spi: stm32: Add Serial Peripheral Interface driver for STM32MP

Add SPI driver support for STM32MP SoCs family.

Signed-off-by: Patrice Chotard <patrice.chotard@st.com>

1 files changed, 615 insertions, 0 deletions

diff --git a/drivers/spi/stm32_spi.c b/drivers/spi/stm32_spi.c
new file mode 100644
index 0000000000..34b217584d
--- /dev/null
+++ b/drivers/spi/stm32_spi.c
@@ -0,0 +1,615 @@
+// SPDX-License-Identifier: GPL-2.0+ OR BSD-3-Clause
+/*
+ * Copyright (C) 2019, STMicroelectronics - All Rights Reserved
+ *
+ * Driver for STMicroelectronics Serial peripheral interface (SPI)
+ */
+#include <common.h>
+#include <clk.h>
+#include <dm.h>
+#include <errno.h>
+#include <reset.h>
+#include <spi.h>
+
+#include <asm/io.h>
+#include <asm/gpio.h>
+#include <linux/bitfield.h>
+#include <linux/iopoll.h>
+
+/* STM32 SPI registers */
+#define STM32_SPI_CR1		0x00
+#define STM32_SPI_CR2		0x04
+#define STM32_SPI_CFG1		0x08
+#define STM32_SPI_CFG2		0x0C
+#define STM32_SPI_SR		0x14
+#define STM32_SPI_IFCR		0x18
+#define STM32_SPI_TXDR		0x20
+#define STM32_SPI_RXDR		0x30
+#define STM32_SPI_I2SCFGR	0x50
+
+/* STM32_SPI_CR1 bit fields */
+#define SPI_CR1_SPE		BIT(0)
+#define SPI_CR1_MASRX		BIT(8)
+#define SPI_CR1_CSTART		BIT(9)
+#define SPI_CR1_CSUSP		BIT(10)
+#define SPI_CR1_HDDIR		BIT(11)
+#define SPI_CR1_SSI		BIT(12)
+
+/* STM32_SPI_CR2 bit fields */
+#define SPI_CR2_TSIZE		GENMASK(15, 0)
+
+/* STM32_SPI_CFG1 bit fields */
+#define SPI_CFG1_DSIZE		GENMASK(4, 0)
+#define SPI_CFG1_DSIZE_MIN	3
+#define SPI_CFG1_FTHLV_SHIFT	5
+#define SPI_CFG1_FTHLV		GENMASK(8, 5)
+#define SPI_CFG1_MBR_SHIFT	28
+#define SPI_CFG1_MBR		GENMASK(30, 28)
+#define SPI_CFG1_MBR_MIN	0
+#define SPI_CFG1_MBR_MAX	FIELD_GET(SPI_CFG1_MBR, SPI_CFG1_MBR)
+
+/* STM32_SPI_CFG2 bit fields */
+#define SPI_CFG2_COMM_SHIFT	17
+#define SPI_CFG2_COMM		GENMASK(18, 17)
+#define SPI_CFG2_MASTER		BIT(22)
+#define SPI_CFG2_LSBFRST	BIT(23)
+#define SPI_CFG2_CPHA		BIT(24)
+#define SPI_CFG2_CPOL		BIT(25)
+#define SPI_CFG2_SSM		BIT(26)
+#define SPI_CFG2_AFCNTR		BIT(31)
+
+/* STM32_SPI_SR bit fields */
+#define SPI_SR_RXP		BIT(0)
+#define SPI_SR_TXP		BIT(1)
+#define SPI_SR_EOT		BIT(3)
+#define SPI_SR_TXTF		BIT(4)
+#define SPI_SR_OVR		BIT(6)
+#define SPI_SR_SUSP		BIT(11)
+#define SPI_SR_RXPLVL_SHIFT	13
+#define SPI_SR_RXPLVL		GENMASK(14, 13)
+#define SPI_SR_RXWNE		BIT(15)
+
+/* STM32_SPI_IFCR bit fields */
+#define SPI_IFCR_ALL		GENMASK(11, 3)
+
+/* STM32_SPI_I2SCFGR bit fields */
+#define SPI_I2SCFGR_I2SMOD	BIT(0)
+
+#define MAX_CS_COUNT	4
+
+/* SPI Master Baud Rate min/max divisor */
+#define STM32_MBR_DIV_MIN	(2 << SPI_CFG1_MBR_MIN)
+#define STM32_MBR_DIV_MAX	(2 << SPI_CFG1_MBR_MAX)
