271 lines
6.2 KiB
C
271 lines
6.2 KiB
C
/* $NetBSD: eeprom.c,v 1.13 1996/12/17 21:10:40 gwr Exp $ */
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/*-
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* Copyright (c) 1996 The NetBSD Foundation, Inc.
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* All rights reserved.
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*
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* This code is derived from software contributed to The NetBSD Foundation
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* by Gordon W. Ross.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the NetBSD
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* Foundation, Inc. and its contributors.
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* 4. Neither the name of The NetBSD Foundation nor the names of its
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* contributors may be used to endorse or promote products derived
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* from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
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* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE
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* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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/*
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* Access functions for the EEPROM (Electrically Eraseable PROM)
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* The main reason for the existence of this module is to
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* handle the painful task of updating the EEPROM contents.
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* After a write, it must not be touched for 10 milliseconds.
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* (See the Sun-3 Architecture Manual sec. 5.9)
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*
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* XXX: Should just keep a copy of the EEPROM contents in RAM
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* (read it once at init time) to avoid the eeprom_uio hair.
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*/
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/device.h>
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#include <sys/conf.h>
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#include <sys/buf.h>
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#include <sys/malloc.h>
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#include <sys/proc.h>
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#include <machine/autoconf.h>
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#include <machine/obio.h>
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#include <machine/eeprom.h>
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#define HZ 100 /* XXX */
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int ee_console; /* for convenience of drivers */
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static int ee_update(caddr_t buf, int off, int cnt);
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static char *eeprom_va;
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static int ee_busy, ee_want;
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static int eeprom_match __P((struct device *, struct cfdata *, void *));
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static void eeprom_attach __P((struct device *, struct device *, void *));
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struct cfattach eeprom_ca = {
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sizeof(struct device), eeprom_match, eeprom_attach
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};
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struct cfdriver eeprom_cd = {
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NULL, "eeprom", DV_DULL
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};
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/* Called very early by internal_configure. */
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void eeprom_init()
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{
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eeprom_va = obio_find_mapping(OBIO_EEPROM, OBIO_EEPROM_SIZE);
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ee_console = ((struct eeprom *)eeprom_va)->eeConsole;
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}
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static int
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eeprom_match(parent, cf, args)
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struct device *parent;
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struct cfdata *cf;
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void *args;
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{
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struct confargs *ca = args;
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/* This driver only supports one unit. */
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if (cf->cf_unit != 0)
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return (0);
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/* Validate the given address. */
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if (ca->ca_paddr != OBIO_EEPROM)
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return (0);
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if (eeprom_va == NULL)
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return (0);
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return (1);
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}
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static void
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eeprom_attach(parent, self, args)
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struct device *parent;
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struct device *self;
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void *args;
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{
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printf("\n");
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}
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/* Take the lock. */
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static int
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ee_take __P((void))
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{
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int error = 0;
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while (ee_busy) {
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ee_want = 1;
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error = tsleep(&ee_busy, PZERO | PCATCH, "eeprom", 0);
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ee_want = 0;
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if (error) /* interrupted */
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goto out;
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}
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ee_busy = 1;
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out:
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return error;
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}
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/* Give the lock. */
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static void
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ee_give __P((void))
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{
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ee_busy = 0;
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if (ee_want) {
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ee_want = 0;
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wakeup(&ee_busy);
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}
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}
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/*
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* XXX - Just keep a soft copy of the eeprom?
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*/
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int
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eeprom_uio(struct uio *uio)
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{
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int error;
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int off; /* NOT off_t */
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u_int cnt;
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caddr_t va;
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caddr_t buf = (caddr_t)0;
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off = uio->uio_offset;
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if (off >= OBIO_EEPROM_SIZE)
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return (EFAULT);
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cnt = uio->uio_resid;
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if (cnt > (OBIO_EEPROM_SIZE - off))
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cnt = (OBIO_EEPROM_SIZE - off);
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if ((error = ee_take()) != 0)
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return (error);
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if (eeprom_va == NULL) {
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error = ENXIO;
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goto out;
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}
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va = eeprom_va;
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if (uio->uio_rw != UIO_READ) {
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/* Write requires a temporary buffer. */
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buf = malloc(OBIO_EEPROM_SIZE, M_DEVBUF, M_WAITOK);
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if (!buf) {
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error = EAGAIN;
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goto out;
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}
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va = buf;
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}
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if ((error = uiomove(va + off, (int)cnt, uio)) != 0)
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goto out;
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if (uio->uio_rw != UIO_READ)
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error = ee_update(buf, off, cnt);
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out:
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if (buf)
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free(buf, M_DEVBUF);
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ee_give();
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return (error);
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}
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/*
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* Update the EEPROM from the passed buf.
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*/
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static int
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ee_update(char *buf, int off, int cnt)
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{
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volatile char *ep;
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char *bp;
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if (eeprom_va == NULL)
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return (ENXIO);
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ep = eeprom_va + off;
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bp = buf + off;
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while (cnt > 0) {
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/*
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* DO NOT WRITE IT UNLESS WE HAVE TO because the
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* EEPROM has a limited number of write cycles.
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* After some number of writes it just fails!
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*/
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if (*ep != *bp) {
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*ep = *bp;
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/*
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* We have written the EEPROM, so now we must
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* sleep for at least 10 milliseconds while
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* holding the lock to prevent all access to
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* the EEPROM while it recovers.
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*/
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(void)tsleep(eeprom_va, PZERO-1, "eeprom", HZ/50);
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}
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/* Make sure the write worked. */
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if (*ep != *bp)
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return (EIO);
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ep++;
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bp++;
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cnt--;
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}
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return(0);
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}
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/*
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* Read a byte out of the EEPROM. This is called from
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* things like the zs driver very early to find out
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* which device should be used as the console.
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*/
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int ee_get_byte(int off, int canwait)
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{
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int c = -1;
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if ((off < 0) || (off >= OBIO_EEPROM_SIZE))
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goto out;
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if (eeprom_va == NULL)
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goto out;
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if (canwait) {
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if (ee_take())
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goto out;
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} else {
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if (ee_busy)
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goto out;
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}
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c = eeprom_va[off] & 0xFF;
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if (canwait)
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ee_give();
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out:
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return c;
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}
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