spi: Add driver for Marvell Armada 3700 SoC

The SPI IP core in the Marvell Armada 3700 is similar to the one in the
other Armada SoCs. But the differences are big enough that it makes
sense to introduce a new driver instead of cluttering the old
kirkwood driver with #ifdef's.

Signed-off-by: Stefan Roese <sr@denx.de>
Cc: Nadav Haklai <nadavh@marvell.com>
Cc: Kostya Porotchkin <kostap@marvell.com>
Cc: Wilson Ding <dingwei@marvell.com>
Cc: Victor Gu <xigu@marvell.com>
Cc: Hua Jing <jinghua@marvell.com>
Cc: Terry Zhou <bjzhou@marvell.com>
Cc: Hanna Hawa <hannah@marvell.com>
Cc: Haim Boot <hayim@marvell.com>
Reviewed-by: Jagan Teki <jteki@openedev.com>

drivers/spi/Kconfig

@@ -68,6 +68,13 @@ config ICH_SPI
 	  access the SPI NOR flash on platforms embedding this Intel
 	  ICH IP core.
 
+config MVEBU_A3700_SPI
+	bool "Marvell Armada 3700 SPI driver"
+	help
+	  Enable the Marvell Armada 3700 SPI driver. This driver can be
+	  used to access the SPI NOR flash on platforms embedding this
+	  Marvell IP core.
+
 config PIC32_SPI
 	bool "Microchip PIC32 SPI driver"
 	depends on MACH_PIC32

drivers/spi/Makefile

@@ -37,6 +37,7 @@ obj-$(CONFIG_KIRKWOOD_SPI) += kirkwood_spi.o
 obj-$(CONFIG_LPC32XX_SSP) += lpc32xx_ssp.o
 obj-$(CONFIG_MPC52XX_SPI) += mpc52xx_spi.o
 obj-$(CONFIG_MPC8XXX_SPI) += mpc8xxx_spi.o
+obj-$(CONFIG_MVEBU_A3700_SPI) += mvebu_a3700_spi.o
 obj-$(CONFIG_MXC_SPI) += mxc_spi.o
 obj-$(CONFIG_MXS_SPI) += mxs_spi.o
 obj-$(CONFIG_OMAP3_SPI) += omap3_spi.o

