spdmem_i2c.c revision 1.15
1/* $NetBSD: spdmem_i2c.c,v 1.15 2018/06/16 21:22:13 thorpej Exp $ */ 2 3/* 4 * Copyright (c) 2007 Nicolas Joly 5 * Copyright (c) 2007 Paul Goyette 6 * Copyright (c) 2007 Tobias Nygren 7 * Copyright (c) 2015 Michael van Elst 8 * All rights reserved. 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 * 3. The name of the author may not be used to endorse or promote products 19 * derived from this software without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS 22 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 23 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 24 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 25 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 26 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 27 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 28 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 29 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 30 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 31 * POSSIBILITY OF SUCH DAMAGE. 32 */ 33 34/* 35 * Serial Presence Detect (SPD) memory identification 36 * 37 * JEDEC standard No. 21-C 38 * JEDEC document 4_01_06R24 39 * - Definitions of the EE1004-v 4 Kbit Serial Presence Detect EEPROM [...] 40 */ 41 42#include <sys/cdefs.h> 43__KERNEL_RCSID(0, "$NetBSD: spdmem_i2c.c,v 1.15 2018/06/16 21:22:13 thorpej Exp $"); 44 45#include <sys/param.h> 46#include <sys/device.h> 47#include <sys/endian.h> 48#include <sys/module.h> 49#include <sys/sysctl.h> 50#include <machine/bswap.h> 51 52#include <dev/i2c/i2cvar.h> 53#include <dev/ic/spdmemreg.h> 54#include <dev/ic/spdmemvar.h> 55 56/* Constants for matching i2c bus address */ 57#define SPDMEM_I2C_ADDRMASK 0xfff8 58#define SPDMEM_I2C_ADDR 0x50 59#define SPDCTL_I2C_ADDR 0x30 60 61/* set write protection */ 62#define SPDCTL_SWP0 (SPDCTL_I2C_ADDR + 1) 63#define SPDCTL_SWP1 (SPDCTL_I2C_ADDR + 4) 64#define SPDCTL_SWP2 (SPDCTL_I2C_ADDR + 5) 65#define SPDCTL_SWP3 (SPDCTL_I2C_ADDR + 0) 66 67/* clear write protections */ 68#define SPDCTL_CWP (SPDCTL_I2C_ADDR + 3) 69 70/* read protection status */ 71#define SPDCTL_RPS0 (SPDCTL_I2C_ADDR + 1) 72#define SPDCTL_RPS1 (SPDCTL_I2C_ADDR + 4) 73#define SPDCTL_RPS2 (SPDCTL_I2C_ADDR + 5) 74#define SPDCTL_RPS3 (SPDCTL_I2C_ADDR + 0) 75 76/* select page address */ 77#define SPDCTL_SPA0 (SPDCTL_I2C_ADDR + 6) 78#define SPDCTL_SPA1 (SPDCTL_I2C_ADDR + 7) 79 80/* read page address */ 81#define SPDCTL_RPA (SPDCTL_I2C_ADDR + 6) 82 83struct spdmem_i2c_softc { 84 struct spdmem_softc sc_base; 85 i2c_tag_t sc_tag; 86 i2c_addr_t sc_addr; /* EEPROM */ 87 i2c_addr_t sc_page0; 88 i2c_addr_t sc_page1; 89}; 90 91static int spdmem_reset_page(struct spdmem_i2c_softc *); 92static int spdmem_i2c_match(device_t, cfdata_t, void *); 93static void spdmem_i2c_attach(device_t, device_t, void *); 94static int spdmem_i2c_detach(device_t, int); 95 96CFATTACH_DECL_NEW(spdmem_iic, sizeof(struct spdmem_i2c_softc), 97 spdmem_i2c_match, spdmem_i2c_attach, spdmem_i2c_detach, NULL); 98 99static int spdmem_i2c_read(struct spdmem_softc *, uint16_t, uint8_t *); 100 101static int 102spdmem_reset_page(struct spdmem_i2c_softc *sc) 103{ 104 uint8_t reg, byte0, byte2; 105 static uint8_t dummy = 0; 106 int rv; 107 108 reg = 0; 109 110 iic_acquire_bus(sc->sc_tag, 0); 111 112 /* 113 * Try to read byte 0 and 2. If it failed, it's not spdmem or a device 114 * doesn't exist at the address. 