1 /* $NetBSD: spdmem_i2c.c,v 1.26 2022/03/30 00:06:50 pgoyette 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 1.26 2022/03/30 00:06:50 pgoyette 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
83 struct 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
91 static int spdmem_reset_page(struct spdmem_i2c_softc *);
92 static int spdmem_i2c_match(device_t, cfdata_t, void *);
93 static void spdmem_i2c_attach(device_t, device_t, void *);
94 static int spdmem_i2c_detach(device_t, int);
95
96 CFATTACH_DECL_NEW(spdmem_iic, sizeof(struct spdmem_i2c_softc),
97 spdmem_i2c_match, spdmem_i2c_attach, spdmem_i2c_detach, NULL);
98
99 static int spdmem_i2c_read(struct spdmem_softc *, uint16_t, uint8_t *);
100
101 static int
spdmem_reset_page(struct spdmem_i2c_softc * sc)102 spdmem_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 rv = iic_acquire_bus(sc->sc_tag, 0);
111 if (rv)
112 return rv;
113
114 /*
115 * Try to read byte 0 and 2. If it failed, it's not spdmem or a device
116 * doesn't exist at the address.
117 */
118 rv = iic_exec(sc->sc_tag, I2C_OP_READ_WITH_STOP, sc->sc_addr, ®, 1,
119 &byte0, 1, 0);
120 if (rv != 0)
121 goto error;
122
123 reg = 2;
124 rv = iic_exec(sc->sc_tag, I2C_OP_READ_WITH_STOP, sc->sc_addr, ®, 1,
125 &byte2, 1, 0);
126 if (rv != 0)
127 goto error;
128
129 /*
130 * Quirk for BIOSes that leave page 1 of a 4kbit EEPROM selected.
131 *
132 * byte0 is the length, byte2 is the memory type. Both of them should
133 * not be zero. If zero, the current page might be 1 (DDR4 and newer).
134 * If page 1 is selected, offset 0 can be 0 (Module Characteristics
135 * (Energy backup is not available)) and also offset 2 can be 0
136 * (Megabytes, and a part of Capacity digits).
137 *
138 * Note: The encoding of byte0 is vary in memory type, so we check
139 * just with zero to be simple.
140 *
141 * Try to see if we are not at page 0. If it's not, select page 0.
142 */
143 if ((byte0 == 0) || (byte2 == 0)) {
144 /*
145 * Note that SDCTL_RPA is the same as sc->sc_page0(SPDCTL_SPA0)
146 * Write is SPA0, read is RPA.
147 *
148 * This call returns 0 on page 0 and returns -1 on page 1.
149 * I don't know whether our icc_exec()'s API is good or not.
150 */
151 rv = iic_exec(sc->sc_tag, I2C_OP_READ_WITH_STOP, sc->sc_page0,
152 ®, 1, &dummy, 1, 0);
153 if (rv != 0) {
154 /*
155 * The possibilities are:
156 * a) page 1 is selected.
157 * b) The device doesn't support page select and
158 * it's not a SPD ROM.
159 * Is there no way to distinguish them now?
160 */
161 rv = iic_exec(sc->sc_tag, I2C_OP_WRITE_WITH_STOP,
162 sc->sc_page0, ®, 1, &dummy, 1, 0);
163 if (rv == 0) {
164 aprint_debug("Page 1 was selected. Page 0 is "
165 "selected now.\n");
166 } else {
167 aprint_debug("Failed to select page 0. This "
168 "device isn't SPD ROM\n");
169 }
170 } else {
171 /* This device isn't SPD ROM */
172 rv = -1;
173 }
174 }
175 error:
176 iic_release_bus(sc->sc_tag, 0);
177
178 return rv;
179 }
180
181 static const struct device_compatible_entry compat_data[] = {
182 { .compat = "atmel,spd" },
183 { .compat = "i2c-at34c02" },
184 DEVICE_COMPAT_EOL
185 };
186
187 static int
spdmem_i2c_match(device_t parent,cfdata_t match,void * aux)188 spdmem_i2c_match(device_t parent, cfdata_t match, void *aux)
189 {
190 struct i2c_attach_args *ia = aux;
191 struct spdmem_i2c_softc sc;
192 int match_result;
193
194 if (iic_use_direct_match(ia, match, compat_data, &match_result))
195 return match_result;
196
197 /*
198 * XXXJRT
199 * Should do this with "compatible" strings. There are also
200 * other problems with this "match" routine. Specifically, if
201 * we are doing direct-config, we know the device is already
202 * there aren't do need to probe. I'll leave the logic for
203 * now and let someone who knows better clean it later.
