FreeCalypso > hg > fc-tourmaline
view src/g23m-gprs/llc/llc_uirxp.c @ 220:0ed36de51973
ABB semaphore protection overhaul
The ABB semaphone protection logic that came with TCS211 from TI
was broken in several ways:
* Some semaphore-protected functions were called from Application_Initialize()
context. NU_Obtain_Semaphore() called with NU_SUSPEND fails with
NU_INVALID_SUSPEND in this context, but the return value wasn't checked,
and NU_Release_Semaphore() would be called unconditionally at the end.
The latter call would increment the semaphore count past 1, making the
semaphore no longer binary and thus no longer effective for resource
protection. The fix is to check the return value from NU_Obtain_Semaphore()
and skip the NU_Release_Semaphore() call if the semaphore wasn't properly
obtained.
* Some SPI hardware manipulation was being done before entering the semaphore-
protected critical section. The fix is to reorder the code: first obtain
the semaphore, then do everything else.
* In the corner case of L1/DSP recovery, l1_abb_power_on() would call some
non-semaphore-protected ABB & SPI init functions. The fix is to skip those
calls in the case of recovery.
* A few additional corner cases existed, all of which are fixed by making
ABB semaphore protection 100% consistent for all ABB functions and code paths.
There is still one remaining problem of priority inversion: suppose a low-
priority task calls an ABB function, and some medium-priority task just happens
to preempt right in the middle of that semaphore-protected ABB operation. Then
the high-priority SPI task is locked out for a non-deterministic time until
that medium-priority task finishes its work and goes back to sleep. This
priority inversion problem remains outstanding for now.
author | Mychaela Falconia <falcon@freecalypso.org> |
---|---|
date | Mon, 26 Apr 2021 20:55:25 +0000 |
parents | fa8dc04885d8 |
children |
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/* +----------------------------------------------------------------------------- | Project : | Modul : +----------------------------------------------------------------------------- | Copyright 2002 Texas Instruments Berlin, AG | All rights reserved. | | This file is confidential and a trade secret of Texas | Instruments Berlin, AG | The receipt of or possession of this file does not convey | any rights to reproduce or disclose its contents or to | manufacture, use, or sell anything it may describe, in | whole, or in part, without the specific written consent of | Texas Instruments Berlin, AG. +----------------------------------------------------------------------------- | Purpose : This modul is part of the entity LLC and implements all | functions to handles the incoming primitives as described in | the SDL-documentation (UIRX-statemachine) +----------------------------------------------------------------------------- */ #ifndef LLC_UIRXP_C #define LLC_UIRXP_C #endif #define ENTITY_LLC /*==== INCLUDES =============================================================*/ #include "typedefs.h" /* to get Condat data types */ #include "vsi.h" /* to get a lot of macros */ #include "macdef.h" #include "gprs.h" #include "gsm.h" /* to get a lot of macros */ #include "cnf_llc.h" /* to get cnf-definitions */ #include "mon_llc.h" /* to get mon-definitions */ #include "prim.h" /* to get the definitions of used SAP and directions */ #include "llc.h" /* to get the global entity definitions */ #include "llc_uirxf.h" /* to get queue management prototypes */ /*==== CONST ================================================================*/ /*==== LOCAL VARS ===========================================================*/ /*==== PRIVATE FUNCTIONS ====================================================*/ /*==== PUBLIC FUNCTIONS =====================================================*/ /* +------------------------------------------------------------------------------ | Function : uirx_ll_getunitdata_req +------------------------------------------------------------------------------ | Description : Handles the primitive LL_GETUNITDATA_REQ | | Parameters : *ll_getunitdata_req - Ptr to primitive payload | +------------------------------------------------------------------------------ */ GLOBAL void uirx_ll_getunitdata_req ( T_LL_GETUNITDATA_REQ *ll_getunitdata_req ) { T_LL_UNITDATA_IND *ll_unitdata_ind; TRACE_FUNCTION( "ll_getunitdata_req" ); SWITCH_LLC (ll_getunitdata_req->sapi); TRACE_1_PARA("s:%d", ll_getunitdata_req->sapi ); switch (GET_STATE(UIRX)) { case UIRX_TLLI_UNASSIGNED_NOT_READY: PFREE (ll_getunitdata_req); SET_STATE (UIRX, UIRX_TLLI_UNASSIGNED_READY); break; case UIRX_ADM_NOT_READY: PFREE (ll_getunitdata_req); /* * First check, if already a frame is waiting. */ if (uirx_queue_retrieve (&ll_unitdata_ind)) { /* * A frame is waiting. Send primitive LL-UNITDATA-IND * to either SNDCP or GSMS, depending on the SAPI (GMM * uses now flow control!). */ switch (ll_unitdata_ind->sapi) { case LL_SAPI_3: case LL_SAPI_5: case LL_SAPI_9: case LL_SAPI_11: TRACE_3_OUT_PARA("s:%d len:%d c:%d", ll_unitdata_ind->sapi, BYTELEN(ll_unitdata_ind->sdu.l_buf), ll_unitdata_ind->cipher); PSEND (hCommSNDCP, ll_unitdata_ind); break; case LL_SAPI_7: #ifdef LL_2to1 TRACE_PRIM_TO("MM"); TRACE_3_OUT_PARA("s:%d len:%d c:%d", ll_unitdata_ind->sapi, BYTELEN(ll_unitdata_ind->sdu.l_buf), ll_unitdata_ind->cipher); PSEND (hCommMM, ll_unitdata_ind); break; #else TRACE_PRIM_TO("GSMS"); TRACE_3_OUT_PARA("s:%d len:%d c:%d", ll_unitdata_ind->sapi, BYTELEN(ll_unitdata_ind->sdu.l_buf), ll_unitdata_ind->cipher); PSEND (hCommGSMS, ll_unitdata_ind); break; #endif default: PFREE (ll_unitdata_ind); TRACE_ERROR ("Invalid SAPI value"); break; } } else { /* * No frame is waiting. Allow straight forwarding * of the next received frame. */ SET_STATE (UIRX, UIRX_ADM_READY); } break; default: PFREE (ll_getunitdata_req); TRACE_ERROR( "LL_GETUNITDATA_REQ unexpected" ); break; } } /* uirx_ll_getunitdata_req() */