115 */ 116 rv = iic_exec(sc->sc_tag, I2C_OP_READ_WITH_STOP, sc->sc_addr, ®, 1, 117 &byte0, 1, I2C_F_POLL); 118 rv |= iic_exec(sc->sc_tag, I2C_OP_READ_WITH_STOP, sc->sc_addr, ®, 1, 119 &byte2, 1, I2C_F_POLL); 120 if (rv != 0) 121 goto error; 122 123 /* 124 * Quirk for BIOSes that leave page 1 of a 4kbit EEPROM selected. 125 * 126 * byte0 is the length, byte2 is the memory type. Both of them should 127 * not be zero. If zero, the current page might be 1 (DDR4 and newer). 128 * If page 1 is selected, offset 0 can be 0 (Module Characteristics 129 * (Energy backup is not available)) and also offset 2 can be 0 130 * (Megabytes, and a part of Capacity digits). 131 * 132 * Note: The encoding of byte0 is vary in memory type, so we check 133 * just with zero to be simple. 134 * 135 * Try to see if we are not at page 0. If it's not, select page 0. 136 */ 137 if ((byte0 == 0) || (byte2 == 0)) { 138 /* 139 * Note that SDCTL_RPA is the same as sc->sc_page0(SPDCTL_SPA0) 140 * Write is SPA0, read is RPA. 141 * 142 * This call returns 0 on page 0 and returns -1 on page 1. 143 * I don't know whether our icc_exec()'s API is good or not. 144 */ 145 rv = iic_exec(sc->sc_tag, I2C_OP_READ_WITH_STOP, sc->sc_page0, 146 ®, 1, &dummy, 1, I2C_F_POLL); 147 if (rv != 0) { 148 /* 149 * The possibilities are: 150 * a) page 1 is selected. 151 * b) The device doesn't support page select and 152 * it's not a SPD ROM. 153 * Is there no way to distinguish them now? 154 */ 155 rv = iic_exec(sc->sc_tag, I2C_OP_WRITE_WITH_STOP, 156 sc->sc_page0, ®, 1, &dummy, 1, I2C_F_POLL); 157 if (rv == 0) { 158 aprint_debug("Page 1 was selected. Page 0 is " 159 "selected now.\n"); 160 } else { 161 aprint_debug("Failed to select page 0. This " 162 "device isn't SPD ROM\n"); 163 } 164 } else { 165 /* This device isn't SPD ROM */ 166 rv = -1; 167 } 168 } 169error: 170 iic_release_bus(sc->sc_tag, 0); 171 172 return rv; 173} 174 175static int 176spdmem_i2c_match(device_t parent, cfdata_t match, void *aux) 177{ 178 struct i2c_attach_args *ia = aux; 179 struct spdmem_i2c_softc sc; 180 181 /* 182 * XXXJRT 183 * Should do this with "compatible" strings. There are also 184 * other problems with this "match" routine. Specifically, if 185 * we are doing direct-config, we know the device is already 186 * there aren't do need to probe. I'll leave the logic for 187 * now and let someone who knows better clean it later. 