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SmartAudio/lichee/linux-4.9/drivers/net/wireless/bcmdhd/include/bcm_ring.h

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/*
* bcm_ring.h : Ring context abstraction
* The ring context tracks the WRITE and READ indices where elements may be
* produced and consumed respectively. All elements in the ring need to be
* fixed size.
*
* NOTE: A ring of size N, may only hold N-1 elements.
*
* Copyright (C) 1999-2017, Broadcom Corporation
*
* Unless you and Broadcom execute a separate written software license
* agreement governing use of this software, this software is licensed to you
* under the terms of the GNU General Public License version 2 (the "GPL"),
* available at http://www.broadcom.com/licenses/GPLv2.php, with the
* following added to such license:
*
* As a special exception, the copyright holders of this software give you
* permission to link this software with independent modules, and to copy and
* distribute the resulting executable under terms of your choice, provided that
* you also meet, for each linked independent module, the terms and conditions of
* the license of that module. An independent module is a module which is not
* derived from this software. The special exception does not apply to any
* modifications of the software.
*
* Notwithstanding the above, under no circumstances may you combine this
* software in any way with any other Broadcom software provided under a license
* other than the GPL, without Broadcom's express prior written consent.
*
*
* <<Broadcom-WL-IPTag/Open:>>
*
* $Id: bcm_ring.h 596126 2015-10-29 19:53:48Z $
*/
#ifndef __bcm_ring_included__
#define __bcm_ring_included__
/*
* API Notes:
*
* Ring manipulation API allows for:
* Pending operations: Often before some work can be completed, it may be
* desired that several resources are available, e.g. space for production in
* a ring. Approaches such as, #1) reserve resources one by one and return them
* if another required resource is not available, or #2) employ a two pass
* algorithm of first testing whether all resources are available, have a
* an impact on performance critical code. The approach taken here is more akin
* to approach #2, where a test for resource availability essentially also
* provides the index for production in an un-committed state.
* The same approach is taken for the consumer side.
*
* - Pending production: Fetch the next index where a ring element may be
* produced. The caller may not commit the WRITE of the element.
* - Pending consumption: Fetch the next index where a ring element may be
* consumed. The caller may not commut the READ of the element.
*
* Producer side API:
* - bcm_ring_is_full : Test whether ring is full
* - bcm_ring_prod : Fetch index where an element may be produced (commit)
* - bcm_ring_prod_pend: Fetch index where an element may be produced (pending)
* - bcm_ring_prod_done: Commit a previous pending produce fetch
* - bcm_ring_prod_avail: Fetch total number free slots eligible for production
*
* Consumer side API:
* - bcm_ring_is_empty : Test whether ring is empty
* - bcm_ring_cons : Fetch index where an element may be consumed (commit)
* - bcm_ring_cons_pend: Fetch index where an element may be consumed (pending)
* - bcm_ring_cons_done: Commit a previous pending consume fetch
* - bcm_ring_cons_avail: Fetch total number elements eligible for consumption
*
* - bcm_ring_sync_read: Sync read offset in peer ring, from local ring
* - bcm_ring_sync_write: Sync write offset in peer ring, from local ring
*
* +----------------------------------------------------------------------------
*
* Design Notes:
* Following items are not tracked in a ring context (design decision)
* - width of a ring element.
* - depth of the ring.
* - base of the buffer, where the elements are stored.
* - count of number of free slots in the ring
*
* Implementation Notes:
* - When BCM_RING_DEBUG is enabled, need explicit bcm_ring_init().
* - BCM_RING_EMPTY and BCM_RING_FULL are (-1)
*
* +----------------------------------------------------------------------------
*
* Usage Notes:
* An application may incarnate a ring of some fixed sized elements, by defining
* - a ring data buffer to store the ring elements.
* - depth of the ring (max number of elements managed by ring context).
* Preferrably, depth may be represented as a constant.
* - width of a ring element: to be used in pointer arithmetic with the ring's
* data buffer base and an index to fetch the ring element.
*
* Use bcm_workq_t to instantiate a pair of workq constructs, one for the
* producer and the other for the consumer, both pointing to the same circular
* buffer. The producer may operate on it's own local workq and flush the write
* index to the consumer. Likewise the consumer may use its local workq and
* flush the read index to the producer. This way we do not repeatedly access
* the peer's context. The two peers may reside on different CPU cores with a
* private L1 data cache.
