spi: Add SPI controller driver for UniPhier SoCs

Add SPI controller driver implemented in Socionext UniPhier SoCs.
This controller has the SPI master mode only.

Signed-off-by: Kunihiko Hayashi <hayashi.kunihiko@socionext.com>

1 files changed, 413 insertions, 0 deletions

diff --git a/drivers/spi/uniphier_spi.c b/drivers/spi/uniphier_spi.c
new file mode 100644
index 0000000000..ef02d07aa4
--- /dev/null
+++ b/drivers/spi/uniphier_spi.c
@@ -0,0 +1,413 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * uniphier_spi.c - Socionext UniPhier SPI driver
+ * Copyright 2019 Socionext, Inc.
+ */
+
+#include <clk.h>
+#include <common.h>
+#include <dm.h>
+#include <linux/bitfield.h>
+#include <linux/io.h>
+#include <spi.h>
+#include <wait_bit.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+#define SSI_CTL			0x00
+#define   SSI_CTL_EN		BIT(0)
+
+#define SSI_CKS			0x04
+#define   SSI_CKS_CKRAT_MASK	GENMASK(7, 0)
+#define   SSI_CKS_CKPHS		BIT(14)
+#define   SSI_CKS_CKINIT	BIT(13)
+#define   SSI_CKS_CKDLY		BIT(12)
+
+#define SSI_TXWDS		0x08
+#define   SSI_TXWDS_WDLEN_MASK	GENMASK(13, 8)
+#define   SSI_TXWDS_TDTF_MASK	GENMASK(7, 6)
+#define   SSI_TXWDS_DTLEN_MASK	GENMASK(5, 0)
+
+#define SSI_RXWDS		0x0c
+#define   SSI_RXWDS_RDTF_MASK	GENMASK(7, 6)
+#define   SSI_RXWDS_DTLEN_MASK	GENMASK(5, 0)
+
+#define SSI_FPS			0x10
+#define   SSI_FPS_FSPOL		BIT(15)
+#define   SSI_FPS_FSTRT		BIT(14)
+
+#define SSI_SR			0x14
+#define   SSI_SR_BUSY		BIT(7)
+#define   SSI_SR_TNF		BIT(5)
+#define   SSI_SR_RNE		BIT(0)
+
+#define SSI_IE			0x18
+
+#define SSI_IC			0x1c
+#define   SSI_IC_TCIC		BIT(4)
+#define   SSI_IC_RCIC		BIT(3)
+#define   SSI_IC_RORIC		BIT(0)
+
+#define SSI_FC			0x20
+#define   SSI_FC_TXFFL		BIT(12)
+#define   SSI_FC_TXFTH_MASK	GENMASK(11, 8)
+#define   SSI_FC_RXFFL		BIT(4)
+#define   SSI_FC_RXFTH_MASK	GENMASK(3, 0)
+
+#define SSI_XDR			0x24	/* TXDR for write, RXDR for read */
+
+#define SSI_FIFO_DEPTH		8U
+
+#define SSI_REG_TIMEOUT		(CONFIG_SYS_HZ / 100)	/* 10 ms */
+#define SSI_XFER_TIMEOUT	(CONFIG_SYS_HZ)		/* 1 sec */
+
+#define SSI_CLK			50000000	/* internal I/O clock: 50MHz */
+
+struct uniphier_spi_platdata {
+	void __iomem *base;
+	u32 frequency;			/* input frequency */
+	u32 speed_hz;
+	uint deactivate_delay_us;	/* Delay to wait after deactivate */
+	uint activate_delay_us;		/* Delay to wait after activate */
+};
+
+struct uniphier_spi_priv {
+	void __iomem *base;
+	u8 mode;
+	u8 fifo_depth;
+	u8 bits_per_word;
+	ulong last_transaction_us;	/* Time of last transaction end */
+};
+
+static void uniphier_spi_enable(struct uniphier_spi_priv *priv, int enable)
+{
+	u32 val;
+
+	val = readl(priv->base + SSI_CTL);
+	if (enable)
+		val |= SSI_CTL_EN;
+	else
+		val &= ~SSI_CTL_EN;
+	writel(val, priv->base + SSI_CTL);
+}
+
+static void uniphier_spi_regdump(struct uniphier_spi_priv *priv)
+{
+	pr_debug("CTL   %08x\n", readl(priv->base + SSI_CTL));
