spi: add support SuperH SPI module

SH7757 has SPI module. This patch supports it.

Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Signed-off-by: Nobuhiro Iwamatsu <iwamatsu@nigauri.org>

1 files changed, 261 insertions, 0 deletions

diff --git a/drivers/spi/sh_spi.c b/drivers/spi/sh_spi.c
new file mode 100644
index 0000000..ba43bec
--- /dev/null
+++ b/drivers/spi/sh_spi.c
@@ -0,0 +1,261 @@
+/*
+ * SH SPI driver
+ *
+ * Copyright (C) 2011 Renesas Solutions Corp.
+ *
+ * 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; version 2 of the License.
+ *
+ * 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
+ *
+ */
+
+#include <common.h>
+#include <malloc.h>
+#include <spi.h>
+#include <asm/io.h>
+#include "sh_spi.h"
+
+static void sh_spi_write(unsigned long data, unsigned long *reg)
+{
+	writel(data, reg);
+}
+
+static unsigned long sh_spi_read(unsigned long *reg)
+{
+	return readl(reg);
+}
+
+static void sh_spi_set_bit(unsigned long val, unsigned long *reg)
+{
+	unsigned long tmp;
+
+	tmp = sh_spi_read(reg);
+	tmp |= val;
+	sh_spi_write(tmp, reg);
+}
+
+static void sh_spi_clear_bit(unsigned long val, unsigned long *reg)
+{
+	unsigned long tmp;
+
+	tmp = sh_spi_read(reg);
+	tmp &= ~val;
+	sh_spi_write(tmp, reg);
+}
+
+static void clear_fifo(struct sh_spi *ss)
+{
+	sh_spi_set_bit(SH_SPI_RSTF, &ss->regs->cr2);
+	sh_spi_clear_bit(SH_SPI_RSTF, &ss->regs->cr2);
+}
+
+static int recvbuf_wait(struct sh_spi *ss)
+{
+	while (sh_spi_read(&ss->regs->cr1) & SH_SPI_RBE) {
+		if (ctrlc())
+			return 1;
+		udelay(10);
+	}
+	return 0;
+}
+
+static int write_fifo_empty_wait(struct sh_spi *ss)
+{
+	while (!(sh_spi_read(&ss->regs->cr1) & SH_SPI_TBE)) {
+		if (ctrlc())
+			return 1;
+		udelay(10);
+	}
+	return 0;
+}
+
+void spi_init(void)
+{
+}
+
+struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs,
+		unsigned int max_hz, unsigned int mode)
+{
+	struct sh_spi *ss;
+
+	if (!spi_cs_is_valid(bus, cs))
+		return NULL;
+
+	ss = malloc(sizeof(struct spi_slave));
+	if (!ss)
+		return NULL;
+
+	ss->slave.bus = bus;
+	ss->slave.cs = cs;
+	ss->regs = (struct sh_spi_regs *)CONFIG_SH_SPI_BASE;
+
+	/* SPI sycle stop */
+	sh_spi_write(0xfe, &ss->regs->cr1);
+	/* CR1 init */
+	sh_spi_write(0x00, &ss->regs->cr1);
+	/* CR3 init */
+	sh_spi_write(0x00, &ss->regs->cr3);
+
+	clear_fifo(ss);
+
+	/* 1/8 clock */
+	sh_spi_write(sh_spi_read(&ss->regs->cr2) | 0x07, &ss->regs->cr2);
+	udelay(10);
+
+	return &ss->slave;
+}
+
+void spi_free_slave(struct spi_slave *slave)
+{
+	struct sh_spi *spi = to_sh_spi(slave);
+
+	free(spi);
+}
+
+int spi_claim_bus(struct spi_slave *slave)
+{
+	return 0;
+}
+
+void spi_release_bus(struct spi_slave *slave)
+{
+	struct sh_spi *ss = to_sh_spi(slave);
+
+	sh_spi_write(sh_spi_read(&ss->regs->cr1) &
+		~(SH_SPI_SSA | SH_SPI_SSDB | SH_SPI_SSD), &ss->regs->cr1);
+}
+
