special bus error recovery code for recovery from bus error due to bus extenders
This commit is contained in:
Jim Kowalkowski
381
src/libvxWorks/bus_error_recovery.c
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381
src/libvxWorks/bus_error_recovery.c
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/*
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Special case bus error recovery code.
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The code in this file will attempt to retry instructions which caused
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bus errors up to 10 times before invoking the standard vxWorks bus
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error handler. The code also records the last 20 bus errors so they
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can be reported using a utility run from the vxWorks console. Database
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records can be used to monitor when bus errors occur - See support
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below.
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The bus error handler only processes bus errors outside the processor's
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local memory which are normal user/supervisor data accesses.
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------------------
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epicsBusErrorPrint - Print the last 20 bus errors that occurred. The
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report includes:
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1) The bus error number
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2) FA - The fault address
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3) PC - The program counter when the fault occurred
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4) SR - Status register
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5) SSW - Special status word
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-------------
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devAiBusError - Simple EPICS ai record device support. Create an
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ai record with DTYP="Bus Error" and SCAN="I/O Intr" to get
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informed when a bus error occurs. You may not get informed if the
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bus error is handled by vxWorks and an important EPICS task is
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suspended as a result. You will always be notified of a bus
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error that has been corrected by retries. The ai record will
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count up every time if is processed. The bus error handler triggers
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processing of the record if the SCAN type is "I/O Intr".
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If a bus error is handled by vxWorks and you do not get notified via
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the ai record, you can sign on the console and run epicsBusErrorPrint
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and see the last 20 bus errors that occurred.
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Add the following line to the cat_ascii/devSup.ascii file:
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"ai" VME_IO "devAiBusError" "Bus Error"
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----------------------
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epicsBusErrorInit68040
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Initialize the bus error handling system. ONLY needs to be run if
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a bus error monitoring record is NOT present in the database. The
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ai record device support above runs with function automatically. You
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need to run this function before iocInit in your vxWorks startup
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script if you do not use the ai record support described above and
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have a record for it in the database.
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*/
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#include <stdio.h>
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#include <types.h>
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#include <vme.h>
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#include <vxWorks.h>
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#include <sysLib.h>
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#include <taskLib.h>
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#include <semLib.h>
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#include <intLib.h>
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#include <dbScan.h>
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#include <devSup.h>
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#include <callback.h>
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#include <aiRecord.h>
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struct accessFault
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{
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unsigned short sr; /* status reg */
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unsigned short* pc; /* program counter */
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unsigned short vo; /* vector offset */
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unsigned long ea; /* effective address */
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unsigned short ssw; /* special status word */
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unsigned short wb3s; /* write-back 3 status */
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unsigned short wb2s; /* write-back 2 status */
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unsigned short wb1s; /* write-back 1 status */
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unsigned char * fa; /* fault address */
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union {
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unsigned long* l; unsigned short* s; unsigned char * c;
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} wb3a; /* write-back 3 address */
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union {
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unsigned long l; unsigned short s; unsigned char c;
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} wb3d; /* write-back 3 */
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union {
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unsigned long* l; unsigned short* s; unsigned char * c;
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} wb2a; /* write-back 2 address */
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union {
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unsigned long l; unsigned short s; unsigned char c;
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} wb2d; /* write-back 2 */
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union {
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unsigned long* l; unsigned short* s; unsigned char * c;
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} wb1a; /* write-back 1 address */
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union {
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unsigned long l; unsigned short s; unsigned char c;
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} wb1d; /* write-back 1 / push data LW0 */
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unsigned long pd1; /* push data LW1 */
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unsigned long pd2; /* push data LW2 */
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unsigned long pd3; /* push data LW3 */
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};
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typedef struct accessFault accessFault;
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struct faultData
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{
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unsigned short* pc;
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unsigned char * fa;
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unsigned short sr;
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unsigned short ssw;
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unsigned char flags; /* 0x01:write back incompleted, >0: valid bus error */
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long cnt;
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};
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typedef struct faultData faultData;
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#define TOTAL_FAULTS 20
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#define ACCESS_FAULT 2
