mirror of https://github.com/hak5/openwrt.git
347 lines
13 KiB
C
347 lines
13 KiB
C
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/*
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*
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* Copyright (c) 2004-2007 Atheros Communications Inc.
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* All rights reserved.
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*
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation;
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*
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* Software distributed under the License is distributed on an "AS
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* IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
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* implied. See the License for the specific language governing
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* rights and limitations under the License.
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*
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*
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*
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*/
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#include "a_config.h"
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#include "athdefs.h"
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#include "a_types.h"
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#include "a_osapi.h"
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#include "a_debug.h"
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#include "htc_api.h"
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#include "common_drv.h"
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/********* CREDIT DISTRIBUTION FUNCTIONS ******************************************/
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#define NO_VO_SERVICE 1 /* currently WMI only uses 3 data streams, so we leave VO service inactive */
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#ifdef NO_VO_SERVICE
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#define DATA_SVCS_USED 3
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#else
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#define DATA_SVCS_USED 4
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#endif
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static void RedistributeCredits(COMMON_CREDIT_STATE_INFO *pCredInfo,
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HTC_ENDPOINT_CREDIT_DIST *pEPDistList);
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static void SeekCredits(COMMON_CREDIT_STATE_INFO *pCredInfo,
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HTC_ENDPOINT_CREDIT_DIST *pEPDistList);
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/* reduce an ep's credits back to a set limit */
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static INLINE void ReduceCredits(COMMON_CREDIT_STATE_INFO *pCredInfo,
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HTC_ENDPOINT_CREDIT_DIST *pEpDist,
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int Limit)
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{
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int credits;
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/* set the new limit */
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pEpDist->TxCreditsAssigned = Limit;
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if (pEpDist->TxCredits <= Limit) {
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return;
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}
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/* figure out how much to take away */
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credits = pEpDist->TxCredits - Limit;
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/* take them away */
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pEpDist->TxCredits -= credits;
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pCredInfo->CurrentFreeCredits += credits;
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}
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/* give an endpoint some credits from the free credit pool */
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#define GiveCredits(pCredInfo,pEpDist,credits) \
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{ \
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(pEpDist)->TxCredits += (credits); \
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(pEpDist)->TxCreditsAssigned += (credits); \
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(pCredInfo)->CurrentFreeCredits -= (credits); \
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}
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/* default credit init callback.
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* This function is called in the context of HTCStart() to setup initial (application-specific)
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* credit distributions */
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static void ar6000_credit_init(void *Context,
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HTC_ENDPOINT_CREDIT_DIST *pEPList,
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int TotalCredits)
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{
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HTC_ENDPOINT_CREDIT_DIST *pCurEpDist;
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int count;
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COMMON_CREDIT_STATE_INFO *pCredInfo = (COMMON_CREDIT_STATE_INFO *)Context;
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pCredInfo->CurrentFreeCredits = TotalCredits;
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pCredInfo->TotalAvailableCredits = TotalCredits;
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pCurEpDist = pEPList;
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/* run through the list and initialize */
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while (pCurEpDist != NULL) {
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/* set minimums for each endpoint */
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pCurEpDist->TxCreditsMin = pCurEpDist->TxCreditsPerMaxMsg;
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if (pCurEpDist->ServiceID == WMI_CONTROL_SVC) {
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/* give control service some credits */
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GiveCredits(pCredInfo,pCurEpDist,pCurEpDist->TxCreditsMin);
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/* control service is always marked active, it never goes inactive EVER */
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SET_EP_ACTIVE(pCurEpDist);
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} else if (pCurEpDist->ServiceID == WMI_DATA_BK_SVC) {
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/* this is the lowest priority data endpoint, save this off for easy access */
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pCredInfo->pLowestPriEpDist = pCurEpDist;
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}
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/* Streams have to be created (explicit | implicit)for all kinds
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* of traffic. BE endpoints are also inactive in the beginning.
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* When BE traffic starts it creates implicit streams that
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* redistributes credits.
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*/
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/* note, all other endpoints have minimums set but are initially given NO credits.
