From 656b7afd40a9f2b0d6cf8ef1972681961b428558 Mon Sep 17 00:00:00 2001 From: Stefan Richter Date: Wed, 7 Jul 2010 13:26:18 +0200 Subject: firewire: core: fix fw_send_request kerneldoc comment The present inline documentation of the fw_send_request() in-kernel API refers to userland code that is not applicable to kernel drivers at all. Reported-by: Ben Gamari While we are at fixing the whole documentation of fw_send_request(), also improve the rest of firewire-core's kerneldoc comments: - Add a bit of text concerning fw_run_transaction()'s call parameters. - Append () to function names and tab-align parameter descriptions as suggested by the example in Documentation/kernel-doc-nano-HOWTO.txt. - Remove kerneldoc markers from comments on static functions. - Remove outdated parameter descriptions at build_tree(). Signed-off-by: Stefan Richter --- drivers/firewire/core-transaction.c | 84 ++++++++++++++++++++----------------- 1 file changed, 46 insertions(+), 38 deletions(-) (limited to 'drivers/firewire/core-transaction.c') diff --git a/drivers/firewire/core-transaction.c b/drivers/firewire/core-transaction.c index fcb455c0820..7813da8a129 100644 --- a/drivers/firewire/core-transaction.c +++ b/drivers/firewire/core-transaction.c @@ -273,43 +273,49 @@ static int allocate_tlabel(struct fw_card *card) } /** - * This function provides low-level access to the IEEE1394 transaction - * logic. Most C programs would use either fw_read(), fw_write() or - * fw_lock() instead - those function are convenience wrappers for - * this function. The fw_send_request() function is primarily - * provided as a flexible, one-stop entry point for languages bindings - * and protocol bindings. + * fw_send_request() - submit a request packet for transmission + * @card: interface to send the request at + * @t: transaction instance to which the request belongs + * @tcode: transaction code + * @destination_id: destination node ID, consisting of bus_ID and phy_ID + * @generation: bus generation in which request and response are valid + * @speed: transmission speed + * @offset: 48bit wide offset into destination's address space + * @payload: data payload for the request subaction + * @length: length of the payload, in bytes + * @callback: function to be called when the transaction is completed + * @callback_data: data to be passed to the transaction completion callback * - * FIXME: Document this function further, in particular the possible - * values for rcode in the callback. In short, we map ACK_COMPLETE to - * RCODE_COMPLETE, internal errors set errno and set rcode to - * RCODE_SEND_ERROR (which is out of range for standard ieee1394 - * rcodes). All other rcodes are forwarded unchanged. For all - * errors, payload is NULL, length is 0. + * Submit a request packet into the asynchronous request transmission queue. + * Can be called from atomic context. If you prefer a blocking API, use + * fw_run_transaction() in a context that can sleep. * - * Can not expect the callback to be called before the function - * returns, though this does happen in some cases (ACK_COMPLETE and - * errors). + * In case of lock requests, specify one of the firewire-core specific %TCODE_ + * constants instead of %TCODE_LOCK_REQUEST in @tcode. * - * The payload is only used for write requests and must not be freed - * until the callback has been called. + * Make sure that the value in @destination_id is not older than the one in + * @generation. Otherwise the request is in danger to be sent to a wrong node. * - * @param card the card from which to send the request - * @param tcode the tcode for this transaction. Do not use - * TCODE_LOCK_REQUEST directly, instead use TCODE_LOCK_MASK_SWAP - * etc. to specify tcode and ext_tcode. - * @param node_id the destination node ID (bus ID and PHY ID concatenated) - * @param generation the generation for which node_id is valid - * @param speed the speed to use for sending the request - * @param offset the 48 bit offset on the destination node - * @param payload the data payload for the request subaction - * @param length the length in bytes of the data to read - * @param callback function to be called when the transaction is completed - * @param callback_data pointer to arbitrary data, which will be - * passed to the callback - * - * In case of asynchronous stream packets i.e. TCODE_STREAM_DATA, the caller + * In case of asynchronous stream packets i.e. %TCODE_STREAM_DATA, the caller * needs to synthesize @destination_id with fw_stream_packet_destination_id(). + * It will contain tag, channel, and sy data instead of a node ID then. + * + * The payload buffer at @data is going to be DMA-mapped except in case of + * quadlet-sized payload or of local (loopback) requests. Hence make sure that + * the buffer complies with the restrictions for DMA-mapped memory. The + * @payload must not be freed before the @callback is called. + * + * In case of request types without payload, @data is NULL and @length is 0. + * + * After the transaction is completed successfully or unsuccessfully, the + * @callback will be called. Among its parameters is the response code which + * is either one of the rcodes per IEEE 1394 or, in case of internal errors, + * the firewire-core specific %RCODE_SEND_ERROR. + * + * Note some timing corner cases: fw_send_request() may complete much earlier + * than when the request packet actually hits the wire. On the other hand, + * transaction completion and hence execution of @callback may happen even + * before fw_send_request() returns. */ void fw_send_request(struct fw_card *card, struct fw_transaction *t, int tcode, int destination_id, int generation, int speed, @@ -375,9 +381,11 @@ static void transaction_callback(struct fw_card *card, int rcode, } /** - * fw_run_transaction - send request and sleep until transaction is completed + * fw_run_transaction() - send request and sleep until transaction is completed * - * Returns the RCODE. + * Returns the RCODE. See fw_send_request() for parameter documentation. + * Unlike fw_send_request(), @data points to the payload of the request or/and + * to the payload of the response. */ int fw_run_transaction(struct fw_card *card, int tcode, int destination_id, int generation, int speed, unsigned long long offset, @@ -495,9 +503,9 @@ static bool is_in_fcp_region(u64 offset, size_t length) } /** - * fw_core_add_address_handler - register for incoming requests - * @handler: callback - * @region: region in the IEEE 1212 node space address range + * fw_core_add_address_handler() - register for incoming requests + * @handler: callback + * @region: region in the IEEE 1212 node space address range * * region->start, ->end, and handler->length have to be quadlet-aligned. * @@ -552,7 +560,7 @@ int fw_core_add_address_handler(struct fw_address_handler *handler, EXPORT_SYMBOL(fw_core_add_address_handler); /** - * fw_core_remove_address_handler - unregister an address handler + * fw_core_remove_address_handler() - unregister an address handler */ void fw_core_remove_address_handler(struct fw_address_handler *handler) { -- cgit v1.2.3