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-rw-r--r--cpu/nios/spi.c158
1 files changed, 158 insertions, 0 deletions
diff --git a/cpu/nios/spi.c b/cpu/nios/spi.c
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--- /dev/null
+++ b/cpu/nios/spi.c
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+/*
+ * (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 */