andes_spi: add andes_spi interface

andes_spi is an spi interface developed by Andes Tech.

Signed-off-by: Macpaul Lin <macpaul@andestech.com>
Cc: Wolfgang Denk <wd@denx.de>
Cc: Mike Frysinger <vapier@gentoo.org>
Acked-by: Mike Frysinger <vapier@gentoo.org>

1 files changed, 302 insertions, 0 deletions

diff --git a/drivers/spi/andes_spi.c b/drivers/spi/andes_spi.c
new file mode 100644
index 0000000..fdde139
--- /dev/null
+++ b/drivers/spi/andes_spi.c
@@ -0,0 +1,302 @@
+/*
+ * Driver of Andes SPI Controller
+ *
+ * (C) Copyright 2011 Andes Technology
+ * Macpaul Lin <macpaul@andestech.com>
+ *
+ * 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 <malloc.h>
+#include <spi.h>
+
+#include <asm/io.h>
+#include "andes_spi.h"
+
+void spi_init(void)
+{
+	/* do nothing */
+}
+
+static void andes_spi_spit_en(struct andes_spi_slave *ds)
+{
+	unsigned int dcr = readl(&ds->regs->dcr);
+
+	debug("%s: dcr: %x, write value: %x\n",
+			__func__, dcr, (dcr | ANDES_SPI_DCR_SPIT));
+
+	writel((dcr | ANDES_SPI_DCR_SPIT), &ds->regs->dcr);
+}
+
+struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs,
+			unsigned int max_hz, unsigned int mode)
+{
+	struct andes_spi_slave	*ds;
+
+	if (!spi_cs_is_valid(bus, cs))
+		return NULL;
+
+	ds = malloc(sizeof(*ds));
+	if (!ds)
+		return NULL;
+
+	ds->slave.bus = bus;
+	ds->slave.cs = cs;
+	ds->regs = (struct andes_spi_regs *)CONFIG_SYS_SPI_BASE;
+
+	/*
+	 * The hardware of andes_spi will set its frequency according
+	 * to APB/AHB bus clock. Hence the hardware doesn't allow changing of
+	 * requency and so the user requested speed is always ignored.
+	 */
+	ds->freq = max_hz;
+
+	return &ds->slave;
+}
+
+void spi_free_slave(struct spi_slave *slave)
+{
+	struct andes_spi_slave *ds = to_andes_spi(slave);
+
+	free(ds);
+}
+
+int spi_claim_bus(struct spi_slave *slave)
+{
+	struct andes_spi_slave *ds = to_andes_spi(slave);
+	unsigned int apb;
+	unsigned int baud;
+
+	/* Enable the SPI hardware */
+	writel(ANDES_SPI_CR_SPIRST, &ds->regs->cr);
+	udelay(1000);
+
+	/* setup format */
+	baud = ((CONFIG_SYS_CLK_FREQ / CONFIG_SYS_SPI_CLK / 2) - 1) & 0xFF;
+
+	/*
+	 * SPI_CLK = AHB bus clock / ((BAUD + 1)*2)
+	 * BAUD = AHB bus clock / SPI_CLK / 2) - 1
+	 */
+	apb = (readl(&ds->regs->apb) & 0xffffff00) | baud;
+	writel(apb, &ds->regs->apb);
+
+	/* no interrupts */
+	writel(0, &ds->regs->ie);
+
+	return 0;
+}
+
+void spi_release_bus(struct spi_slave *slave)
+{
+	struct andes_spi_slave *ds = to_andes_spi(slave);
+
+	/* Disable the SPI hardware */
+	writel(ANDES_SPI_CR_SPIRST, &ds->regs->cr);
+}
+
+static int andes_spi_read(struct spi_slave *slave, unsigned int len,
+			    u8 *rxp, unsigned long flags)
+{
+	struct andes_spi_slave *ds = to_andes_spi(slave);
+	unsigned int i, left;
+	unsigned int data;
+
+	debug("%s: slave: %x, len: %d, rxp: %x, flags: %d\n",
+		__func__, slave, len, rxp, flags);
+
+	debug("%s: data: ", __func__);
+	while (len > 0) {
+		left = min(len, 4);
+		data = readl(&ds->regs->data);
+
+		debug(" ");
+		for (i = 0; i < left; i++) {
+			debug("%02x ", data & 0xff);
+			*rxp++ = data;
+			data >>= 8;
+			len--;
+		}
+	}
+	debug("\n");
+
+	return 0;
+}
+
+static int andes_spi_write(struct spi_slave *slave, unsigned int wlen,
+			unsigned int rlen, const u8 *txp, unsigned long flags)
+{
+	struct andes_spi_slave *ds = to_andes_spi(slave);
+	unsigned int data;
+	unsigned int i, left;
+	unsigned int spit_enabled = 0;
+
+	debug("%s: slave: %x, wlen: %d, rlen: %d, txp: %x, flags: %x\n",
+		__func__, slave, wlen, rlen, txp, flags);
+
+	/* The value of wlen and rlen wrote to register must minus 1 */
+	if (rlen == 0)					/* write only */
+		writel(ANDES_SPI_DCR_MODE_WO | ANDES_SPI_DCR_WCNT(wlen-1) |
