xref: /titanic_50/usr/src/uts/common/sys/ramdisk.h (revision 84f7a9b9dca4f23b5f50edef0e59d7eb44301114)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License, Version 1.0 only
6  * (the "License").  You may not use this file except in compliance
7  * with the License.
8  *
9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10  * or http://www.opensolaris.org/os/licensing.
11  * See the License for the specific language governing permissions
12  * and limitations under the License.
13  *
14  * When distributing Covered Code, include this CDDL HEADER in each
15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16  * If applicable, add the following below this CDDL HEADER, with the
17  * fields enclosed by brackets "[]" replaced with your own identifying
18  * information: Portions Copyright [yyyy] [name of copyright owner]
19  *
20  * CDDL HEADER END
21  */
22 /*
23  * Copyright 2004 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 
27 #ifndef	_SYS_RAMDISK_H
28 #define	_SYS_RAMDISK_H
29 
30 #pragma ident	"%Z%%M%	%I%	%E% SMI"
31 
32 #include <sys/types.h>
33 #include <sys/time.h>
34 #include <sys/vtoc.h>
35 #include <sys/dkio.h>
36 #include <sys/vnode.h>
37 
38 #ifdef	__cplusplus
39 extern "C" {
40 #endif
41 
42 /*
43  * /dev names:
44  *	/dev/ramdiskctl		- control device
45  *	/dev/ramdisk/<name>	- block devices
46  *	/dev/rramdisk/<name>	- character devices
47  */
48 #define	RD_DRIVER_NAME		"ramdisk"
49 #define	RD_BLOCK_NAME		RD_DRIVER_NAME
50 #define	RD_CHAR_NAME		"r" RD_DRIVER_NAME
51 
52 #define	RD_CTL_NODE		"ctl"
53 #define	RD_CTL_NAME		RD_DRIVER_NAME RD_CTL_NODE
54 
55 /*
56  * Minor number 0 is reserved for the controlling device.  All other ramdisks
57  * are assigned minor numbers 1..rd_max_disks.  The minor number is used as
58  * an index into the 'rd_devstate' structures.
59  */
60 #define	RD_CTL_MINOR		0
61 
62 /*
63  * Maximum number of ramdisks supported by this driver.
64  */
65 #define	RD_MAX_DISKS		1024
66 
67 /*
68  * Properties exported by the driver.
69  */
70 #define	NBLOCKS_PROP_NAME	"Nblocks"
71 #define	SIZE_PROP_NAME		"Size"
72 
73 /*
74  * Strip any "ramdisk-" prefix from the name of OBP-created ramdisks.
75  */
76 #define	RD_OBP_PFXSTR		"ramdisk-"
77 #define	RD_OBP_PFXLEN		(sizeof (RD_OBP_PFXSTR) - 1)
78 
79 #define	RD_STRIP_PREFIX(newname, oldname) \
80 	{ \
81 		char	*onm = oldname; \
82 		newname = strncmp(onm, RD_OBP_PFXSTR, RD_OBP_PFXLEN) == 0 ? \
83 		    (onm + RD_OBP_PFXLEN) : onm; \
84 	}
85 
86 /*
87  * Strip any ",raw" suffix from the name of pseudo ramdisk devices.
88  */
89 #define	RD_STRIP_SUFFIX(name) \
90 	{ \
91 		char	*str = strstr((name), ",raw"); \
92 		if (str != NULL) \
93 			*str = '\0'; \
94 	}
95 
96 /*
97  * Interface between the ramdisk(7D) driver and ramdiskadm(1M).  Use is:
98  *
99  *	fd = open("/dev/ramdiskctl", O_RDWR | O_EXCL);
100  *
101  * 'ramdiskctl' must be opened exclusively. Access is controlled by permissions
102  * on the device, which is 0644 by default.  Write-access is required for the
103  * allocation and deletion of ramdisks, but only read-access is required for
104  * the remaining ioctls which simply return information.
105  *
106  * ioctl usage:
107  *
108  *	struct rd_ioctl ri;
109  *
110  *	strlcpy(ri.ri_name, "somediskname", sizeof (ri.ri_name));
111  *	ri.ri_size = somedisksize;
112  *	ioctl(fd, RD_CREATE_DISK, &ri);
113  *
114  *	strlcpy(ri.ri_name, "somediskname", sizeof (ri.ri_name));
115  *	ioctl(fd, RD_DELETE_DISK, &ri);
116  *
117  * (only ramdisks created using the RD_CREATE_DISK ioctl can be deleted
118  *  by the RD_DELETE_DISK ioctl).
119  *
120  * Note that these ioctls are completely private, and only for the use of
121  * ramdiskadm(1M).
