nvram driver for i386 through /dev/nvram

currently read-only

ok grange@, marius@

6 files changed, 248 insertions, 4 deletions

diff --git a/etc/etc.i386/MAKEDEV.md b/etc/etc.i386/MAKEDEV.md
index b8935c7634a..246531eabd1 100644
--- a/etc/etc.i386/MAKEDEV.md
+++ b/etc/etc.i386/MAKEDEV.md
@@ -1,5 +1,5 @@
 vers(__file__,
-	{-$OpenBSD: MAKEDEV.md,v 1.27 2004/09/06 10:06:05 deraadt Exp $-},
+	{-$OpenBSD: MAKEDEV.md,v 1.28 2004/10/03 21:28:34 jcs Exp $-},
 etc.MACHINE)dnl
 dnl
 dnl Copyright (c) 2001-2004 Todd T. Fries <todd@OpenBSD.org>
@@ -17,6 +17,8 @@ dnl ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 dnl OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 dnl
 dnl
+__devitem(nvram, nvram, NVRAM access)dnl
+_mkdev(nvram, nvram, {-M nvram c major_nvram_c 0 440 kmem-})dnl
 _TITLE(make)
 _DEV(all)
 _DEV(ramdisk)
@@ -76,6 +78,7 @@ _DEV(iop, 75)
 _DEV(joy, 26)
 _DEV(lkm, 28)
 _DEV(music, 53)
+_DEV(nvram, 84)
 _DEV(pci, 72)
 _DEV(pctr, 46)
 _DEV(pf, 73)
@@ -127,6 +130,7 @@ target(all, vnd, 0, 1, 2, 3)dnl
 target(all, ccd, 0, 1, 2, 3)dnl
 target(all, bktr, 0)dnl
 target(all, gpio, 0, 1, 2)dnl
+target(all, nvram)dnl
 target(ramd, tty0, 0, 1, 2, 3)dnl
 twrget(ramd, wsdisp, ttyC, 0)dnl
 target(ramd, wt, 0)dnl
diff --git a/share/man/man4/man4.i386/nvram.4 b/share/man/man4/man4.i386/nvram.4
new file mode 100644
index 00000000000..c131dc1cfda
--- /dev/null
+++ b/share/man/man4/man4.i386/nvram.4
@@ -0,0 +1,63 @@
+.\"	$OpenBSD: nvram.4,v 1.1 2004/10/03 21:28:34 jcs Exp $
+.\"
+.\" Copyright 2004 Joshua Stein <jcs@openbsd.org>
+.\" 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.
+.\" 
+.\" 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.
+.\"
+.Dd October 3, 2004
+.Dt NVRAM 4 i386
+.Os
+.Sh NAME
+.Nm nvram
+.Nd driver for reading PC NVRAM contents
+.Sh SYNOPSIS
+.Cd "pseudo-device nvram 1"
+.Sh DESCRIPTION
+The
+.Nm
+device provides read-only access to the non-volatile memory contained in the
+MC146818 real-time clock.
+.Pp
+This data is provided as a seekable character device,
+.Pa /dev/nvram .
+Checksums of the NVRAM contents are calculated over bytes 2 to 31 and stored
+in byte 32.
+A valid checksum is required for the driver to initialize.
+.Pp
+Only one process may have this device open at any given time;
+.Xr open 2
+and
+.Xr close 2
+are used to lock and relinquish it.
+An attempt to
+.Fn open
+when another process has the device locked will return \-1 with an
+.Er EBUSY
+error indication.
+.Sh FILES
+.Bl -tag -width /dev/nvram
+.It Pa /dev/nvram
+.El
+.Sh HISTORY
+.Nm
+support was originally included in
+.Ox 3.7 .
diff --git a/sys/arch/i386/conf/GENERIC b/sys/arch/i386/conf/GENERIC
index a71ca96fd60..592a73fb8d5 100644
--- a/sys/arch/i386/conf/GENERIC
+++ b/sys/arch/i386/conf/GENERIC
@@ -1,4 +1,4 @@
-#	$OpenBSD: GENERIC,v 1.378 2004/09/16 10:37:21 grange Exp $
+#	$OpenBSD: GENERIC,v 1.379 2004/10/03 21:28:34 jcs Exp $
 #
 #	GENERIC -- everything that's currently supported
 #
@@ -569,6 +569,7 @@ scsibus* at ioprbs?
 
