1 /* $OpenBSD: smc93cx6.c,v 1.16 2003/08/15 23:41:47 fgsch Exp $ */ 2 /* $FreeBSD: sys/dev/aic7xxx/93cx6.c,v 1.5 2000/01/07 23:08:17 gibbs Exp $ */ 3 /* 4 * Interface for the 93C66/56/46/26/06 serial eeprom parts. 5 * 6 * Copyright (c) 1995, 1996 Daniel M. Eischen 7 * All rights reserved. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice immediately at the beginning of the file, without modification, 14 * 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. Absolutely no warranty of function or purpose is made by the author 19 * Daniel M. Eischen. 20 * 4. Modifications may be freely made to this file if the above conditions 21 * are met. 22 */ 23 24 /* 25 * The instruction set of the 93C66/56/46/26/06 chips are as follows: 26 * 27 * Start OP * 28 * Function Bit Code Address** Data Description 29 * ------------------------------------------------------------------- 30 * READ 1 10 A5 - A0 Reads data stored in memory, 31 * starting at specified address 32 * EWEN 1 00 11XXXX Write enable must precede 33 * all programming modes 34 * ERASE 1 11 A5 - A0 Erase register A5A4A3A2A1A0 35 * WRITE 1 01 A5 - A0 D15 - D0 Writes register 36 * ERAL 1 00 10XXXX Erase all registers 37 * WRAL 1 00 01XXXX D15 - D0 Writes to all registers 38 * EWDS 1 00 00XXXX Disables all programming 39 * instructions 40 * *Note: A value of X for address is a don't care condition. 41 * **Note: There are 8 address bits for the 93C56/66 chips unlike 42 * the 93C46/26/06 chips which have 6 address bits. 43 * 44 * The 93C46 has a four wire interface: clock, chip select, data in, and 45 * data out. In order to perform one of the above functions, you need 46 * to enable the chip select for a clock period (typically a minimum of 47 * 1 usec, with the clock high and low a minimum of 750 and 250 nsec 48 * respectively). While the chip select remains high, you can clock in 49 * the instructions (above) starting with the start bit, followed by the 50 * OP code, Address, and Data (if needed). For the READ instruction, the 51 * requested 16-bit register contents is read from the data out line but 52 * is preceded by an initial zero (leading 0, followed by 16-bits, MSB 53 * first). The clock cycling from low to high initiates the next data 54 * bit to be sent from the chip. 55 * 56 */ 57 58 #include <sys/param.h> 59 #include <sys/systm.h> 60 #include <machine/bus.h> 61 #include <dev/ic/smc93cx6var.h> 62 63 /* 64 * Right now, we only have to read the SEEPROM. But we make it easier to 65 * add other 93Cx6 functions. 