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* Credits will be distributed as traffic activity demands */
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pCurEpDist = pCurEpDist->pNext;
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}
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if (pCredInfo->CurrentFreeCredits <= 0) {
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AR_DEBUG_PRINTF(ATH_LOG_INF, ("Not enough credits (%d) to do credit distributions \n", TotalCredits));
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A_ASSERT(FALSE);
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return;
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}
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/* reset list */
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pCurEpDist = pEPList;
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/* now run through the list and set max operating credit limits for everyone */
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while (pCurEpDist != NULL) {
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if (pCurEpDist->ServiceID == WMI_CONTROL_SVC) {
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/* control service max is just 1 max message */
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pCurEpDist->TxCreditsNorm = pCurEpDist->TxCreditsPerMaxMsg;
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} else {
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/* for the remaining data endpoints, we assume that each TxCreditsPerMaxMsg are
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* the same.
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* We use a simple calculation here, we take the remaining credits and
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* determine how many max messages this can cover and then set each endpoint's
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* normal value equal to half this amount.
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* */
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count = (pCredInfo->CurrentFreeCredits/pCurEpDist->TxCreditsPerMaxMsg) * pCurEpDist->TxCreditsPerMaxMsg;
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count = count >> 1;
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count = max(count,pCurEpDist->TxCreditsPerMaxMsg);
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/* set normal */
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pCurEpDist->TxCreditsNorm = count;
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}
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pCurEpDist = pCurEpDist->pNext;
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}
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}
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/* default credit distribution callback
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* This callback is invoked whenever endpoints require credit distributions.
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* A lock is held while this function is invoked, this function shall NOT block.
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* The pEPDistList is a list of distribution structures in prioritized order as
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* defined by the call to the HTCSetCreditDistribution() api.
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*
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*/
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static void ar6000_credit_distribute(void *Context,
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HTC_ENDPOINT_CREDIT_DIST *pEPDistList,
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HTC_CREDIT_DIST_REASON Reason)
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{
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HTC_ENDPOINT_CREDIT_DIST *pCurEpDist;
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COMMON_CREDIT_STATE_INFO *pCredInfo = (COMMON_CREDIT_STATE_INFO *)Context;
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switch (Reason) {
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case HTC_CREDIT_DIST_SEND_COMPLETE :
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pCurEpDist = pEPDistList;
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/* we are given the start of the endpoint distribution list.
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* There may be one or more endpoints to service.
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* Run through the list and distribute credits */
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while (pCurEpDist != NULL) {
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if (pCurEpDist->TxCreditsToDist > 0) {
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/* return the credits back to the endpoint */
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pCurEpDist->TxCredits += pCurEpDist->TxCreditsToDist;
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/* always zero out when we are done */
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pCurEpDist->TxCreditsToDist = 0;
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if (pCurEpDist->TxCredits > pCurEpDist->TxCreditsAssigned) {
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/* reduce to the assigned limit, previous credit reductions
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* could have caused the limit to change */
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ReduceCredits(pCredInfo, pCurEpDist, pCurEpDist->TxCreditsAssigned);
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}
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if (pCurEpDist->TxCredits > pCurEpDist->TxCreditsNorm) {
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/* oversubscribed endpoints need to reduce back to normal */
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ReduceCredits(pCredInfo, pCurEpDist, pCurEpDist->TxCreditsNorm);
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}
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}
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pCurEpDist = pCurEpDist->pNext;
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}
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A_ASSERT(pCredInfo->CurrentFreeCredits <= pCredInfo->TotalAvailableCredits);
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break;
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case HTC_CREDIT_DIST_ACTIVITY_CHANGE :
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RedistributeCredits(pCredInfo,pEPDistList);
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break;
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case HTC_CREDIT_DIST_SEEK_CREDITS :
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SeekCredits(pCredInfo,pEPDistList);
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break;
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case HTC_DUMP_CREDIT_STATE :
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AR_DEBUG_PRINTF(ATH_LOG_INF, ("Credit Distribution, total : %d, free : %d\n",
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pCredInfo->TotalAvailableCredits, pCredInfo->CurrentFreeCredits));
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break;
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default:
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break;
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}
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}
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/* redistribute credits based on activity change */
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static void RedistributeCredits(COMMON_CREDIT_STATE_INFO *pCredInfo,
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HTC_ENDPOINT_CREDIT_DIST *pEPDistList)
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{
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HTC_ENDPOINT_CREDIT_DIST *pCurEpDist = pEPDistList;
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/* walk through the list and remove credits from inactive endpoints */
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while (pCurEpDist != NULL) {
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if (pCurEpDist->ServiceID != WMI_CONTROL_SVC) {
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if (!IS_EP_ACTIVE(pCurEpDist)) {
