X-Git-Url: http://rtime.felk.cvut.cz/gitweb/lincan.git/blobdiff_plain/4aae63139869c3eb9150a3fd49ff682084e2072d..04ac67cc3cac14cd601daacd0592121ec0b84012:/lincan/include/can_queue.h diff --git a/lincan/include/can_queue.h b/lincan/include/can_queue.h index 107074c..a600b80 100644 --- a/lincan/include/can_queue.h +++ b/lincan/include/can_queue.h @@ -1,3 +1,36 @@ +/**************************************************************************/ +/* File: can_queue.h - CAN queues and message passing infrastructure */ +/* */ +/* LinCAN - (Not only) Linux CAN bus driver */ +/* Copyright (C) 2002-2009 DCE FEE CTU Prague */ +/* Copyright (C) 2002-2009 Pavel Pisa */ +/* Funded by OCERA and FRESCOR IST projects */ +/* */ +/* LinCAN is free software; you can redistribute it and/or modify it */ +/* under terms of the GNU General Public License as published by the */ +/* Free Software Foundation; either version 2, or (at your option) any */ +/* later version. LinCAN is distributed in the hope that it will be */ +/* useful, but WITHOUT ANY WARRANTY; without even the implied warranty */ +/* of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU */ +/* General Public License for more details. You should have received a */ +/* copy of the GNU General Public License along with LinCAN; see file */ +/* COPYING. If not, write to the Free Software Foundation, 675 Mass Ave, */ +/* Cambridge, MA 02139, USA. */ +/* */ +/* To allow use of LinCAN in the compact embedded systems firmware */ +/* and RT-executives (RTEMS for example), main authors agree with next */ +/* special exception: */ +/* */ +/* Including LinCAN header files in a file, instantiating LinCAN generics */ +/* or templates, or linking other files with LinCAN objects to produce */ +/* an application image/executable, does not by itself cause the */ +/* resulting application image/executable to be covered by */ +/* the GNU General Public License. */ +/* This exception does not however invalidate any other reasons */ +/* why the executable file might be covered by the GNU Public License. */ +/* Publication of enhanced or derived LinCAN files is required although. */ +/**************************************************************************/ + #ifndef _CAN_QUEUE_H #define _CAN_QUEUE_H @@ -6,7 +39,7 @@ #include "./can_sysdep.h" /** - * struct canque_slot_t - one CAN message slot in the CAN FIFO queue + * struct canque_slot_t - one CAN message slot in the CAN FIFO queue * @next: pointer to the next/younger slot * @slot_flags: space for flags and optional command describing action * associated with slot data @@ -27,9 +60,9 @@ * @fifo_flags: this field holds global flags describing state of the FIFO. * %CAN_FIFOF_ERROR is set when some error condition occurs. * %CAN_FIFOF_ERR2BLOCK defines, that error should lead to the FIFO block state. - * %CAN_FIFOF_BLOCK state blocks insertion of the next messages. - * %CAN_FIFOF_OVERRUN attempt to acquire new slot, when FIFO is full. - * %CAN_FIFOF_FULL indicates FIFO full state. + * %CAN_FIFOF_BLOCK state blocks insertion of the next messages. + * %CAN_FIFOF_OVERRUN attempt to acquire new slot, when FIFO is full. + * %CAN_FIFOF_FULL indicates FIFO full state. * %CAN_FIFOF_EMPTY indicates no allocated slot in the FIFO. * %CAN_FIFOF_DEAD condition indication. Used when FIFO is beeing destroyed. * @error_code: futher description of error condition @@ -41,7 +74,7 @@ * @fifo_lock: the lock to ensure atomicity of slot manipulation operations. * @slotsnr: number of allocated slots * - * This structure represents CAN FIFO queue. It is implemented as + * This structure represents CAN FIFO queue. It is implemented as * a single linked list of slots prepared for processing. The empty slots * are stored in single linked list (@flist). */ @@ -97,7 +130,7 @@ struct canque_fifo_t { /** - * canque_fifo_get_inslot - allocate slot for the input of one CAN message + * canque_fifo_get_inslot - allocate slot for the input of one CAN message * @fifo: pointer to the FIFO structure * @slotp: pointer to location to store pointer to the allocated slot. * @cmd: optional command associated with allocated slot. @@ -265,7 +298,7 @@ int canque_fifo_init_slots(struct canque_fifo_t *fifo); /* Forward declarations for external types */ struct msgobj_t; -struct