+
+#define STM32_SPI_TIMEOUT_US	100000
+
+/* SPI Communication mode */
+#define SPI_FULL_DUPLEX		0
+#define SPI_SIMPLEX_TX		1
+#define SPI_SIMPLEX_RX		2
+#define SPI_HALF_DUPLEX		3
+
+struct stm32_spi_priv {
+	void __iomem *base;
+	struct clk clk;
+	struct reset_ctl rst_ctl;
+	struct gpio_desc cs_gpios[MAX_CS_COUNT];
+	ulong bus_clk_rate;
+	unsigned int fifo_size;
+	unsigned int cur_bpw;
+	unsigned int cur_hz;
+	unsigned int cur_xferlen; /* current transfer length in bytes */
+	int tx_len;		  /* number of data to be written in bytes */
+	int rx_len;		  /* number of data to be read in bytes */
+	const void *tx_buf;	  /* data to be written, or NULL */
+	void *rx_buf;		  /* data to be read, or NULL */
+	u32 cur_mode;
+	bool cs_high;
+};
+
+static void stm32_spi_write_txfifo(struct stm32_spi_priv *priv)
+{
+	while ((priv->tx_len > 0) &&
+	       (readl(priv->base + STM32_SPI_SR) & SPI_SR_TXP)) {
+		u32 offs = priv->cur_xferlen - priv->tx_len;
+
+		if (priv->tx_len >= sizeof(u32) &&
+		    IS_ALIGNED((uintptr_t)(priv->tx_buf + offs), sizeof(u32))) {
+			const u32 *tx_buf32 = (const u32 *)(priv->tx_buf + offs);
+
+			writel(*tx_buf32, priv->base + STM32_SPI_TXDR);
+			priv->tx_len -= sizeof(u32);
+		} else if (priv->tx_len >= sizeof(u16) &&
+			   IS_ALIGNED((uintptr_t)(priv->tx_buf + offs), sizeof(u16))) {
+			const u16 *tx_buf16 = (const u16 *)(priv->tx_buf + offs);
+
+			writew(*tx_buf16, priv->base + STM32_SPI_TXDR);
+			priv->tx_len -= sizeof(u16);
+		} else {
+			const u8 *tx_buf8 = (const u8 *)(priv->tx_buf + offs);
+
+			writeb(*tx_buf8, priv->base + STM32_SPI_TXDR);
+			priv->tx_len -= sizeof(u8);
+		}
+	}
+
+	debug("%s: %d bytes left\n", __func__, priv->tx_len);
+}
+
+static void stm32_spi_read_rxfifo(struct stm32_spi_priv *priv)
+{
+	u32 sr = readl(priv->base + STM32_SPI_SR);
+	u32 rxplvl = (sr & SPI_SR_RXPLVL) >> SPI_SR_RXPLVL_SHIFT;
+
+	while ((priv->rx_len > 0) &&
+	       ((sr & SPI_SR_RXP) ||
+	       ((sr & SPI_SR_EOT) && ((sr & SPI_SR_RXWNE) || (rxplvl > 0))))) {
+		u32 offs = priv->cur_xferlen - priv->rx_len;
+
+		if (IS_ALIGNED((uintptr_t)(priv->rx_buf + offs), sizeof(u32)) &&
+		    (priv->rx_len >= sizeof(u32) || (sr & SPI_SR_RXWNE))) {
+			u32 *rx_buf32 = (u32 *)(priv->rx_buf + offs);
+
+			*rx_buf32 = readl(priv->base + STM32_SPI_RXDR);
+			priv->rx_len -= sizeof(u32);
+		} else if (IS_ALIGNED((uintptr_t)(priv->rx_buf + offs), sizeof(u16)) &&
+			   (priv->rx_len >= sizeof(u16) ||
+			    (!(sr & SPI_SR_RXWNE) &&
+			    (rxplvl >= 2 || priv->cur_bpw > 8)))) {
+			u16 *rx_buf16 = (u16 *)(priv->rx_buf + offs);
+
+			*rx_buf16 = readw(priv->base + STM32_SPI_RXDR);
