[U-Boot] [PATCH v2 1/4] dm: spi: add BCM63xx HSSPI driver

["Álvaro Fernández Rojas" <noltari@gmail.com>]

This driver is a simplified version of linux/drivers/spi/spi-bcm63xx-hsspi.c

Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
---
v2: Introduce changes suggested by Simon Glass:
 - Split bcm63xx_hsspi_xfer() into smaller functions.
 - Check possible clock errors.
 - Check possible reset errors.
 - Switch to devfdt_get_addr_size_index().
 - Use setbits32_be() for clock gate.

 drivers/spi/Kconfig         |   8 +
 drivers/spi/Makefile        |   1 +
 drivers/spi/bcm63xx_hsspi.c | 413 ++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 422 insertions(+)
 create mode 100644 drivers/spi/bcm63xx_hsspi.c

diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
index 0b408db..e49ec36 100644
--- a/drivers/spi/Kconfig
+++ b/drivers/spi/Kconfig
@@ -40,6 +40,14 @@ config ATMEL_SPI
 	  many AT32 (AVR32) and AT91 (ARM) chips. This driver can be
 	  used to access the SPI Flash, such as AT25DF321.
 
+config BCM6328_HSSPI
+	bool "BCM6328 HSSPI driver"
+	depends on ARCH_BMIPS
+	help
+	  Enable the BCM6328 HSSPI driver. This driver can be used to
+	  access the SPI NOR flash on platforms embedding this Broadcom
+	  SPI core.
+
 choice
 	prompt "BCM63xx SPI driver"
 	depends on ARCH_BMIPS
diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile
index 2795a34..7ad0da1 100644
--- a/drivers/spi/Makefile
+++ b/drivers/spi/Makefile
@@ -19,6 +19,7 @@ obj-$(CONFIG_ALTERA_SPI) += altera_spi.o
 obj-$(CONFIG_ATH79_SPI) += ath79_spi.o
 obj-$(CONFIG_ATMEL_DATAFLASH_SPI) += atmel_dataflash_spi.o
 obj-$(CONFIG_ATMEL_SPI) += atmel_spi.o
+obj-$(CONFIG_BCM6328_HSSPI) += bcm63xx_hsspi.o
 obj-$(CONFIG_BCM6348_SPI)$(CONFIG_BCM6358_SPI) += bcm63xx_spi.o
 obj-$(CONFIG_CADENCE_QSPI) += cadence_qspi.o cadence_qspi_apb.o
 obj-$(CONFIG_CF_SPI) += cf_spi.o
diff --git a/drivers/spi/bcm63xx_hsspi.c b/drivers/spi/bcm63xx_hsspi.c
new file mode 100644
index 0000000..538c4ec
--- /dev/null
+++ b/drivers/spi/bcm63xx_hsspi.c
@@ -0,0 +1,413 @@
+/*
+ * Copyright (C) 2017 Álvaro Fernández Rojas <noltari@gmail.com>
+ *
+ * Derived from linux/drivers/spi/spi-bcm63xx-hsspi.c:
+ *	Copyright (C) 2000-2010 Broadcom Corporation
+ *	Copyright (C) 2012-2013 Jonas Gorski <jogo@openwrt.org>
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ */
+
+#include <common.h>
+#include <clk.h>
+#include <dm.h>
+#include <spi.h>
+#include <reset.h>
+#include <asm/io.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+#define SPI_PP_SEL			0
+
+#define SPI_MAX_SYNC_CLOCK		30000000
+
+/* SPI Control register */
+#define SPI_CTL_REG			0x000
+#define SPI_CTL_CS_POL_SHIFT		0
+#define SPI_CTL_CS_POL_MASK		(0xff << SPI_CTL_CS_POL_SHIFT)
+#define SPI_CTL_CLK_GATE_SHIFT		16
+#define SPI_CTL_CLK_GATE_MASK		(1 << SPI_CTL_CLK_GATE_SHIFT)
+#define SPI_CTL_CLK_POL_SHIFT		17
+#define SPI_CTL_CLK_POL_MASK		(1 << SPI_CTL_CLK_POL_SHIFT)
+
+/* SPI Interrupts registers */
+#define SPI_IR_STAT_REG			0x008
+#define SPI_IR_ST_MASK_REG		0x00c
+#define SPI_IR_MASK_REG			0x010
+
+#define SPI_IR_CLEAR_ALL		0xff001f1f
+
+/* SPI Ping-Pong Command registers */