204 */
205
206 if (ia->ia_name) {
207 /* add other names as we find more firmware variations */
208 if (strcmp(ia->ia_name, "dimm-spd") &&
209 strcmp(ia->ia_name, "dimm"))
210 return 0;
211 }
212
213 /* only do this lame test when not using direct config */
214 if (ia->ia_name == NULL) {
215 if ((ia->ia_addr & SPDMEM_I2C_ADDRMASK) != SPDMEM_I2C_ADDR)
216 return 0;
217 }
218
219 sc.sc_tag = ia->ia_tag;
220 sc.sc_addr = ia->ia_addr;
221 sc.sc_page0 = SPDCTL_SPA0;
222 sc.sc_page1 = SPDCTL_SPA1;
223 sc.sc_base.sc_read = spdmem_i2c_read;
224
225 /* Check the bank and reset to the page 0 */
226 if (spdmem_reset_page(&sc) != 0)
227 return 0;
228
229 if (spdmem_common_probe(&sc.sc_base)) {
230 return ia->ia_name ? I2C_MATCH_DIRECT_SPECIFIC
231 : I2C_MATCH_ADDRESS_AND_PROBE;
232 }
233 return 0;
234 }
235
236 static void
spdmem_i2c_attach(device_t parent,device_t self,void * aux)237 spdmem_i2c_attach(device_t parent, device_t self, void *aux)
238 {
239 struct spdmem_i2c_softc *sc = device_private(self);
240 struct i2c_attach_args *ia = aux;
241
242 sc->sc_tag = ia->ia_tag;
243 sc->sc_addr = ia->ia_addr;
244 sc->sc_page0 = SPDCTL_SPA0;
245 sc->sc_page1 = SPDCTL_SPA1;
246 sc->sc_base.sc_read = spdmem_i2c_read;
247
248 if (!pmf_device_register(self, NULL, NULL))
249 aprint_error_dev(self, "couldn't establish power handler\n");
250
251 spdmem_common_attach(&sc->sc_base, self);
252 }
253
254 static int
spdmem_i2c_detach(device_t self,int flags)255 spdmem_i2c_detach(device_t self, int flags)
256 {
257 struct spdmem_i2c_softc *sc = device_private(self);
258
259 pmf_device_deregister(self);
260
261 return spdmem_common_detach(&sc->sc_base, self);
262 }
263
264 static int
spdmem_i2c_read(struct spdmem_softc * softc,uint16_t addr,uint8_t * val)265 spdmem_i2c_read(struct spdmem_softc *softc, uint16_t addr, uint8_t *val)
266 {
267 uint8_t reg;
268 struct spdmem_i2c_softc *sc = (struct spdmem_i2c_softc *)softc;
269 static uint8_t dummy = 0;
270 int rv;
271
272 reg = addr & 0xff;
273
274 rv = iic_acquire_bus(sc->sc_tag, 0);
275 if (rv)
276 return rv;
277
278 if (addr & 0x100) {
279 rv = iic_exec(sc->sc_tag, I2C_OP_WRITE_WITH_STOP, sc->sc_page1,
280 &dummy, 1, &dummy, 1, 0);
281 rv |= iic_exec(sc->sc_tag, I2C_OP_READ_WITH_STOP, sc->sc_addr,
282 ®, 1, val, 1, 0);
283 rv |= iic_exec(sc->sc_tag, I2C_OP_WRITE_WITH_STOP,
284 sc->sc_page0, &dummy, 1, &dummy, 1, 0);
285 } else {
286 rv = iic_exec(sc->sc_tag, I2C_OP_READ_WITH_STOP, sc->sc_addr,
287 ®, 1, val, 1, 0);
288 }
289
290 iic_release_bus(sc->sc_tag, 0);
291
292 return rv;
293 }
294
295 MODULE(MODULE_CLASS_DRIVER, spdmem, "iic");
296
297 #ifdef _MODULE
298 #include "ioconf.c"
299 #endif
300
301 static int
spdmem_modcmd(modcmd_t cmd,void * opaque)302 spdmem_modcmd(modcmd_t cmd, void *opaque)
303 {
304 int error = 0;
305 #ifdef _MODULE
306 static struct sysctllog *spdmem_sysctl_clog;
307 #endif
308
309 switch (cmd) {
310 case MODULE_CMD_INIT:
311 #ifdef _MODULE
312 error = config_init_component(cfdriver_ioconf_spdmem,
313 cfattach_ioconf_spdmem, cfdata_ioconf_spdmem);
314 #endif
315 return error;
316 case MODULE_CMD_FINI:
317 #ifdef _MODULE
318 error = config_fini_component(cfdriver_ioconf_spdmem,
319 cfattach_ioconf_spdmem, cfdata_ioconf_spdmem);
320 sysctl_teardown(&spdmem_sysctl_clog);
321 #endif
322 return error;
323 default:
324 return ENOTTY;
325 }
326 }
327