 pseudo-device	pctr		1
 pseudo-device	mtrr		1	# Memory range attributes control
+pseudo-device	nvram		1
 pseudo-device	sequencer	1
 #pseudo-device	raid		4	# RAIDframe disk driver
 pseudo-device	bio		1	# ioctl multiplexing device
diff --git a/sys/arch/i386/conf/files.i386 b/sys/arch/i386/conf/files.i386
index 0492169db7d..a2ab778cb38 100644
--- a/sys/arch/i386/conf/files.i386
+++ b/sys/arch/i386/conf/files.i386
@@ -1,4 +1,4 @@
-#	$OpenBSD: files.i386,v 1.128 2004/09/16 09:14:03 mickey Exp $
+#	$OpenBSD: files.i386,v 1.129 2004/10/03 21:28:34 jcs Exp $
 #
 # new style config file for i386 architecture
 #
@@ -218,6 +218,9 @@ file	arch/i386/i386/pctr.c		pctr needs-flag
 pseudo-device	mtrr
 file 	arch/i386/i386/mtrr.c		mtrr needs-flag
 
+pseudo-device	nvram
+file	arch/i386/i386/nvram.c	nvram needs-flag
+
 #
 # EISA-only drivers
 #
diff --git a/sys/arch/i386/i386/conf.c b/sys/arch/i386/i386/conf.c
index 20f4b26245c..38072585d96 100644
--- a/sys/arch/i386/i386/conf.c
+++ b/sys/arch/i386/i386/conf.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: conf.c,v 1.108 2004/06/03 18:13:13 grange Exp $	*/
+/*	$OpenBSD: conf.c,v 1.109 2004/10/03 21:28:34 jcs Exp $	*/
 /*	$NetBSD: conf.c,v 1.75 1996/05/03 19:40:20 christos Exp $	*/
 
 /*
@@ -120,6 +120,13 @@ int	nblkdev = sizeof(bdevsw) / sizeof(bdevsw[0]);
 	(dev_type_write((*))) enodev, dev_init(c,n,ioctl), \
 	(dev_type_stop((*))) enodev, 0, seltrue, (dev_type_mmap((*))) enodev }
 
+/* open, close, read */
+#define cdev_nvram_init(c,n) { \
+	dev_init(c,n,open), dev_init(c,n,close), dev_init(c,n,read), \
+	(dev_type_write((*))) enodev, (dev_type_ioctl((*))) enodev, \
+	(dev_type_stop((*))) enodev, 0, seltrue, \
+	(dev_type_mmap((*))) enodev, 0 }
+
 
 #define	mmread	mmrw
 #define	mmwrite	mmrw
@@ -184,6 +191,8 @@ cdev_decl(wdt);
 cdev_decl(cztty);
 #include "radio.h"
 #include "gpr.h"
+#include "nvram.h"
+cdev_decl(nvram);
 
 /* XXX -- this needs to be supported by config(8)! */
 #if (NCOM > 0) && (NPCCOM > 0)
@@ -314,6 +323,7 @@ struct cdevsw	cdevsw[] =
 	cdev_ptm_init(NPTY,ptm),	/* 81: pseudo-tty ptm device */
 	cdev_hotplug_init(NHOTPLUG,hotplug), /* 82: devices hot plugging */
 	cdev_gpio_init(NGPIO,gpio),	/* 83: GPIO interface */
+	cdev_nvram_init(NNVRAM,nvram),	/* 84: NVRAM interface */
 };
 int	nchrdev = sizeof(cdevsw) / sizeof(cdevsw[0]);
 
