diff options
Diffstat (limited to 'cpu/nios/spi.c')
| -rw-r--r-- | cpu/nios/spi.c | 158 |
1 files changed, 158 insertions, 0 deletions
diff --git a/cpu/nios/spi.c b/cpu/nios/spi.c new file mode 100644 index 0000000..f37146b --- /dev/null +++ b/cpu/nios/spi.c @@ -0,0 +1,158 @@ +/* + * (C) Copyright 2004, Li-Pro.Net <www.li-pro.net> + * Stephan Linz <linz@li-pro.net> + * + * See file CREDITS for list of people who contributed to this + * project. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License as + * published by the Free Software Foundation; either version 2 of + * the License, or (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, + * MA 02111-1307 USA + */ + +#include <common.h> +#include <linux/ctype.h> + +#if defined(CONFIG_NIOS_SPI) +#include <nios-io.h> +#include <spi.h> + +#if !defined(CFG_NIOS_SPIBASE) +#error "*** CFG_NIOS_SPIBASE not defined ***" +#endif + +#if !defined(CFG_NIOS_SPIBITS) +#error "*** CFG_NIOS_SPIBITS not defined ***" +#endif + +#if (CFG_NIOS_SPIBITS != 8) && (CFG_NIOS_SPIBITS != 16) +#error "*** CFG_NIOS_SPIBITS should be either 8 or 16 ***" +#endif + +static nios_spi_t *spi = (nios_spi_t *)CFG_NIOS_SPIBASE; + +/* Warning: + * You cannot enable DEBUG for early system initalization, i. e. when + * this driver is used to read environment parameters like "baudrate" + * from EEPROM which are used to initialize the serial port which is + * needed to print the debug messages... + */ +#undef DEBUG + +#ifdef DEBUG + +#define DPRINT(a) printf a; +/* ----------------------------------------------- + * Helper functions to peek into tx and rx buffers + * ----------------------------------------------- */ +static const char * const hex_digit = "0123456789ABCDEF"; + +static char quickhex (int i) +{ + return hex_digit[i]; +} + +static void memdump (void *pv, int num) +{ + int i; + unsigned char *pc = (unsigned char *) pv; + + for (i = 0; i < num; i++) + printf ("%c%c ", quickhex (pc[i] >> 4), quickhex (pc[i] & 0x0f)); + printf ("\t"); + for (i = 0; i < num; i++) + printf ("%c", isprint (pc[i]) ? pc[i] : '.'); + printf ("\n"); +} +#else /* !DEBUG */ + +#define DPRINT(a) +#define memdump(p,n) + +#endif /* DEBUG */ + + +/* + * SPI transfer: + * + * See include/spi.h and http://www.altera.com/literature/ds/ds_nios_spi.pdf + * for more informations. + */ +int spi_xfer(spi_chipsel_type chipsel, int bitlen, uchar *dout, uchar *din) +{ + int j; + + DPRINT(("spi_xfer: chipsel %08X dout %08X din %08X bitlen %d\n", + (int)chipsel, *(uint *)dout, *(uint *)din, bitlen)); + + memdump((void*)dout, (bitlen + 7) / 8); + + if(chipsel != NULL) { + chipsel(1); /* select the target chip */ + } + + if (bitlen > CFG_NIOS_SPIBITS) { /* leave chip select active */ + spi->control |= NIOS_SPI_SSO; + } + + for ( j = 0; /* count each byte in */ + j < ((bitlen + 7) / 8); /* dout[] and din[] */ + +#if (CFG_NIOS_SPIBITS == 8) + j++) { + + while ((spi->status & NIOS_SPI_TRDY) == 0) + ; + spi->txdata = (unsigned)(dout[j]); + + while ((spi->status & NIOS_SPI_RRDY) == 0) + ; + din[j] = (unsigned char)(spi->rxdata & 0xff); + +#elif (CFG_NIOS_SPIBITS == 16) + j++, j++) { + + while ((spi->status & NIOS_SPI_TRDY) == 0) + ; + if ((j+1) < ((bitlen + 7) / 8)) + spi->txdata = (unsigned)((dout[j] << 8) | dout[j+1]); + else + spi->txdata = (unsigned)(dout[j] << 8); + + while ((spi->status & NIOS_SPI_RRDY) == 0) + ; + din[j] = (unsigned char)((spi->rxdata >> 8) & 0xff); + if ((j+1) < ((bitlen + 7) / 8)) + din[j+1] = (unsigned char)(spi->rxdata & 0xff); + +#else +#error "*** unsupported value of CFG_NIOS_SPIBITS ***" +#endif + + } + + if (bitlen > CFG_NIOS_SPIBITS) { + spi->control &= ~NIOS_SPI_SSO; + } + + if(chipsel != NULL) { + chipsel(0); /* deselect the target chip */ + } + + memdump((void*)din, (bitlen + 7) / 8); + + return 0; +} + +#endif /* CONFIG_NIOS_SPI */ |