+static int sh_spi_send(struct sh_spi *ss, const unsigned char *tx_data,
+			unsigned int len, unsigned long flags)
+{
+	int i, cur_len, ret = 0;
+	int remain = (int)len;
+	unsigned long tmp;
+
+	if (len >= SH_SPI_FIFO_SIZE)
+		sh_spi_set_bit(SH_SPI_SSA, &ss->regs->cr1);
+
+	while (remain > 0) {
+		cur_len = (remain < SH_SPI_FIFO_SIZE) ?
+				remain : SH_SPI_FIFO_SIZE;
+		for (i = 0; i < cur_len &&
+			!(sh_spi_read(&ss->regs->cr4) & SH_SPI_WPABRT) &&
+			!(sh_spi_read(&ss->regs->cr1) & SH_SPI_TBF);
+				i++)
+			sh_spi_write(tx_data[i], &ss->regs->tbr_rbr);
+
+		cur_len = i;
+
+		if (sh_spi_read(&ss->regs->cr4) & SH_SPI_WPABRT) {
+			/* Abort the transaction */
+			flags |= SPI_XFER_END;
+			sh_spi_set_bit(SH_SPI_WPABRT, &ss->regs->cr4);
+			ret = 1;
+			break;
+		}
+
+		remain -= cur_len;
+		tx_data += cur_len;
+
+		if (remain > 0)
+			write_fifo_empty_wait(ss);
+	}
+
+	if (flags & SPI_XFER_END) {
+		tmp = sh_spi_read(&ss->regs->cr1);
+		tmp = tmp & ~(SH_SPI_SSD | SH_SPI_SSDB);
+		sh_spi_write(tmp, &ss->regs->cr1);
+		sh_spi_set_bit(SH_SPI_SSA, &ss->regs->cr1);
+		udelay(100);
+		write_fifo_empty_wait(ss);
+	}
+
+	return ret;
+}
+
+static int sh_spi_receive(struct sh_spi *ss, unsigned char *rx_data,
+			  unsigned int len, unsigned long flags)
+{
+	int i;
+	unsigned long tmp;
+
+	if (len > SH_SPI_MAX_BYTE)
+		sh_spi_write(SH_SPI_MAX_BYTE, &ss->regs->cr3);
+	else
+		sh_spi_write(len, &ss->regs->cr3);
+
+	tmp = sh_spi_read(&ss->regs->cr1);
+	tmp = tmp & ~(SH_SPI_SSD | SH_SPI_SSDB);
+	sh_spi_write(tmp, &ss->regs->cr1);
+	sh_spi_set_bit(SH_SPI_SSA, &ss->regs->cr1);
+
+	for (i = 0; i < len; i++) {
+		if (recvbuf_wait(ss))
+			return 0;
+
+		rx_data[i] = (unsigned char)sh_spi_read(&ss->regs->tbr_rbr);
+	}
+	sh_spi_write(0, &ss->regs->cr3);
+
+	return 0;
+}
+
+int  spi_xfer(struct spi_slave *slave, unsigned int bitlen, const void *dout,
+		void *din, unsigned long flags)
+{
+	struct sh_spi *ss = to_sh_spi(slave);
+	const unsigned char *tx_data = dout;
+	unsigned char *rx_data = din;
+	unsigned int len = bitlen / 8;
+	int ret = 0;
+
+	if (flags & SPI_XFER_BEGIN)
+		sh_spi_write(sh_spi_read(&ss->regs->cr1) & ~SH_SPI_SSA,
+				&ss->regs->cr1);
+
+	if (tx_data)
+		ret = sh_spi_send(ss, tx_data, len, flags);
+
+	if (ret == 0 && rx_data)
+		ret = sh_spi_receive(ss, rx_data, len, flags);
+
+	if (flags & SPI_XFER_END) {
+		sh_spi_set_bit(SH_SPI_SSD, &ss->regs->cr1);
+		udelay(100);
+
+		sh_spi_clear_bit(SH_SPI_SSA | SH_SPI_SSDB | SH_SPI_SSD,
+				 &ss->regs->cr1);
+		clear_fifo(ss);
+	}
+
+	return ret;
+}
+
+int  spi_cs_is_valid(unsigned int bus, unsigned int cs)
+{
+	/* This driver supports "bus = 0" and "cs = 0" only. */
+	if (!bus && !cs)
+		return 1;
+	else
+		return 0;
+}
+
+void spi_cs_activate(struct spi_slave *slave)
+{
+
+}
+
+void spi_cs_deactivate(struct spi_slave *slave)
+{
+
+}
+