cpu/nios/spi.c

   1 /*
   2  * (C) Copyright 2004, Li-Pro.Net <www.li-pro.net>
   3  * Stephan Linz <linz@li-pro.net>
   4  *
   5  * See file CREDITS for list of people who contributed to this
   6  * project.
   7  *
   8  * This program is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU General Public License as
  10  * published by the Free Software Foundation; either version 2 of
  11  * the License, or (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program; if not, write to the Free Software
  20  * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
  21  * MA 02111-1307 USA
  22  */
  23
  24 #include <common.h>
  25 #include <linux/ctype.h>
  26
  27 #if defined(CONFIG_NIOS_SPI)
  28 #include <nios-io.h>
  29 #include <spi.h>
  30
  31 #if !defined(CFG_NIOS_SPIBASE)
  32 #error "*** CFG_NIOS_SPIBASE not defined ***"
  33 #endif
  34
  35 #if !defined(CFG_NIOS_SPIBITS)
  36 #error "*** CFG_NIOS_SPIBITS not defined ***"
  37 #endif
  38
  39 #if (CFG_NIOS_SPIBITS != 8) && (CFG_NIOS_SPIBITS != 16)
  40 #error "*** CFG_NIOS_SPIBITS should be either 8 or 16 ***"
  41 #endif
  42
  43 static nios_spi_t       *spi    = (nios_spi_t *)CFG_NIOS_SPIBASE;
  44
  45 /* Warning:
  46  * You cannot enable DEBUG for early system initalization, i. e. when
  47  * this driver is used to read environment parameters like "baudrate"
  48  * from EEPROM which are used to initialize the serial port which is
  49  * needed to print the debug messages...
  50  */
  51 #undef  DEBUG
  52
  53 #ifdef  DEBUG
  54
  55 #define DPRINT(a)       printf a;
  56 /* -----------------------------------------------
  57  * Helper functions to peek into tx and rx buffers
  58  * ----------------------------------------------- */
  59 static const char * const hex_digit = "0123456789ABCDEF";
  60
  61 static char quickhex (int i)
  62 {
  63         return hex_digit[i];
  64 }
  65
  66 static void memdump (void *pv, int num)
  67 {
  68         int i;
  69         unsigned char *pc = (unsigned char *) pv;
  70
  71         for (i = 0; i < num; i++)
  72                 printf ("%c%c ", quickhex (pc[i] >> 4), quickhex (pc[i] & 0x0f));
  73         printf ("\t");
  74         for (i = 0; i < num; i++)
  75                 printf ("%c", isprint (pc[i]) ? pc[i] : '.');
  76         printf ("\n");
  77 }
  78 #else   /* !DEBUG */
  79
  80 #define DPRINT(a)
  81 #define memdump(p,n)
  82
  83 #endif  /* DEBUG */
  84
  85
  86 /*
  87  * SPI transfer:
  88  *
  89  * See include/spi.h and http://www.altera.com/literature/ds/ds_nios_spi.pdf
  90  * for more informations.
  91  */
  92 int spi_xfer(spi_chipsel_type chipsel, int bitlen, uchar *dout, uchar *din)
  93 {
  94         int j;
  95
  96         DPRINT(("spi_xfer: chipsel %08X dout %08X din %08X bitlen %d\n",
  97                 (int)chipsel, *(uint *)dout, *(uint *)din, bitlen));
  98
  99         memdump((void*)dout, (bitlen + 7) / 8);
 100
 101         if(chipsel != NULL) {
 102                 chipsel(1);     /* select the target chip */
 103         }
 104
 105         if (bitlen > CFG_NIOS_SPIBITS) {        /* leave chip select active */
 106                 spi->control |= NIOS_SPI_SSO;
 107         }
 108
 109         for (   j = 0;                          /* count each byte in */
 110                 j < ((bitlen + 7) / 8);         /* dout[] and din[] */
 111
 112 #if     (CFG_NIOS_SPIBITS == 8)
 113                 j++) {
 114
 115                 while ((spi->status & NIOS_SPI_TRDY) == 0)
 116                         ;
 117                 spi->txdata = (unsigned)(dout[j]);
 118
 119                 while ((spi->status & NIOS_SPI_RRDY) == 0)
 120                         ;
 121                 din[j] = (unsigned char)(spi->rxdata & 0xff);
 122
 123 #elif   (CFG_NIOS_SPIBITS == 16)
 124                 j++, j++) {
 125
 126                 while ((spi->status & NIOS_SPI_TRDY) == 0)
 127                         ;
 128                 if ((j+1) < ((bitlen + 7) / 8))
 129                         spi->txdata = (unsigned)((dout[j] << 8) | dout[j+1]);
 130                 else
 131                         spi->txdata = (unsigned)(dout[j] << 8);
 132
 133                 while ((spi->status & NIOS_SPI_RRDY) == 0)
 134                         ;
 135                 din[j] = (unsigned char)((spi->rxdata >> 8) & 0xff);
 136                 if ((j+1) < ((bitlen + 7) / 8))
 137                         din[j+1] = (unsigned char)(spi->rxdata & 0xff);
 138
 139 #else
 140 #error "*** unsupported value of CFG_NIOS_SPIBITS ***"
 141 #endif
 142
 143         }
 144
 145         if (bitlen > CFG_NIOS_SPIBITS) {
 146                 spi->control &= ~NIOS_SPI_SSO;
 147         }
 148
 149         if(chipsel != NULL) {
 150                 chipsel(0);     /* deselect the target chip */
 151         }
 152
 153         memdump((void*)din, (bitlen + 7) / 8);
 154
 155         return 0;
 156 }
 157
 158 #endif /* CONFIG_NIOS_SPI */