* +----------------------------------------------------------------------------
*
* Copyright (C) 1999-2017, Broadcom Corporation
*
* Unless you and Broadcom execute a separate written software license
* agreement governing use of this software, this software is licensed to you
* under the terms of the GNU General Public License version 2 (the "GPL"),
* available at http://www.broadcom.com/licenses/GPLv2.php, with the
* following added to such license:
*
* As a special exception, the copyright holders of this software give you
* permission to link this software with independent modules, and to copy and
* distribute the resulting executable under terms of your choice, provided that
* you also meet, for each linked independent module, the terms and conditions of
* the license of that module. An independent module is a module which is not
* derived from this software. The special exception does not apply to any
* modifications of the software.
*
* Notwithstanding the above, under no circumstances may you combine this
* software in any way with any other Broadcom software provided under a license
* other than the GPL, without Broadcom's express prior written consent.
*
* $Id: bcm_ring.h 596126 2015-10-29 19:53:48Z $
*
* -*- Mode: C; tab-width: 4; indent-tabs-mode: t; c-basic-offset: 4 -*-
* vim: set ts=4 noet sw=4 tw=80:
*
* +----------------------------------------------------------------------------
*/
#ifdef ____cacheline_aligned
#define __ring_aligned ____cacheline_aligned
#else
#define __ring_aligned
#endif
/* Conditional compile for debug */
/* #define BCM_RING_DEBUG */
#define BCM_RING_EMPTY (-1)
#define BCM_RING_FULL (-1)
#define BCM_RING_NULL ((bcm_ring_t *)NULL)
#if defined(BCM_RING_DEBUG)
#define RING_ASSERT(exp) ASSERT(exp)
#define BCM_RING_IS_VALID(ring) (((ring) != BCM_RING_NULL) && \
((ring)->self == (ring)))
#else /* ! BCM_RING_DEBUG */
#define RING_ASSERT(exp) do {} while (0)
#define BCM_RING_IS_VALID(ring) ((ring) != BCM_RING_NULL)
#endif /* ! BCM_RING_DEBUG */
#define BCM_RING_SIZE_IS_VALID(ring_size) ((ring_size) > 0)
/*
* +----------------------------------------------------------------------------
* Ring Context
* +----------------------------------------------------------------------------
*/
typedef struct bcm_ring { /* Ring context */
#if defined(BCM_RING_DEBUG)
struct bcm_ring *self; /* ptr to self for IS VALID test */
#endif /* BCM_RING_DEBUG */
int write __ring_aligned; /* WRITE index in a circular ring */
int read __ring_aligned; /* READ index in a circular ring */
} bcm_ring_t;
static INLINE void bcm_ring_init(bcm_ring_t *ring);
static INLINE void bcm_ring_copy(bcm_ring_t *to, bcm_ring_t *from);
static INLINE bool bcm_ring_is_empty(bcm_ring_t *ring);
static INLINE int __bcm_ring_next_write(bcm_ring_t *ring, const int ring_size);
static INLINE bool __bcm_ring_full(bcm_ring_t *ring, int next_write);
static INLINE bool bcm_ring_is_full(bcm_ring_t *ring, const int ring_size);
static INLINE void bcm_ring_prod_done(bcm_ring_t *ring, int write);
static INLINE int bcm_ring_prod_pend(bcm_ring_t *ring, int *pend_write,
const int ring_size);
static INLINE int bcm_ring_prod(bcm_ring_t *ring, const int ring_size);
static INLINE void bcm_ring_cons_done(bcm_ring_t *ring, int read);
static INLINE int bcm_ring_cons_pend(bcm_ring_t *ring, int *pend_read,
const int ring_size);
static INLINE int bcm_ring_cons(bcm_ring_t *ring, const int ring_size);
static INLINE void bcm_ring_sync_read(bcm_ring_t *peer, const bcm_ring_t *self);
static INLINE void bcm_ring_sync_write(bcm_ring_t *peer, const bcm_ring_t *self);
static INLINE int bcm_ring_prod_avail(const bcm_ring_t *ring,
const int ring_size);
static INLINE int bcm_ring_cons_avail(const bcm_ring_t *ring,
const int ring_size);
static INLINE void bcm_ring_cons_all(bcm_ring_t *ring);
/**
* bcm_ring_init - initialize a ring context.
* @ring: pointer to a ring context
*/
static INLINE void
bcm_ring_init(bcm_ring_t *ring)
{
ASSERT(ring != (bcm_ring_t *)NULL);
#if defined(BCM_RING_DEBUG)
ring->self = ring;
#endif /* BCM_RING_DEBUG */
ring->write = 0;
ring->read = 0;
}
/**
* bcm_ring_copy - copy construct a ring
* @to: pointer to the new ring context
* @from: pointer to orig ring context
*/
static INLINE void
bcm_ring_copy(bcm_ring_t *to, bcm_ring_t *from)
{
bcm_ring_init(to);
to->write = from->write;
to->read = from->read;
}
/**
* bcm_ring_is_empty - "Boolean" test whether ring is empty.
