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(CONFIG_SYS_NIOS_SPIBASE)
  32 #error "*** CONFIG_SYS_NIOS_SPIBASE not defined ***"
  33 #endif
  34
  35 #if !defined(CONFIG_SYS_NIOS_SPIBITS)
  36 #error "*** CONFIG_SYS_NIOS_SPIBITS not defined ***"
  37 #endif
  38
  39 #if (CONFIG_SYS_NIOS_SPIBITS != 8) && (CONFIG_SYS_NIOS_SPIBITS != 16)
  40 #error "*** CONFIG_SYS_NIOS_SPIBITS should be either 8 or 16 ***"
  41 #endif
  42
  43 static nios_spi_t       *spi    = (nios_spi_t *)CONFIG_SYS_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 (const void *pv, int num)
  67 {
  68         int i;
  69         const unsigned char *pc = (const 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 struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs,
  87                 unsigned int max_hz, unsigned int mode)
  88 {
  89         struct spi_slave *slave;
  90
  91         if (!spi_cs_is_valid(bus, cs))
  92                 return NULL;
  93
  94         slave = malloc(sizeof(struct spi_slave));
  95         if (!slave)
  96                 return NULL;
  97
  98         slave->bus = bus;
  99         slave->cs = cs;
 100
 101         /* TODO: Add support for different modes and speeds */
 102
 103         return slave;
 104 }
 105
 106 void spi_free_slave(struct spi_slave *slave)
 107 {
 108         free(slave);
 109 }
 110
 111 int spi_claim_bus(struct spi_slave *slave)
 112 {
 113         return 0;
 114 }
 115
 116 void spi_release_bus(struct spi_slave *slave)
 117 {
 118
 119 }
 120
 121 /*
 122  * SPI transfer:
 123  *
 124  * See include/spi.h and http://www.altera.com/literature/ds/ds_nios_spi.pdf
 125  * for more informations.
 126  */
 127 int spi_xfer(struct spi_slave *slave, int bitlen, const void *dout,
 128                 void *din, unsigned long flags)
 129 {
 130         const u8 *txd = dout;
 131         u8 *rxd = din;
 132         int j;
 133
 134         DPRINT(("spi_xfer: slave %u:%u dout %08X din %08X bitlen %d\n",
 135                 slave->bus, slave->cs, *(uint *)dout, *(uint *)din, bitlen));
 136
 137         memdump(dout, (bitlen + 7) / 8);
 138
 139         if (flags & SPI_XFER_BEGIN)
 140                 spi_cs_activate(slave);
 141
 142         if (!(flags & SPI_XFER_END) || bitlen > CONFIG_SYS_NIOS_SPIBITS) {
 143                 /* leave chip select active */
 144                 spi->control |= NIOS_SPI_SSO;
 145         }
 146
 147         for (   j = 0;                          /* count each byte in */
 148                 j < ((bitlen + 7) / 8);         /* dout[] and din[] */
 149
 150 #if     (CONFIG_SYS_NIOS_SPIBITS == 8)
 151                 j++) {
 152
 153                 while ((spi->status & NIOS_SPI_TRDY) == 0)
 154                         ;
 155                 spi->txdata = (unsigned)(txd[j]);
 156
 157                 while ((spi->status & NIOS_SPI_RRDY) == 0)
 158                         ;
 159                 rxd[j] = (unsigned char)(spi->rxdata & 0xff);
 160
 161 #elif   (CONFIG_SYS_NIOS_SPIBITS == 16)
 162                 j++, j++) {
 163
 164                 while ((spi->status & NIOS_SPI_TRDY) == 0)
 165                         ;
 166                 if ((j+1) < ((bitlen + 7) / 8))
 167                         spi->txdata = (unsigned)((txd[j] << 8) | txd[j+1]);
 168                 else
 169                         spi->txdata = (unsigned)(txd[j] << 8);
 170
 171                 while ((spi->status & NIOS_SPI_RRDY) == 0)
 172                         ;
 173                 rxd[j] = (unsigned char)((spi->rxdata >> 8) & 0xff);
 174                 if ((j+1) < ((bitlen + 7) / 8))
 175                         rxd[j+1] = (unsigned char)(spi->rxdata & 0xff);
 176
 177 #else
 178 #error "*** unsupported value of CONFIG_SYS_NIOS_SPIBITS ***"
 179 #endif
 180
 181         }
 182
 183         if (bitlen > CONFIG_SYS_NIOS_SPIBITS && (flags & SPI_XFER_END)) {
 184                 spi->control &= ~NIOS_SPI_SSO;
 185         }
 186
 187         if (flags & SPI_XFER_END)
 188                 spi_cs_deactivate(slave);
 189
 190         memdump(din, (bitlen + 7) / 8);
 191
 192         return 0;
 193 }
 194
 195 #endif /* CONFIG_NIOS_SPI */