+			priv->rx_len -= sizeof(u16);
+		} else {
+			u8 *rx_buf8 = (u8 *)(priv->rx_buf + offs);
+
+			*rx_buf8 = readb(priv->base + STM32_SPI_RXDR);
+			priv->rx_len -= sizeof(u8);
+		}
+
+		sr = readl(priv->base + STM32_SPI_SR);
+		rxplvl = (sr & SPI_SR_RXPLVL) >> SPI_SR_RXPLVL_SHIFT;
+	}
+
+	debug("%s: %d bytes left\n", __func__, priv->rx_len);
+}
+
+static int stm32_spi_enable(struct stm32_spi_priv *priv)
+{
+	debug("%s\n", __func__);
+
+	/* Enable the SPI hardware */
+	setbits_le32(priv->base + STM32_SPI_CR1, SPI_CR1_SPE);
+
+	return 0;
+}
+
+static int stm32_spi_disable(struct stm32_spi_priv *priv)
+{
+	debug("%s\n", __func__);
+
+	/* Disable the SPI hardware */
+	clrbits_le32(priv->base + STM32_SPI_CR1, SPI_CR1_SPE);
+
+	return 0;
+}
+
+static int stm32_spi_claim_bus(struct udevice *slave)
+{
+	struct udevice *bus = dev_get_parent(slave);
+	struct stm32_spi_priv *priv = dev_get_priv(bus);
+
+	debug("%s\n", __func__);
+
+	/* Enable the SPI hardware */
+	return stm32_spi_enable(priv);
+}
+
+static int stm32_spi_release_bus(struct udevice *slave)
+{
+	struct udevice *bus = dev_get_parent(slave);
+	struct stm32_spi_priv *priv = dev_get_priv(bus);
+
+	debug("%s\n", __func__);
+
+	/* Disable the SPI hardware */
+	return stm32_spi_disable(priv);
+}
+
+static void stm32_spi_stopxfer(struct udevice *dev)
+{
+	struct stm32_spi_priv *priv = dev_get_priv(dev);
+	u32 cr1, sr;
+	int ret;
+
+	debug("%s\n", __func__);
+
+	cr1 = readl(priv->base + STM32_SPI_CR1);
+
+	if (!(cr1 & SPI_CR1_SPE))
+		return;
+
+	/* Wait on EOT or suspend the flow */
+	ret = readl_poll_timeout(priv->base + STM32_SPI_SR, sr,
+				 !(sr & SPI_SR_EOT), 100000);
+	if (ret < 0) {
+		if (cr1 & SPI_CR1_CSTART) {
+			writel(cr1 | SPI_CR1_CSUSP, priv->base + STM32_SPI_CR1);
+			if (readl_poll_timeout(priv->base + STM32_SPI_SR,
+					       sr, !(sr & SPI_SR_SUSP),
+					       100000) < 0)
+				dev_err(dev, "Suspend request timeout\n");
+		}
+	}
+
+	/* clear status flags */
+	setbits_le32(priv->base + STM32_SPI_IFCR, SPI_IFCR_ALL);
+}
+
+static int stm32_spi_set_cs(struct udevice *dev, unsigned int cs, bool enable)
+{
+	struct stm32_spi_priv *priv = dev_get_priv(dev);
+
+	debug("%s: cs=%d enable=%d\n", __func__, cs, enable);
+
+	if (cs >= MAX_CS_COUNT)
+		return -ENODEV;
+
+	if (!dm_gpio_is_valid(&priv->cs_gpios[cs]))
+		return -EINVAL;
+
+	if (priv->cs_high)
+		enable = !enable;
+
+	return dm_gpio_set_value(&priv->cs_gpios[cs], enable ? 1 : 0);
+}
+
+static int stm32_spi_set_mode(struct udevice *bus, uint mode)
+{
+	struct stm32_spi_priv *priv = dev_get_priv(bus);
+	u32 cfg2_clrb = 0, cfg2_setb = 0;
+
+	debug("%s: mode=%d\n", __func__, mode);
