From a7d7a6dcc6d75fd1f142851b74ff6225385cde92 Mon Sep 17 00:00:00 2001 From: "R. Steve McKown" Date: Wed, 15 Sep 2010 12:44:11 -0600 Subject: [PATCH] Add SharedArbiterC. --- tos/system/SharedArbiterC.nc | 61 ++++++++++ tos/system/SharedArbiterP.nc | 224 +++++++++++++++++++++++++++++++++++ 2 files changed, 285 insertions(+) create mode 100644 tos/system/SharedArbiterC.nc create mode 100644 tos/system/SharedArbiterP.nc diff --git a/tos/system/SharedArbiterC.nc b/tos/system/SharedArbiterC.nc new file mode 100644 index 00000000..19499784 --- /dev/null +++ b/tos/system/SharedArbiterC.nc @@ -0,0 +1,61 @@ +/* + * Copyright (c) 2010, Titanium Mirror, Inc. + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * - Redistributions of source code must retain the above copyright notice, + * this list of conditions and the following disclaimer. + * - Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * - Neither the name of the Technische Universität Berlin nor the names + * of its contributors may be used to endorse or promote products derived + * from this software without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT + * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR + * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT + * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, + * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED + * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, + * OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY + * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE + * USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + */ + +/** + * A shared arbiter that allows 1...N clients to acquire the resource + * simultaneously, with the intention of returning control to the default + * owner upon release by all clients. + * + * @author R. Steve McKown + */ + +generic configuration SharedArbiterC(char resourceName[]) { + provides { + interface Resource[uint8_t id]; + interface ResourceDefaultOwner; + interface ArbiterInfo; + } +} +implementation { + enum { CLIENTS = uniqueCount(resourceName) }; + + components new SharedArbiterP(); + Resource = SharedArbiterP; + ResourceDefaultOwner = SharedArbiterP; + ArbiterInfo = SharedArbiterP; + + components new BitVectorC(CLIENTS) as GrantedVectorC; + SharedArbiterP.GrantedVector -> GrantedVectorC; + + components new BitVectorC(CLIENTS) as RequestingVectorC; + SharedArbiterP.RequestingVector -> RequestingVectorC; + + components new StateC(); + SharedArbiterP.State -> StateC; +} diff --git a/tos/system/SharedArbiterP.nc b/tos/system/SharedArbiterP.nc new file mode 100644 index 00000000..b912fa19 --- /dev/null +++ b/tos/system/SharedArbiterP.nc @@ -0,0 +1,224 @@ +/* + * Copyright (c) 2010, Titanium Mirror, Inc. + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * - Redistributions of source code must retain the above copyright notice, + * this list of conditions and the following disclaimer. + * - Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * - Neither the name of the Technische Universität Berlin nor the names + * of its contributors may be used to endorse or promote products derived + * from this software without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT + * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR + * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT + * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, + * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED + * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, + * OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY + * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE + * USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + */ + +/** + * A shared arbiter that allows 1...N clients to acquire the resource + * simultaneously. The purpose of this arbiter to allow access to a shared, + * switched subsystem. For example, a communications bus that can handle IO + * for multiple clients simultaneously, but is powered down when not in use. + * + * @author R. Steve McKown + */ + +generic module SharedArbiterP() { + provides { + interface Resource[uint8_t id]; + interface ResourceDefaultOwner; + interface ArbiterInfo; + } + uses { + interface BitVector as GrantedVector; + interface BitVector as RequestingVector; + interface State; + } +} +implementation { + enum { + S_IDLE = 0, /* Resource is not in use; owned by default owner */ + S_REQUESTING, /* Requesting the resource from the default owner */ + S_IMMREQUESTING, /* Immediate resource request from the default owner */ + S_GRANTED, /* One or more clients have been granted the resource */ + + NO_CLIENT = 0xff, + }; + + uint8_t m_granted; /* Count of clients granted the resource */ + uint8_t m_requesting; /* Count of clients requesting the resource */ + + uint8_t addRequesting(uint8_t id) + { + atomic { + call RequestingVector.set(id); + return ++m_requesting; + } + } + + uint8_t rmRequesting(uint8_t id) + { + atomic { + call RequestingVector.clear(id); + return --m_requesting; + } + } + + uint8_t addGranted(uint8_t id) + { + atomic { + call GrantedVector.set(id); + return ++m_granted; + } + } + + uint8_t rmGranted(uint8_t id) + { + atomic { + call GrantedVector.clear(id); + return --m_granted; + } + } + + task void grantedTask() + { + unsigned id; + + atomic { + if (m_requesting == 0) + return; + } + + for (id = 0; id < call RequestingVector.size(); id++) { + bool grant = FALSE; + + atomic { + if (call RequestingVector.get(id)) { + rmRequesting(id); + addGranted(id); + grant = TRUE; + } + } + if (grant) + signal Resource.granted[id](); + } + } + + async command error_t Resource.request[uint8_t id]() + { + /* The Resource docs do not say what happens when a user calls + * Resource.request() after the resource has already been granted. We + * elect to call EBUSY, as if the request was still in process. + */ + if (call RequestingVector.get(id) || call GrantedVector.get(id)) + return EBUSY; + + addRequesting(id); + if (call State.requestState(S_REQUESTING) == SUCCESS) + signal ResourceDefaultOwner.requested(); + else if (call State.isState(S_GRANTED)) + post grantedTask(); + return SUCCESS; + } + + async command error_t Resource.immediateRequest[uint8_t id]() + { + /* The Resource docs do not say what happens when a user calls + * Resource.request() after the resource has already been granted. We + * elect to call EBUSY, as if the request was still in process. + */ + if (call RequestingVector.get(id) || call GrantedVector.get(id)) + return EBUSY; + + if (call State.requestState(S_IMMREQUESTING) == SUCCESS) { + signal ResourceDefaultOwner.immediateRequested(); + if (call State.isState(S_IMMREQUESTING)) + call State.toIdle(); + } + if (call State.isState(S_GRANTED)) { + addGranted(id); + return SUCCESS; + } + return FAIL; + } + + async command error_t Resource.release[uint8_t id]() + { + if (!call GrantedVector.get(id)) + return FAIL; + + if (rmGranted(id) == 0) { + call State.toIdle(); + signal ResourceDefaultOwner.granted(); + } + return SUCCESS; + } + + async command error_t ResourceDefaultOwner.release() + { + if (call State.isState(S_REQUESTING)) { + call State.forceState(S_GRANTED); + post grantedTask(); + return SUCCESS; + } else if (call State.isState(S_IMMREQUESTING)) { + call State.forceState(S_GRANTED); + return SUCCESS; + } else + return FAIL; + } + + async command bool ArbiterInfo.inUse() + { + atomic { + if (m_granted) + return TRUE; + } + return FALSE; + } + + /* The ArbiterInfo interface doesn't work so well for a shared resource, as + * 1+ users may hold the resource at any time. + */ + async command uint8_t ArbiterInfo.userId() + { + atomic { + if (m_granted) + return 1; + } + return NO_CLIENT; + } + + async command uint8_t Resource.isOwner[uint8_t id]() + { + atomic return call GrantedVector.get(id); + } + + async command uint8_t ResourceDefaultOwner.isOwner() + { + atomic return !(call State.isState(S_GRANTED)); + } + + default event void Resource.granted[uint8_t id]() {} + default async event void ResourceDefaultOwner.granted() {} + default async event void ResourceDefaultOwner.requested() + { + call ResourceDefaultOwner.release(); + } + default async event void ResourceDefaultOwner.immediateRequested() + { + call ResourceDefaultOwner.release(); + } +} -- 2.39.2