188 */ 189 190 if (ia->ia_name) { 191 /* add other names as we find more firmware variations */ 192 if (strcmp(ia->ia_name, "dimm-spd") && 193 strcmp(ia->ia_name, "dimm")) 194 return 0; 195 } 196 197 /* only do this lame test when not using direct config */ 198 if (ia->ia_name == NULL) { 199 if ((ia->ia_addr & SPDMEM_I2C_ADDRMASK) != SPDMEM_I2C_ADDR) 200 return 0; 201 } 202 203 sc.sc_tag = ia->ia_tag; 204 sc.sc_addr = ia->ia_addr; 205 sc.sc_page0 = SPDCTL_SPA0; 206 sc.sc_page1 = SPDCTL_SPA1; 207 sc.sc_base.sc_read = spdmem_i2c_read; 208 209 /* Check the bank and reset to the page 0 */ 210 if (spdmem_reset_page(&sc) != 0) 211 return 0; 212 213 if (spdmem_common_probe(&sc.sc_base)) { 214 return ia->ia_name ? I2C_MATCH_DIRECT_SPECIFIC 215 : I2C_MATCH_ADDRESS_AND_PROBE; 216 } 217 return 0; 218} 219 220static void 221spdmem_i2c_attach(device_t parent, device_t self, void *aux) 222{ 223 struct spdmem_i2c_softc *sc = device_private(self); 224 struct i2c_attach_args *ia = aux; 225 226 sc->sc_tag = ia->ia_tag; 227 sc->sc_addr = ia->ia_addr; 228 sc->sc_page0 = SPDCTL_SPA0; 229 sc->sc_page1 = SPDCTL_SPA1; 230 sc->sc_base.sc_read = spdmem_i2c_read; 231 232 if (!pmf_device_register(self, NULL, NULL)) 233 aprint_error_dev(self, "couldn't establish power handler\n"); 234 235 spdmem_common_attach(&sc->sc_base, self); 236} 237 238static int 239spdmem_i2c_detach(device_t self, int flags) 240{ 241 struct spdmem_i2c_softc *sc = device_private(self); 242 243 pmf_device_deregister(self); 244 245 return spdmem_common_detach(&sc->sc_base, self); 246} 247 248static int 249spdmem_i2c_read(struct spdmem_softc *softc, uint16_t addr, uint8_t *val) 250{ 251 uint8_t reg; 252 struct spdmem_i2c_softc *sc = (struct spdmem_i2c_softc *)softc; 253 static uint8_t dummy = 0; 254 int rv; 255 256 reg = addr & 0xff; 257 258 iic_acquire_bus(sc->sc_tag, 0); 259 260 if (addr & 0x100) { 261 rv = iic_exec(sc->sc_tag, I2C_OP_WRITE_WITH_STOP, sc->sc_page1, 262 &dummy, 1, &dummy, 1, I2C_F_POLL); 263 rv |= iic_exec(sc->sc_tag, I2C_OP_READ_WITH_STOP, sc->sc_addr, 264 ®, 1, val, 1, I2C_F_POLL); 265 rv |= iic_exec(sc->sc_tag, I2C_OP_WRITE_WITH_STOP, 266 sc->sc_page0, &dummy, 1, &dummy, 1, I2C_F_POLL); 267 } else { 268 rv = iic_exec(sc->sc_tag, I2C_OP_READ_WITH_STOP, sc->sc_addr, 269 ®, 1, val, 1, I2C_F_POLL); 270 } 271 272 iic_release_bus(sc->sc_tag, 0); 273 274 return rv; 275} 276 277MODULE(MODULE_CLASS_DRIVER, spdmem, "i2cexec"); 278 279#ifdef _MODULE 280#include "ioconf.c" 281#endif 282 283static int 284spdmem_modcmd(modcmd_t cmd, void *opaque) 285{ 286 int error = 0; 287#ifdef _MODULE 288 static struct sysctllog *spdmem_sysctl_clog; 289#endif 290 291 switch (cmd) { 292 case MODULE_CMD_INIT: 293#ifdef _MODULE 294 error = config_init_component(cfdriver_ioconf_spdmem, 295 cfattach_ioconf_spdmem, cfdata_ioconf_spdmem); 296#endif 297 return error; 298 case MODULE_CMD_FINI: 299#ifdef _MODULE 300 error = config_fini_component(cfdriver_ioconf_spdmem, 301 cfattach_ioconf_spdmem, cfdata_ioconf_spdmem); 302 sysctl_teardown(&spdmem_sysctl_clog); 303#endif 304 return error; 305 default: 306 return ENOTTY; 307 } 308} 309