firewire: core: implement variations to send request and wait for response with time stamp

In the previous commit, the core function of Linux FireWire subsystem
was changed for two cases to operate asynchronous transaction with or
without time stamp.

This commit changes kernel API for the two cases. Current kernel API,
fw_send_request(), is changed to be static inline function to call
__fw_send_request(), which receives two argument for union and flag of
callback function. The new kernel API, fw_send_request_with_tstamp() is
also added as static inline function, too. When calling, the two
arguments are copied to internal structure, then used in softIRQ
context.

Link: https://lore.kernel.org/r/20230529113406.986289-7-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>

Author: takaswie

drivers/firewire/core-transaction.c

@@ -316,7 +316,8 @@ static int allocate_tlabel(struct fw_card *card)
 }
 
 /**
- * fw_send_request() - submit a request packet for transmission
+ * __fw_send_request() - submit a request packet for transmission to generate callback for response
+ *			 subaction with or without time stamp.
  * @card:		interface to send the request at
  * @t:			transaction instance to which the request belongs
  * @tcode:		transaction code
@@ -326,7 +327,9 @@ static int allocate_tlabel(struct fw_card *card)
  * @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:		union of two functions whether to receive time stamp or not for response
+ *			subaction.
+ * @with_tstamp:	Whether to receive time stamp or not for response subaction.
  * @callback_data:	data to be passed to the transaction completion callback
  *
  * Submit a request packet into the asynchronous request transmission queue.
@@ -363,10 +366,10 @@ static int allocate_tlabel(struct fw_card *card)
  * 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,
-		     unsigned long long offset, void *payload, size_t length,
-		     fw_transaction_callback_t callback, void *callback_data)
+void __fw_send_request(struct fw_card *card, struct fw_transaction *t, int tcode,
+		int destination_id, int generation, int speed, unsigned long long offset,
+		void *payload, size_t length, union fw_transaction_callback callback,
+		bool with_tstamp, void *callback_data)
 {
 	unsigned long flags;
 	int tlabel;
@@ -381,22 +384,32 @@ void fw_send_request(struct fw_card *card, struct fw_transaction *t, int tcode,
 	tlabel = allocate_tlabel(card);
 	if (tlabel < 0) {
 		spin_unlock_irqrestore(&card->lock, flags);
-		callback(card, RCODE_SEND_ERROR, NULL, 0, callback_data);
+		if (!with_tstamp) {
+			callback.without_tstamp(card, RCODE_SEND_ERROR, NULL, 0, callback_data);
+		} else {
+			// Timestamping on behalf of hardware.
+			u32 curr_cycle_time = 0;
+			u32 tstamp;
+
+			(void)fw_card_read_cycle_time(card, &curr_cycle_time);
+			tstamp = cycle_time_to_ohci_tstamp(curr_cycle_time);
+
+			callback.with_tstamp(card, RCODE_SEND_ERROR, tstamp, tstamp, NULL, 0,
+					     callback_data);
+		}
 		return;
 	}
 
 	t->node_id = destination_id;
 	t->tlabel = tlabel;
 	t->card = card;
 	t->is_split_transaction = false;
-	timer_setup(&t->split_timeout_timer,
-		    split_transaction_timeout_callback, 0);
-	t->callback.without_tstamp = callback;
-	t->with_tstamp = false;
+	timer_setup(&t->split_timeout_timer, split_transaction_timeout_callback, 0);
+	t->callback = callback;
+	t->with_tstamp = with_tstamp;
 	t->callback_data = callback_data;
 
-	fw_fill_request(&t->packet, tcode, t->tlabel,
-			destination_id, card->node_id, generation,
+	fw_fill_request(&t->packet, tcode, t->tlabel, destination_id, card->node_id, generation,
 			speed, offset, payload, length);
 	t->packet.callback = transmit_complete_callback;
 
@@ -406,7 +419,7 @@ void fw_send_request(struct fw_card *card, struct fw_transaction *t, int tcode,
 
 	card->driver->send_request(card, &t->packet);
 }
-EXPORT_SYMBOL(fw_send_request);
+EXPORT_SYMBOL_GPL(__fw_send_request);
 
 struct transaction_callback_data {
 	struct completion done;

include/linux/firewire.h

@@ -356,10 +356,71 @@ void fw_send_response(struct fw_card *card,
 		      struct fw_request *request, int rcode);
 int fw_get_request_speed(struct fw_request *request);
 u32 fw_request_get_timestamp(const struct fw_request *request);
-void fw_send_request(struct fw_card *card, struct fw_transaction *t,
-		     int tcode, int destination_id, int generation, int speed,
-		     unsigned long long offset, void *payload, size_t length,
-		     fw_transaction_callback_t callback, void *callback_data);
+
+void __fw_send_request(struct fw_card *card, struct fw_transaction *t, int tcode,
+		int destination_id, int generation, int speed, unsigned long long offset,
+		void *payload, size_t length, union fw_transaction_callback callback,
+		bool with_tstamp, void *callback_data);
+
+/**
+ * fw_send_request() - submit a request packet for transmission to generate callback for response
+ *		       subaction without time stamp.
+ * @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
+ *
+ * A variation of __fw_send_request() to generate callback for response subaction without time
+ * stamp.
+ */
+static inline void fw_send_request(struct fw_card *card, struct fw_transaction *t, int tcode,
+				   int destination_id, int generation, int speed,
+				   unsigned long long offset, void *payload, size_t length,
+				   fw_transaction_callback_t callback, void *callback_data)
+{
+	union fw_transaction_callback cb = {
+		.without_tstamp = callback,
+	};
+	__fw_send_request(card, t, tcode, destination_id, generation, speed, offset, payload,
+			  length, cb, false, callback_data);
+}
+
+/**
+ * fw_send_request_with_tstamp() - submit a request packet for transmission to generate callback for
+ *				   response with time stamp.
+ * @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
+ *
+ * A variation of __fw_send_request() to generate callback for response subaction with time stamp.
+ */
+static inline void fw_send_request_with_tstamp(struct fw_card *card, struct fw_transaction *t,
+	int tcode, int destination_id, int generation, int speed, unsigned long long offset,
+	void *payload, size_t length, fw_transaction_callback_with_tstamp_t callback,
+	void *callback_data)
+{
+	union fw_transaction_callback cb = {
+		.with_tstamp = callback,
+	};
+	__fw_send_request(card, t, tcode, destination_id, generation, speed, offset, payload,
+			  length, cb, true, callback_data);
+}
+
 int fw_cancel_transaction(struct fw_card *card,
 			  struct fw_transaction *transaction);
 int fw_run_transaction(struct fw_card *card, int tcode, int destination_id,