1 /*
2 * Interface for the 93C66/56/46/26/06 serial eeprom parts.
3 *
4 * Copyright (c) 1995, 1996 Daniel M. Eischen
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions, and the following disclaimer,
12 * without modification.
13 * 2. The name of the author may not be used to endorse or promote products
14 * derived from this software without specific prior written permission.
15 *
16 * Alternatively, this software may be distributed under the terms of the
17 * GNU General Public License ("GPL").
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
23 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 *
31 * $Id: //depot/aic7xxx/aic7xxx/aic7xxx_93cx6.c#19 $
32 */
33
34 /*
35 * The instruction set of the 93C66/56/46/26/06 chips are as follows:
36 *
37 * Start OP *
38 * Function Bit Code Address** Data Description
39 * -------------------------------------------------------------------
40 * READ 1 10 A5 - A0 Reads data stored in memory,
41 * starting at specified address
42 * EWEN 1 00 11XXXX Write enable must precede
43 * all programming modes
44 * ERASE 1 11 A5 - A0 Erase register A5A4A3A2A1A0
45 * WRITE 1 01 A5 - A0 D15 - D0 Writes register
46 * ERAL 1 00 10XXXX Erase all registers
47 * WRAL 1 00 01XXXX D15 - D0 Writes to all registers
48 * EWDS 1 00 00XXXX Disables all programming
49 * instructions
50 * *Note: A value of X for address is a don't care condition.
51 * **Note: There are 8 address bits for the 93C56/66 chips unlike
52 * the 93C46/26/06 chips which have 6 address bits.
53 *
54 * The 93C46 has a four wire interface: clock, chip select, data in, and
55 * data out. In order to perform one of the above functions, you need
56 * to enable the chip select for a clock period (typically a minimum of
57 * 1 usec, with the clock high and low a minimum of 750 and 250 nsec
58 * respectively). While the chip select remains high, you can clock in
59 * the instructions (above) starting with the start bit, followed by the
60 * OP code, Address, and Data (if needed). For the READ instruction, the
61 * requested 16-bit register contents is read from the data out line but
62 * is preceded by an initial zero (leading 0, followed by 16-bits, MSB
63 * first). The clock cycling from low to high initiates the next data
64 * bit to be sent from the chip.
65 */
66
67 #include "aic7xxx_osm.h"
68 #include "aic7xxx_inline.h"
69 #include "aic7xxx_93cx6.h"
70
71 /*
72 * Right now, we only have to read the SEEPROM. But we make it easier to
73 * add other 93Cx6 functions.
74 */
75 struct seeprom_cmd {
76 uint8_t len;
77 uint8_t bits[11];
78 };
79
80 /* Short opcodes for the c46 */
81 static const struct seeprom_cmd seeprom_ewen = {9, {1, 0, 0, 1, 1, 0, 0, 0, 0}};
82 static const struct seeprom_cmd seeprom_ewds = {9, {1, 0, 0, 0, 0, 0, 0, 0, 0}};
83
84 /* Long opcodes for the C56/C66 */
85 static const struct seeprom_cmd seeprom_long_ewen = {11, {1, 0, 0, 1, 1, 0, 0, 0, 0}};
86 static const struct seeprom_cmd seeprom_long_ewds = {11, {1, 0, 0, 0, 0, 0, 0, 0, 0}};
87
88 /* Common opcodes */
89 static const struct seeprom_cmd seeprom_write = {3, {1, 0, 1}};
90 static const struct seeprom_cmd seeprom_read = {3, {1, 1, 0}};
91
92 /*
93 * Wait for the SEERDY to go high; about 800 ns.
