADER_LENGTH must be a multiple of the context's header_size. + * If the HEADER_LENGTH is larger than the context's header_size, multiple + * packets are queued for this entry. + * + * The @control.SY and TAG fields are ignored. + * + * If the @control.SYNC flag is set, the context drops all packets until a + * packet with a sy field is received which matches &fw_cdev_start_iso.sync. + * + * @control.PAYLOAD_LENGTH defines how many payload bytes can be received for + * one packet (in addition to payload quadlets that have been defined as headers + * and are stripped and returned in the &fw_cdev_event_iso_interrupt structure). + * If more bytes are received, the additional bytes are dropped. If less bytes + * are received, the remaining bytes in this part of the payload buffer will not + * be written to, not even by the next packet. I.e., packets received in + * consecutive frames will not necessarily be consecutive in memory. If an + * entry has queued multiple packets, the PAYLOAD_LENGTH is divided equally + * among them. + * + * When a packet with the @control.INTERRUPT flag set has been completed, an * &fw_cdev_event_iso_interrupt event will be sent. An entry that has queued * multiple receive packets is completed when its last packet is completed. + * + * Context type %FW_CDEV_ISO_CONTEXT_RECEIVE_MULTICHANNEL: + * + * Here, &fw_cdev_iso_packet would be more aptly named _iso_buffer_chunk since + * it specifies a chunk of the mmap()'ed buffer, while the number and alignment + * of packets to be placed into the buffer chunk is not known beforehand. + * + * @control.PAYLOAD_LENGTH is the size of the buffer chunk and specifies room + * for header, payload, padding, and trailer bytes of one or more packets. + * It must be a multiple of 4. + * + * @control.HEADER_LENGTH, TAG and SY are ignored. SYNC is treated as described + * for single-channel reception. + * + * When a buffer chunk with the @control.INTERRUPT flag set has been filled + * entirely, an &fw_cdev_event_iso_interrupt_mc event will be sent. */ struct fw_cdev_iso_packet { __u32 control; @@ -689,9 +795,9 @@ struct fw_cdev_iso_packet { /** * struct fw_cdev_queue_iso - Queue isochronous packets for I/O - * @packets: Userspace pointer to packet data + * @packets: Userspace pointer to an array of &fw_cdev_iso_packet * @data: Pointer into mmap()'ed payload buffer - * @size: Size of packet data in bytes + * @size: Size of the @packets array, in bytes * @handle: Isochronous context handle * * Queue a number of isochronous packets for reception or transmission. @@ -704,6 +810,9 @@ struct fw_cdev_iso_packet { * The kernel may or may not queue all packets, but will write back updated * values of the @packets, @data and @size fields, so the ioctl can be * resubmitted easily. + * + * In case of a multichannel receive context, @data must be quadlet-aligned + * relative to the buffer start. */ struct fw_cdev_queue_iso { __u64 packets; -- cgit v1.2.3