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bertos/drv/spi_bitbang.c

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+/**
+ * \file
+ * <!--
+ * This file is part of BeRTOS.
+ *
+ * Bertos 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., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ *
+ * As a special exception, you may use this file as part of a free software
+ * library without restriction.  Specifically, if other files instantiate
+ * templates or use macros or inline functions from this file, or you compile
+ * this file and link it with other files to produce an executable, this
+ * file does not by itself cause the resulting executable to be covered by
+ * the GNU General Public License.  This exception does not however
+ * invalidate any other reasons why the executable file might be covered by
+ * the GNU General Public License.
+ *
+ * Copyright 2003, 2004, 2006 Develer S.r.l. (http://www.develer.com/)
+ * Copyright 2000 Bernie Innocenti <bernie@codewiz.org>
+ *
+ * -->
+ *
+ * \brief Emulated SPI Master for DSP firmware download (impl.)
+ *
+ *
+ * \author Francesco Sacchi <batt@develer.com>
+ * \author Daniele Basile <asterix@develer.com>
+ */
+
+
+#include "spi_bitbang.h"
+#include "hw/hw_spi.h"
+
+#include "cfg/cfg_spi_bitbang.h"
+#include <cfg/module.h>
+
+#include <cpu/irq.h>
+
+void spi_assertSS(void)
+{
+	ATOMIC(SS_ACTIVE());
+}
+
+void spi_deassertSS(void)
+{
+	ATOMIC(SS_INACTIVE());
+}
+
+/**
+ * Send byte \c c over MOSI line, CONFIG_SPI_DATAORDER first.
+ * SS pin state is left unchanged.
+ */
+uint8_t spi_sendRecv(uint8_t c)
+{
+	uint8_t data = 0;
+	uint8_t shift = SPI_DATAORDER_START;
+
+
+	ATOMIC(
+		for (int i = 0; i < 8; i++)
+		{
+			/* Shift the i-th bit to MOSI */
+			if (c & shift)
+				MOSI_HIGH();
+			else
+				MOSI_LOW();
+			/* Assert clock */
+			SCK_ACTIVE();
+			data |= IS_MISO_HIGH() ? shift : 0;
+			/* De-assert clock */
+			SCK_INACTIVE();
+			SPI_DATAORDER_SHIFT(shift);
+		}
+	);
+	return data;
+}
+
+MOD_DEFINE(spi);
+void spi_init(void)
+{
+	ATOMIC(SPI_HW_INIT());
+	MOD_INIT(spi);
+}
+
+/**
+ * Read \param len from spi, and put it in \param _buff .
+ */
+void spi_read(void *_buff, size_t len)
+{
+	uint8_t *buff = (uint8_t *)_buff;
+
+	while (len--)
+		/* Read byte from spi and put it in buffer. */
+		*buff++ = spi_sendRecv(0);
+
+}
+
+/**
+ * Write \param len to spi, and take it from \param _buff .
+ */
+void spi_write(const void *_buff, size_t len)
+{
+	const uint8_t *buff = (const uint8_t *)_buff;
+
+	while (len--)
+		/* Write byte pointed at by *buff to spi */
+		spi_sendRecv(*buff++);
+
+}