just use a buffer and make onewire_crc16() operate like onewire_crc()

from j0@cox.net (author of owctr)

diff --git a/sys/dev/onewire/onewire_subr.c b/sys/dev/onewire/onewire_subr.c
index d4de796..27a6a79 100644 (file)
--- a/sys/dev/onewire/onewire_subr.c
+++ b/sys/dev/onewire/onewire_subr.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: onewire_subr.c,v 1.3 2010/07/06 19:59:59 deraadt Exp $        */
+/*     $OpenBSD: onewire_subr.c,v 1.4 2010/07/19 23:44:09 deraadt Exp $        */
 
 /*
  * Copyright (c) 2006 Alexander Yurchenko <grange@openbsd.org>
@@ -150,15 +150,21 @@ onewire_crc(const void *buf, int len)
 }
 
 u_int16_t
-onewire_crc16(u_int16_t crc16, u_int8_t data)
+onewire_crc16(const void *buf, int len)
 {
+       const u_int8_t *p = buf;
+       u_int16_t crc = 0;
+       u_int16_t tmpcrc;
        int idx;
-       u_int16_t newcrc16;
 
-       idx = (crc16 & 0xff) ^ data;
-       newcrc16 = crc16_table_high[idx] << 8;
-       newcrc16 |= crc16_table_low[idx] ^ (crc16 >> 8);
-       return (newcrc16);
+       while (len--) {
+               idx = (crc & 0xff) ^ *p++;
+               tmpcrc = crc16_table_high[idx] << 8;
+               tmpcrc |= crc16_table_low[idx] ^ (crc >> 8);
+               crc = tmpcrc;
+       }
+
+       return (crc);
 }
 
 const char *

diff --git a/sys/dev/onewire/onewirevar.h b/sys/dev/onewire/onewirevar.h
index 296c951..ab3776f 100644 (file)
--- a/sys/dev/onewire/onewirevar.h
+++ b/sys/dev/onewire/onewirevar.h
@@ -1,4 +1,4 @@
-/*     $OpenBSD: onewirevar.h,v 1.6 2010/07/06 19:59:59 deraadt Exp $  */
+/*     $OpenBSD: onewirevar.h,v 1.7 2010/07/19 23:44:09 deraadt Exp $  */
 
 /*
  * Copyright (c) 2006 Alexander Yurchenko <grange@openbsd.org>
@@ -77,7 +77,7 @@ struct onewire_matchfam {
 
 /* Miscellaneous routines */
 int            onewire_crc(const void *, int);
-u_int16_t      onewire_crc16(u_int16_t, u_int8_t);
+u_int16_t      onewire_crc16(const void *, int);
 const char *   onewire_famname(int);
 int            onewire_matchbyfam(struct onewire_attach_args *,
                    const struct onewire_matchfam *, int);

diff --git a/sys/dev/onewire/owctr.c b/sys/dev/onewire/owctr.c
index 5f0beb9..918c41c 100644 (file)
--- a/sys/dev/onewire/owctr.c
+++ b/sys/dev/onewire/owctr.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: owctr.c,v 1.3 2010/07/08 07:19:54 jasper Exp $        */
+/*     $OpenBSD: owctr.c,v 1.4 2010/07/19 23:44:09 deraadt Exp $       */
 /*
  * Copyright (c) 2010 John L. Scarfone <john@scarfone.net>
  *
@@ -26,6 +26,7 @@
 #include <sys/systm.h>
 #include <sys/device.h>
 #include <sys/kernel.h>
+#include <sys/malloc.h>
 #include <sys/proc.h>
 #include <sys/rwlock.h>
 #include <sys/sensors.h>
@@ -41,6 +42,12 @@
 #define DS2423_COUNTER_BANK_A          0x1c0
 #define DS2423_COUNTER_BANK_B          0x1e0
 
+/* Buffer offsets */
+#define DS2423_COUNTER_BUF_COUNTER     35
+#define DS2423_COUNTER_BUF_CRC         43
+
+#define DS2423_COUNTER_BUFSZ           45
+
 struct owctr_softc {
        struct device           sc_dev;
 
@@ -153,78 +160,60 @@ owctr_update_counter(void *arg, int bank)
        struct owctr_softc *sc = arg;
        u_int32_t counter;
        u_int16_t crc;
-       int data;
-       int i;
+       u_int8_t *buf;
 
        rw_enter_write(&sc->sc_lock);
        onewire_lock(sc->sc_onewire, 0);
        if (onewire_reset(sc->sc_onewire) != 0)
                goto done;
 