drivers/spi/mvebu_a3700_spi.c

@@ -0,0 +1,295 @@
+/*
+ * Copyright (C) 2015 Marvell International Ltd.
+ *
+ * Copyright (C) 2016 Stefan Roese <sr@denx.de>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <malloc.h>
+#include <spi.h>
+#include <wait_bit.h>
+#include <asm/io.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+#define MVEBU_SPI_A3700_XFER_RDY		BIT(1)
+#define MVEBU_SPI_A3700_FIFO_FLUSH		BIT(9)
+#define MVEBU_SPI_A3700_BYTE_LEN		BIT(5)
+#define MVEBU_SPI_A3700_CLK_PHA			BIT(6)
+#define MVEBU_SPI_A3700_CLK_POL			BIT(7)
+#define MVEBU_SPI_A3700_FIFO_EN			BIT(17)
+#define MVEBU_SPI_A3700_SPI_EN_0		BIT(16)
+#define MVEBU_SPI_A3700_CLK_PRESCALE_BIT	0
+#define MVEBU_SPI_A3700_CLK_PRESCALE_MASK	\
+	(0x1f << MVEBU_SPI_A3700_CLK_PRESCALE_BIT)
+
+/* SPI registers */
+struct spi_reg {
+	u32 ctrl;	/* 0x10600 */
+	u32 cfg;	/* 0x10604 */
+	u32 dout;	/* 0x10608 */
+	u32 din;	/* 0x1060c */
+};
+
+struct mvebu_spi_platdata {
+	struct spi_reg *spireg;
+	unsigned int frequency;
+	unsigned int clock;
+};
+
+static void spi_cs_activate(struct spi_reg *reg, int cs)
+{
+	setbits_le32(&reg->ctrl, MVEBU_SPI_A3700_SPI_EN_0 << cs);
+}
+
+static void spi_cs_deactivate(struct spi_reg *reg, int cs)
+{
+	clrbits_le32(&reg->ctrl, MVEBU_SPI_A3700_SPI_EN_0 << cs);
+}
+
+/**
+ * spi_legacy_shift_byte() - triggers the real SPI transfer
+ * @bytelen:	Indicate how many bytes to transfer.
+ * @dout:	Buffer address of what to send.
+ * @din:	Buffer address of where to receive.
+ *
+ * This function triggers the real SPI transfer in legacy mode. It
+ * will shift out char buffer from @dout, and shift in char buffer to
+ * @din, if necessary.
+ *
+ * This function assumes that only one byte is shifted at one time.
+ * However, it is not its responisbility to set the transfer type to
+ * one-byte. Also, it does not guarantee that it will work if transfer
+ * type becomes two-byte. See spi_set_legacy() for details.
+ *
+ * In legacy mode, simply write to the SPI_DOUT register will trigger
+ * the transfer.
+ *
+ * If @dout == NULL, which means no actual data needs to be sent out,
+ * then the function will shift out 0x00 in order to shift in data.
+ * The XFER_RDY flag is checked every time before accessing SPI_DOUT
+ * and SPI_DIN register.
+ *
+ * The number of transfers to be triggerred is decided by @bytelen.
+ *
+ * Return:	0 - cool
+ *		-ETIMEDOUT - XFER_RDY flag timeout
+ */
+static int spi_legacy_shift_byte(struct spi_reg *reg, unsigned int bytelen,
+				 const void *dout, void *din)
+{
+	const u8 *dout_8;
+	u8 *din_8;
+	int ret;
+
+	/* Use 0x00 as dummy dout */
+	const u8 dummy_dout = 0x0;
+	u32 pending_dout = 0x0;
+
+	/* dout_8: pointer of current dout */
+	dout_8 = dout;
+	/* din_8: pointer of current din */
+	din_8 = din;
+
+	while (bytelen) {
+		ret = wait_for_bit(__func__, &reg->ctrl,
+				   MVEBU_SPI_A3700_XFER_RDY, true, 100, false);
+		if (ret)
+			return ret;
+
+		if (dout)
+			pending_dout = (u32)*dout_8;
+		else
+			pending_dout = (u32)dummy_dout;
+
+		/* Trigger the xfer */
+		writel(pending_dout, &reg->dout);
+
+		if (din) {
+			ret = wait_for_bit(__func__, &reg->ctrl,
+					   MVEBU_SPI_A3700_XFER_RDY,
+					   true, 100, false);
+			if (ret)
+				return ret;
+
+			/* Read what is transferred in */
+			*din_8 = (u8)readl(&reg->din);
+		}
+
+		/* Don't increment the current pointer if NULL */
+		if (dout)
+			dout_8++;
+		if (din)
+			din_8++;
+
+		bytelen--;
+	}
+
+	return 0;
+}
+
+static int mvebu_spi_xfer(struct udevice *dev, unsigned int bitlen,
+			  const void *dout, void *din, unsigned long flags)
+{
+	struct udevice *bus = dev->parent;
+	struct mvebu_spi_platdata *plat = dev_get_platdata(bus);
+	struct spi_reg *reg = plat->spireg;
+	unsigned int bytelen;
+	int ret;
+
+	bytelen = bitlen / 8;
+
+	if (dout && din)
+		debug("This is a duplex transfer.\n");
+
+	/* Activate CS */
+	if (flags & SPI_XFER_BEGIN) {
+		debug("SPI: activate cs.\n");
+		spi_cs_activate(reg, spi_chip_select(dev));
+	}
+
+	/* Send and/or receive */
+	if (dout || din) {
+		ret = spi_legacy_shift_byte(reg, bytelen, dout, din);
+		if (ret)
+			return ret;
+	}
+
+	/* Deactivate CS */
+	if (flags & SPI_XFER_END) {
+		ret = wait_for_bit(__func__, &reg->ctrl,
+				   MVEBU_SPI_A3700_XFER_RDY, true, 100, false);
+		if (ret)
+			return ret;
+
+		debug("SPI: deactivate cs.\n");
+		spi_cs_deactivate(reg, spi_chip_select(dev));
+	}
+
+	return 0;
+}
+
+static int mvebu_spi_set_speed(struct udevice *bus, uint hz)
+{
+	struct mvebu_spi_platdata *plat = dev_get_platdata(bus);
+	struct spi_reg *reg = plat->spireg;
+	u32 data;
+
+	data = readl(&reg->cfg);
+
+	/* Set Prescaler */
+	data &= ~MVEBU_SPI_A3700_CLK_PRESCALE_MASK;
+
+	/* Calculate Prescaler = (spi_input_freq / spi_max_freq) */
+	if (hz > plat->frequency)
+		hz = plat->frequency;
+	data |= plat->clock / hz;
+
+	writel(data, &reg->cfg);
+
+	return 0;
+}
+
+static int mvebu_spi_set_mode(struct udevice *bus, uint mode)
+{
+	struct mvebu_spi_platdata *plat = dev_get_platdata(bus);
+	struct spi_reg *reg = plat->spireg;
+
+	/*
+	 * Set SPI polarity
+	 * 0: Serial interface clock is low when inactive
+	 * 1: Serial interface clock is high when inactive
+	 */
+	if (mode & SPI_CPOL)
+		setbits_le32(&reg->cfg, MVEBU_SPI_A3700_CLK_POL);
+	else
+		clrbits_le32(&reg->cfg, MVEBU_SPI_A3700_CLK_POL);
+	if (mode & SPI_CPHA)
+		setbits_le32(&reg->cfg, MVEBU_SPI_A3700_CLK_PHA);
+	else
+		clrbits_le32(&reg->cfg, MVEBU_SPI_A3700_CLK_PHA);
+
+	return 0;
+}
+
+static int mvebu_spi_probe(struct udevice *bus)
+{
+	struct mvebu_spi_platdata *plat = dev_get_platdata(bus);
+	struct spi_reg *reg = plat->spireg;
+	u32 data;
+	int ret;
+
+	/*
+	 * Settings SPI controller to be working in legacy mode, which
+	 * means use only DO pin (I/O 1) for Data Out, and DI pin (I/O 0)
+	 * for Data In.
+	 */
+
+	/* Flush read/write FIFO */
+	data = readl(&reg->cfg);
+	writel(data | MVEBU_SPI_A3700_FIFO_FLUSH, &reg->cfg);
+	ret = wait_for_bit(__func__, &reg->cfg, MVEBU_SPI_A3700_FIFO_FLUSH,
+			   false, 1000, false);
+	if (ret)
+		return ret;
+
+	/* Disable FIFO mode */
+	data &= ~MVEBU_SPI_A3700_FIFO_EN;
+
+	/* Always shift 1 byte at a time */
+	data &= ~MVEBU_SPI_A3700_BYTE_LEN;
+
+	writel(data, &reg->cfg);
+
+	return 0;
+}
+
+static int mvebu_spi_ofdata_to_platdata(struct udevice *bus)
+{
+	struct mvebu_spi_platdata *plat = dev_get_platdata(bus);
+
+	plat->spireg = (struct spi_reg *)dev_get_addr(bus);
+
+	/*
+	 * FIXME
+	 * Right now, mvebu does not have a clock infrastructure in U-Boot
+	 * which should be used to query the input clock to the SPI
+	 * controller. Once this clock driver is integrated into U-Boot
+	 * it should be used to read the input clock and the DT property
+	 * can be removed.
+	 */
+	plat->clock = fdtdec_get_int(gd->fdt_blob, bus->of_offset,
+				     "clock-frequency", 160000);
+	plat->frequency = fdtdec_get_int(gd->fdt_blob, bus->of_offset,
+					 "spi-max-frequency", 40000);
+
+	return 0;
+}
+
+static const struct dm_spi_ops mvebu_spi_ops = {
+	.xfer		= mvebu_spi_xfer,
+	.set_speed	= mvebu_spi_set_speed,
+	.set_mode	= mvebu_spi_set_mode,
+	/*
+	 * cs_info is not needed, since we require all chip selects to be
+	 * in the device tree explicitly
+	 */
+};
+
+static const struct udevice_id mvebu_spi_ids[] = {
+	{ .compatible = "marvell,armada-3700-spi" },
+	{ }
+};
+
+U_BOOT_DRIVER(mvebu_spi) = {
+	.name = "mvebu_spi",
+	.id = UCLASS_SPI,
+	.of_match = mvebu_spi_ids,
+	.ops = &mvebu_spi_ops,
+	.ofdata_to_platdata = mvebu_spi_ofdata_to_platdata,
+	.platdata_auto_alloc_size = sizeof(struct mvebu_spi_platdata),
+	.probe = mvebu_spi_probe,
+};