smc93cx6.c revision 1.17
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 */ 70static 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 */ 94int 95read_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} 182