chip_t; +struct canchip_t; /** * struct canque_edge_t - CAN message delivery subsystem graph edge @@ -289,7 +322,7 @@ struct chip_t; * @pending_inops: bitmask of pending operations * @pending_outops: bitmask of pending operations * - * This structure represents one direction connection from messages source + * This structure represents one direction connection from messages source * (@inends) to message consumer (@outends) fifo ends hub. The edge contains * &struct canque_fifo_t for message fifo implementation. */ @@ -316,7 +349,7 @@ struct canque_edge_t { * struct canque_ends_t - CAN message delivery subsystem graph vertex (FIFO ends) * @ends_flags: this field holds flags describing state of the ENDS structure. * @active: the array of the lists of active edges directed to the ends structure - * with ready messages. The array is indexed by the edges priorities. + * with ready messages. The array is indexed by the edges priorities. * @idle: the list of the edges directed to the ends structure with empty FIFOs. * @inlist: the list of outgoing edges input sides. * @outlist: the list of all incoming edges output sides. Each of there edges @@ -324,7 +357,7 @@ struct canque_edge_t { * @ends_lock: the lock synchronizing operations between threads accessing * same ends structure. * @notify: pointer to notify procedure. The next state changes are notified. - * %CANQUEUE_NOTIFY_EMPTY (out->in call) - all slots are processed by FIFO out side. + * %CANQUEUE_NOTIFY_EMPTY (out->in call) - all slots are processed by FIFO out side. * %CANQUEUE_NOTIFY_SPACE (out->in call) - full state negated => there is space for new message. * %CANQUEUE_NOTIFY_PROC (in->out call) - empty state negated => out side is requested to process slots. * %CANQUEUE_NOTIFY_NOUSR (both) - notify, that the last user has released the edge usage @@ -374,7 +407,7 @@ struct canque_ends_t { #endif /*CAN_WITH_RTL*/ struct { struct msgobj_t *msgobj; - struct chip_t *chip; + struct canchip_t *chip; #ifndef CAN_WITH_RTL wait_queue_head_t daemonq; #else /*CAN_WITH_RTL*/ @@ -445,7 +478,8 @@ void canque_notify_bothends(struct canque_edge_t *qedge, int what) * @inends: input side of the edge * * Function call moves output side of the edge from idle onto active edges - * list. + * list. This function has to be called with edge reference count held. + * that is same as for most of other edge functions. */ static inline void canque_activate_edge(struct canque_ends_t *inends, struct canque_edge_t *qedge) @@ -454,19 +488,16 @@ void canque_activate_edge(struct canque_ends_t *inends, struct canque_edge_t *qe struct canque_ends_t *outends; if(qedge->edge_prio>=CANQUEUE_PRIO_NR) qedge->edge_prio=CANQUEUE_PRIO_NR-1; - can_spin_lock_irqsave(&inends->ends_lock, flags); if((outends=qedge->outends)){ - can_spin_lock(&outends->ends_lock); + can_spin_lock_irqsave(&outends->ends_lock, flags); can_spin_lock(&qedge->fifo.fifo_lock); if(!canque_fifo_test_fl(&qedge->fifo,EMPTY)){ list_del(&qedge->activepeers); list_add_tail(&qedge->activepeers,&outends->active[qedge->edge_prio]); } can_spin_unlock(&qedge->fifo.fifo_lock); - can_spin_unlock(&outends->ends_lock); - + can_spin_unlock_irqrestore(&outends->ends_lock, flags); } - can_spin_unlock_irqrestore(&inends->ends_lock, flags); } /** @@ -486,11 +517,11 @@ unsigned int canque_filtid2internal(unsigned long id, int filtflags) int canque_get_inslot(struct canque_ends_t *qends, struct canque_edge_t **qedgep, struct canque_slot_t **slotp, int cmd); - + int canque_get_inslot4id(struct canque_ends_t *qends, struct canque_edge_t **qedgep, struct canque_slot_t **slotp, int cmd, unsigned long id, int prio); - + int canque_put_inslot(struct canque_ends_t *qends, struct canque_edge_t *qedge, struct canque_slot_t *slot); @@ -510,7 +541,7 @@ int canque_again_outslot(struct canque_ends_t *qends, int canque_set_filt(struct canque_edge_t *qedge, unsigned long filtid, unsigned long filtmask, int flags); - + int canque_flush(struct canque_edge_t *qedge); int canqueue_disconnect_edge(struct canque_edge_t *qedge); @@ -535,8 +566,12 @@ int canqueue_ends_flush_outlist(struct canque_ends_t *qends); /* edge reference and traversal functions */ -void canque_edge_do_dead(struct canque_edge_t *edge, int dead_fl); +void canque_edge_do_dead(struct canque_edge_t *edge); +/** + * canque_edge_incref - increments edge reference count + * @edge: pointer to the edge structure + */ static inline void canque_edge_incref(struct canque_edge_t *edge) { @@ -544,28 +579,83 @@ void canque_edge_incref(struct canque_edge_t *edge) } static inline -void canque_edge_decref(struct canque_edge_t *edge) +can_spin_irqflags_t canque_edge_lock_both_ends(struct canque_ends_t *inends, struct canque_ends_t *outends) +{ + can_spin_irqflags_t flags; + if(inendsends_lock, flags); + can_spin_lock(&outends->ends_lock); + }else{ + can_spin_lock_irqsave(&outends->ends_lock, flags); + if(outends!