aic7xxx_93cx6.c revision 39220
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 immediately at the beginning of the file, without modification, 12 * this list of conditions, and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. Absolutely no warranty of function or purpose is made by the author 17 * Daniel M. Eischen. 18 * 4. Modifications may be freely made to this file if the above conditions 19 * are met. 20 * 21 * $Id: 93cx6.c,v 1.10 1997/02/22 09:38:36 peter Exp $ 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 preceed 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_memio.h> 61#include <machine/bus_pio.h> 62#include <machine/bus.h> 63#include <dev/aic7xxx/93cx6.h> 64 65/* 66 * Right now, we only have to read the SEEPROM. But we make it easier to 67 * add other 93Cx6 functions. 68 */ 69static struct seeprom_cmd { 70 unsigned char len; 71 unsigned char bits[3]; 72} seeprom_read = {3, {1, 1, 0}}; 73 74/* 75 * Wait for the SEERDY to go high; about 800 ns. 76 */ 77#define CLOCK_PULSE(sd, rdy) \ 78 while ((SEEPROM_STATUS_INB(sd) & rdy) == 0) { \ 79 ; /* Do nothing */ \ 80 } \ 81 (void)SEEPROM_INB(sd); /* Clear clock */ 82 83/* 84 * Read the serial EEPROM and returns 1 if successful and 0 if 85 * not successful. 86 */ 87int 88read_seeprom(sd, buf, start_addr, count) 89 struct seeprom_descriptor *sd; 90 u_int16_t *buf; 91 bus_size_t start_addr; 92 bus_size_t count; 93{ 94 int i = 0; 95 u_int k = 0; 96 u_int16_t v; 97 u_int8_t temp; 98 99 /* 100 * Read the requested registers of the seeprom. The loop 101 * will range from 0 to count-1. 102 */ 103 for (k = start_addr; k < count + start_addr; k++) { 104 /* Send chip select for one clock cycle. */ 105 temp = sd->sd_MS ^ sd->sd_CS; 106 SEEPROM_OUTB(sd, temp ^ sd->sd_CK); 107 CLOCK_PULSE(sd, sd->sd_RDY); 108 109 /* 110 * Now we're ready to send the read command followed by the 111 * address of the 16-bit register we want to read. 112 */ 113 for (i = 0; i < seeprom_read.len; i++) { 114 if (seeprom_read.bits[i] != 0) 115 temp ^= sd->sd_DO; 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 if (seeprom_read.bits[i] != 0) 121 temp ^= sd->sd_DO; 122 } 123 /* Send the 6 or 8 bit address (MSB first, LSB last). */ 124 for (i = (sd->sd_chip - 1); i >= 0; i--) { 125 if ((k & (1 << i)) != 0) 126 temp ^= sd->sd_DO; 127 SEEPROM_OUTB(sd, temp); 128 CLOCK_PULSE(sd, sd->sd_RDY); 129 SEEPROM_OUTB(sd, temp ^ sd->sd_CK); 130 CLOCK_PULSE(sd, sd->sd_RDY); 131 if ((k & (1 << i)) != 0) 132 temp ^= sd->sd_DO; 133 } 134 135 /* 136 * Now read the 16 bit register. An initial 0 precedes the 137 * register contents which begins with bit 15 (MSB) and ends 138 * with bit 0 (LSB). The initial 0 will be shifted off the 139 * top of our word as we let the loop run from 0 to 16. 140 */ 141 v = 0; 142 for (i = 16; i >= 0; i--) { 143 SEEPROM_OUTB(sd, temp); 144 CLOCK_PULSE(sd, sd->sd_RDY); 145 v <<= 1; 146 if (SEEPROM_DATA_INB(sd) & sd->sd_DI) 147 v |= 1; 148 SEEPROM_OUTB(sd, temp ^ sd->sd_CK); 149 CLOCK_PULSE(sd, sd->sd_RDY); 150 } 151 152 buf[k - start_addr] = v; 153 154 /* Reset the chip select for the next command cycle. */ 155 temp = sd->sd_MS; 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 SEEPROM_OUTB(sd, temp); 161 CLOCK_PULSE(sd, sd->sd_RDY); 162 } 163#ifdef 93CX6_DUMP_EEPROM 164 printf("\nSerial EEPROM:"); 165 for (k = 0; k < count; k = k + 1) { 166 if (((k % 8) == 0) && (k != 0)) { 167 printf ("\n "); 168 } 169 printf (" 0x%x", buf[k]); 170 } 171 printf ("\n"); 172#endif 173 return (1); 174} 175