+	pr_debug("CKS   %08x\n", readl(priv->base + SSI_CKS));
+	pr_debug("TXWDS %08x\n", readl(priv->base + SSI_TXWDS));
+	pr_debug("RXWDS %08x\n", readl(priv->base + SSI_RXWDS));
+	pr_debug("FPS   %08x\n", readl(priv->base + SSI_FPS));
+	pr_debug("SR    %08x\n", readl(priv->base + SSI_SR));
+	pr_debug("IE    %08x\n", readl(priv->base + SSI_IE));
+	pr_debug("IC    %08x\n", readl(priv->base + SSI_IC));
+	pr_debug("FC    %08x\n", readl(priv->base + SSI_FC));
+	pr_debug("XDR   %08x\n", readl(priv->base + SSI_XDR));
+}
+
+static void spi_cs_activate(struct udevice *dev)
+{
+	struct udevice *bus = dev->parent;
+	struct uniphier_spi_platdata *plat = bus->platdata;
+	struct uniphier_spi_priv *priv = dev_get_priv(bus);
+	ulong delay_us;		/* The delay completed so far */
+	u32 val;
+
+	/* If it's too soon to do another transaction, wait */
+	if (plat->deactivate_delay_us && priv->last_transaction_us) {
+		delay_us = timer_get_us() - priv->last_transaction_us;
+		if (delay_us < plat->deactivate_delay_us)
+			udelay(plat->deactivate_delay_us - delay_us);
+	}
+
+	val = readl(priv->base + SSI_FPS);
+	if (priv->mode & SPI_CS_HIGH)
+		val |= SSI_FPS_FSPOL;
+	else
+		val &= ~SSI_FPS_FSPOL;
+	writel(val, priv->base + SSI_FPS);
+
+	if (plat->activate_delay_us)
+		udelay(plat->activate_delay_us);
+}
+
+static void spi_cs_deactivate(struct udevice *dev)
+{
+	struct udevice *bus = dev->parent;
+	struct uniphier_spi_platdata *plat = bus->platdata;
+	struct uniphier_spi_priv *priv = dev_get_priv(bus);
+	u32 val;
+
+	val = readl(priv->base + SSI_FPS);
+	if (priv->mode & SPI_CS_HIGH)
+		val &= ~SSI_FPS_FSPOL;
+	else
+		val |= SSI_FPS_FSPOL;
+	writel(val, priv->base + SSI_FPS);
+
+	/* Remember time of this transaction so we can honour the bus delay */
+	if (plat->deactivate_delay_us)
+		priv->last_transaction_us = timer_get_us();
+}
+
+static int uniphier_spi_claim_bus(struct udevice *dev)
+{
+	struct udevice *bus = dev->parent;
+	struct uniphier_spi_priv *priv = dev_get_priv(bus);
+	u32 val, size;
+
+	uniphier_spi_enable(priv, false);
+
+	/* disable interrupts */
+	writel(0, priv->base + SSI_IE);
+
+	/* bits_per_word */
+	size = priv->bits_per_word;
+	val = readl(priv->base + SSI_TXWDS);
+	val &= ~(SSI_TXWDS_WDLEN_MASK | SSI_TXWDS_DTLEN_MASK);
+	val |= FIELD_PREP(SSI_TXWDS_WDLEN_MASK, size);
+	val |= FIELD_PREP(SSI_TXWDS_DTLEN_MASK, size);
+	writel(val, priv->base + SSI_TXWDS);
+
+	val = readl(priv->base + SSI_RXWDS);
+	val &= ~SSI_RXWDS_DTLEN_MASK;
+	val |= FIELD_PREP(SSI_RXWDS_DTLEN_MASK, size);
+	writel(val, priv->base + SSI_RXWDS);
+
+	/* reset FIFOs */
+	val = SSI_FC_TXFFL | SSI_FC_RXFFL;
+	writel(val, priv->base + SSI_FC);
+
+	/* FIFO threthold */
+	val = readl(priv->base + SSI_FC);
+	val &= ~(SSI_FC_TXFTH_MASK | SSI_FC_RXFTH_MASK);
+	val |= FIELD_PREP(SSI_FC_TXFTH_MASK, priv->fifo_depth);
+	val |= FIELD_PREP(SSI_FC_RXFTH_MASK, priv->fifo_depth);
