sys/dev/ic/smc93cx6.c

   1 /*      $NetBSD: smc93cx6.c,v 1.14 2007/10/19 12:00:02 ad Exp $ */
   2
   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  * $FreeBSD: src/sys/dev/aic7xxx/93cx6.c,v 1.5 2000/01/07 23:08:17 gibbs Exp $
  24  */
  25
  26 /*
  27  *   The instruction set of the 93C66/56/46/26/06 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 precede
  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  *    **Note: There are 8 address bits for the 93C56/66 chips unlike
  44  *            the 93C46/26/06 chips which have 6 address bits.
  45  *
  46  *   The 93C46 has a four wire interface: clock, chip select, data in, and
  47  *   data out.  In order to perform one of the above functions, you need
  48  *   to enable the chip select for a clock period (typically a minimum of
  49  *   1 usec, with the clock high and low a minimum of 750 and 250 nsec
  50  *   respectively).  While the chip select remains high, you can clock in
  51  *   the instructions (above) starting with the start bit, followed by the
  52  *   OP code, Address, and Data (if needed).  For the READ instruction, the
  53  *   requested 16-bit register contents is read from the data out line but
  54  *   is preceded by an initial zero (leading 0, followed by 16-bits, MSB
  55  *   first).  The clock cycling from low to high initiates the next data
  56  *   bit to be sent from the chip.
  57  *
  58  */
  59
  60 #include <sys/cdefs.h>
  61 __KERNEL_RCSID(0, "$NetBSD: smc93cx6.c,v 1.14 2007/10/19 12:00:02 ad Exp $");
  62
  63 #ifndef __NetBSD__
  64 #include "opt_aic7xxx.h"
  65 #endif
  66
  67 #include <sys/param.h>
  68 #include <sys/systm.h>
  69 #include <sys/bus.h>
  70 #ifdef __NetBSD__
  71 #include <dev/ic/smc93cx6var.h>
  72 #else
  73 #include <machine/bus_memio.h>
  74 #include <machine/bus_pio.h>
  75 #include <dev/aic7xxx/93cx6.h>
  76 #endif
  77
  78 /*
  79  * Right now, we only have to read the SEEPROM.  But we make it easier to
  80  * add other 93Cx6 functions.
  81  */
  82 static struct seeprom_cmd {
  83         unsigned char len;
  84         unsigned char bits[3];
  85 } seeprom_read = {3, {1, 1, 0}};
  86
  87 /* XXX bus barriers */
  88 #define CLOCK_PULSE(sd, rdy)    do {                                    \
  89         /*                                                              \
  90          * Wait for the SEERDY to go high; about 800 ns.                \
  91          */                                                             \
  92         int cpi = 1000;                                                 \
  93         if (rdy == 0) {                                                 \
  94                 DELAY(4); /* more than long enough */                   \
  95                 break;                                                  \
  96         }                                                               \
  97         while ((SEEPROM_STATUS_INB(sd) & rdy) == 0 && cpi-- > 0) {      \
  98                 ;  /* Do nothing */                                     \
  99         }                                                               \
 100         (void)SEEPROM_INB(sd);  /* Clear clock */                       \
 101 } while (0)
 102
 103 /*
 104  * Read the serial EEPROM and returns 1 if successful and 0 if
 105  * not successful.
 106  */
 107 int
 108 read_seeprom(struct seeprom_descriptor *sd, u_int16_t *buf, bus_size_t start_addr, bus_size_t count)
 109 {
 110         int i = 0;
 111         u_int k = 0;
 112         u_int16_t v;
 113         u_int32_t temp;
 114
 115         /*
 116          * Read the requested registers of the seeprom.  The loop
 117          * will range from 0 to count-1.
 118          */
 119         for (k = start_addr; k < count + start_addr; k++) {
 120                 /* Send chip select for one clock cycle. */
 121                 temp = sd->sd_MS ^ sd->sd_CS;
 122                 SEEPROM_OUTB(sd, temp ^ sd->sd_CK);
 123                 CLOCK_PULSE(sd, sd->sd_RDY);
 124
 125                 /*
 126                  * Now we're ready to send the read command followed by the
 127                  * address of the 16-bit register we want to read.
 128                  */
 129                 for (i = 0; i < seeprom_read.len; i++) {
 130                         if (seeprom_read.bits[i] != 0)
 131                                 temp ^= sd->sd_DO;
 132                         SEEPROM_OUTB(sd, temp);
 133                         CLOCK_PULSE(sd, sd->sd_RDY);
 134                         SEEPROM_OUTB(sd, temp ^ sd->sd_CK);
 135                         CLOCK_PULSE(sd, sd->sd_RDY);
 136                         if (seeprom_read.bits[i] != 0)
 137                                 temp ^= sd->sd_DO;
 138                 }
 139                 /* Send the 6 or 8 bit address (MSB first, LSB last). */
 140                 for (i = (sd->sd_chip - 1); i >= 0; i--) {
 141                         if ((k & (1 << i)) != 0)
 142                                 temp ^= sd->sd_DO;
 143                         SEEPROM_OUTB(sd, temp);
 144                         CLOCK_PULSE(sd, sd->sd_RDY);
 145                         SEEPROM_OUTB(sd, temp ^ sd->sd_CK);
 146                         CLOCK_PULSE(sd, sd->sd_RDY);
 147                         if ((k & (1 << i)) != 0)
 148                                 temp ^= sd->sd_DO;
 149                 }
 150
 151                 /*
 152                  * Now read the 16 bit register.  An initial 0 precedes the
 153                  * register contents which begins with bit 15 (MSB) and ends
 154                  * with bit 0 (LSB).  The initial 0 will be shifted off the
 155                  * top of our word as we let the loop run from 0 to 16.
 156                  */
 157                 v = 0;
 158                 for (i = 16; i >= 0; i--) {
 159                         SEEPROM_OUTB(sd, temp);
 160                         CLOCK_PULSE(sd, sd->sd_RDY);
 161                         v <<= 1;
 162                         if (SEEPROM_DATA_INB(sd) & sd->sd_DI)
 163                                 v |= 1;
 164                         SEEPROM_OUTB(sd, temp ^ sd->sd_CK);
 165                         CLOCK_PULSE(sd, sd->sd_RDY);
 166                 }
 167
 168                 buf[k - start_addr] = v;
 169
 170                 /* Reset the chip select for the next command cycle. */
 171                 temp = sd->sd_MS;
 172                 SEEPROM_OUTB(sd, temp);
 173                 CLOCK_PULSE(sd, sd->sd_RDY);
 174                 SEEPROM_OUTB(sd, temp ^ sd->sd_CK);
 175                 CLOCK_PULSE(sd, sd->sd_RDY);
 176                 SEEPROM_OUTB(sd, temp);
 177                 CLOCK_PULSE(sd, sd->sd_RDY);
 178         }
 179 #ifdef AHC_DUMP_EEPROM
 180         printf("\nSerial EEPROM:\n\t");
 181         for (k = 0; k < count; k = k + 1) {
 182                 if (((k % 8) == 0) && (k != 0)) {
 183                         printf ("\n\t");
 184                 }
 185                 printf (" 0x%x", buf[k]);
 186         }
 187         printf ("\n");
 188 #endif
 189         return (1);
 190 }