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#define BS_PRI 199
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#define NUM_RETRIES 10
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long epicsBusErrorInit68040(void);
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long epicsBusErrorHandler(void* v);
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void epicsBusErrorPrint(void);
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void epicsBusError(void);
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volatile long epicsBusErrorTotal=0;
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volatile long epicsBusErrorLastRC=0;
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static volatile faultData* fault_table=NULL;
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static volatile int pos_handler=0;
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static unsigned char * be_mem_top=NULL;
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static unsigned char * be_mem_bottom=0;
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static FUNCPTR* vbr;
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static FUNCPTR vx_access_fault;
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static IOSCANPVT ioscan;
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static unsigned short* curr_pc=NULL;
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static unsigned short* last_pc=NULL;
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static unsigned short count=0;
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static unsigned long regs[64];
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static unsigned long* regs_addr=regs;
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static int init_run=0;
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FUNCPTR* epicsGetVBR()
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{
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unsigned long x;
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asm ("movec vbr,%0" : "=g" (x) );
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return (FUNCPTR*)x;
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}
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/* ------------------- ai record to monitor bus errors -------------------- */
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struct aStats
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{
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long number;
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DEVSUPFUN report;
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DEVSUPFUN init;
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DEVSUPFUN init_record;
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DEVSUPFUN get_ioint_info;
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DEVSUPFUN read_write;
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DEVSUPFUN special_linconv;
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};
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typedef struct aStats aStats;
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static long aiInit(int pass)
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{
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if(pass) return 0;
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if(init_run==0)
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{
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epicsBusErrorInit68040();
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init_run=1;
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}
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return 0;
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}
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static long aiInitRecord(aiRecord* pr)
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{
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unsigned long* x = (unsigned long*)&pr->dpvt;
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x=0;
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pr->linr=0;
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return 0;
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}
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static long aiIointInfo(int cmd,aiRecord* pr,IOSCANPVT* iopvt)
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{
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*iopvt=ioscan;
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return 0;
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}
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static long aiRead(aiRecord* pr)
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{
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unsigned long* x = (unsigned long*)&pr->dpvt;
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pr->val=++(*x);
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pr->udf=0;
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return 2;
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}
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aStats devAiBusError=
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{ 6,NULL,aiInit,aiInitRecord,aiIointInfo,aiRead,NULL };
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/* ------------------- ai record to monitor bus errors -------------------- */
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long epicsBusErrorInit68040(void)
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{
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long rc=0;
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int i;
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if(init_run)
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return 0;
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else
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init_run=1;
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vbr=epicsGetVBR(); /* vbr=intVecBaseGet(); */
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be_mem_top=(unsigned char *)sysMemTop();
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vx_access_fault=vbr[ACCESS_FAULT];
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scanIoInit(&ioscan);
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/*
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printf("VBR=0x%8.8x\n",vbr);
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printf("MemTop=0x%8.8x\n",be_mem_top);
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printf("vxWorks Access Fault Handler=0x%8.8x\n",vx_access_fault);
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*/
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/* up to TOTAL_FAULTS number of interrupts can occur before printing */
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fault_table=(volatile faultData*)malloc(sizeof(faultData)*TOTAL_FAULTS);
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for(i=0;i<TOTAL_FAULTS;i++) fault_table[i].flags=0x00;
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/* replace the bus error handler from vxWorks */
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vbr[ACCESS_FAULT]=(FUNCPTR)epicsBusError;
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return rc;
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}
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void epicsBusErrorPrint(void)
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{
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volatile int pos;
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int i;
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for(i=0;i<TOTAL_FAULTS;i++)
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{
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if(fault_table[i].flags)
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{
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printf("%ld: FA=0x%8.8x PC=0x%8.8x SR=0x%4.4x, SSW=0x%4.4x ",
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fault_table[i].cnt,
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fault_table[i].fa,
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fault_table[i].pc,
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fault_table[i].sr,
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fault_table[i].ssw);
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switch(fault_table[i].flags)
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{
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case 0x01: /* write back failed */
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printf(" Write back incomplete\n");
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break;
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case 0x02: /* normal retry */
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printf(" Normal Retry\n");
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break;
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case 0x04: /* vxWorks process */
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printf(" vxWorks Handled\n");
