ref: 6b84c3a6548f1c577948763b0a09a7b6e2460e04
dir: /os/mpc/spi.c/
#include "u.h" #include "../port/lib.h" #include "mem.h" #include "dat.h" #include "fns.h" #include "io.h" #include "../port/error.h" /* * basic read/write interface to mpc8xx Serial Peripheral Interface; * used by devtouch.c and devspi.c */ typedef struct Ctlr Ctlr; enum { /* spi-specific BD flags */ BDContin= 1<<9, /* continuous mode */ RxeOV= 1<<1, /* overrun */ TxeUN= 1<<1, /* underflow */ BDme= 1<<0, /* multimaster error */ BDrxerr= RxeOV|BDme, BDtxerr= TxeUN|BDme, /* spmod */ MLoop= 1<<14, /* loopback mode */ MClockInv= 1<<13, /* inactive state of SPICLK is high */ MClockPhs= 1<<12, /* SPCLK starts toggling at beginning of transfer */ MDiv16= 1<<11, /* use BRGCLK/16 as input to SPI baud rate */ MRev= 1<<10, /* normal operation */ MMaster= 1<<9, MSlave= 0<<9, MEnable= 1<<8, /* LEN, PS fields */ /* spcom */ STR= 1<<7, /* start transmit */ /* spie */ MME = 1<<5, TXE = 1<<4, BSY = 1<<2, TXB = 1<<1, RXB = 1<<0, /* port B bits */ SPIMISO = IBIT(28), /* master mode input */ SPIMOSI = IBIT(29), /* master mode output */ SPICLK = IBIT(30), /* maximum SPI I/O (can change) */ Bufsize = 64, }; /* * SPI software structures */ struct Ctlr { Lock; QLock io; int init; SPI* spi; IOCparam* sp; BD* rd; BD* td; int phase; Rendez r; char* txbuf; char* rxbuf; }; static Ctlr spictlr[1]; /* dcflush isn't needed if rxbuf and txbuf allocated in uncached IMMR memory */ #define DCFLUSH(a,n) static void interrupt(Ureg*, void*); /* * called by the reset routine of any driver using the SPI */ void spireset(void) { IMM *io; SPI *spi; IOCparam *sp; CPMdev *cpm; Ctlr *ctlr; ctlr = spictlr; if(ctlr->init) return; ctlr->init = 1; cpm = cpmdev(CPspi); spi = cpm->regs; ctlr->spi = spi; sp = cpm->param; if(sp == nil){ print("SPI: can't allocate new parameter memory\n"); return; } ctlr->sp = sp; if(ctlr->rxbuf == nil) ctlr->rxbuf = cpmalloc(Bufsize, 2); if(ctlr->txbuf == nil) ctlr->txbuf = cpmalloc(Bufsize, 2); if(ctlr->rd == nil){ ctlr->rd = bdalloc(1); ctlr->rd->addr = PADDR(ctlr->rxbuf); ctlr->rd->length = 0; ctlr->rd->status = BDWrap; } if(ctlr->td == nil){ ctlr->td = bdalloc(1); ctlr->td->addr = PADDR(ctlr->txbuf); ctlr->td->length = 0; ctlr->td->status = BDWrap|BDLast; } /* select port pins */ io = ioplock(); io->pbdir |= SPICLK | SPIMOSI | SPIMISO; io->pbpar |= SPICLK | SPIMOSI | SPIMISO; iopunlock(); /* explicitly initialise parameters, because InitRxTx can't be used (see i2c/spi relocation errata) */ sp = ctlr->sp; sp->rbase = PADDR(ctlr->rd); sp->tbase = PADDR(ctlr->td); sp->rfcr = 0x18; sp->tfcr = 0x18; sp->mrblr = Bufsize; sp->rstate = 0; sp->rptr = 0; sp->rbptr = sp->rbase; sp->rcnt = 0; sp->tstate = 0; sp->tbptr = sp->tbase; sp->tptr = 0; sp->tcnt = 0; eieio(); spi->spmode = MDiv16 | MRev | MMaster | ((8-1)<<4) | 1; /* 8 bit characters */ if(0) spi->spmode |= MLoop; /* internal loop back mode for testing */ spi->spie = ~0; /* clear events */ eieio(); spi->spim = MME|TXE|BSY|TXB|RXB; eieio(); spi->spmode |= MEnable; intrenable(VectorCPIC+cpm->irq, interrupt, spictlr, BUSUNKNOWN, "spi"); } enum { Idling, Waitval, Readyval }; static void interrupt(Ureg*, void *arg) { int events; Ctlr *ctlr; SPI *spi; ctlr = arg; spi = ctlr->spi; events = spi->spie; eieio(); spi->spie = events; if(events & (MME|BSY|TXE)){ print("SPI#%x\n", events); if(ctlr->phase != Idling){ ctlr->phase = Idling; wakeup(&ctlr->r); } }else if(events & RXB){ if(ctlr->phase == Waitval){ ctlr->phase = Readyval; wakeup(&ctlr->r); } } } static int done(void *a) { return ((Ctlr*)a)->phase != Waitval; } /* * send `nout' bytes on SPI from `out' and read as many bytes of reply into buffer `in'; * return the number of bytes received, or -1 on error. */ long spioutin(void *out, long nout, void *in) { Ctlr *ctlr; int nb, p; ctlr = spictlr; if(nout > Bufsize) return -1; qlock(&ctlr->io); if(waserror()){ qunlock(&ctlr->io); return -1; } if(ctlr->phase != Idling) sleep(&ctlr->r, done, ctlr); memmove(ctlr->txbuf, out, nout); DCFLUSH(ctlr->txbuf, Bufsize); DCFLUSH(ctlr->rxbuf, Bufsize); ilock(ctlr); ctlr->phase = Waitval; ctlr->td->length = nout; ctlr->rd->status = BDEmpty|BDWrap|BDInt; ctlr->td->status = BDReady|BDWrap|BDLast; eieio(); ctlr->spi->spcom = STR; eieio(); iunlock(ctlr); sleep(&ctlr->r, done, ctlr); nb = ctlr->rd->length; if(nb > nout) nb = nout; /* shouldn't happen */ p = ctlr->phase; poperror(); qunlock(&ctlr->io); if(p != Readyval) return -1; memmove(in, ctlr->rxbuf, nb); return nb; }