94 */
95 #define CLOCK_PULSE(sd, rdy) \
96 while ((SEEPROM_STATUS_INB(sd) & rdy) == 0) { \
97 ; /* Do nothing */ \
98 } \
99 (void)SEEPROM_INB(sd); /* Clear clock */
100
101 /*
102 * Send a START condition and the given command
103 */
104 static void
send_seeprom_cmd(struct seeprom_descriptor * sd,const struct seeprom_cmd * cmd)105 send_seeprom_cmd(struct seeprom_descriptor *sd, const struct seeprom_cmd *cmd)
106 {
107 uint8_t temp;
108 int i = 0;
109
110 /* Send chip select for one clock cycle. */
111 temp = sd->sd_MS ^ sd->sd_CS;
112 SEEPROM_OUTB(sd, temp ^ sd->sd_CK);
113 CLOCK_PULSE(sd, sd->sd_RDY);
114
115 for (i = 0; i < cmd->len; i++) {
116 if (cmd->bits[i] != 0)
117 temp ^= sd->sd_DO;
118 SEEPROM_OUTB(sd, temp);
119 CLOCK_PULSE(sd, sd->sd_RDY);
120 SEEPROM_OUTB(sd, temp ^ sd->sd_CK);
121 CLOCK_PULSE(sd, sd->sd_RDY);
122 if (cmd->bits[i] != 0)
123 temp ^= sd->sd_DO;
124 }
125 }
126
127 /*
128 * Clear CS put the chip in the reset state, where it can wait for new commands.
129 */
130 static void
reset_seeprom(struct seeprom_descriptor * sd)131 reset_seeprom(struct seeprom_descriptor *sd)
132 {
133 uint8_t temp;
134
135 temp = sd->sd_MS;
136 SEEPROM_OUTB(sd, temp);
137 CLOCK_PULSE(sd, sd->sd_RDY);
138 SEEPROM_OUTB(sd, temp ^ sd->sd_CK);
139 CLOCK_PULSE(sd, sd->sd_RDY);
140 SEEPROM_OUTB(sd, temp);
141 CLOCK_PULSE(sd, sd->sd_RDY);
142 }
143
144 /*
145 * Read the serial EEPROM and returns 1 if successful and 0 if
146 * not successful.
147 */
148 int
ahc_read_seeprom(struct seeprom_descriptor * sd,uint16_t * buf,u_int start_addr,u_int count)149 ahc_read_seeprom(struct seeprom_descriptor *sd, uint16_t *buf,
150 u_int start_addr, u_int count)
151 {
152 int i = 0;
153 u_int k = 0;
154 uint16_t v;
155 uint8_t temp;
156
157 /*
158 * Read the requested registers of the seeprom. The loop
159 * will range from 0 to count-1.
160 */
161 for (k = start_addr; k < count + start_addr; k++) {
162 /*
163 * Now we're ready to send the read command followed by the
164 * address of the 16-bit register we want to read.
165 */
166 send_seeprom_cmd(sd, &seeprom_read);
167
168 /* Send the 6 or 8 bit address (MSB first, LSB last). */
169 temp = sd->sd_MS ^ sd->sd_CS;
170 for (i = (sd->sd_chip - 1); i >= 0; i--) {
171 if ((k & (1 << i)) != 0)
172 temp ^= sd->sd_DO;
173 SEEPROM_OUTB(sd, temp);
174 CLOCK_PULSE(sd, sd->sd_RDY);
175 SEEPROM_OUTB(sd, temp ^ sd->sd_CK);
176 CLOCK_PULSE(sd, sd->sd_RDY);
177 if ((k & (1 << i)) != 0)
178 temp ^= sd->sd_DO;
179 }
180
181 /*
182 * Now read the 16 bit register. An initial 0 precedes the
183 * register contents which begins with bit 15 (MSB) and ends
184 * with bit 0 (LSB). The initial 0 will be shifted off the
185 * top of our word as we let the loop run from 0 to 16.
186 */
187 v = 0;
188 for (i = 16; i >= 0; i--) {
189 SEEPROM_OUTB(sd, temp);
190 CLOCK_PULSE(sd, sd->sd_RDY);
191 v <<= 1;
192 if (SEEPROM_DATA_INB(sd) & sd->sd_DI)
193 v |= 1;
194 SEEPROM_OUTB(sd, temp ^ sd->sd_CK);
195 CLOCK_PULSE(sd, sd->sd_RDY);
196 }
197
198 buf[k - start_addr] = v;
199
200 /* Reset the chip select for the next command cycle. */
201 reset_seeprom(sd);
202 }
203 #ifdef AHC_DUMP_EEPROM
204 printk("\nSerial EEPROM:\n\t");
205 for (k = 0; k < count; k = k + 1) {
206 if (((k % 8) == 0) && (k != 0)) {
207 printk(KERN_CONT "\n\t");
208 }
209 printk(KERN_CONT " 0x%x", buf[k]);
210 }
211 printk(KERN_CONT "\n");
212 #endif
213 return (1);
214 }
215
216 /*
217 * Write the serial EEPROM and return 1 if successful and 0 if
218 * not successful.