66 */ 67 static struct seeprom_cmd { 68 unsigned char len; 69 unsigned char bits[9]; 70 } seeprom_read = {3, {1, 1, 0}}; 71 72 /* 73 * Wait for the SEERDY to go high; about 800 ns. 74 */ 75 #define CLOCK_PULSE(sd, rdy) \ 76 while ((SEEPROM_STATUS_INB(sd) & rdy) == 0) { \ 77 ; /* Do nothing */ \ 78 } \ 79 (void)SEEPROM_INB(sd); /* Clear clock */ 80 81 /* 82 * Send a START condition and the given command 83 */ 84 static void 85 send_seeprom_cmd(struct seeprom_descriptor *sd, struct seeprom_cmd *cmd) 86 { 87 u_int8_t temp; 88 int i = 0; 89 90 /* Send chip select for one clock cycle. */ 91 temp = sd->sd_MS ^ sd->sd_CS; 92 SEEPROM_OUTB(sd, temp ^ sd->sd_CK); 93 CLOCK_PULSE(sd, sd->sd_RDY); 94 95 for (i = 0; i < cmd->len; i++) { 96 if (cmd->bits[i] != 0) 97 temp ^= sd->sd_DO; 98 SEEPROM_OUTB(sd, temp); 99 CLOCK_PULSE(sd, sd->sd_RDY); 100 SEEPROM_OUTB(sd, temp ^ sd->sd_CK); 101 CLOCK_PULSE(sd, sd->sd_RDY); 102 if (cmd->bits[i] != 0) 103 temp ^= sd->sd_DO; 104 } 105 } 106 107 /* 108 * Clear CS put the chip in the reset state, where it can wait for new commands. 109 */ 110 static void 111 reset_seeprom(struct seeprom_descriptor *sd) 112 { 113 u_int8_t temp; 114 115 temp = sd->sd_MS; 116 SEEPROM_OUTB(sd, temp); 117 CLOCK_PULSE(sd, sd->sd_RDY); 118 SEEPROM_OUTB(sd, temp ^ sd->sd_CK); 119 CLOCK_PULSE(sd, sd->sd_RDY); 120 SEEPROM_OUTB(sd, temp); 121 CLOCK_PULSE(sd, sd->sd_RDY); 122 } 123 124 /* 125 * Read the serial EEPROM and returns 1 if successful and 0 if 126 * not successful. 127 */ 128 int 129 read_seeprom(sd, buf, start_addr, count) 130 struct seeprom_descriptor *sd; 131 u_int16_t *buf; 132 bus_size_t start_addr; 133 bus_size_t count; 134 { 135 int i = 0; 136 u_int k = 0; 137 u_int16_t v; 138 u_int8_t temp; 139 140 /* 141 * Read the requested registers of the seeprom. The loop 142 * will range from 0 to count-1. 143 */ 144 for (k = start_addr; k < count + start_addr; k++) { 145 /* 146 * Now we're ready to send the read command followed by the 147 * address of the 16-bit register we want to read. 148 */ 149 send_seeprom_cmd(sd, &seeprom_read); 150 151 /* Send the 6 or 8 bit address (MSB first, LSB last). */ 152 temp = sd->sd_MS ^ sd->sd_CS; 153 for (i = (sd->sd_chip - 1); i >= 0; i--) { 154 if ((k & (1 << i)) != 0) 155 temp ^= sd->sd_DO; 156 SEEPROM_OUTB(sd, temp); 157 CLOCK_PULSE(sd, sd->sd_RDY); 158 SEEPROM_OUTB(sd, temp ^ sd->sd_CK); 159 CLOCK_PULSE(sd, sd->sd_RDY); 160 if ((k & (1 << i)) != 0) 161 temp ^= sd->sd_DO; 162 } 163 164 /* 165 * Now read the 16 bit register. An initial 0 precedes the 166 * register contents which begins with bit 15 (MSB) and ends 167 * with bit 0 (LSB). The initial 0 will be shifted off the 168 * top of our word as we let the loop run from 0 to 16. 169 */ 170 v = 0; 171 for (i = 16; i >= 0; i--) { 172 SEEPROM_OUTB(sd, temp); 173 CLOCK_PULSE(sd, sd->sd_RDY); 174 v <<= 1; 175 if (SEEPROM_DATA_INB(sd) & sd->sd_DI) 176 v |= 1; 177 SEEPROM_OUTB(sd, temp ^ sd->sd_CK); 178 CLOCK_PULSE(sd, sd->sd_RDY); 179 } 180 181 buf[k - start_addr] = v; 182 183 /* Reset the chip select for the next command cycle. */ 184 reset_seeprom(sd); 185 } 186 #ifdef AHC_DUMP_EEPROM 187 printf("\nSerial EEPROM:\n\t"); 188 for (k = 0; k < count; k = k + 1) { 189 if (((k % 8) == 0) && (k != 0)) { 190 printf ("\n\t"); 191 } 192 printf (" 0x%x", buf[k]); 193 } 194 printf ("\n"); 195 #endif 196 return (1); 197 } 198