xref: /titanic_41/usr/src/uts/common/sys/ramdisk.h (revision 986fd29a0dc13f7608ef7f508f6e700bd7bc2720)
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 (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 /*
22  * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
23  * Use is subject to license terms.
24  */
25 
26 #ifndef	_SYS_RAMDISK_H
27 #define	_SYS_RAMDISK_H
28 
29 #pragma ident	"%Z%%M%	%I%	%E% SMI"
30 
31 #include <sys/types.h>
32 #include <sys/time.h>
33 #include <sys/vtoc.h>
34 #include <sys/dkio.h>
35 #include <sys/vnode.h>
36 
37 #ifdef	__cplusplus
38 extern "C" {
39 #endif
40 
41 /*
42  * /dev names:
43  *	/dev/ramdiskctl		- control device
44  *	/dev/ramdisk/<name>	- block devices
45  *	/dev/rramdisk/<name>	- character devices
46  */
47 #define	RD_DRIVER_NAME		"ramdisk"
48 #define	RD_BLOCK_NAME		RD_DRIVER_NAME
49 #define	RD_CHAR_NAME		"r" RD_DRIVER_NAME
50 
51 #define	RD_CTL_NODE		"ctl"
52 #define	RD_CTL_NAME		RD_DRIVER_NAME RD_CTL_NODE
53 
54 /*
55  * Minor number 0 is reserved for the controlling device.  All other ramdisks
56  * are assigned minor numbers 1..rd_max_disks.  The minor number is used as
57  * an index into the 'rd_devstate' structures.
58  */
59 #define	RD_CTL_MINOR		0
60 
61 /*
62  * Maximum number of ramdisks supported by this driver.
63  */
64 #define	RD_MAX_DISKS		1024
65 
66 /*
67  * Properties exported by the driver.
68  */
69 #define	NBLOCKS_PROP_NAME	"Nblocks"
70 #define	SIZE_PROP_NAME		"Size"
71 
72 /*
73  * Strip any "ramdisk-" prefix from the name of OBP-created ramdisks.
74  */
75 #define	RD_OBP_PFXSTR		"ramdisk-"
76 #define	RD_OBP_PFXLEN		(sizeof (RD_OBP_PFXSTR) - 1)
77 
78 #define	RD_STRIP_PREFIX(newname, oldname) \
79 	{ \
80 		char	*onm = oldname; \
81 		newname = strncmp(onm, RD_OBP_PFXSTR, RD_OBP_PFXLEN) == 0 ? \
82 		    (onm + RD_OBP_PFXLEN) : onm; \
83 	}
84 
85 /*
86  * Strip any ",raw" suffix from the name of pseudo ramdisk devices.
87  */
88 #define	RD_STRIP_SUFFIX(name) \
89 	{ \
90 		char	*str = strstr((name), ",raw"); \
91 		if (str != NULL) \
92 			*str = '\0'; \
93 	}
94 
95 /*
96  * Interface between the ramdisk(7D) driver and ramdiskadm(1M).  Use is:
97  *
98  *	fd = open("/dev/ramdiskctl", O_RDWR | O_EXCL);
99  *
100  * 'ramdiskctl' must be opened exclusively. Access is controlled by permissions
101  * on the device, which is 0644 by default.  Write-access is required for the
102  * allocation and deletion of ramdisks, but only read-access is required for
103  * the remaining ioctls which simply return information.
104  *
105  * ioctl usage:
106  *
107  *	struct rd_ioctl ri;
108  *
109  *	strlcpy(ri.ri_name, "somediskname", sizeof (ri.ri_name));
110  *	ri.ri_size = somedisksize;
111  *	ioctl(fd, RD_CREATE_DISK, &ri);
112  *
113  *	strlcpy(ri.ri_name, "somediskname", sizeof (ri.ri_name));
114  *	ioctl(fd, RD_DELETE_DISK, &ri);
115  *
116  * (only ramdisks created using the RD_CREATE_DISK ioctl can be deleted
117  *  by the RD_DELETE_DISK ioctl).
118  *
119  * Note that these ioctls are completely private, and only for the use of
120  * ramdiskadm(1M).
