spi: Add Amlogic Meson SPI Flash Controller driver

The Amlogic Meson SoCs embeds a Flash oriented SPI Controller name SPIFC.
This driver, ported from the Linux meson-spi-spifc driver, add support
for this controller on the Amlogic Meson GX SoCs in U-Boot.

Tested-by: Jerome Brunet <jbrunet@baylibre.com>
Reviewed-by: Jagan Teki <jagan@openedev.com>
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>

drivers/spi/Kconfig

@@ -116,6 +116,14 @@ config ICH_SPI
 	  access the SPI NOR flash on platforms embedding this Intel
 	  ICH IP core.
 
+config MESON_SPIFC
+	bool "Amlogic Meson SPI Flash Controller driver"
+	depends on ARCH_MESON
+	help
+	  Enable the Amlogic Meson SPI Flash Controller SPIFC) driver.
+	  This driver can be used to access the SPI NOR flash chips on
+	  Amlogic Meson SoCs.
+
 config MT7621_SPI
 	bool "MediaTek MT7621 SPI driver"
 	depends on ARCH_MT7620

drivers/spi/Makefile

@@ -31,6 +31,7 @@ obj-$(CONFIG_FSL_QSPI) += fsl_qspi.o
 obj-$(CONFIG_ICH_SPI) +=  ich.o
 obj-$(CONFIG_KIRKWOOD_SPI) += kirkwood_spi.o
 obj-$(CONFIG_LPC32XX_SSP) += lpc32xx_ssp.o
+obj-$(CONFIG_MESON_SPIFC) += meson_spifc.o
 obj-$(CONFIG_MPC8XX_SPI) += mpc8xx_spi.o
 obj-$(CONFIG_MPC8XXX_SPI) += mpc8xxx_spi.o
 obj-$(CONFIG_MT7621_SPI) += mt7621_spi.o