+				ANDES_SPI_DCR_RCNT(0), &ds->regs->dcr);
+	else						/* write then read */
+		writel(ANDES_SPI_DCR_MODE_WR | ANDES_SPI_DCR_WCNT(wlen-1) |
+				ANDES_SPI_DCR_RCNT(rlen-1), &ds->regs->dcr);
+
+	/* wait till SPIBSY is cleared */
+	while (readl(&ds->regs->st) & ANDES_SPI_ST_SPIBSY)
+		;
+
+	/* data write process */
+	debug("%s: txp: ", __func__);
+	while (wlen > 0) {
+		/* clear the data */
+		data = 0;
+
+		/* data are usually be read 32bits once a time */
+		left = min(wlen, 4);
+
+		for (i = 0; i < left; i++) {
+			debug("%x ", *txp);
+			data |= *txp++ << (i * 8);
+			wlen--;
+		}
+		debug("\n");
+
+		debug("data: %08x\n", data);
+		debug("streg before write: %08x\n", readl(&ds->regs->st));
+		/* wait till TXFULL is deasserted */
+		while (readl(&ds->regs->st) & ANDES_SPI_ST_TXFEL)
+			;
+		writel(data, &ds->regs->data);
+		debug("streg after write: %08x\n", readl(&ds->regs->st));
+
+
+		if (spit_enabled == 0) {
+			/* enable SPIT bit -  trigger the tx and rx progress */
+			andes_spi_spit_en(ds);
+			spit_enabled = 1;
+		}
+
+	}
+	debug("\n");
+
+	return 0;
+}
+
+/*
+ * spi_xfer:
+ *	Since andes_spi doesn't support independent command transaction,
+ *	that is, write and than read must be operated in continuous
+ *	execution, there is no need to set dcr and trigger spit again in
+ *	RX process.
+ */
+int spi_xfer(struct spi_slave *slave, unsigned int bitlen,
+	     const void *dout, void *din, unsigned long flags)
+{
+	unsigned int len;
+	static int op_nextime;
+	static u8 tmp_cmd[5];
+	static int tmp_wlen;
+	unsigned int i;
+
+	if (bitlen == 0)
+		/* Finish any previously submitted transfers */
+		goto out;
+
+	if (bitlen % 8) {
+		/* Errors always terminate an ongoing transfer */
+		flags |= SPI_XFER_END;
+		goto out;
+	}
+
+	len = bitlen / 8;
+
+	debug("%s: slave: %08x, bitlen: %d, dout: "
+		"%08x, din: %08x, flags: %d, len: %d\n",
+		__func__, slave, bitlen, dout, din, flags, len);
+
+	/*
+	 * Important:
+	 *	andes_spi's hardware doesn't support 2 data channel. The read
+	 *	and write cmd/data share the same register (data register).
+	 *
+	 *	If a command has write and read transaction, you cannot do write
+	 *	this time and then do read on next time.
+	 *
+	 *	A command writes first with a read response must indicating
+	 *	the read length in write operation. Hence the write action must
+	 *	be stored temporary and wait until the next read action has been
+	 *	arrived. Then we flush the write and read action out together.
+	 */
+	if (!dout) {
+		if (op_nextime == 1) {
+			/* flags should be SPI_XFER_END, value is 2 */
+			op_nextime = 0;
+			andes_spi_write(slave, tmp_wlen, len, tmp_cmd, flags);
+		}
+		return andes_spi_read(slave, len, din, flags);
+	} else if (!din) {
+		if (flags == SPI_XFER_BEGIN) {
+			/* store the write command and do operation next time */
+			op_nextime = 1;
+			memset(tmp_cmd, 0, sizeof(tmp_cmd));
+			memcpy(tmp_cmd, dout, len);
+
+			debug("%s: tmp_cmd: ", __func__);
+			for (i = 0; i < len; i++)
+				debug("%x ", *(tmp_cmd + i));
+			debug("\n");
+
+			tmp_wlen = len;
+		} else {
+			/*
+			 * flags should be (SPI_XFER_BEGIN | SPI_XFER_END),
+			 * the value is 3.
+			 */
+			if (op_nextime == 1) {
+				/* flags should be SPI_XFER_END, value is 2 */
+				op_nextime = 0;
+				/* flags 3 implies write only */
+				andes_spi_write(slave, tmp_wlen, 0, tmp_cmd, 3);
+			}
+
+			debug("flags: %x\n", flags);
+			return andes_spi_write(slave, len, 0, dout, flags);
+		}
+	}
+
+out:
+	return 0;
+}
+
+int spi_cs_is_valid(unsigned int bus, unsigned int cs)
+{
+	return bus == 0 && cs == 0;
+}
+
+void spi_cs_activate(struct spi_slave *slave)
+{
+	/* do nothing */
+}
+
+void spi_cs_deactivate(struct spi_slave *slave)
+{
+	/* do nothing */
+}