121  */
122 #define	RD_IOC_BASE		(('R' << 16) | ('D' << 8))
123 
124 #define	RD_CREATE_DISK		(RD_IOC_BASE | 0x01)
125 #define	RD_DELETE_DISK		(RD_IOC_BASE | 0x02)
126 
127 #define	RD_NAME_LEN		32	/* Max length of ramdisk name */
128 #define	RD_NAME_PAD		7	/* Pad ri_name to 8-bytes */
129 
130 struct rd_ioctl {
131 	char		ri_name[RD_NAME_LEN + 1];
132 	char		_ri_pad[RD_NAME_PAD];
133 	uint64_t	ri_size;
134 };
135 
136 #if defined(_KERNEL)
137 
138 /*
139  * We limit the maximum number of active ramdisk devices to 32, tuneable
140  * up to a maximum of 1023.  Minor 0 is always reserved for the controlling
141  * device.  You can change this by setting a value for 'max_disks' in
142  * ramdisk.conf.
143  */
144 #define	RD_DFLT_DISKS	32
145 
146 /*
147  * The maximum amount of memory that can be consumed before starving the
148  * kernel depends loosely on the number of cpus, the speed of those cpus,
149  * and other hardware characteristics, and is thus highly machine-dependent.
150  * The default value of 'rd_percent_physmem' is 25% of physical memory,
151  * but this can be changed by setting a value for 'percent_physmem' in
152  * ramdisk.conf.
153  */
154 #define	RD_DEFAULT_PERCENT_PHYSMEM	25
155 
156 /*
157  * Maximum size of a physical transfer?
158  */
159 #define	RD_DEFAULT_MAXPHYS	(63 * 1024)	/* '126b' */
160 
161 /*
162  * A real OBP-created ramdisk consists of one or more physical address
163  * ranges; these are described by the 'existing' property, whose value
164  * is a (corresponding) number of {phys,size} pairs.
165  */
166 #define	OBP_EXISTING_PROP_NAME	"existing"
167 #define	OBP_ADDRESS_PROP_NAME	"address"
168 #define	OBP_SIZE_PROP_NAME	"size"
169 
170 #define	RD_EXISTING_PROP_NAME	"existing"	/* for x86 */
171 
172 typedef struct {
173 	uint64_t	phys;			/* Phys addr of range */
174 	uint64_t	size;			/* Size of range */
175 } rd_existing_t;
176 
177 
178 #define	RD_WINDOW_NOT_MAPPED	1	/* Valid window is on page boundary */
179 
180 /*
181  * The entire state of each ramdisk device.  The rd_dip field will reference
182  * the actual devinfo for real OBP-created ramdisks, or the generic devinfo
183  * 'rd_dip' for pseudo ramdisk devices.
184  */
185 typedef struct rd_devstate {
186 	kmutex_t	rd_device_lock;		/* Per device lock */
187 	char		rd_name[RD_NAME_LEN + 1];
188 	dev_info_t	*rd_dip;		/* My devinfo handle */
189 	minor_t		rd_minor;		/* Full minor number */
190 	size_t		rd_size;		/* Size in bytes */
191 	/*
192 	 * {rd_nexisting, rd_existing} and {rd_npages, rd_ppa} are
193 	 * mutually exclusive; the former describe an OBP-created
194 	 * ramdisk, the latter a 'pseudo' ramdisk.
195 	 */
196 	uint_t		rd_nexisting;		/* # 'existing' structs */
197 	rd_existing_t	*rd_existing;
198 	pgcnt_t		rd_npages;		/* # physical pages */
199 	page_t		**rd_ppa;
200 	/*
201 	 * Fields describing a virtual window onto the physical ramdisk,
202 	 * giving the offset within the ramdisk of the window, its size,
203 	 * and its virtual address (in the kernel heap).
204 	 */
205 	uint_t		rd_window_obp;		/* using OBP's vaddr */
206 	offset_t	rd_window_base;
207 	uint64_t	rd_window_size;
208 	caddr_t		rd_window_virt;
209 	/*
210 	 * Fields to count opens/closes of the ramdisk.
211 	 */
212 	uint32_t	rd_blk_open;
213 	uint32_t	rd_chr_open;
214 	uint32_t	rd_lyr_open_cnt;
215 	/*
216 	 * Fields to maintain a faked geometry of the disk.
217 	 */
218 	struct dk_geom	rd_dkg;
219 	struct vtoc	rd_vtoc;
220 	struct dk_cinfo	rd_ci;
221 	/*
222 	 * Kstat stuff.
223 	 */
224 	kmutex_t	rd_kstat_lock;
225 	kstat_t		*rd_kstat;
226 } rd_devstate_t;
227 
228 extern int	is_pseudo_device(dev_info_t *);
229 
230 #endif
231 
232 #ifdef	__cplusplus
233 }
234 #endif
235 
236 #endif	/* _SYS_RAMDISK_H */
237