+	writel(val, priv->base + SSI_FC);
+
+	/* clear interrupts */
+	writel(SSI_IC_TCIC | SSI_IC_RCIC | SSI_IC_RORIC,
+	       priv->base + SSI_IC);
+
+	uniphier_spi_enable(priv, true);
+
+	return 0;
+}
+
+static int uniphier_spi_release_bus(struct udevice *dev)
+{
+	struct udevice *bus = dev->parent;
+	struct uniphier_spi_priv *priv = dev_get_priv(bus);
+
+	uniphier_spi_enable(priv, false);
+
+	return 0;
+}
+
+static int uniphier_spi_xfer(struct udevice *dev, unsigned int bitlen,
+			     const void *dout, void *din, unsigned long flags)
+{
+	struct udevice *bus = dev->parent;
+	struct uniphier_spi_priv *priv = dev_get_priv(bus);
+	const u8 *tx_buf = dout;
+	u8 *rx_buf = din, buf;
+	u32 len = bitlen / 8;
+	u32 tx_len, rx_len;
+	u32 ts, status;
+	int ret = 0;
+
+	if (bitlen % 8) {
+		dev_err(dev, "Non byte aligned SPI transfer\n");
+		return -EINVAL;
+	}
+
+	if (flags & SPI_XFER_BEGIN)
+		spi_cs_activate(dev);
+
+	uniphier_spi_enable(priv, true);
+
+	ts = get_timer(0);
+	tx_len = len;
+	rx_len = len;
+
+	uniphier_spi_regdump(priv);
+
+	while (tx_len || rx_len) {
+		ret = wait_for_bit_le32(priv->base + SSI_SR, SSI_SR_BUSY, false,
+					SSI_REG_TIMEOUT * 1000, false);
+		if (ret) {
+			if (ret == -ETIMEDOUT)
+				dev_err(dev, "access timeout\n");
+			break;
+		}
+
+		status = readl(priv->base + SSI_SR);
+		/* write the data into TX */
+		if (tx_len && (status & SSI_SR_TNF)) {
+			buf = tx_buf ? *tx_buf++ : 0;
+			writel(buf, priv->base + SSI_XDR);
+			tx_len--;
+		}
+
+		/* read the data from RX */
+		if (rx_len && (status & SSI_SR_RNE)) {
+			buf = readl(priv->base + SSI_XDR);
+			if (rx_buf)
+				*rx_buf++ = buf;
+			rx_len--;
+		}
+
+		if (get_timer(ts) >= SSI_XFER_TIMEOUT) {
+			dev_err(dev, "transfer timeout\n");
+			ret = -ETIMEDOUT;
+			break;
+		}
+	}
+
+	if (flags & SPI_XFER_END)
+		spi_cs_deactivate(dev);
+
+	uniphier_spi_enable(priv, false);
+
+	return ret;
+}
+
+static int uniphier_spi_set_speed(struct udevice *bus, uint speed)
+{
+	struct uniphier_spi_platdata *plat = bus->platdata;
+	struct uniphier_spi_priv *priv = dev_get_priv(bus);
+	u32 val, ckdiv;
+
+	if (speed > plat->frequency)
+		speed = plat->frequency;
+
+	/* baudrate */
+	ckdiv = DIV_ROUND_UP(SSI_CLK, speed);
+	ckdiv = round_up(ckdiv, 2);
+
+	val = readl(priv->base + SSI_CKS);
+	val &= ~SSI_CKS_CKRAT_MASK;
+	val |= ckdiv & SSI_CKS_CKRAT_MASK;
+	writel(val, priv->base + SSI_CKS);
+
+	return 0;
+}
+
+static int uniphier_spi_set_mode(struct udevice *bus, uint mode)
+{
+	struct uniphier_spi_priv *priv = dev_get_priv(bus);
+	u32 val1, val2;
+
+	/*
+	 * clock setting
+	 * CKPHS    capture timing. 0:rising edge, 1:falling edge
+	 * CKINIT   clock initial level. 0:low, 1:high
+	 * CKDLY    clock delay. 0:no delay, 1:delay depending on FSTRT
+	 *          (FSTRT=0: 1 clock, FSTRT=1: 0.5 clock)
+	 *
+	 * frame setting
+	 * FSPOL    frame signal porarity. 0: low, 1: high
