ColdFire: Queued SPI driver

This patch adds a driver for Freescale Colfire Queued SPI bus.
Coded to work with 8 bits per transfer to use with SPI flash.
CPOL, CPHA, and CS_ACTIVE_HIGH can be configured.

Tested with MCF5270 which have 4 chip selects.

Activate by #define CONFIG_CF_QSPI in board config.

Signed-off-by: Richard Retanubun <richardretanubun@ruggedcom.com>

1 files changed, 373 insertions, 0 deletions

diff --git a/drivers/spi/cf_qspi.c b/drivers/spi/cf_qspi.c
new file mode 100644
index 000000000..72dd1a520
--- /dev/null
+++ b/drivers/spi/cf_qspi.c
@@ -0,0 +1,373 @@
+/*
+ * Freescale Coldfire Queued SPI driver
+ *
+ * NOTE:
+ * This driver is written to transfer 8 bit at-a-time and uses the dedicated
+ * SPI slave select pins as bit-banged GPIO to work with spi_flash subsystem.
+ *
+ *
+ * Copyright (C) 2011 Ruggedcom, Inc.
+ * Richard Retanubun (richardretanubun@freescale.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/immap.h>
+#include <asm/io.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+#define clamp(x, low, high) (min(max(low, x), high))
+#define to_cf_qspi_slave(s) container_of(s, struct cf_qspi_slave, s)
+
+struct cf_qspi_slave {
+	struct spi_slave slave;	/* Specific bus:cs ID for each device */
+	qspi_t *regs;		/* Pointer to SPI controller registers */
+	u16 qmr;		/* QMR: Queued Mode Register */
+	u16 qwr;		/* QWR: Queued Wrap Register */
+	u16 qcr;		/* QCR: Queued Command Ram */
+};
+
+/* Register write wrapper functions */
+static void write_qmr(volatile qspi_t *qspi, u16 val)   { qspi->mr = val; }
+static void write_qdlyr(volatile qspi_t *qspi, u16 val) { qspi->dlyr = val; }
+static void write_qwr(volatile qspi_t *qspi, u16 val)   { qspi->wr = val; }
+static void write_qir(volatile qspi_t *qspi, u16 val)   { qspi->ir = val; }
+static void write_qar(volatile qspi_t *qspi, u16 val)   { qspi->ar = val; }
+static void write_qdr(volatile qspi_t *qspi, u16 val)   { qspi->dr = val; }
+/* Register read wrapper functions */
+static u16 read_qdlyr(volatile qspi_t *qspi) { return qspi->dlyr; }
+static u16 read_qwr(volatile qspi_t *qspi)   { return qspi->wr; }
+static u16 read_qir(volatile qspi_t *qspi)   { return qspi->ir; }
+static u16 read_qdr(volatile qspi_t *qspi)   { return qspi->dr; }
+
+/* These call points may be different for each ColdFire CPU */
+extern void cfspi_port_conf(void);
+static void cfspi_cs_activate(uint bus, uint cs, uint cs_active_high);
+static void cfspi_cs_deactivate(uint bus, uint cs, uint cs_active_high);
+
+int spi_claim_bus(struct spi_slave *slave)
+{
+	return 0;
+}
+void spi_release_bus(struct spi_slave *slave)
+{
+}
+
+__attribute__((weak))
+void spi_init(void)
+{
+	cfspi_port_conf();
+}
+
+__attribute__((weak))
+void spi_cs_activate(struct spi_slave *slave)
+{
+	struct cf_qspi_slave *dev = to_cf_qspi_slave(slave);
+
+	cfspi_cs_activate(slave->bus, slave->cs, !(dev->qwr & QSPI_QWR_CSIV));
+}
+