+
+	if (mode & SPI_CPOL)
+		cfg2_setb |= SPI_CFG2_CPOL;
+	else
+		cfg2_clrb |= SPI_CFG2_CPOL;
+
+	if (mode & SPI_CPHA)
+		cfg2_setb |= SPI_CFG2_CPHA;
+	else
+		cfg2_clrb |= SPI_CFG2_CPHA;
+
+	if (mode & SPI_LSB_FIRST)
+		cfg2_setb |= SPI_CFG2_LSBFRST;
+	else
+		cfg2_clrb |= SPI_CFG2_LSBFRST;
+
+	if (cfg2_clrb || cfg2_setb)
+		clrsetbits_le32(priv->base + STM32_SPI_CFG2,
+				cfg2_clrb, cfg2_setb);
+
+	if (mode & SPI_CS_HIGH)
+		priv->cs_high = true;
+	else
+		priv->cs_high = false;
+	return 0;
+}
+
+static int stm32_spi_set_fthlv(struct udevice *dev, u32 xfer_len)
+{
+	struct stm32_spi_priv *priv = dev_get_priv(dev);
+	u32 fthlv, half_fifo;
+
+	/* data packet should not exceed 1/2 of fifo space */
+	half_fifo = (priv->fifo_size / 2);
+
+	/* data_packet should not exceed transfer length */
+	fthlv = (half_fifo > xfer_len) ? xfer_len : half_fifo;
+
+	/* align packet size with data registers access */
+	fthlv -= (fthlv % 4);
+
+	if (!fthlv)
+		fthlv = 1;
+	clrsetbits_le32(priv->base + STM32_SPI_CFG1, SPI_CFG1_FTHLV,
+			(fthlv - 1) << SPI_CFG1_FTHLV_SHIFT);
+
+	return 0;
+}
+
+static int stm32_spi_set_speed(struct udevice *bus, uint hz)
+{
+	struct stm32_spi_priv *priv = dev_get_priv(bus);
+	u32 div, mbrdiv;
+
+	debug("%s: hz=%d\n", __func__, hz);
+
+	if (priv->cur_hz == hz)
+		return 0;
+
+	div = DIV_ROUND_UP(priv->bus_clk_rate, hz);
+
+	if (div < STM32_MBR_DIV_MIN ||
+	    div > STM32_MBR_DIV_MAX)
+		return -EINVAL;
+
+	/* Determine the first power of 2 greater than or equal to div */
+	if (div & (div - 1))
+		mbrdiv = fls(div);
+	else
+		mbrdiv = fls(div) - 1;
+
+	if ((mbrdiv - 1) < 0)
+		return -EINVAL;
+
+	clrsetbits_le32(priv->base + STM32_SPI_CFG1, SPI_CFG1_MBR,
+			(mbrdiv - 1) << SPI_CFG1_MBR_SHIFT);
+
+	priv->cur_hz = hz;
+
+	return 0;
+}
+
+static int stm32_spi_xfer(struct udevice *slave, unsigned int bitlen,
+			  const void *dout, void *din, unsigned long flags)
+{
+	struct udevice *bus = dev_get_parent(slave);
+	struct dm_spi_slave_platdata *slave_plat;
+	struct stm32_spi_priv *priv = dev_get_priv(bus);
+	u32 sr;
+	u32 ifcr = 0;
+	u32 xferlen;
+	u32 mode;
+	int xfer_status = 0;
+
+	xferlen = bitlen / 8;
+
+	if (xferlen <= SPI_CR2_TSIZE)
+		writel(xferlen, priv->base + STM32_SPI_CR2);
+	else
+		return -EMSGSIZE;
+
+	priv->tx_buf = dout;
+	priv->rx_buf = din;
+	priv->tx_len = priv->tx_buf ? bitlen / 8 : 0;
+	priv->rx_len = priv->rx_buf ? bitlen / 8 : 0;
+
+	mode = SPI_FULL_DUPLEX;
+	if (!priv->tx_buf)
+		mode = SPI_SIMPLEX_RX;
+	else if (!priv->rx_buf)
+		mode = SPI_SIMPLEX_TX;
+
+	if (priv->cur_xferlen != xferlen || priv->cur_mode != mode) {
+		priv->cur_mode = mode;