+	 * FSTRT    start frame timing
+	 *          0: rising edge of clock, 1: falling edge of clock
+	 */
+	val1 = readl(priv->base + SSI_CKS);
+	val2 = readl(priv->base + SSI_FPS);
+
+	switch (mode & (SPI_CPOL | SPI_CPHA)) {
+	case SPI_MODE_0:
+		/* CKPHS=1, CKINIT=0, CKDLY=1, FSTRT=0 */
+		val1 |= SSI_CKS_CKPHS | SSI_CKS_CKDLY;
+		val1 &= ~SSI_CKS_CKINIT;
+		val2 &= ~SSI_FPS_FSTRT;
+		break;
+	case SPI_MODE_1:
+		/* CKPHS=0, CKINIT=0, CKDLY=0, FSTRT=1 */
+		val1 &= ~(SSI_CKS_CKPHS | SSI_CKS_CKINIT | SSI_CKS_CKDLY);
+		val2 |= SSI_FPS_FSTRT;
+		break;
+	case SPI_MODE_2:
+		/* CKPHS=0, CKINIT=1, CKDLY=1, FSTRT=1 */
+		val1 |= SSI_CKS_CKINIT | SSI_CKS_CKDLY;
+		val1 &= ~SSI_CKS_CKPHS;
+		val2 |= SSI_FPS_FSTRT;
+		break;
+	case SPI_MODE_3:
+		/* CKPHS=1, CKINIT=1, CKDLY=0, FSTRT=0 */
+		val1 |= SSI_CKS_CKPHS | SSI_CKS_CKINIT;
+		val1 &= ~SSI_CKS_CKDLY;
+		val2 &= ~SSI_FPS_FSTRT;
+		break;
+	}
+
+	writel(val1, priv->base + SSI_CKS);
+	writel(val2, priv->base + SSI_FPS);
+
+	/* format */
+	val1 = readl(priv->base + SSI_TXWDS);
+	val2 = readl(priv->base + SSI_RXWDS);
+	if (mode & SPI_LSB_FIRST) {
+		val1 |= FIELD_PREP(SSI_TXWDS_TDTF_MASK, 1);
+		val2 |= FIELD_PREP(SSI_RXWDS_RDTF_MASK, 1);
+	}
+	writel(val1, priv->base + SSI_TXWDS);
+	writel(val2, priv->base + SSI_RXWDS);
+
+	priv->mode = mode;
+
+	return 0;
+}
+
+static int uniphier_spi_ofdata_to_platdata(struct udevice *bus)
+{
+	struct uniphier_spi_platdata *plat = bus->platdata;
+	const void *blob = gd->fdt_blob;
+	int node = dev_of_offset(bus);
+
+	plat->base = devfdt_get_addr_ptr(bus);
+
+	plat->frequency =
+		fdtdec_get_int(blob, node, "spi-max-frequency", 12500000);
+	plat->deactivate_delay_us =
+		fdtdec_get_int(blob, node, "spi-deactivate-delay", 0);
+	plat->activate_delay_us =
+		fdtdec_get_int(blob, node, "spi-activate-delay", 0);
+	plat->speed_hz = plat->frequency / 2;
+
+	return 0;
+}
+
+static int uniphier_spi_probe(struct udevice *bus)
+{
+	struct uniphier_spi_platdata *plat = dev_get_platdata(bus);
+	struct uniphier_spi_priv *priv = dev_get_priv(bus);
+
+	priv->base = plat->base;
+	priv->fifo_depth = SSI_FIFO_DEPTH;
+	priv->bits_per_word = 8;
+
+	return 0;
+}
+
+static const struct dm_spi_ops uniphier_spi_ops = {
+	.claim_bus	= uniphier_spi_claim_bus,
+	.release_bus	= uniphier_spi_release_bus,
+	.xfer		= uniphier_spi_xfer,
+	.set_speed	= uniphier_spi_set_speed,
+	.set_mode	= uniphier_spi_set_mode,
+};
+
+static const struct udevice_id uniphier_spi_ids[] = {
+	{ .compatible = "socionext,uniphier-scssi" },
+	{ /* Sentinel */ }
+};
+
+U_BOOT_DRIVER(uniphier_spi) = {
+	.name	= "uniphier_spi",
+	.id	= UCLASS_SPI,
+	.of_match = uniphier_spi_ids,
+	.ops	= &uniphier_spi_ops,
+	.ofdata_to_platdata = uniphier_spi_ofdata_to_platdata,
+	.platdata_auto_alloc_size = sizeof(struct uniphier_spi_platdata),
+	.priv_auto_alloc_size = sizeof(struct uniphier_spi_priv),
+	.probe	= uniphier_spi_probe,
+};