122  */
123 #define	RD_IOC_BASE		(('R' << 16) | ('D' << 8))
124 
125 #define	RD_CREATE_DISK		(RD_IOC_BASE | 0x01)
126 #define	RD_DELETE_DISK		(RD_IOC_BASE | 0x02)
127 
128 #define	RD_NAME_LEN		32	/* Max length of ramdisk name */
129 #define	RD_NAME_PAD		7	/* Pad ri_name to 8-bytes */
130 
131 struct rd_ioctl {
132 	char		ri_name[RD_NAME_LEN + 1];
133 	char		_ri_pad[RD_NAME_PAD];
134 	uint64_t	ri_size;
135 };
136 
137 #if defined(_KERNEL)
138 
139 /*
140  * We limit the maximum number of active ramdisk devices to 32, tuneable
141  * up to a maximum of 1023.  Minor 0 is always reserved for the controlling
142  * device.  You can change this by setting a value for 'max_disks' in
143  * ramdisk.conf.
144  */
145 #define	RD_DFLT_DISKS	32
146 
147 /*
148  * The maximum amount of memory that can be consumed before starving the
149  * kernel depends loosely on the number of cpus, the speed of those cpus,
150  * and other hardware characteristics, and is thus highly machine-dependent.
151  * The default value of 'rd_percent_physmem' is 25% of physical memory,
152  * but this can be changed by setting a value for 'percent_physmem' in
153  * ramdisk.conf.
154  */
155 #define	RD_DEFAULT_PERCENT_PHYSMEM	25
156 
157 /*
158  * Maximum size of a physical transfer?
159  */
160 #define	RD_DEFAULT_MAXPHYS	(63 * 1024)	/* '126b' */
161 
162 /*
163  * A real OBP-created ramdisk consists of one or more physical address
164  * ranges; these are described by the 'existing' property, whose value
165  * is a (corresponding) number of {phys,size} pairs.
166  */
167 #define	RD_EXISTING_PROP_NAME	"existing"
168 
169 typedef struct {
170 	uint64_t	phys;			/* Phys addr of range */
171 	uint64_t	size;			/* Size of range */
172 } rd_existing_t;
173 
174 
175 #define	RD_WINDOW_NOT_MAPPED	1	/* Valid window is on page boundary */
176 
177 /*
178  * The entire state of each ramdisk device.  The rd_dip field will reference
179  * the actual devinfo for real OBP-created ramdisks, or the generic devinfo
180  * 'rd_dip' for pseudo ramdisk devices.
181  */
182 typedef struct rd_devstate {
183 	kmutex_t	rd_device_lock;		/* Per device lock */
184 	char		rd_name[RD_NAME_LEN + 1];
185 	dev_info_t	*rd_dip;		/* My devinfo handle */
186 	minor_t		rd_minor;		/* Full minor number */
187 	size_t		rd_size;		/* Size in bytes */
188 	/*
189 	 * {rd_nexisting, rd_existing} and {rd_npages, rd_ppa} are
190 	 * mutually exclusive; the former describe an OBP-created
191 	 * ramdisk, the latter a 'pseudo' ramdisk.
192 	 */
193 	uint_t		rd_nexisting;		/* # 'existing' structs */
194 	rd_existing_t	*rd_existing;
195 	pgcnt_t		rd_npages;		/* # physical pages */
196 	page_t		**rd_ppa;
197 	/*
198 	 * Fields describing a virtual window onto the physical ramdisk,
199 	 * giving the offset within the ramdisk of the window, its size,
200 	 * and its virtual address (in the kernel heap).
201 	 */
202 	offset_t	rd_window_base;
203 	uint64_t	rd_window_size;
204 	caddr_t		rd_window_virt;
205 	/*
206 	 * Fields to count opens/closes of the ramdisk.
207 	 */
208 	uint32_t	rd_blk_open;
209 	uint32_t	rd_chr_open;
210 	uint32_t	rd_lyr_open_cnt;
211 	/*
212 	 * Fields to maintain a faked geometry of the disk.
213 	 */
214 	struct dk_geom	rd_dkg;
215 	struct vtoc	rd_vtoc;
216 	struct dk_cinfo	rd_ci;
217 	/*
218 	 * Kstat stuff.
219 	 */
220 	kmutex_t	rd_kstat_lock;
221 	kstat_t		*rd_kstat;
222 } rd_devstate_t;
223 
224 extern int	is_pseudo_device(dev_info_t *);
225 
226 #endif
227 
228 #ifdef	__cplusplus
229 }
230 #endif
231 
232 #endif	/* _SYS_RAMDISK_H */
233