--- /dev/null
+/*
+ * 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) 1999-2019, Broadcom.
+ *
+ * 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 700321 2017-05-18 16:09:07Z $
+ */
+#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) 1999-2019, Broadcom.
+ *
+ * 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 700321 2017-05-18 16:09:07Z $
+ *
+ * -*- 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 // 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__ */
projects / GitHub / LineageOS / G12 / android_hardware_amlogic_kernel-modules_dhd-driver.git / blobdiff