+		priv->cur_xferlen = xferlen;
+
+		/* Disable the SPI hardware to unlock CFG1/CFG2 registers */
+		stm32_spi_disable(priv);
+
+		clrsetbits_le32(priv->base + STM32_SPI_CFG2, SPI_CFG2_COMM,
+				mode << SPI_CFG2_COMM_SHIFT);
+
+		stm32_spi_set_fthlv(bus, xferlen);
+
+		/* Enable the SPI hardware */
+		stm32_spi_enable(priv);
+	}
+
+	debug("%s: priv->tx_len=%d priv->rx_len=%d\n", __func__,
+	      priv->tx_len, priv->rx_len);
+
+	slave_plat = dev_get_parent_platdata(slave);
+	if (flags & SPI_XFER_BEGIN)
+		stm32_spi_set_cs(bus, slave_plat->cs, false);
+
+	/* Be sure to have data in fifo before starting data transfer */
+	if (priv->tx_buf)
+		stm32_spi_write_txfifo(priv);
+
+	setbits_le32(priv->base + STM32_SPI_CR1, SPI_CR1_CSTART);
+
+	while (1) {
+		sr = readl(priv->base + STM32_SPI_SR);
+
+		if (sr & SPI_SR_OVR) {
+			dev_err(bus, "Overrun: RX data lost\n");
+			xfer_status = -EIO;
+			break;
+		}
+
+		if (sr & SPI_SR_SUSP) {
+			dev_warn(bus, "System too slow is limiting data throughput\n");
+
+			if (priv->rx_buf && priv->rx_len > 0)
+				stm32_spi_read_rxfifo(priv);
+
+			ifcr |= SPI_SR_SUSP;
+		}
+
+		if (sr & SPI_SR_TXTF)
+			ifcr |= SPI_SR_TXTF;
+
+		if (sr & SPI_SR_TXP)
+			if (priv->tx_buf && priv->tx_len > 0)
+				stm32_spi_write_txfifo(priv);
+
+		if (sr & SPI_SR_RXP)
+			if (priv->rx_buf && priv->rx_len > 0)
+				stm32_spi_read_rxfifo(priv);
+
+		if (sr & SPI_SR_EOT) {
+			if (priv->rx_buf && priv->rx_len > 0)
+				stm32_spi_read_rxfifo(priv);
+			break;
+		}
+
+		writel(ifcr, priv->base + STM32_SPI_IFCR);
+	}
+
+	/* clear status flags */
+	setbits_le32(priv->base + STM32_SPI_IFCR, SPI_IFCR_ALL);
+	stm32_spi_stopxfer(bus);
+
+	if (flags & SPI_XFER_END)
+		stm32_spi_set_cs(bus, slave_plat->cs, true);
+
+	return xfer_status;
+}
+
+static int stm32_spi_get_fifo_size(struct udevice *dev)
+{
+	struct stm32_spi_priv *priv = dev_get_priv(dev);
+	u32 count = 0;
+
+	stm32_spi_enable(priv);
+
+	while (readl(priv->base + STM32_SPI_SR) & SPI_SR_TXP)
+		writeb(++count, priv->base + STM32_SPI_TXDR);
+
+	stm32_spi_disable(priv);
+
+	debug("%s %d x 8-bit fifo size\n", __func__, count);
+
+	return count;
+}
+
+static int stm32_spi_probe(struct udevice *dev)
+{
+	struct stm32_spi_priv *priv = dev_get_priv(dev);
+	unsigned long clk_rate;
+	int ret;
+	int i;
+
+	priv->base = dev_remap_addr(dev);
+	if (!priv->base)
+		return -EINVAL;
+
+	/* enable clock */
+	ret = clk_get_by_index(dev, 0, &priv->clk);
+	if (ret < 0)
+		return ret;
+
+	ret = clk_enable(&priv->clk);
+	if (ret < 0)
+		return ret;
+
+	clk_rate = clk_get_rate(&priv->clk);
+	if (!clk_rate) {
+		ret = -EINVAL;
+		goto clk_err;
+	}
+
+	priv->bus_clk_rate = clk_rate;