+__attribute__((weak))
+void spi_cs_deactivate(struct spi_slave *slave)
+{
+	struct cf_qspi_slave *dev = to_cf_qspi_slave(slave);
+
+	cfspi_cs_deactivate(slave->bus, slave->cs, !(dev->qwr & QSPI_QWR_CSIV));
+}
+
+__attribute__((weak))
+int spi_cs_is_valid(unsigned int bus, unsigned int cs)
+{
+	/* Only 1 bus and 4 chipselect per controller */
+	if (bus == 0 && (cs >= 0 && cs < 4))
+		return 1;
+	else
+		return 0;
+}
+
+void spi_free_slave(struct spi_slave *slave)
+{
+	struct cf_qspi_slave *dev = to_cf_qspi_slave(slave);
+
+	free(dev);
+}
+
+/* Translate information given by spi_setup_slave to members of cf_qspi_slave */
+struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs,
+				  unsigned int max_hz, unsigned int mode)
+{
+	struct cf_qspi_slave *dev = NULL;
+
+	if (!spi_cs_is_valid(bus, cs))
+		return NULL;
+
+	dev = malloc(sizeof(struct cf_qspi_slave));
+	if (!dev)
+		return NULL;
+
+	/* Initialize to known value */
+	dev->slave.bus = bus;
+	dev->slave.cs  = cs;
+	dev->regs      = (qspi_t *)MMAP_QSPI;
+	dev->qmr       = 0;
+	dev->qwr       = 0;
+	dev->qcr       = 0;
+
+
+	/* Map max_hz to QMR[BAUD] */
+	if (max_hz == 0) /* Go as fast as possible */
+		dev->qmr = 2u;
+	else /* Get the closest baud rate */
+		dev->qmr = clamp(((gd->bus_clk >> 2) + max_hz - 1)/max_hz,
+					2u, 255u);
+
+	/* Map mode to QMR[CPOL] and QMR[CPHA] */
+	if (mode & SPI_CPOL)
+		dev->qmr |= QSPI_QMR_CPOL;
+
+	if (mode & SPI_CPHA)
+		dev->qmr |= QSPI_QMR_CPHA;
+
+	/* Hardcode bit length to 8 bit per transter */
+	dev->qmr |= QSPI_QMR_BITS_8;
+
+	/* Set QMR[MSTR] to enable QSPI as master */
+	dev->qmr |= QSPI_QMR_MSTR;
+
+	/*
+	 * Set QCR and QWR to default values for spi flash operation.
+	 * If more custom QCR and QRW are needed, overload mode variable
+	 */
+	dev->qcr = (QSPI_QDR_CONT | QSPI_QDR_BITSE);
+
+	if (!(mode & SPI_CS_HIGH))
+		dev->qwr |= QSPI_QWR_CSIV;
+
+	return &dev->slave;
+}
+
+/* Transfer 8 bit at a time */
+int spi_xfer(struct spi_slave *slave, unsigned int bitlen, const void *dout,
+	     void *din, unsigned long flags)
+{
+	struct cf_qspi_slave *dev = to_cf_qspi_slave(slave);
+	volatile qspi_t *qspi = dev->regs;
+	u8 *txbuf = (u8 *)dout;
+	u8 *rxbuf = (u8 *)din;
+	u32 count = ((bitlen / 8) + (bitlen % 8 ? 1 : 0));
+	u32 n, i = 0;
+
+	/* Sanitize arguments */
+	if (slave == NULL) {
+		printf("%s: NULL slave ptr\n", __func__);
+		return -1;
+	}
+
+	if (flags & SPI_XFER_BEGIN)
+		spi_cs_activate(slave);
+
+	/* There is something to send, lets process it. spi_xfer is also called
+	 * just to toggle chip select, so bitlen of 0 is valid */
+	if (count > 0) {
+		/*
+		* NOTE: Since chip select is driven as a bit-bang-ed GPIO
+		* using spi_cs_activate() and spi_cs_deactivate(),
+		* the chip select settings inside the controller
+		* (i.e. QCR[CONT] and QWR[CSIV]) are moot. The bits are set to
+		* keep the controller settings consistent with the actual
+		* operation of the bus.
