smc93cx6.c revision 1.2
1 /* $NetBSD: smc93cx6.c,v 1.2 1996/07/10 22:50:49 explorer Exp $ */ 2 3 /* 4 * Interface for the 93C46/26/06 serial eeprom parts. 5 * 6 * Copyright (c) 1995 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 * from Id: 93cx6.c,v 1.5 1996/05/30 07:19:54 gibbs Exp 24 */ 25 26 /* 27 * The instruction set of the 93C46/26/06 chips are as follows: 28 * 29 * Start OP 30 * Function Bit Code Address Data Description 31 * ------------------------------------------------------------------- 32 * READ 1 10 A5 - A0 Reads data stored in memory, 33 * starting at specified address 34 * EWEN 1 00 11XXXX Write enable must preceed 35 * all programming modes 36 * ERASE 1 11 A5 - A0 Erase register A5A4A3A2A1A0 37 * WRITE 1 01 A5 - A0 D15 - D0 Writes register 38 * ERAL 1 00 10XXXX Erase all registers 39 * WRAL 1 00 01XXXX D15 - D0 Writes to all registers 40 * EWDS 1 00 00XXXX Disables all programming 41 * instructions 42 * *Note: A value of X for address is a don't care condition. 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 #if defined(__FreeBSD__) 61 #include <machine/clock.h> 62 #include <i386/scsi/93cx6.h> 63 #elif defined(__NetBSD__) 64 #include <machine/bus.h> 65 #include <dev/ic/smc93cx6var.h> 66 #endif 67 68 /* 69 * Right now, we only have to read the SEEPROM. But we make it easier to 70 * add other 93Cx6 functions. 71 */ 72 static struct seeprom_cmd { 73 unsigned char len; 74 unsigned char bits[3]; 75 } seeprom_read = {3, {1, 1, 0}}; 76 77 /* 78 * Wait for the SEERDY to go high; about 800 ns. 79 */ 80 #define CLOCK_PULSE(sd, rdy) \ 81 while ((SEEPROM_INB(sd) & rdy) == 0) { \ 82 ; /* Do nothing */ \ 83 } 84 85 /* 86 * Read the serial EEPROM and returns 1 if successful and 0 if 87 * not successful. 88 */ 89 int 90 read_seeprom(sd, buf, start_addr, count) 91 struct seeprom_descriptor *sd; 92 u_int16_t *buf; 93 #if defined(__FreeBSD__) 94 u_int start_addr; 95 int count; 96 #elif defined(__NetBSD__) 97 bus_io_size_t start_addr; 98 bus_io_size_t count; 99 #endif 100 { 101 int i = 0, k = 0; 102 u_int16_t v; 103 u_int8_t temp; 104 105 /* 106 * Read the requested registers of the seeprom. The loop 107 * will range from 0 to count-1. 108 */ 109 for (k = start_addr; k < count + start_addr; k++) { 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 /* 116 * Now we're ready to send the read command followed by the 117 * address of the 16-bit register we want to read. 118 */ 119 for (i = 0; i < seeprom_read.len; i++) { 120 if (seeprom_read.bits[i] != 0) 121 temp ^= sd->sd_DO; 122 SEEPROM_OUTB(sd, temp); 123 CLOCK_PULSE(sd, sd->sd_RDY); 124 SEEPROM_OUTB(sd, temp ^ sd->sd_CK); 125 CLOCK_PULSE(sd, sd->sd_RDY); 126 if (seeprom_read.bits[i] != 0) 127 temp ^= sd->sd_DO; 128 } 129 /* Send the 6 bit address (MSB first, LSB last). */ 130 for (i = 5; i >= 0; i--) { 131 if ((k & (1 << i)) != 0) 132 temp ^= sd->sd_DO; 133 SEEPROM_OUTB(sd, temp); 134 CLOCK_PULSE(sd, sd->sd_RDY); 135 SEEPROM_OUTB(sd, temp ^ sd->sd_CK); 136 CLOCK_PULSE(sd, sd->sd_RDY); 137 if ((k & (1 << i)) != 0) 138 temp ^= sd->sd_DO; 139 } 140 141 /* 142 * Now read the 16 bit register. An initial 0 precedes the 143 * register contents which begins with bit 15 (MSB) and ends 144 * with bit 0 (LSB). The initial 0 will be shifted off the 145 * top of our word as we let the loop run from 0 to 16. 146 */ 147 v = 0; 148 for (i = 16; i >= 0; i--) { 149 SEEPROM_OUTB(sd, temp); 150 CLOCK_PULSE(sd, sd->sd_RDY); 151 v <<= 1; 152 if (SEEPROM_INB(sd) & sd->sd_DI) 153 v |= 1; 154 SEEPROM_OUTB(sd, temp ^ sd->sd_CK); 155 CLOCK_PULSE(sd, sd->sd_RDY); 156 } 157 158 buf[k - start_addr] = v; 159 160 /* Reset the chip select for the next command cycle. */ 161 temp = sd->sd_MS; 162 SEEPROM_OUTB(sd, temp); 163 CLOCK_PULSE(sd, sd->sd_RDY); 164 SEEPROM_OUTB(sd, temp ^ sd->sd_CK); 165 CLOCK_PULSE(sd, sd->sd_RDY); 166 SEEPROM_OUTB(sd, temp); 167 CLOCK_PULSE(sd, sd->sd_RDY); 168 } 169 #if 0 170 printf ("Serial EEPROM:"); 171 for (k = 0; k < count; k = k + 1) { 172 if (((k % 8) == 0) && (k != 0)) 173 { 174 printf ("\n "); 175 } 176 printf (" 0x%x", buf[k]); 177 } 178 printf ("\n"); 179 #endif 180 return (1); 181 } 182
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