+
+	/* perform reset */
+	ret = reset_get_by_index(dev, 0, &priv->rst_ctl);
+	if (ret < 0)
+		goto clk_err;
+
+	reset_assert(&priv->rst_ctl);
+	udelay(2);
+	reset_deassert(&priv->rst_ctl);
+
+	ret = gpio_request_list_by_name(dev, "cs-gpios", priv->cs_gpios,
+					ARRAY_SIZE(priv->cs_gpios), 0);
+	if (ret < 0) {
+		pr_err("Can't get %s cs gpios: %d", dev->name, ret);
+		goto reset_err;
+	}
+
+	priv->fifo_size = stm32_spi_get_fifo_size(dev);
+
+	priv->cur_mode = SPI_FULL_DUPLEX;
+	priv->cur_xferlen = 0;
+	priv->cur_bpw = SPI_DEFAULT_WORDLEN;
+	clrsetbits_le32(priv->base + STM32_SPI_CFG1, SPI_CFG1_DSIZE,
+			priv->cur_bpw - 1);
+
+	for (i = 0; i < ARRAY_SIZE(priv->cs_gpios); i++) {
+		if (!dm_gpio_is_valid(&priv->cs_gpios[i]))
+			continue;
+
+		dm_gpio_set_dir_flags(&priv->cs_gpios[i],
+				      GPIOD_IS_OUT | GPIOD_IS_OUT_ACTIVE);
+	}
+
+	/* Ensure I2SMOD bit is kept cleared */
+	clrbits_le32(priv->base + STM32_SPI_I2SCFGR, SPI_I2SCFGR_I2SMOD);
+
+	/*
+	 * - SS input value high
+	 * - transmitter half duplex direction
+	 * - automatic communication suspend when RX-Fifo is full
+	 */
+	setbits_le32(priv->base + STM32_SPI_CR1,
+		     SPI_CR1_SSI | SPI_CR1_HDDIR | SPI_CR1_MASRX);
+
+	/*
+	 * - Set the master mode (default Motorola mode)
+	 * - Consider 1 master/n slaves configuration and
+	 *   SS input value is determined by the SSI bit
+	 * - keep control of all associated GPIOs
+	 */
+	setbits_le32(priv->base + STM32_SPI_CFG2,
+		     SPI_CFG2_MASTER | SPI_CFG2_SSM | SPI_CFG2_AFCNTR);
+
+	return 0;
+
+reset_err:
+	reset_free(&priv->rst_ctl);
+
+clk_err:
+	clk_disable(&priv->clk);
+	clk_free(&priv->clk);
+
+	return ret;
+};
+
+static int stm32_spi_remove(struct udevice *dev)
+{
+	struct stm32_spi_priv *priv = dev_get_priv(dev);
+	int ret;
+
+	stm32_spi_stopxfer(dev);
+	stm32_spi_disable(priv);
+
+	ret = reset_assert(&priv->rst_ctl);
+	if (ret < 0)
+		return ret;
+
+	reset_free(&priv->rst_ctl);
+
+	ret = clk_disable(&priv->clk);
+	if (ret < 0)
+		return ret;
+
+	clk_free(&priv->clk);
+
+	return ret;
+};
+
+static const struct dm_spi_ops stm32_spi_ops = {
+	.claim_bus	= stm32_spi_claim_bus,
+	.release_bus	= stm32_spi_release_bus,
+	.set_mode	= stm32_spi_set_mode,
+	.set_speed	= stm32_spi_set_speed,
+	.xfer		= stm32_spi_xfer,
+};
+
+static const struct udevice_id stm32_spi_ids[] = {
+	{ .compatible = "st,stm32h7-spi", },
+	{ }
+};
+
+U_BOOT_DRIVER(stm32_spi) = {
+	.name			= "stm32_spi",
+	.id			= UCLASS_SPI,
+	.of_match		= stm32_spi_ids,
+	.ops			= &stm32_spi_ops,
+	.priv_auto_alloc_size	= sizeof(struct stm32_spi_priv),
+	.probe			= stm32_spi_probe,
+	.remove			= stm32_spi_remove,
+};