+		*/
+
+		/* Write the slave device's settings for the controller.*/
+		write_qmr(qspi, dev->qmr);
+		write_qwr(qspi, dev->qwr);
+
+		/* Limit transfer to 16 at a time */
+		n = min(count, 16u);
+		do {
+			/* Setup queue end point */
+			write_qwr(qspi, ((read_qwr(qspi) & QSPI_QWR_ENDQP_MASK)
+				| QSPI_QWR_ENDQP((n-1))));
+
+			/* Write Command RAM */
+			write_qar(qspi, QSPI_QAR_CMD);
+			for (i = 0; i < n; ++i)
+				write_qdr(qspi, dev->qcr);
+
+			/* Write TxBuf, if none given, fill with ZEROes */
+			write_qar(qspi, QSPI_QAR_TRANS);
+			if (txbuf) {
+				for (i = 0; i < n; ++i)
+					write_qdr(qspi, *txbuf++);
+			} else {
+				for (i = 0; i < n; ++i)
+					write_qdr(qspi, 0);
+			}
+
+			/* Clear QIR[SPIF] by writing a 1 to it */
+			write_qir(qspi, read_qir(qspi) | QSPI_QIR_SPIF);
+			/* Set QDLYR[SPE] to start sending */
+			write_qdlyr(qspi, read_qdlyr(qspi) | QSPI_QDLYR_SPE);
+
+			/* Poll QIR[SPIF] for transfer completion */
+			while ((read_qir(qspi) & QSPI_QIR_SPIF) != 1)
+				udelay(1);
+
+			/* If given read RxBuf, load data to it */
+			if (rxbuf) {
+				write_qar(qspi, QSPI_QAR_RECV);
+				for (i = 0; i < n; ++i)
+					*rxbuf++ = read_qdr(qspi);
+			}
+
+			/* Decrement count */
+			count -= n;
+		} while (count);
+	}
+
+	if (flags & SPI_XFER_END)
+		spi_cs_deactivate(slave);
+
+	return 0;
+}
+
+/* Each MCF CPU may have different pin assignments for chip selects. */
+#if defined(CONFIG_M5271)
+/* Assert chip select, val = [1|0] , dir = out, mode = GPIO */
+void cfspi_cs_activate(uint bus, uint cs, uint cs_active_high)
+{
+	debug("%s: bus %d cs %d cs_active_high %d\n",
+		__func__, bus, cs, cs_active_high);
+
+	switch (cs) {
+	case 0: /* QSPI_CS[0] = PQSPI[3] */
+		if (cs_active_high)
+			mbar_writeByte(MCF_GPIO_PPDSDR_QSPI, 0x08);
+		else
+			mbar_writeByte(MCF_GPIO_PCLRR_QSPI, 0xF7);
+
+		mbar_writeByte(MCF_GPIO_PDDR_QSPI,
+			mbar_readByte(MCF_GPIO_PDDR_QSPI) | 0x08);
+
+		mbar_writeByte(MCF_GPIO_PAR_QSPI,
+			mbar_readByte(MCF_GPIO_PAR_QSPI) & 0xDF);
+		break;
+	case 1: /* QSPI_CS[1] = PQSPI[4] */
+		if (cs_active_high)
+			mbar_writeByte(MCF_GPIO_PPDSDR_QSPI, 0x10);
+		else
+			mbar_writeByte(MCF_GPIO_PCLRR_QSPI, 0xEF);
+
+		mbar_writeByte(MCF_GPIO_PDDR_QSPI,
+			mbar_readByte(MCF_GPIO_PDDR_QSPI) | 0x10);
+
+		mbar_writeByte(MCF_GPIO_PAR_QSPI,
+			mbar_readByte(MCF_GPIO_PAR_QSPI) & 0x3F);
+		break;
+	case 2: /* QSPI_CS[2] = PTIMER[7] */
+		if (cs_active_high)
+			mbar_writeByte(MCF_GPIO_PPDSDR_TIMER, 0x80);
+		else
+			mbar_writeByte(MCF_GPIO_PCLRR_TIMER, 0x7F);
+
+		mbar_writeByte(MCF_GPIO_PDDR_TIMER,
+			mbar_readByte(MCF_GPIO_PDDR_TIMER) | 0x80);
+
+		mbar_writeShort(MCF_GPIO_PAR_TIMER,
+			mbar_readShort(MCF_GPIO_PAR_TIMER) & 0x3FFF);
+		break;
+	case 3: /* QSPI_CS[3] = PTIMER[3] */
+		if (cs_active_high)
+			mbar_writeByte(MCF_GPIO_PPDSDR_TIMER, 0x08);
+		else
+			mbar_writeByte(MCF_GPIO_PCLRR_TIMER, 0xF7);
+
+		mbar_writeByte(MCF_GPIO_PDDR_TIMER,
+			mbar_readByte(MCF_GPIO_PDDR_TIMER) | 0x08);
+
+		mbar_writeShort(MCF_GPIO_PAR_TIMER,
+			mbar_readShort(MCF_GPIO_PAR_TIMER) & 0xFF3F);
+		break;
+	}
+}
+
+/* Deassert chip select, val = [1|0], dir = in, mode = GPIO
+ * direction set as IN to undrive the pin, external pullup/pulldown will bring
+ * bus to deassert state.
+ */
+void cfspi_cs_deactivate(uint bus, uint cs, uint cs_active_high)
+{
+	debug("%s: bus %d cs %d cs_active_high %d\n",
+		__func__, bus, cs, cs_active_high);
+
+	switch (cs) {
+	case 0: /* QSPI_CS[0] = PQSPI[3] */
+		if (cs_active_high)
+			mbar_writeByte(MCF_GPIO_PCLRR_QSPI, 0xF7);
+		else
+			mbar_writeByte(MCF_GPIO_PPDSDR_QSPI, 0x08);
+
+		mbar_writeByte(MCF_GPIO_PDDR_QSPI,
+			mbar_readByte(MCF_GPIO_PDDR_QSPI) & 0xF7);
+
+		mbar_writeByte(MCF_GPIO_PAR_QSPI,
+			mbar_readByte(MCF_GPIO_PAR_QSPI) & 0xDF);
+		break;
+	case 1: /* QSPI_CS[1] = PQSPI[4] */
+		if (cs_active_high)
+			mbar_writeByte(MCF_GPIO_PCLRR_QSPI, 0xEF);
+		else
+			mbar_writeByte(MCF_GPIO_PPDSDR_QSPI, 0x10);
+
+		mbar_writeByte(MCF_GPIO_PDDR_QSPI,
+			mbar_readByte(MCF_GPIO_PDDR_QSPI) & 0xEF);
+
+		mbar_writeByte(MCF_GPIO_PAR_QSPI,
+			mbar_readByte(MCF_GPIO_PAR_QSPI) & 0x3F);
+		break;
+	case 2: /* QSPI_CS[2] = PTIMER[7] */
+		if (cs_active_high)
+			mbar_writeByte(MCF_GPIO_PCLRR_TIMER, 0x7F);
+		else
+			mbar_writeByte(MCF_GPIO_PPDSDR_TIMER, 0x80);
+
+		mbar_writeByte(MCF_GPIO_PDDR_TIMER,
+			mbar_readByte(MCF_GPIO_PDDR_TIMER) & 0x7F);
+
+		mbar_writeShort(MCF_GPIO_PAR_TIMER,
+			mbar_readShort(MCF_GPIO_PAR_TIMER) & 0x3FFF);
+		break;
+	case 3: /* QSPI_CS[3] = PTIMER[3] */
+		if (cs_active_high)
+			mbar_writeByte(MCF_GPIO_PCLRR_TIMER, 0xF7);
+		else
+			mbar_writeByte(MCF_GPIO_PPDSDR_TIMER, 0x08);
+
+		mbar_writeByte(MCF_GPIO_PDDR_TIMER,
+			mbar_readByte(MCF_GPIO_PDDR_TIMER) & 0xF7);
+
+		mbar_writeShort(MCF_GPIO_PAR_TIMER,
+			mbar_readShort(MCF_GPIO_PAR_TIMER) & 0xFF3F);
+		break;
+	}
+}
+#endif /* CONFIG_M5271 */