=inends) can_spin_lock(&inends->ends_lock); + } + return flags; +} + +static inline +void canque_edge_unlock_both_ends(struct canque_ends_t *inends, struct canque_ends_t *outends, can_spin_irqflags_t flags) +{ + if(outends!=inends) can_spin_unlock(&outends->ends_lock); + can_spin_unlock_irqrestore(&inends->ends_lock, flags); +} + +/* Non-inlined version of edge reference decrement */ +void __canque_edge_decref(struct canque_edge_t *edge); + +static inline +void __canque_edge_decref_body(struct canque_edge_t *edge) { can_spin_irqflags_t flags; + int dead_fl=0; struct canque_ends_t *inends=edge->inends; struct canque_ends_t *outends=edge->outends; - int dead_fl; - - can_spin_lock_irqsave(&inends->ends_lock, flags); - can_spin_lock(&outends->ends_lock); + + flags=canque_edge_lock_both_ends(inends, outends); if(atomic_dec_and_test(&edge->edge_used)) { - dead_fl=canque_fifo_test_and_set_fl(&edge->fifo,DEAD); - /* Because of former evolution of edge references + dead_fl=!canque_fifo_test_and_set_fl(&edge->fifo,DEAD); + /* Because of former evolution of edge references management notify of CANQUEUE_NOTIFY_NOUSR could be moved to canque_edge_do_dead :-) */ - can_spin_unlock(&outends->ends_lock); - can_spin_unlock_irqrestore(&inends->ends_lock, flags); - canque_edge_do_dead(edge, dead_fl); - } else { - can_spin_unlock(&outends->ends_lock); - can_spin_unlock_irqrestore(&inends->ends_lock, flags); } + canque_edge_unlock_both_ends(inends, outends, flags); + if(dead_fl) canque_edge_do_dead(edge); +} + +#ifndef CAN_HAVE_ARCH_CMPXCHG +/** + * canque_edge_decref - decrements edge reference count + * @edge: pointer to the edge structure + * + * This function has to be called without lock held for both ends of edge. + * If reference count drops to 0, function canque_edge_do_dead() + * is called. + */ +static inline +void canque_edge_decref(struct canque_edge_t *edge) +{ + __canque_edge_decref_body(edge); +} +#else +static inline +void canque_edge_decref(struct canque_edge_t *edge) +{ + int x, y; + + x = atomic_read(&edge->edge_used); + do{ + if(x<=1) + return __canque_edge_decref(edge); + y=x; + #ifdef CAN_HAVE_ATOMIC_CMPXCHG + atomic_cmpxchg(&edge->edge_used, x, x-1); + #else /* workaround for case that atomic_cmpxchg is not defined */ + /* This code strongly depends on the definition of atomic_t !!!! */ + x=__cmpxchg(&edge->edge_used, x, x-1, sizeof(atomic_t)); + /* If even this does not help, comment out CAN_HAVE_ARCH_CMPXCHG in can_sysdep.h */ + #endif + } while(x!=y); } +#endif static inline struct canque_edge_t *canque_first_inedge(struct canque_ends_t *qends) @@ -573,7 +663,7 @@ struct canque_edge_t *canque_first_inedge(struct canque_ends_t *qends) can_spin_irqflags_t flags; struct list_head *entry; struct canque_edge_t *edge; - + can_spin_lock_irqsave(&qends->ends_lock, flags); entry=qends->inlist.next; skip_dead: @@ -598,7 +688,7 @@ struct canque_edge_t *canque_next_inedge(struct canque_ends_t *qends, struct can can_spin_irqflags_t flags; struct list_head *entry; struct canque_edge_t *next; - + can_spin_lock_irqsave(&qends->ends_lock, flags); entry=edge->inpeers.next; skip_dead: @@ -626,7 +716,7 @@ struct canque_edge_t *canque_first_outedge(struct canque_ends_t *qends) can_spin_irqflags_t flags; struct list_head *entry; struct canque_edge_t *edge; - + can_spin_lock_irqsave(&qends->ends_lock, flags); entry=qends->outlist.next; skip_dead: @@ -651,7 +741,7 @@ struct canque_edge_t *canque_next_outedge(struct canque_ends_t *qends, struct ca can_spin_irqflags_t flags; struct list_head *entry; struct canque_edge_t *next; - + can_spin_lock_irqsave(&qends->ends_lock, flags); entry=edge->outpeers.next; skip_dead: