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