219 */
220 int
ahc_write_seeprom(struct seeprom_descriptor * sd,uint16_t * buf,u_int start_addr,u_int count)221 ahc_write_seeprom(struct seeprom_descriptor *sd, uint16_t *buf,
222 u_int start_addr, u_int count)
223 {
224 const struct seeprom_cmd *ewen, *ewds;
225 uint16_t v;
226 uint8_t temp;
227 int i, k;
228
229 /* Place the chip into write-enable mode */
230 if (sd->sd_chip == C46) {
231 ewen = &seeprom_ewen;
232 ewds = &seeprom_ewds;
233 } else if (sd->sd_chip == C56_66) {
234 ewen = &seeprom_long_ewen;
235 ewds = &seeprom_long_ewds;
236 } else {
237 printk("ahc_write_seeprom: unsupported seeprom type %d\n",
238 sd->sd_chip);
239 return (0);
240 }
241
242 send_seeprom_cmd(sd, ewen);
243 reset_seeprom(sd);
244
245 /* Write all requested data out to the seeprom. */
246 temp = sd->sd_MS ^ sd->sd_CS;
247 for (k = start_addr; k < count + start_addr; k++) {
248 /* Send the write command */
249 send_seeprom_cmd(sd, &seeprom_write);
250
251 /* Send the 6 or 8 bit address (MSB first). */
252 for (i = (sd->sd_chip - 1); i >= 0; i--) {
253 if ((k & (1 << i)) != 0)
254 temp ^= sd->sd_DO;
255 SEEPROM_OUTB(sd, temp);
256 CLOCK_PULSE(sd, sd->sd_RDY);
257 SEEPROM_OUTB(sd, temp ^ sd->sd_CK);
258 CLOCK_PULSE(sd, sd->sd_RDY);
259 if ((k & (1 << i)) != 0)
260 temp ^= sd->sd_DO;
261 }
262
263 /* Write the 16 bit value, MSB first */
264 v = buf[k - start_addr];
265 for (i = 15; i >= 0; i--) {
266 if ((v & (1 << i)) != 0)
267 temp ^= sd->sd_DO;
268 SEEPROM_OUTB(sd, temp);
269 CLOCK_PULSE(sd, sd->sd_RDY);
270 SEEPROM_OUTB(sd, temp ^ sd->sd_CK);
271 CLOCK_PULSE(sd, sd->sd_RDY);
272 if ((v & (1 << i)) != 0)
273 temp ^= sd->sd_DO;
274 }
275
276 /* Wait for the chip to complete the write */
277 temp = sd->sd_MS;
278 SEEPROM_OUTB(sd, temp);
279 CLOCK_PULSE(sd, sd->sd_RDY);
280 temp = sd->sd_MS ^ sd->sd_CS;
281 do {
282 SEEPROM_OUTB(sd, temp);
283 CLOCK_PULSE(sd, sd->sd_RDY);
284 SEEPROM_OUTB(sd, temp ^ sd->sd_CK);
285 CLOCK_PULSE(sd, sd->sd_RDY);
286 } while ((SEEPROM_DATA_INB(sd) & sd->sd_DI) == 0);
287
288 reset_seeprom(sd);
289 }
290
291 /* Put the chip back into write-protect mode */
292 send_seeprom_cmd(sd, ewds);
293 reset_seeprom(sd);
294
295 return (1);
296 }
297
298 int
ahc_verify_cksum(struct seeprom_config * sc)299 ahc_verify_cksum(struct seeprom_config *sc)
300 {
301 int i;
302 int maxaddr;
303 uint32_t checksum;
304 uint16_t *scarray;
305
306 maxaddr = (sizeof(*sc)/2) - 1;
307 checksum = 0;
308 scarray = (uint16_t *)sc;
309
310 for (i = 0; i < maxaddr; i++)
311 checksum = checksum + scarray[i];
312 if (checksum == 0
313 || (checksum & 0xFFFF) != sc->checksum) {
314 return (0);
315 } else {
316 return(1);
317 }
318 }
319