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/* EP is inactive, reduce credits back to zero */
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ReduceCredits(pCredInfo, pCurEpDist, 0);
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}
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}
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/* NOTE in the active case, we do not need to do anything further,
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* when an EP goes active and needs credits, HTC will call into
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* our distribution function using a reason code of HTC_CREDIT_DIST_SEEK_CREDITS */
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pCurEpDist = pCurEpDist->pNext;
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}
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A_ASSERT(pCredInfo->CurrentFreeCredits <= pCredInfo->TotalAvailableCredits);
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}
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/* HTC has an endpoint that needs credits, pEPDist is the endpoint in question */
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static void SeekCredits(COMMON_CREDIT_STATE_INFO *pCredInfo,
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HTC_ENDPOINT_CREDIT_DIST *pEPDist)
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{
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HTC_ENDPOINT_CREDIT_DIST *pCurEpDist;
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int credits = 0;
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int need;
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do {
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if (pEPDist->ServiceID == WMI_CONTROL_SVC) {
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/* we never oversubscribe on the control service, this is not
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* a high performance path and the target never holds onto control
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* credits for too long */
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break;
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}
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/* for all other services, we follow a simple algorithm of
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* 1. checking the free pool for credits
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* 2. checking lower priority endpoints for credits to take */
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if (pCredInfo->CurrentFreeCredits >= 2 * pEPDist->TxCreditsSeek) {
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/* try to give more credits than it needs */
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credits = 2 * pEPDist->TxCreditsSeek;
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} else {
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/* give what we can */
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credits = min(pCredInfo->CurrentFreeCredits,pEPDist->TxCreditsSeek);
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}
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if (credits >= pEPDist->TxCreditsSeek) {
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/* we found some to fullfill the seek request */
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break;
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}
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/* we don't have enough in the free pool, try taking away from lower priority services
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*
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* The rule for taking away credits:
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* 1. Only take from lower priority endpoints
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* 2. Only take what is allocated above the minimum (never starve an endpoint completely)
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* 3. Only take what you need.
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*
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* */
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/* starting at the lowest priority */
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pCurEpDist = pCredInfo->pLowestPriEpDist;
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/* work backwards until we hit the endpoint again */
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while (pCurEpDist != pEPDist) {
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/* calculate how many we need so far */
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need = pEPDist->TxCreditsSeek - pCredInfo->CurrentFreeCredits;
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if ((pCurEpDist->TxCreditsAssigned - need) > pCurEpDist->TxCreditsMin) {
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/* the current one has been allocated more than it's minimum and it
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* has enough credits assigned above it's minimum to fullfill our need
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* try to take away just enough to fullfill our need */
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ReduceCredits(pCredInfo,
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pCurEpDist,
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pCurEpDist->TxCreditsAssigned - need);
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if (pCredInfo->CurrentFreeCredits >= pEPDist->TxCreditsSeek) {
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/* we have enough */
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break;
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}
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}
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pCurEpDist = pCurEpDist->pPrev;
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}
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/* return what we can get */
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credits = min(pCredInfo->CurrentFreeCredits,pEPDist->TxCreditsSeek);
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} while (FALSE);
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/* did we find some credits? */
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if (credits) {
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/* give what we can */
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GiveCredits(pCredInfo, pEPDist, credits);
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}
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}
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/* initialize and setup credit distribution */
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A_STATUS ar6000_setup_credit_dist(HTC_HANDLE HTCHandle, COMMON_CREDIT_STATE_INFO *pCredInfo)
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{
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HTC_SERVICE_ID servicepriority[5];
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A_MEMZERO(pCredInfo,sizeof(COMMON_CREDIT_STATE_INFO));
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servicepriority[0] = WMI_CONTROL_SVC; /* highest */
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servicepriority[1] = WMI_DATA_VO_SVC;
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servicepriority[2] = WMI_DATA_VI_SVC;
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servicepriority[3] = WMI_DATA_BE_SVC;
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servicepriority[4] = WMI_DATA_BK_SVC; /* lowest */
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/* set callbacks and priority list */
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HTCSetCreditDistribution(HTCHandle,
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pCredInfo,
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ar6000_credit_distribute,
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ar6000_credit_init,
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servicepriority,
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5);
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return A_OK;
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}
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