drivers/spi/meson_spifc.c

@@ -0,0 +1,320 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2014 Beniamino Galvani <b.galvani@gmail.com>
+ * Copyright (C) 2018 BayLibre, SAS
+ * Author: Neil Armstrong <narmstrong@baylibre.com>
+ *
+ * Amlogic Meson SPI Flash Controller driver
+ */
+
+#include <common.h>
+#include <spi.h>
+#include <clk.h>
+#include <dm.h>
+#include <regmap.h>
+#include <errno.h>
+#include <asm/io.h>
+#include <linux/bitfield.h>
+
+/* register map */
+#define REG_CMD			0x00
+#define REG_ADDR		0x04
+#define REG_CTRL		0x08
+#define REG_CTRL1		0x0c
+#define REG_STATUS		0x10
+#define REG_CTRL2		0x14
+#define REG_CLOCK		0x18
+#define REG_USER		0x1c
+#define REG_USER1		0x20
+#define REG_USER2		0x24
+#define REG_USER3		0x28
+#define REG_USER4		0x2c
+#define REG_SLAVE		0x30
+#define REG_SLAVE1		0x34
+#define REG_SLAVE2		0x38
+#define REG_SLAVE3		0x3c
+#define REG_C0			0x40
+#define REG_B8			0x60
+#define REG_MAX			0x7c
+
+/* register fields */
+#define CMD_USER		BIT(18)
+#define CTRL_ENABLE_AHB		BIT(17)
+#define CLOCK_SOURCE		BIT(31)
+#define CLOCK_DIV_SHIFT		12
+#define CLOCK_DIV_MASK		(0x3f << CLOCK_DIV_SHIFT)
+#define CLOCK_CNT_HIGH_SHIFT	6
+#define CLOCK_CNT_HIGH_MASK	(0x3f << CLOCK_CNT_HIGH_SHIFT)
+#define CLOCK_CNT_LOW_SHIFT	0
+#define CLOCK_CNT_LOW_MASK	(0x3f << CLOCK_CNT_LOW_SHIFT)
+#define USER_DIN_EN_MS		BIT(0)
+#define USER_CMP_MODE		BIT(2)
+#define USER_CLK_NOT_INV	BIT(7)
+#define USER_UC_DOUT_SEL	BIT(27)
+#define USER_UC_DIN_SEL		BIT(28)
+#define USER_UC_MASK		((BIT(5) - 1) << 27)
+#define USER1_BN_UC_DOUT_SHIFT	17
+#define USER1_BN_UC_DOUT_MASK	(0xff << 16)
+#define USER1_BN_UC_DIN_SHIFT	8
+#define USER1_BN_UC_DIN_MASK	(0xff << 8)
+#define USER4_CS_POL_HIGH	BIT(23)
+#define USER4_IDLE_CLK_HIGH	BIT(29)
+#define USER4_CS_ACT		BIT(30)
+#define SLAVE_TRST_DONE		BIT(4)
+#define SLAVE_OP_MODE		BIT(30)
+#define SLAVE_SW_RST		BIT(31)
+
+#define SPIFC_BUFFER_SIZE	64
+
+struct meson_spifc_priv {
+	struct regmap			*regmap;
+	struct clk			clk;
+};
+
+/**
+ * meson_spifc_drain_buffer() - copy data from device buffer to memory
+ * @spifc:	the Meson SPI device
+ * @buf:	the destination buffer
+ * @len:	number of bytes to copy
+ */
+static void meson_spifc_drain_buffer(struct meson_spifc_priv *spifc,
+				     u8 *buf, int len)
+{
+	u32 data;
+	int i = 0;
+
+	while (i < len) {
+		regmap_read(spifc->regmap, REG_C0 + i, &data);
+
+		if (len - i >= 4) {
+			*((u32 *)buf) = data;
+			buf += 4;
+		} else {
+			memcpy(buf, &data, len - i);
+			break;
+		}
+		i += 4;
+	}
+}
+
+/**
+ * meson_spifc_fill_buffer() - copy data from memory to device buffer
+ * @spifc:	the Meson SPI device
+ * @buf:	the source buffer
+ * @len:	number of bytes to copy
+ */
+static void meson_spifc_fill_buffer(struct meson_spifc_priv *spifc,
+				    const u8 *buf, int len)
+{
+	u32 data = 0;
+	int i = 0;
+
+	while (i < len) {
+		if (len - i >= 4)
+			data = *(u32 *)buf;
+		else
+			memcpy(&data, buf, len - i);
+
+		regmap_write(spifc->regmap, REG_C0 + i, data);
+
+		buf += 4;
+		i += 4;
+	}
+}
+
+/**
+ * meson_spifc_txrx() - transfer a chunk of data
+ * @spifc:	the Meson SPI device
+ * @dout:	data buffer for TX
+ * @din:	data buffer for RX
+ * @offset:	offset of the data to transfer
+ * @len:	length of the data to transfer
+ * @last_xfer:	whether this is the last transfer of the message
+ * @last_chunk:	whether this is the last chunk of the transfer
+ * Return:	0 on success, a negative value on error
+ */
+static int meson_spifc_txrx(struct meson_spifc_priv *spifc,
+			    const u8 *dout, u8 *din, int offset,
+			    int len, bool last_xfer, bool last_chunk)
+{
+	bool keep_cs = true;
+	u32 data;
+	int ret;
+
+	if (dout)
+		meson_spifc_fill_buffer(spifc, dout + offset, len);
+
+	/* enable DOUT stage */
+	regmap_update_bits(spifc->regmap, REG_USER, USER_UC_MASK,
+			   USER_UC_DOUT_SEL);
+	regmap_write(spifc->regmap, REG_USER1,
+		     (8 * len - 1) << USER1_BN_UC_DOUT_SHIFT);
+
+	/* enable data input during DOUT */
+	regmap_update_bits(spifc->regmap, REG_USER, USER_DIN_EN_MS,
+			   USER_DIN_EN_MS);
+
+	if (last_chunk && last_xfer)
+		keep_cs = false;
+
+	regmap_update_bits(spifc->regmap, REG_USER4, USER4_CS_ACT,
+			   keep_cs ? USER4_CS_ACT : 0);
+
+	/* clear transition done bit */