* @ring: pointer to a ring context
*
* PS. does not return BCM_RING_EMPTY value.
*/
static INLINE bool
bcm_ring_is_empty(bcm_ring_t *ring)
{
RING_ASSERT(BCM_RING_IS_VALID(ring));
return (ring->read == ring->write);
}
/**
* __bcm_ring_next_write - determine the index where the next write may occur
* (with wrap-around).
* @ring: pointer to a ring context
* @ring_size: size of the ring
*
* PRIVATE INTERNAL USE ONLY.
*/
static INLINE int
__bcm_ring_next_write(bcm_ring_t *ring, const int ring_size)
{
RING_ASSERT(BCM_RING_IS_VALID(ring) && BCM_RING_SIZE_IS_VALID(ring_size));
return ((ring->write + 1) % ring_size);
}
/**
* __bcm_ring_full - support function for ring full test.
* @ring: pointer to a ring context
* @next_write: next location in ring where an element is to be produced
*
* PRIVATE INTERNAL USE ONLY.
*/
static INLINE bool
__bcm_ring_full(bcm_ring_t *ring, int next_write)
{
return (next_write == ring->read);
}
/**
* bcm_ring_is_full - "Boolean" test whether a ring is full.
* @ring: pointer to a ring context
* @ring_size: size of the ring
*
* PS. does not return BCM_RING_FULL value.
*/
static INLINE bool
bcm_ring_is_full(bcm_ring_t *ring, const int ring_size)
{
int next_write;
RING_ASSERT(BCM_RING_IS_VALID(ring) && BCM_RING_SIZE_IS_VALID(ring_size));
next_write = __bcm_ring_next_write(ring, ring_size);
return __bcm_ring_full(ring, next_write);
}
/**
* bcm_ring_prod_done - commit a previously pending index where production
* was requested.
* @ring: pointer to a ring context
* @write: index into ring upto where production was done.
* +----------------------------------------------------------------------------
*/
static INLINE void
bcm_ring_prod_done(bcm_ring_t *ring, int write)
{
RING_ASSERT(BCM_RING_IS_VALID(ring));
ring->write = write;
}
/**
* bcm_ring_prod_pend - Fetch in "pend" mode, the index where an element may be
* produced.
* @ring: pointer to a ring context
* @pend_write: next index, after the returned index
* @ring_size: size of the ring
*/
static INLINE int
bcm_ring_prod_pend(bcm_ring_t *ring, int *pend_write, const int ring_size)
{
int rtn;
RING_ASSERT(BCM_RING_IS_VALID(ring) && BCM_RING_SIZE_IS_VALID(ring_size));
*pend_write = __bcm_ring_next_write(ring, ring_size);
if (__bcm_ring_full(ring, *pend_write)) {
*pend_write = BCM_RING_FULL;
rtn = BCM_RING_FULL;
} else {
/* production is not committed, caller needs to explicitly commit */
rtn = ring->write;
}
return rtn;
}
/**
* bcm_ring_prod - Fetch and "commit" the next index where a ring element may
* be produced.
* @ring: pointer to a ring context
* @ring_size: size of the ring
*/
static INLINE int
bcm_ring_prod(bcm_ring_t *ring, const int ring_size)
{
int next_write, prod_write;
RING_ASSERT(BCM_RING_IS_VALID(ring) && BCM_RING_SIZE_IS_VALID(ring_size));
next_write = __bcm_ring_next_write(ring, ring_size);
if (__bcm_ring_full(ring, next_write)) {
prod_write = BCM_RING_FULL;
} else {
prod_write = ring->write;
bcm_ring_prod_done(ring, next_write); /* "commit" production */
}
return prod_write;
}
/**
* bcm_ring_cons_done - commit a previously pending read
* @ring: pointer to a ring context
* @read: index upto which elements have been consumed.
*/
static INLINE void
bcm_ring_cons_done(bcm_ring_t *ring, int read)
{
RING_ASSERT(BCM_RING_IS_VALID(ring));
ring->read = read;
}
/**
* bcm_ring_cons_pend - fetch in "pend" mode, the next index where a ring
* element may be consumed.
* @ring: pointer to a ring context
* @pend_read: index into ring upto which elements may be consumed.