+#define SPI_PP_CMD_REG			(0x080 + (0x40 * (SPI_PP_SEL)) + 0x00)
+#define SPI_PP_CMD_OP_SHIFT		0
+#define SPI_PP_CMD_OP_START		(0x1 << SPI_PP_CMD_OP_SHIFT)
+#define SPI_PP_CMD_PFL_SHIFT		8
+#define SPI_PP_CMD_PFL_MASK		(0x7 << SPI_PP_CMD_PFL_SHIFT)
+#define SPI_PP_CMD_SLAVE_SHIFT		12
+#define SPI_PP_CMD_SLAVE_MASK		(0x7 << SPI_PP_CMD_SLAVE_SHIFT)
+
+/* SPI Ping-Pong Status registers */
+#define SPI_PP_STAT_REG			(0x080 + (0x40 * (SPI_PP_SEL)) + 0x04)
+#define SPI_PP_STAT_SRCBUSY_SHIFT	1
+#define SPI_PP_STAT_SRCBUSY_MASK	(1 << SPI_PP_STAT_SRCBUSY_SHIFT)
+
+/* SPI Profile Clock registers */
+#define SPI_PFL_CLK_REG(x)		(0x100 + (0x20 * (x)) + 0x00)
+#define SPI_PFL_CLK_FREQ_SHIFT		0
+#define SPI_PFL_CLK_FREQ_MASK		(0x3fff << SPI_PFL_CLK_FREQ_SHIFT)
+#define SPI_PFL_CLK_RSTLOOP_SHIFT	15
+#define SPI_PFL_CLK_RSTLOOP_MASK	(1 << SPI_PFL_CLK_RSTLOOP_SHIFT)
+
+/* SPI Profile Signal registers */
+#define SPI_PFL_SIG_REG(x)		(0x100 + (0x20 * (x)) + 0x04)
+#define SPI_PFL_SIG_LATCHRIS_SHIFT	12
+#define SPI_PFL_SIG_LATCHRIS_MASK	(1 << SPI_PFL_SIG_LATCHRIS_SHIFT)
+#define SPI_PFL_SIG_LAUNCHRIS_SHIFT	13
+#define SPI_PFL_SIG_LAUNCHRIS_MASK	(1 << SPI_PFL_SIG_LAUNCHRIS_SHIFT)
+#define SPI_PFL_SIG_ASYNCIN_SHIFT	16
+#define SPI_PFL_SIG_ASYNCIN_MASK	(1 << SPI_PFL_SIG_ASYNCIN_SHIFT)
+
+/* SPI Profile Mode registers */
+#define SPI_PFL_MODE_REG(x)		(0x100 + (0x20 * (x)) + 0x08)
+#define SPI_PFL_MODE_FILL_SHIFT		0
+#define SPI_PFL_MODE_FILL_MASK		(0xff << SPI_PFL_MODE_FILL_SHIFT)
+#define SPI_PFL_MODE_MDRDSZ_SHIFT	16
+#define SPI_PFL_MODE_MDRDSZ_MASK	(1 << SPI_PFL_MODE_MDRDSZ_SHIFT)
+#define SPI_PFL_MODE_MDWRSZ_SHIFT	18
+#define SPI_PFL_MODE_MDWRSZ_MASK	(1 << SPI_PFL_MODE_MDWRSZ_SHIFT)
+#define SPI_PFL_MODE_3WIRE_SHIFT	20
+#define SPI_PFL_MODE_3WIRE_MASK		(1 << SPI_PFL_MODE_3WIRE_SHIFT)
+
+/* SPI Ping-Pong FIFO registers */
+#define SPI_PP_FIFO_SIZE		0x200
+#define SPI_PP_FIFO_BASE		(0x200 + \
+					 (SPI_PP_FIFO_SIZE * SPI_PP_SEL))
+
+/* SPI Ping-Pong FIFO OP register */
+#define SPI_PP_FIFO_OP_SIZE		0x2
+#define SPI_PP_FIFO_OP_REG		(SPI_PP_FIFO_BASE + 0x00)
+#define SPI_PP_FIFO_OP_BYTES_SHIFT	0
+#define SPI_PP_FIFO_OP_BYTES_MASK	(0x3ff << SPI_PP_FIFO_OP_BYTES_SHIFT)
+#define SPI_PP_FIFO_OP_MBIT_SHIFT	11
+#define SPI_PP_FIFO_OP_MBIT_MASK	(1 << SPI_PP_FIFO_OP_MBIT_SHIFT)
+#define SPI_PP_FIFO_OP_CODE_SHIFT	13
+#define SPI_PP_FIFO_OP_CODE_RW		(1 << SPI_PP_FIFO_OP_CODE_SHIFT)
+#define SPI_PP_FIFO_OP_CODE_W		(2 << SPI_PP_FIFO_OP_CODE_SHIFT)
+#define SPI_PP_FIFO_OP_CODE_R		(3 << SPI_PP_FIFO_OP_CODE_SHIFT)
+
+struct bcm63xx_hsspi_priv {
+	void __iomem *regs;
+	ulong clk_rate;
+	uint8_t num_cs;
+	uint8_t cs_pols;
+	uint speed;
+};
+
+static int bcm63xx_hsspi_cs_info(struct udevice *bus, uint cs,
+			   struct spi_cs_info *info)
+{
+	struct bcm63xx_hsspi_priv *priv = dev_get_priv(bus);
+
+	if (cs >= priv->num_cs) {
+		error("no cs %u\n", cs);
+		return -ENODEV;
+	}
+
+	return 0;
+}
+
+static int bcm63xx_hsspi_set_mode(struct udevice *bus, uint mode)
+{
+	struct bcm63xx_hsspi_priv *priv = dev_get_priv(bus);
+
+	/* clock polarity */
+	if (mode & SPI_CPOL)
+		setbits_be32(priv->regs + SPI_CTL_REG, SPI_CTL_CLK_POL_MASK);
+	else
