1 /* $NetBSD: eeprom.c,v 1.35 2024/12/20 23:52:00 tsutsui Exp $ */ 2 3 /*- 4 * Copyright (c) 1996 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Gordon W. Ross. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 29 * POSSIBILITY OF SUCH DAMAGE. 30 */ 31 32 /* 33 * Access functions for the EEPROM (Electrically Eraseable PROM) 34 * The main reason for the existence of this module is to 35 * handle the painful task of updating the EEPROM contents. 36 * After a write, it must not be touched for 10 milliseconds. 37 * (See the Sun-3 Architecture Manual sec. 5.9) 38 */ 39 40 #include <sys/cdefs.h> 41 __KERNEL_RCSID(0, "$NetBSD: eeprom.c,v 1.35 2024/12/20 23:52:00 tsutsui Exp $"); 42 43 #include <sys/param.h> 44 #include <sys/systm.h> 45 #include <sys/device.h> 46 #include <sys/conf.h> 47 #include <sys/buf.h> 48 #include <sys/kmem.h> 49 #include <sys/proc.h> 50 #include <sys/kernel.h> 51 52 #include <machine/autoconf.h> 53 #include <machine/idprom.h> 54 #include <machine/eeprom.h> 55 56 #ifndef EEPROM_SIZE 57 #define EEPROM_SIZE 0x800 58 #endif 59 60 struct eeprom *eeprom_copy; /* soft copy. */ 61 62 static int ee_update(int off, int cnt); 63 64 static uint8_t *eeprom_va; /* mapping to actual device */ 65 static int ee_size; /* size of usable part. */ 66 67 static int ee_busy, ee_want; /* serialization */ 68 69 static int eeprom_match(device_t, cfdata_t, void *); 70 static void eeprom_attach(device_t, device_t, void *); 71 72 CFATTACH_DECL_NEW(eeprom, 0, 73 eeprom_match, eeprom_attach, NULL, NULL); 74 75 static int 76 eeprom_match(device_t parent, cfdata_t cf, void *args) 77 { 78 struct confargs *ca = args; 79 80 /* This driver only supports one instance. */ 81 if (eeprom_va != NULL) 82 return 0; 83 84 if (bus_peek(ca->ca_bustype, ca->ca_paddr, 1) == -1) 85 return 0; 86 87 return 1; 88 } 89 90 static void 91 eeprom_attach(device_t parent, device_t self, void *args) 92 { 93 struct confargs *ca = args; 94 uint8_t *src, *dst, *lim; 95 96 aprint_normal("\n"); 97 #ifdef DIAGNOSTIC 98 if (sizeof(struct eeprom) != EEPROM_SIZE) 99 panic("eeprom struct wrong"); 100 #endif 101 102 ee_size = EEPROM_SIZE; 103 eeprom_va = bus_mapin(ca->ca_bustype, ca->ca_paddr, ee_size); 104 if (eeprom_va == NULL) 105 panic("%s: can't map va", __func__); 106 107 /* Keep a "soft" copy of the EEPROM to make access simpler. */ 108 eeprom_copy = kmem_alloc(ee_size, KM_SLEEP); 109 110 /* 111 * On the 3/80, do not touch the last 40 bytes! 112 * Writes there are ignored, reads show zero. 113 * Reduce ee_size and clear the last part of the 114 * soft copy. Note: ee_update obeys ee_size. 115 */ 116 if (cpu_machine_id == ID_SUN3X_80) 117 ee_size -= 40; 118 119 /* Do only byte access in the EEPROM. */ 120 src = eeprom_va; 121 dst = (uint8_t *)eeprom_copy; 122 lim = dst + ee_size; 123 124 do { 125 *dst++ = *src++; 126 } while (dst < lim); 127 128 if (ee_size < EEPROM_SIZE) { 129 /* Clear out the last part. */ 130 memset(dst, 0, (EEPROM_SIZE - ee_size)); 131 } 132 } 133 134 135 /* Take the lock. */ 136 static int 137 ee_take(void) 138 { 139 int error = 0; 140 141 while (ee_busy) { 142 ee_want = 1; 143 error = tsleep(&ee_busy, PZERO | PCATCH, "eeprom", 0); 144 ee_want = 0; 145 if (error) /* interrupted */ 146 return error; 147 } 148 ee_busy = 1; 149 return error; 150 } 151 152 /* Give the lock. */ 153 static void 154 ee_give(void) 155 { 156 ee_busy = 0; 157 if (ee_want) { 158 ee_want = 0; 159 wakeup(&ee_busy); 160 } 161 } 162 163 /* 164 * This is called by mem.c to handle /dev/eeprom 165 */ 166 int 167 eeprom_uio(struct uio *uio) 168 { 169 int cnt, error; 170 int off; /* NOT off_t */ 171 uint8_t *va; 172 173 if (eeprom_copy == NULL) 174 return ENXIO; 175 176 off = uio->uio_offset; 177 if ((off < 0) || (off > EEPROM_SIZE)) 178 return EFAULT; 179 180 cnt = uimin(uio->uio_resid, (EEPROM_SIZE - off)); 181 if (cnt == 0) 182 return 0; /* EOF */ 183 184 va = ((uint8_t *)eeprom_copy) + off; 185 error = uiomove(va, (int)cnt, uio); 186 187 /* If we wrote the rambuf, update the H/W. */ 188 if (error == 0 && (uio->uio_rw != UIO_READ)) { 189 error = ee_take(); 190 if (error == 0) 191 error = ee_update(off, cnt); 192 ee_give(); 193 } 194 195 return error; 196 } 197 198 /* 199 * Update the EEPROM from the soft copy. 200 * Other than the attach function, this is 201 * the ONLY place we touch the EEPROM H/W. 202 */ 203 static int 204 ee_update(int off, int cnt) 205 { 206 volatile uint8_t *ep; 207 uint8_t *bp; 208 int errcnt; 209 210 if (eeprom_va == NULL) 211 return (ENXIO); 212 213 /* 214 * This check is NOT redundant with the one in 215 * eeprom_uio above if we are on a 3/80 where 216 * ee_size < EEPROM_SIZE 217 */ 218 if (cnt > (ee_size - off)) 219 cnt = (ee_size - off); 220 221 bp = ((uint8_t *)eeprom_copy) + off; 222 ep = eeprom_va + off; 223 errcnt = 0; 224 225 while (cnt > 0) { 226 /* 227 * DO NOT WRITE IT UNLESS WE HAVE TO because the 228 * EEPROM has a limited number of write cycles. 229 * After some number of writes it just fails! 230 */ 231 if (*ep != *bp) { 232 *ep = *bp; 233 /* 234 * We have written the EEPROM, so now we must 235 * sleep for at least 10 milliseconds while 236 * holding the lock to prevent all access to 237 * the EEPROM while it recovers. 238 */ 239 (void)tsleep(eeprom_va, PZERO - 1, "eeprom", hz / 50); 240 } 241 /* Make sure the write worked. */ 242 if (*ep != *bp) 243 errcnt++; 244 ep++; 245 bp++; 246 cnt--; 247 } 248 return errcnt ? EIO : 0; 249 } 250
Indexes created Sun Sep 21 14:09:52 GMT 2025