diff --git a/sys/arch/i386/i386/nvram.c b/sys/arch/i386/i386/nvram.c
new file mode 100644
index 00000000000..4ea95891f35
--- /dev/null
+++ b/sys/arch/i386/i386/nvram.c
@@ -0,0 +1,163 @@
+/*	$OpenBSD: nvram.c,v 1.1 2004/10/03 21:28:34 jcs Exp $ */
+
+/*
+ * Copyright (c) 2004 Joshua Stein <jcs@openbsd.org>
+ * 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.
+ *
+ * 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.
+ */
+
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/uio.h>
+#include <sys/fcntl.h>
+#include <sys/conf.h>
+
+#include <dev/ic/mc146818reg.h>
+#include <i386/isa/nvram.h>
+
+/* checksum is calculated over bytes 2 to 31 and stored in byte 32 */
+#define NVRAM_CSUM_START	(MC_NVRAM_START + 2)
+#define NVRAM_CSUM_END		(MC_NVRAM_START + 31)
+#define NVRAM_CSUM_LOC		(MC_NVRAM_START + 32)
+
+#define NVRAM_SIZE		(128 - MC_NVRAM_START)
+
+/* #define NVRAM_DEBUG 1 */
+
+void nvramattach(int);
+
+int nvramopen(dev_t dev, int flag, int mode, struct proc *p);
+int nvramclose(dev_t dev, int flag, int mode, struct proc *p);
+int nvramread(dev_t dev, struct uio *uio, int flags);
+
+int nvram_csum_valid(void);
+int nvram_get_byte(int byteno);
+
+static int nvram_opened;
+static int nvram_initialized;
+
+void
+nvramattach(int num)
+{
+	if (num > 1)
+		return;
+
+	if (nvram_initialized || nvram_csum_valid()) {
+#ifdef NVRAM_DEBUG
+		printf("nvram: initialized\n");
+#endif NVRAM_DEBUG
+
+		nvram_initialized = 1;
+		nvram_opened = 0;
+	} else
+		printf("nvram: invalid checksum\n");
+}
+
+int
+nvramopen(dev_t dev, int flag, int mode, struct proc *p)
+{
+	/* TODO: re-calc checksum on every open? */
+
+	if ((minor(dev) != 0) || (!nvram_initialized))
+		return (ENXIO);
+
+	if (nvram_opened)
+		return (EBUSY);
+
+	if ((flag & FWRITE))
+		return (EPERM);
+
+	nvram_opened = 1;
+
+	return (0);
+}
+
+int
+nvramclose(dev_t dev, int flag, int mode, struct proc *p)
+{
+	nvram_opened = 0;
+
+	return (0);
+}
+
+int
+nvramread(dev_t dev, struct uio *uio, int flags)
+{
+	u_char buf[NVRAM_SIZE];
+	u_int pos = uio->uio_offset;
+	u_char *tmp;
+	int count = min(sizeof(buf), uio->uio_resid);
+	int ret;
+
+	if (!nvram_initialized)
+		return (ENXIO);
+
+	if (uio->uio_resid == 0)
+		return (0);
+
+#ifdef NVRAM_DEBUG
+	printf("attempting to read %d bytes at offset %d\n", count, pos);
+#endif
+
+	for (tmp = buf; count-- > 0 && pos < NVRAM_SIZE; ++pos, ++tmp)
+		*tmp = nvram_get_byte(pos);
+
+#ifdef NVRAM_DEBUG
+	printf("nvramread read %d bytes (%s)\n", (tmp - buf), tmp);
+#endif
+
+	ret = uiomove((caddr_t)buf, (tmp - buf), uio);
+
+	uio->uio_offset += uio->uio_resid;
+
+	return (ret);
+}
+
+int
+nvram_get_byte(int byteno)
+{
+	if (!nvram_initialized)
+		return (ENXIO);
+
+	return (mc146818_read(NULL, byteno + MC_NVRAM_START) & 0xff);
+}
+
+int
+nvram_csum_valid()
+{
+	u_short csum = 0;
+	u_short csumexpect;
+	int nreg;
+
+	for (nreg = NVRAM_CSUM_START; nreg <= NVRAM_CSUM_END; nreg++)
+		csum += mc146818_read(NULL, nreg);
+
+	csumexpect = mc146818_read(NULL, NVRAM_CSUM_LOC) << 8 |
+	    mc146818_read(NULL, NVRAM_CSUM_LOC + 1);
+
+#ifdef NVRAM_DEBUG
+	printf("nvram: checksum is %x, expecting %x\n", (csum & 0xffff),
+		csumexpect);
+#endif
+
+	return ((csum & 0xffff) == csumexpect);
+}