-       onewire_matchrom(sc->sc_onewire, sc->sc_rom);
-       onewire_write_byte(sc->sc_onewire, DSCTR_CMD_READ_MEMCOUNTER);
-       crc = onewire_crc16(0, DSCTR_CMD_READ_MEMCOUNTER);
-       onewire_write_byte(sc->sc_onewire, bank);
-       crc = onewire_crc16(crc, bank);
-       onewire_write_byte(sc->sc_onewire, bank >> 8);
-       crc = onewire_crc16(crc, bank >> 8);
-       for (i=0; i<32; ++i)
-       {
-               data = onewire_read_byte(sc->sc_onewire);
-               crc = onewire_crc16(crc, data);
-       }
-       data = onewire_read_byte(sc->sc_onewire);
-       crc = onewire_crc16(crc, data);
-       counter = data;
-       data = onewire_read_byte(sc->sc_onewire);
-       crc = onewire_crc16(crc, data);
-       counter |= data << 8;
-       data = onewire_read_byte(sc->sc_onewire);
-       crc = onewire_crc16(crc, data);
-       counter |= data << 16;
-       data = onewire_read_byte(sc->sc_onewire);
-       crc = onewire_crc16(crc, data);
-       counter |= data << 24;
-       for (i=0; i<4; ++i)
-       {
-               onewire_read_byte(sc->sc_onewire);
-               crc = onewire_crc16(crc, data);
+       buf = malloc(DS2423_COUNTER_BUFSZ, M_DEVBUF, M_NOWAIT);
+       if (buf == NULL) {
+               printf("%s: malloc() failed\n", sc->sc_dev.dv_xname);
+               goto done;
        }
-       data = onewire_read_byte(sc->sc_onewire);
-       crc ^= data;
-       data = onewire_read_byte(sc->sc_onewire);
-       crc ^= data << 8;
-       if ( crc != 0xffff)
-       {
+
+       onewire_matchrom(sc->sc_onewire, sc->sc_rom);
+       buf[0] = DSCTR_CMD_READ_MEMCOUNTER;
+       buf[1] = bank;
+       buf[2] = bank >> 8;
+       onewire_write_byte(sc->sc_onewire, buf[0]);
+       onewire_write_byte(sc->sc_onewire, buf[1]);
+       onewire_write_byte(sc->sc_onewire, buf[2]);
+       onewire_read_block(sc->sc_onewire, &buf[3], DS2423_COUNTER_BUFSZ-3);
+
+       crc = onewire_crc16(buf, DS2423_COUNTER_BUFSZ-2);
+       crc ^= buf[DS2423_COUNTER_BUF_CRC]
+               | (buf[DS2423_COUNTER_BUF_CRC+1] << 8);
+       if ( crc != 0xffff) {
                printf("%s: invalid CRC\n", sc->sc_dev.dv_xname);
                if (bank == DS2423_COUNTER_BANK_A) {
                        sc->sc_counterA.value = 0;
                        sc->sc_counterA.status = SENSOR_S_UNKNOWN;
                        sc->sc_counterA.flags |= SENSOR_FUNKNOWN;
-               }
-               else
-               {
+               } else {
                        sc->sc_counterB.value = 0;
                        sc->sc_counterB.status = SENSOR_S_UNKNOWN;
                        sc->sc_counterB.flags |= SENSOR_FUNKNOWN;
                }
-       }
-       else
-       {
-               if (bank == DS2423_COUNTER_BANK_A)
-               {
+       } else {
+               counter = buf[DS2423_COUNTER_BUF_COUNTER]
+                       | (buf[DS2423_COUNTER_BUF_COUNTER+1] << 8)
+                       | (buf[DS2423_COUNTER_BUF_COUNTER+2] << 16)
+                       | (buf[DS2423_COUNTER_BUF_COUNTER+3] << 24);
+               if (bank == DS2423_COUNTER_BANK_A) {
                        sc->sc_counterA.value = counter;
                        sc->sc_counterA.status = SENSOR_S_UNSPEC;
                        sc->sc_counterA.flags &= ~SENSOR_FUNKNOWN;
-               }
-               else
-               {
+               } else {
                        sc->sc_counterB.value = counter;
                        sc->sc_counterB.status = SENSOR_S_UNSPEC;
                        sc->sc_counterB.flags &= ~SENSOR_FUNKNOWN;
                }
        }
+
        onewire_reset(sc->sc_onewire);
+       free(buf, M_DEVBUF);
 
 done:
        onewire_unlock(sc->sc_onewire);