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break;
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}
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}
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}
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}
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/* sp+60+sizeof(access fault stack frame) ---> 60+60 */
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asm(" .text");
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asm(" .even");
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asm(" .globl _epicsBusError");
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asm("_epicsBusError:");
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asm(" moveml #0xfffe,sp@-"); /* save the registers */
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asm(" pea sp@(60)"); /* get address of access error stack frame */
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asm(" jbsr _epicsBusErrorHandler"); /* call my bus error handler */
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asm(" addql #4,sp");
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asm(" tstl d0"); /* check return code from bus error handler */
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asm(" jeq L1"); /* exit OK if zero return code */
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asm(" moveml sp@+,#0x7fff"); /* restore regs */
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asm(" movel _vx_access_fault,sp@-"); /* put vxWorks handler addr on stack */
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asm(" rts "); /* load PC from stack (vxWorks handler) */
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asm("L1:");
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asm(" moveml sp@+,#0x7fff"); /* restore regs */
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asm(" rte");
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/*
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see section 8.4.6 of M68040 user's manual, page 8-24
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see section 5.3, page 5-5 for Transfer attribute signals (TT/TM)
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SIZ: 00=long word, 01=byte, 10=word
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TT: 00=normal, 01=move16, 10=alternate, 11=ack cycle
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TM: 001=user data, 010=user code, 101=sup data, 110=sup code
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R/W: set indicates a read access
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*/
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long epicsBusErrorHandler(void* v)
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{
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long rc;
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unsigned char f;
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volatile int pos,posp;
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volatile accessFault* af = (volatile accessFault*)v;
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unsigned short size,op_code;
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unsigned short* ppc;
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int len;
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curr_pc=af->pc;
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if(curr_pc==last_pc) ++count;
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if( count<NUM_RETRIES &&
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((af->ssw & 0x0018) == 0) && ((af->ssw & 0xfc00) == 0) &&
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((af->ssw & 0x0001) || (af->ssw & 0x0005)) &&
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(af->fa >= be_mem_top) )
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{
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/* TT=normal TM=user/sup data access bus-errors */
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rc=0;
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f=0x02;
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/*
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Don't force PC to next instruction, just retry several times
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Note: the current instruction may not have caused the fault
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*/
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/* correct bus error here */
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if(af->wb1s & 0x0080)
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{
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/* this is where the fault occured if write */
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if(af->wb1a.c < be_mem_top)
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{
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size=(af->wb1s & 0060)>>5;
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if(size==0x0000) *(af->wb1a.l)=af->wb1d.l;
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else if(size==0x0001) *(af->wb1a.c)=af->wb1d.c;
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else if(size==0x0010) *(af->wb1a.s)=af->wb1d.s;
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}
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}
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if(af->wb2s & 0x0080)
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{
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if(af->wb2a.c < be_mem_top)
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{
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size=(af->wb2s & 0060)>>5;
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if(size==0x0000) *(af->wb2a.l)=af->wb2d.l;
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else if(size==0x0001) *(af->wb2a.c)=af->wb2d.c;
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else if(size==0x0010) *(af->wb2a.s)=af->wb2d.s;
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}
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else
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f|=0x01;
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}
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if(af->wb3s & 0x0080)
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{
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if(af->wb3a.c < be_mem_top)
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{
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size=(af->wb3s & 0060)>>5;
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if(size==0x0000) *(af->wb3a.l)=af->wb3d.l;
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else if(size==0x0001) *(af->wb3a.c)=af->wb3d.c;
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else if(size==0x0010) *(af->wb3a.s)=af->wb3d.s;
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}
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else
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f|=0x01;
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}
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}
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else
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{
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f=0x04;
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rc=-1; /* let vxWorks handle it */
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}
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if(count==0 || count>=NUM_RETRIES)
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{
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if((++pos_handler)>=TOTAL_FAULTS) pos_handler=0;
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fault_table[pos_handler].pc=af->pc;
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fault_table[pos_handler].fa=af->fa;
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fault_table[pos_handler].sr=af->sr;
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fault_table[pos_handler].ssw=af->ssw;
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fault_table[pos_handler].cnt=epicsBusErrorTotal;
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fault_table[pos_handler].flags=f;
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if(count>=NUM_RETRIES)
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{
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count=0;
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curr_pc=NULL;
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}
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else
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scanIoRequest(ioscan);
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++epicsBusErrorTotal;
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}
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epicsBusErrorLastRC=rc;
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last_pc=curr_pc;
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return rc;
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}
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