spi: Add Marvell Kirkwood SPI driver

This patch adds a SPI driver for the Marvell Kirkwood SoC's.

Signed-off-by: Prafulla Wadaskar <prafulla@marvell.com>

1 files changed, 185 insertions, 0 deletions

diff --git a/drivers/spi/kirkwood_spi.c b/drivers/spi/kirkwood_spi.c
new file mode 100644
index 0000000..a1c3070
--- /dev/null
+++ b/drivers/spi/kirkwood_spi.c
@@ -0,0 +1,185 @@
+/*
+ * (C) Copyright 2009
+ * Marvell Semiconductor <www.marvell.com>
+ * Written-by: Prafulla Wadaskar <prafulla@marvell.com>
+ *
+ * Derived from drivers/spi/mpc8xxx_spi.c
+ *
+ * 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., 51 Franklin Street, Fifth Floor, Boston,
+ * MA 02110-1301 USA
+ */
+
+#include <common.h>
+#include <malloc.h>
+#include <spi.h>
+#include <asm/arch/kirkwood.h>
+#include <asm/arch/spi.h>
+#include <asm/arch/mpp.h>
+
+static struct kwspi_registers *spireg = (struct kwspi_registers *)KW_SPI_BASE;
+
+struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs,
+				unsigned int max_hz, unsigned int mode)
+{
+	struct spi_slave *slave;
+	u32 data;
+	u32 kwspi_mpp_config[] = {
+		MPP0_GPIO,
+		MPP7_SPI_SCn,
+		0
+	};
+
+	if (!spi_cs_is_valid(bus, cs))
+		return NULL;
+
+	slave = malloc(sizeof(struct spi_slave));
+	if (!slave)
+		return NULL;
+
+	slave->bus = bus;
+	slave->cs = cs;
+
+	writel(~KWSPI_CSN_ACT | KWSPI_SMEMRDY, &spireg->ctrl);
+
+	/* calculate spi clock prescaller using max_hz */
+	data = ((CONFIG_SYS_TCLK / 2) / max_hz) & KWSPI_CLKPRESCL_MASK;
+	data |= 0x10;
+
+	/* program spi clock prescaller using max_hz */
+	writel(KWSPI_ADRLEN_3BYTE | data, &spireg->cfg);
+	debug("data = 0x%08x \n", data);
+
+	writel(KWSPI_SMEMRDIRQ, &spireg->irq_cause);
+	writel(KWSPI_IRQMASK, spireg->irq_mask);
+
+	/* program mpp registers to select  SPI_CSn */
+	if (cs) {
+		kwspi_mpp_config[0] = MPP0_GPIO;
+		kwspi_mpp_config[1] = MPP7_SPI_SCn;
+	} else {
+		kwspi_mpp_config[0] = MPP0_SPI_SCn;
+		kwspi_mpp_config[1] = MPP7_GPO;
+	}
+	kirkwood_mpp_conf(kwspi_mpp_config);
+
+	return slave;
+}
+
+void spi_free_slave(struct spi_slave *slave)
+{
+	free(slave);
+}
+
+int spi_claim_bus(struct spi_slave *slave)
+{
+	return 0;
+}
+
+void spi_release_bus(struct spi_slave *slave)
+{
+}
+
+#ifndef CONFIG_SPI_CS_IS_VALID
+/*
+ * you can define this function board specific
+ * define above CONFIG in board specific config file and
+ * provide the function in board specific src file
+ */
+int spi_cs_is_valid(unsigned int bus, unsigned int cs)
+{
+	return (bus == 0 && (cs == 0 || cs == 1));
+}
+#endif
+
+void spi_cs_activate(struct spi_slave *slave)
+{
+	writel(readl(&spireg->ctrl) | KWSPI_IRQUNMASK, &spireg->ctrl);
+}
+
+void spi_cs_deactivate(struct spi_slave *slave)
+{
+	writel(readl(&spireg->ctrl) & KWSPI_IRQMASK, &spireg->ctrl);
+}
+
+int spi_xfer(struct spi_slave *slave, unsigned int bitlen, const void *dout,
+	     void *din, unsigned long flags)
+{
+	unsigned int tmpdout, tmpdin;
+	int tm, isread = 0;
+
+	debug("spi_xfer: slave %u:%u dout %08X din %08X bitlen %u\n",
+	      slave->bus, slave->cs, dout, din, bitlen);
+
+	if (flags & SPI_XFER_BEGIN)
+		spi_cs_activate(slave);
+
+	/*
+	 * handle data in 8-bit chunks
+	 * TBD: 2byte xfer mode to be enabled
+	 */
+	writel(((readl(&spireg->cfg) & ~KWSPI_XFERLEN_MASK) |
+		KWSPI_XFERLEN_1BYTE), &spireg->cfg);
+
+	while (bitlen > 4) {
+		debug("loopstart bitlen %d\n", bitlen);
+		tmpdout = 0;
+
+		/* Shift data so it's msb-justified */
+		if (dout)
+			tmpdout = *(u32 *) dout & 0x0ff;
+
+		writel(~KWSPI_SMEMRDIRQ, &spireg->irq_cause);
+		writel(tmpdout, &spireg->dout);	/* Write the data out */
+		debug("*** spi_xfer: ... %08x written, bitlen %d\n",
+		      tmpdout, bitlen);
+
+		/*
+		 * Wait for SPI transmit to get out
+		 * or time out (1 second = 1000 ms)
+		 * The NE event must be read and cleared first
+		 */
+		for (tm = 0, isread = 0; tm < KWSPI_TIMEOUT; ++tm) {
+			if (readl(&spireg->irq_cause) & KWSPI_SMEMRDIRQ) {
+				isread = 1;
+				tmpdin = readl(&spireg->din);
+				debug
+					("spi_xfer: din %08x..%08x read\n",
+					din, tmpdin);
+
+				if (din) {
+					*((u8 *) din) = (u8) tmpdin;
+					din += 1;
+				}
+				if (dout)
+					dout += 1;
+				bitlen -= 8;
+			}
+			if (isread)
+				break;
+		}
+		if (tm >= KWSPI_TIMEOUT)
+			printf("*** spi_xfer: Time out during SPI transfer\n");
+
+		debug("loopend bitlen %d\n", bitlen);
+	}
+
+	if (flags & SPI_XFER_END)
+		spi_cs_deactivate(slave);
+
+	return 0;
+}