Annotation of sys/dev/ic/smc93cx6.c, Revision 1.1.1.1
1.1 nbrk 1: /* $OpenBSD: smc93cx6.c,v 1.17 2003/09/25 06:43:34 fgsch Exp $ */
2: /* $NetBSD: smc93cx6.c,v 1.10 2003/05/02 19:12:19 dyoung Exp $ */
3:
4: /*
5: * Interface for the 93C66/56/46/26/06 serial eeprom parts.
6: *
7: * Copyright (c) 1995, 1996 Daniel M. Eischen
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 immediately at the beginning of the file, without modification,
15: * this list of conditions, and the following disclaimer.
16: * 2. Redistributions in binary form must reproduce the above copyright
17: * notice, this list of conditions and the following disclaimer in the
18: * documentation and/or other materials provided with the distribution.
19: * 3. Absolutely no warranty of function or purpose is made by the author
20: * Daniel M. Eischen.
21: * 4. Modifications may be freely made to this file if the above conditions
22: * are met.
23: *
24: * $FreeBSD: src/sys/dev/aic7xxx/93cx6.c,v 1.5 2000/01/07 23:08:17 gibbs Exp $
25: */
26:
27: /*
28: * The instruction set of the 93C66/56/46/26/06 chips are as follows:
29: *
30: * Start OP *
31: * Function Bit Code Address** Data Description
32: * -------------------------------------------------------------------
33: * READ 1 10 A5 - A0 Reads data stored in memory,
34: * starting at specified address
35: * EWEN 1 00 11XXXX Write enable must precede
36: * all programming modes
37: * ERASE 1 11 A5 - A0 Erase register A5A4A3A2A1A0
38: * WRITE 1 01 A5 - A0 D15 - D0 Writes register
39: * ERAL 1 00 10XXXX Erase all registers
40: * WRAL 1 00 01XXXX D15 - D0 Writes to all registers
41: * EWDS 1 00 00XXXX Disables all programming
42: * instructions
43: * *Note: A value of X for address is a don't care condition.
44: * **Note: There are 8 address bits for the 93C56/66 chips unlike
45: * the 93C46/26/06 chips which have 6 address bits.
46: *
47: * The 93C46 has a four wire interface: clock, chip select, data in, and
48: * data out. In order to perform one of the above functions, you need
49: * to enable the chip select for a clock period (typically a minimum of
50: * 1 usec, with the clock high and low a minimum of 750 and 250 nsec
51: * respectively). While the chip select remains high, you can clock in
52: * the instructions (above) starting with the start bit, followed by the
53: * OP code, Address, and Data (if needed). For the READ instruction, the
54: * requested 16-bit register contents is read from the data out line but
55: * is preceded by an initial zero (leading 0, followed by 16-bits, MSB
56: * first). The clock cycling from low to high initiates the next data
57: * bit to be sent from the chip.
58: *
59: */
60:
61: #include <sys/param.h>
62: #include <sys/systm.h>
63: #include <machine/bus.h>
64: #include <dev/ic/smc93cx6var.h>
65:
66: /*
67: * Right now, we only have to read the SEEPROM. But we make it easier to
68: * add other 93Cx6 functions.
69: */
70: static struct seeprom_cmd {
71: unsigned char len;
72: unsigned char bits[3];
73: } seeprom_read = {3, {1, 1, 0}};
74:
75: #define CLOCK_PULSE(sd, rdy) do { \
76: /* \
77: * Wait for the SEERDY to go high; about 800 ns. \
78: */ \
79: int cpi = 1000; \
80: if (rdy == 0) { \
81: DELAY(4); /* more than long enough */ \
82: break; \
83: } \
84: while ((SEEPROM_STATUS_INB(sd) & rdy) == 0 && cpi-- > 0) { \
85: ; /* Do nothing */ \
86: } \
87: (void)SEEPROM_INB(sd); /* Clear clock */ \
88: } while (0)
89:
90: /*
91: * Read the serial EEPROM and returns 1 if successful and 0 if
92: * not successful.