* @ring_size: size of the ring
*/
static INLINE int
bcm_ring_cons_pend(bcm_ring_t *ring, int *pend_read, const int ring_size)
{
int rtn;
RING_ASSERT(BCM_RING_IS_VALID(ring) && BCM_RING_SIZE_IS_VALID(ring_size));
if (bcm_ring_is_empty(ring)) {
*pend_read = BCM_RING_EMPTY;
rtn = BCM_RING_EMPTY;
} else {
*pend_read = (ring->read + 1) % ring_size;
/* production is not committed, caller needs to explicitly commit */
rtn = ring->read;
}
return rtn;
}
/**
* bcm_ring_cons - fetch and "commit" the next index where a ring element may
* be consumed.
* @ring: pointer to a ring context
* @ring_size: size of the ring
*/
static INLINE int
bcm_ring_cons(bcm_ring_t *ring, const int ring_size)
{
int cons_read;
RING_ASSERT(BCM_RING_IS_VALID(ring) && BCM_RING_SIZE_IS_VALID(ring_size));
if (bcm_ring_is_empty(ring)) {
cons_read = BCM_RING_EMPTY;
} else {
cons_read = ring->read;
ring->read = (ring->read + 1) % ring_size; /* read is committed */
}
return cons_read;
}
/**
* bcm_ring_sync_read - on consumption, update peer's read index.
* @peer: pointer to peer's producer ring context
* @self: pointer to consumer's ring context
*/
static INLINE void
bcm_ring_sync_read(bcm_ring_t *peer, const bcm_ring_t *self)
{
RING_ASSERT(BCM_RING_IS_VALID(peer));
RING_ASSERT(BCM_RING_IS_VALID(self));
peer->read = self->read; /* flush read update to peer producer */
}
/**
* bcm_ring_sync_write - on consumption, update peer's write index.
* @peer: pointer to peer's consumer ring context
* @self: pointer to producer's ring context
*/
static INLINE void
bcm_ring_sync_write(bcm_ring_t *peer, const bcm_ring_t *self)
{
RING_ASSERT(BCM_RING_IS_VALID(peer));
RING_ASSERT(BCM_RING_IS_VALID(self));
peer->write = self->write; /* flush write update to peer consumer */
}
/**
* bcm_ring_prod_avail - fetch total number of available empty slots in the
* ring for production.
* @ring: pointer to a ring context
* @ring_size: size of the ring
*/
static INLINE int
bcm_ring_prod_avail(const bcm_ring_t *ring, const int ring_size)
{
int prod_avail;
RING_ASSERT(BCM_RING_IS_VALID(ring) && BCM_RING_SIZE_IS_VALID(ring_size));
if (ring->write >= ring->read) {
prod_avail = (ring_size - (ring->write - ring->read) - 1);
} else {
prod_avail = (ring->read - (ring->write + 1));
}
ASSERT(prod_avail < ring_size);
return prod_avail;
}
/**
* bcm_ring_cons_avail - fetch total number of available elements for consumption.
* @ring: pointer to a ring context
* @ring_size: size of the ring
*/
static INLINE int
bcm_ring_cons_avail(const bcm_ring_t *ring, const int ring_size)
{
int cons_avail;
RING_ASSERT(BCM_RING_IS_VALID(ring) && BCM_RING_SIZE_IS_VALID(ring_size));
if (ring->read == ring->write) {
cons_avail = 0;
} else if (ring->read > ring->write) {
cons_avail = ((ring_size - ring->read) + ring->write);
} else {
cons_avail = ring->write - ring->read;
}
ASSERT(cons_avail < ring_size);
return cons_avail;
}
/**
* bcm_ring_cons_all - set ring in state where all elements are consumed.
* @ring: pointer to a ring context
*/
static INLINE void
bcm_ring_cons_all(bcm_ring_t *ring)
{
ring->read = ring->write;
}
/**
* Work Queue
* A work Queue is composed of a ring of work items, of a specified depth.
* It HAS-A bcm_ring object, comprising of a RD and WR offset, to implement a
* producer/consumer circular ring.