+	regmap_update_bits(spifc->regmap, REG_SLAVE, SLAVE_TRST_DONE, 0);
+	/* start transfer */
+	regmap_update_bits(spifc->regmap, REG_CMD, CMD_USER, CMD_USER);
+
+	/* wait for the current operation to terminate */
+	ret = regmap_read_poll_timeout(spifc->regmap, REG_SLAVE, data,
+				       (data & SLAVE_TRST_DONE),
+				       0, 5 * CONFIG_SYS_HZ);
+
+	if (!ret && din)
+		meson_spifc_drain_buffer(spifc, din + offset, len);
+
+	return ret;
+}
+
+/**
+ * meson_spifc_xfer() - perform a single transfer
+ * @dev:	the SPI controller device
+ * @bitlen:	length of the transfer
+ * @dout:	data buffer for TX
+ * @din:	data buffer for RX
+ * @flags:	transfer flags
+ * Return:	0 on success, a negative value on error
+ */
+static int meson_spifc_xfer(struct udevice *slave, unsigned int bitlen,
+			    const void *dout, void *din, unsigned long flags)
+{
+	struct meson_spifc_priv *spifc = dev_get_priv(slave->parent);
+	int blen = bitlen / 8;
+	int len, done = 0, ret = 0;
+
+	if (bitlen % 8)
+		return -EINVAL;
+
+	debug("xfer len %d (%d) dout %p din %p\n", bitlen, blen, dout, din);
+
+	regmap_update_bits(spifc->regmap, REG_CTRL, CTRL_ENABLE_AHB, 0);
+
+	while (done < blen && !ret) {
+		len = min_t(int, blen - done, SPIFC_BUFFER_SIZE);
+		ret = meson_spifc_txrx(spifc, dout, din, done, len,
+				       flags & SPI_XFER_END,
+				       done + len >= blen);
+		done += len;
+	}
+
+	regmap_update_bits(spifc->regmap, REG_CTRL, CTRL_ENABLE_AHB,
+			   CTRL_ENABLE_AHB);
+
+	return ret;
+}
+
+/**
+ * meson_spifc_set_speed() - program the clock divider
+ * @dev:	the SPI controller device
+ * @speed:	desired speed in Hz
+ */
+static int meson_spifc_set_speed(struct udevice *dev, uint speed)
+{
+	struct meson_spifc_priv *spifc = dev_get_priv(dev);
+	unsigned long parent, value;
+	int n;
+
+	parent = clk_get_rate(&spifc->clk);
+	n = max_t(int, parent / speed - 1, 1);
+
+	debug("parent %lu, speed %u, n %d\n", parent, speed, n);
+
+	value = (n << CLOCK_DIV_SHIFT) & CLOCK_DIV_MASK;
+	value |= (n << CLOCK_CNT_LOW_SHIFT) & CLOCK_CNT_LOW_MASK;
+	value |= (((n + 1) / 2 - 1) << CLOCK_CNT_HIGH_SHIFT) &
+		CLOCK_CNT_HIGH_MASK;
+
+	regmap_write(spifc->regmap, REG_CLOCK, value);
+
+	return 0;
+}
+
+/**
+ * meson_spifc_set_mode() - setups the SPI bus mode
+ * @dev:	the SPI controller device
+ * @mode:	desired mode bitfield
+ * Return:	0 on success, -ENODEV on error
+ */
+static int meson_spifc_set_mode(struct udevice *dev, uint mode)
+{
+	struct meson_spifc_priv *spifc = dev_get_priv(dev);
+
+	if (mode & (SPI_CPHA | SPI_RX_QUAD | SPI_RX_DUAL |
+		    SPI_TX_QUAD | SPI_TX_DUAL))
+		return -ENODEV;
+
+	regmap_update_bits(spifc->regmap, REG_USER, USER_CLK_NOT_INV,
+			   mode & SPI_CPOL ? USER_CLK_NOT_INV : 0);
+
+	regmap_update_bits(spifc->regmap, REG_USER4, USER4_CS_POL_HIGH,
+			   mode & SPI_CS_HIGH ? USER4_CS_POL_HIGH : 0);
+
+	return 0;
+}
+
+/**
+ * meson_spifc_hw_init() - reset and initialize the SPI controller
+ * @spifc:	the Meson SPI device
+ */
+static void meson_spifc_hw_init(struct meson_spifc_priv *spifc)
+{
+	/* reset device */
+	regmap_update_bits(spifc->regmap, REG_SLAVE, SLAVE_SW_RST,
+			   SLAVE_SW_RST);
+	/* disable compatible mode */
+	regmap_update_bits(spifc->regmap, REG_USER, USER_CMP_MODE, 0);
+	/* set master mode */
+	regmap_update_bits(spifc->regmap, REG_SLAVE, SLAVE_OP_MODE, 0);
+}
+
+static const struct dm_spi_ops meson_spifc_ops = {
+	.xfer		= meson_spifc_xfer,
+	.set_speed	= meson_spifc_set_speed,
+	.set_mode	= meson_spifc_set_mode,
+};
+
+static int meson_spifc_probe(struct udevice *dev)
+{
+	struct meson_spifc_priv *priv = dev_get_priv(dev);
+	int ret;
+
+	ret = regmap_init_mem(dev_ofnode(dev), &priv->regmap);
+	if (ret)
+		return ret;
+
+	ret = clk_get_by_index(dev, 0, &priv->clk);
+	if (ret)
+		return ret;
+
+	ret = clk_enable(&priv->clk);
+	if (ret)
+		return ret;
+
+	meson_spifc_hw_init(priv);
+
+	return 0;
+}
+
+static const struct udevice_id meson_spifc_ids[] = {
+	{ .compatible = "amlogic,meson-gxbb-spifc", },
+	{ }
+};
+
+U_BOOT_DRIVER(meson_spifc) = {
+	.name		= "meson_spifc",
+	.id		= UCLASS_SPI,
+	.of_match	= meson_spifc_ids,
+	.ops		= &meson_spifc_ops,
+	.probe		= meson_spifc_probe,
+	.priv_auto_alloc_size = sizeof(struct meson_spifc_priv),
+};