93: */
94: int
95: read_seeprom(sd, buf, start_addr, count)
96: struct seeprom_descriptor *sd;
97: u_int16_t *buf;
98: bus_size_t start_addr;
99: bus_size_t count;
100: {
101: int i = 0;
102: u_int k = 0;
103: u_int16_t v;
104: u_int32_t temp;
105:
106: /*
107: * Read the requested registers of the seeprom. The loop
108: * will range from 0 to count-1.
109: */
110: for (k = start_addr; k < count + start_addr; k++) {
111: /* Send chip select for one clock cycle. */
112: temp = sd->sd_MS ^ sd->sd_CS;
113: SEEPROM_OUTB(sd, temp ^ sd->sd_CK);
114: CLOCK_PULSE(sd, sd->sd_RDY);
115:
116: /*
117: * Now we're ready to send the read command followed by the
118: * address of the 16-bit register we want to read.
119: */
120: for (i = 0; i < seeprom_read.len; i++) {
121: if (seeprom_read.bits[i] != 0)
122: temp ^= sd->sd_DO;
123: SEEPROM_OUTB(sd, temp);
124: CLOCK_PULSE(sd, sd->sd_RDY);
125: SEEPROM_OUTB(sd, temp ^ sd->sd_CK);
126: CLOCK_PULSE(sd, sd->sd_RDY);
127: if (seeprom_read.bits[i] != 0)
128: temp ^= sd->sd_DO;
129: }
130: /* Send the 6 or 8 bit address (MSB first, LSB last). */
131: for (i = (sd->sd_chip - 1); i >= 0; i--) {
132: if ((k & (1 << i)) != 0)
133: temp ^= sd->sd_DO;
134: SEEPROM_OUTB(sd, temp);
135: CLOCK_PULSE(sd, sd->sd_RDY);
136: SEEPROM_OUTB(sd, temp ^ sd->sd_CK);
137: CLOCK_PULSE(sd, sd->sd_RDY);
138: if ((k & (1 << i)) != 0)
139: temp ^= sd->sd_DO;
140: }
141:
142: /*
143: * Now read the 16 bit register. An initial 0 precedes the
144: * register contents which begins with bit 15 (MSB) and ends
145: * with bit 0 (LSB). The initial 0 will be shifted off the
146: * top of our word as we let the loop run from 0 to 16.
147: */
148: v = 0;
149: for (i = 16; i >= 0; i--) {
150: SEEPROM_OUTB(sd, temp);
151: CLOCK_PULSE(sd, sd->sd_RDY);
152: v <<= 1;
153: if (SEEPROM_DATA_INB(sd) & sd->sd_DI)
154: v |= 1;
155: SEEPROM_OUTB(sd, temp ^ sd->sd_CK);
156: CLOCK_PULSE(sd, sd->sd_RDY);
157: }
158:
159: buf[k - start_addr] = v;
160:
161: /* Reset the chip select for the next command cycle. */
162: temp = sd->sd_MS;
163: SEEPROM_OUTB(sd, temp);
164: CLOCK_PULSE(sd, sd->sd_RDY);
165: SEEPROM_OUTB(sd, temp ^ sd->sd_CK);
166: CLOCK_PULSE(sd, sd->sd_RDY);
167: SEEPROM_OUTB(sd, temp);
168: CLOCK_PULSE(sd, sd->sd_RDY);
169: }
170: #ifdef AHC_DUMP_EEPROM
171: printf("\nSerial EEPROM:\n\t");
172: for (k = 0; k < count; k = k + 1) {
173: if (((k % 8) == 0) && (k != 0)) {
174: printf ("\n\t");
175: }
176: printf (" 0x%x", buf[k]);
177: }
178: printf ("\n");
179: #endif
180: return (1);
181: }
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