*/
struct bcm_workq {
bcm_ring_t ring; /* Ring context abstraction */
struct bcm_workq *peer; /* Peer workq context */
void *buffer; /* Buffer storage for work items in workQ */
int ring_size; /* Depth of workQ */
} __ring_aligned;
typedef struct bcm_workq bcm_workq_t;
/* #define BCM_WORKQ_DEBUG */
#if defined(BCM_WORKQ_DEBUG)
#define WORKQ_ASSERT(exp) ASSERT(exp)
#else /* ! BCM_WORKQ_DEBUG */
#define WORKQ_ASSERT(exp) do {} while (0)
#endif /* ! BCM_WORKQ_DEBUG */
#define WORKQ_AUDIT(workq) \
WORKQ_ASSERT((workq) != BCM_WORKQ_NULL); \
WORKQ_ASSERT(WORKQ_PEER(workq) != BCM_WORKQ_NULL); \
WORKQ_ASSERT((workq)->buffer == WORKQ_PEER(workq)->buffer); \
WORKQ_ASSERT((workq)->ring_size == WORKQ_PEER(workq)->ring_size);
#define BCM_WORKQ_NULL ((bcm_workq_t *)NULL)
#define WORKQ_PEER(workq) ((workq)->peer)
#define WORKQ_RING(workq) (&((workq)->ring))
#define WORKQ_PEER_RING(workq) (&((workq)->peer->ring))
#define WORKQ_ELEMENT(__elem_type, __workq, __index) ({ \
WORKQ_ASSERT((__workq) != BCM_WORKQ_NULL); \
WORKQ_ASSERT((__index) < ((__workq)->ring_size)); \
((__elem_type *)((__workq)->buffer)) + (__index); \
})
static INLINE void bcm_workq_init(bcm_workq_t *workq, bcm_workq_t *workq_peer,
void *buffer, int ring_size);
static INLINE bool bcm_workq_is_empty(bcm_workq_t *workq_prod);
static INLINE void bcm_workq_prod_sync(bcm_workq_t *workq_prod);
static INLINE void bcm_workq_cons_sync(bcm_workq_t *workq_cons);
static INLINE void bcm_workq_prod_refresh(bcm_workq_t *workq_prod);
static INLINE void bcm_workq_cons_refresh(bcm_workq_t *workq_cons);
/**
* bcm_workq_init - initialize a workq
* @workq: pointer to a workq context
* @buffer: pointer to a pre-allocated circular buffer to serve as a ring
* @ring_size: size of the ring in terms of max number of elements.
*/
static INLINE void
bcm_workq_init(bcm_workq_t *workq, bcm_workq_t *workq_peer,
void *buffer, int ring_size)
{
ASSERT(workq != BCM_WORKQ_NULL);
ASSERT(workq_peer != BCM_WORKQ_NULL);
ASSERT(buffer != NULL);
ASSERT(ring_size > 0);
WORKQ_PEER(workq) = workq_peer;
WORKQ_PEER(workq_peer) = workq;
bcm_ring_init(WORKQ_RING(workq));
bcm_ring_init(WORKQ_RING(workq_peer));
workq->buffer = workq_peer->buffer = buffer;
workq->ring_size = workq_peer->ring_size = ring_size;
}
/**
* bcm_workq_empty - test whether there is work
* @workq_prod: producer's workq
*/
static INLINE bool
bcm_workq_is_empty(bcm_workq_t *workq_prod)
{
return bcm_ring_is_empty(WORKQ_RING(workq_prod));
}
/**
* bcm_workq_prod_sync - Commit the producer write index to peer workq's ring
* @workq_prod: producer's workq whose write index must be synced to peer
*/
static INLINE void
bcm_workq_prod_sync(bcm_workq_t *workq_prod)
{
WORKQ_AUDIT(workq_prod);
/* cons::write <--- prod::write */
bcm_ring_sync_write(WORKQ_PEER_RING(workq_prod), WORKQ_RING(workq_prod));
}
/**
* bcm_workq_cons_sync - Commit the consumer read index to the peer workq's ring
* @workq_cons: consumer's workq whose read index must be synced to peer
*/
static INLINE void
bcm_workq_cons_sync(bcm_workq_t *workq_cons)
{
WORKQ_AUDIT(workq_cons);
/* prod::read <--- cons::read */
bcm_ring_sync_read(WORKQ_PEER_RING(workq_cons), WORKQ_RING(workq_cons));
}
/**
* bcm_workq_prod_refresh - Fetch the updated consumer's read index
* @workq_prod: producer's workq whose read index must be refreshed from peer
*/
static INLINE void
bcm_workq_prod_refresh(bcm_workq_t *workq_prod)
{
WORKQ_AUDIT(workq_prod);
/* prod::read <--- cons::read */
bcm_ring_sync_read(WORKQ_RING(workq_prod), WORKQ_PEER_RING(workq_prod));
}
/**
* bcm_workq_cons_refresh - Fetch the updated producer's write index
* @workq_cons: consumer's workq whose write index must be refreshed from peer
*/
static INLINE void
bcm_workq_cons_refresh(bcm_workq_t *workq_cons)
{
WORKQ_AUDIT(workq_cons);
/* cons::write <--- prod::write */
bcm_ring_sync_write(WORKQ_RING(workq_cons), WORKQ_PEER_RING(workq_cons));
}
#endif /* ! __bcm_ring_h_included__ */
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