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/* $NetBSD: eeprom.c,v 1.6 1995/05/24 20:47:41 gwr Exp $ */
/*
* Copyright (c) 1994 Gordon W. Ross
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/*
* Access functions for the EEPROM (Electrically Eraseable PROM)
* The main reason for the existence of this module is to
* handle the painful task of updating the EEPROM contents.
* After a write, it must not be touched for 10 milliseconds.
* (See the Sun-3 Architecture Manual sec. 5.9)
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/device.h>
#include <sys/conf.h>
#include <sys/buf.h>
#include <sys/malloc.h>
#include <machine/autoconf.h>
#include <machine/obio.h>
#include <machine/eeprom.h>
#define HZ 100 /* XXX */
int ee_console; /* for convenience of drivers */
static int ee_update(caddr_t buf, int off, int cnt);
static char *eeprom_va;
static int ee_busy, ee_want;
int eeprom_match __P((struct device *, void *vcf, void *args));
void eeprom_attach __P((struct device *, struct device *, void *));
struct cfdriver eepromcd = {
NULL, "eeprom", eeprom_match, eeprom_attach,
DV_DULL, sizeof(struct device), 0 };
/* Called very early by internal_configure. */
void eeprom_init()
{
eeprom_va = obio_find_mapping(OBIO_EEPROM, OBIO_EEPROM_SIZE);
ee_console = ((struct eeprom *)eeprom_va)->eeConsole;
}
int eeprom_match(parent, vcf, args)
struct device *parent;
void *vcf, *args;
{
struct cfdata *cf = vcf;
struct confargs *ca = args;
/* This driver only supports one unit. */
if (cf->cf_unit != 0)
return (0);
if (eeprom_va == NULL)
return (0);
if (ca->ca_paddr == -1)
ca->ca_paddr = OBIO_EEPROM;
return (1);
}
void eeprom_attach(parent, self, args)
struct device *parent;
struct device *self;
void *args;
{
struct confargs *ca = args;
printf("\n");
}
static int ee_take() /* Take the lock. */
{
int error = 0;
while (ee_busy) {
ee_want = 1;
error = tsleep(&ee_busy, PZERO | PCATCH, "eeprom", 0);
ee_want = 0;
if (error) /* interrupted */
goto out;
}
ee_busy = 1;
out:
return error;
}
static void ee_give() /* Give the lock. */
{
ee_busy = 0;
if (ee_want) {
ee_want = 0;
wakeup(&ee_busy);
}
}
int eeprom_uio(struct uio *uio)
{
int error;
int off; /* NOT off_t */
u_int cnt;
caddr_t va;
caddr_t buf = (caddr_t)0;
off = uio->uio_offset;
if (off >= OBIO_EEPROM_SIZE)
return (EFAULT);
cnt = uio->uio_resid;
if (cnt > (OBIO_EEPROM_SIZE - off))
cnt = (OBIO_EEPROM_SIZE - off);
if ((error = ee_take()) != 0)
return (error);
if (eeprom_va == NULL) {
error = ENXIO;
goto out;
}
va = eeprom_va;
if (uio->uio_rw != UIO_READ) {
/* Write requires a temporary buffer. */
buf = malloc(OBIO_EEPROM_SIZE, M_DEVBUF, M_WAITOK);
if (!buf) {
error = EAGAIN;
goto out;
}
va = buf;
}
if ((error = uiomove(va + off, (int)cnt, uio)) != 0)
goto out;
if (uio->uio_rw != UIO_READ)
error = ee_update(buf, off, cnt);
out:
if (buf)
free(buf, M_DEVBUF);
ee_give();
return (error);
}
/*
* Update the EEPROM from the passed buf.
*/
static int ee_update(char *buf, int off, int cnt)
{
volatile char *ep;
char *bp;
if (eeprom_va == NULL)
return (ENXIO);
ep = eeprom_va + off;
bp = buf + off;
while (cnt > 0) {
/*
* DO NOT WRITE IT UNLESS WE HAVE TO because the
* EEPROM has a limited number of write cycles.
* After some number of writes it just fails!
*/
if (*ep != *bp) {
*ep = *bp;
/*
* We have written the EEPROM, so now we must
* sleep for at least 10 milliseconds while
* holding the lock to prevent all access to
* the EEPROM while it recovers.
*/
(void)tsleep(eeprom_va, PZERO-1, "eeprom", HZ/50);
}
/* Make sure the write worked. */
if (*ep != *bp)
return (EIO);
ep++;
bp++;
cnt--;
}
return(0);
}
/*
* Read a byte out of the EEPROM. This is called from
* things like the zs driver very early to find out
* which device should be used as the console.
*/
int ee_get_byte(int off, int canwait)
{
int c = -1;
if ((off < 0) || (off >= OBIO_EEPROM_SIZE))
goto out;
if (eeprom_va == NULL)
goto out;
if (canwait) {
if (ee_take())
goto out;
} else {
if (ee_busy)
goto out;
}
c = eeprom_va[off] & 0xFF;
if (canwait)
ee_give();
out:
return c;
}
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