+		clrbits_be32(priv->regs + SPI_CTL_REG, SPI_CTL_CLK_POL_MASK);
+
+	return 0;
+}
+
+static int bcm63xx_hsspi_set_speed(struct udevice *bus, uint speed)
+{
+	struct bcm63xx_hsspi_priv *priv = dev_get_priv(bus);
+
+	priv->speed = speed;
+
+	return 0;
+}
+
+static void bcm63xx_hsspi_claim_cs(struct bcm63xx_hsspi_priv *priv,
+				   struct dm_spi_slave_platdata *plat)
+{
+	uint32_t clr, set;
+
+	/* profile clock */
+	set = DIV_ROUND_UP(priv->clk_rate, priv->speed);
+	set = DIV_ROUND_UP(2048, set);
+	set &= SPI_PFL_CLK_FREQ_MASK;
+	set |= SPI_PFL_CLK_RSTLOOP_MASK;
+	writel_be(set, priv->regs + SPI_PFL_CLK_REG(plat->cs));
+
+	/* profile signal */
+	set = 0;
+	clr = SPI_PFL_SIG_LAUNCHRIS_MASK |
+	      SPI_PFL_SIG_LATCHRIS_MASK |
+	      SPI_PFL_SIG_ASYNCIN_MASK;
+
+	/* latch/launch config */
+	if (plat->mode & SPI_CPHA)
+		set |= SPI_PFL_SIG_LAUNCHRIS_MASK;
+	else
+		set |= SPI_PFL_SIG_LATCHRIS_MASK;
+
+	/* async clk */
+	if (priv->speed > SPI_MAX_SYNC_CLOCK)
+		set |= SPI_PFL_SIG_ASYNCIN_MASK;
+
+	clrsetbits_be32(priv->regs + SPI_PFL_SIG_REG(plat->cs), clr, set);
+
+	/* global control */
+	set = 0;
+	clr = 0;
+
+	/* invert cs polarity */
+	if (priv->cs_pols & BIT(plat->cs))
+		clr |= BIT(plat->cs);
+	else
+		set |= BIT(plat->cs);
+
+	/* invert dummy cs polarity */
+	if (priv->cs_pols & BIT(!plat->cs))
+		clr |= BIT(!plat->cs);
+	else
+		set |= BIT(!plat->cs);
+
+	clrsetbits_be32(priv->regs + SPI_CTL_REG, clr, set);
+}
+
+static void bcm63xx_hsspi_release_cs(struct bcm63xx_hsspi_priv *priv)
+{
+	/* restore cs polarities */
+	clrsetbits_be32(priv->regs + SPI_CTL_REG, SPI_CTL_CS_POL_MASK,
+			priv->cs_pols);
+}
+
+/*
+ * BCM63xx HSSPI driver doesn't allow keeping CS active between transfers
+ * because they are controlled by HW.
+ * However, it provides a mechanism to prepend write transfers prior to read
+ * transfers (with a maximum prepend of 15 bytes), which is usually enough for
+ * SPI-connected flashes since reading requires prepending a write transfer of
+ * 5 bytes. On the other hand it also provides a way to invert each CS
+ * polarity, not only between transfers like the older BCM63xx SPI driver, but
+ * also the rest of the time.
+ *
+ * Instead of using the prepend mechanism, this implementation inverts the
+ * polarity of both the desired CS and another dummy CS when the bus is
+ * claimed. This way, the dummy CS is restored to its inactive value when
+ * transfers are issued and the desired CS is preserved in its active value
+ * all the time. This hack is also used in the upstream linux driver and
+ * allows keeping CS active between trasnfers even if the HW doesn't give
+ * this possibility.
+ */
+static int bcm63xx_hsspi_xfer(struct udevice *dev, unsigned int bitlen,
+		const void *dout, void *din, unsigned long flags)
+{
+	struct bcm63xx_hsspi_priv *priv = dev_get_priv(dev->parent);
+	struct dm_spi_slave_platdata *plat = dev_get_parent_platdata(dev);
+	size_t data_bytes = bitlen / 8;
+	size_t step_size = SPI_PP_FIFO_SIZE;
+	uint16_t opcode = 0;
+	uint32_t val;
+	const uint8_t *tx = dout;
+	uint8_t *rx = din;
+
+	if (flags & SPI_XFER_BEGIN)
+		bcm63xx_hsspi_claim_cs(priv, plat);
+
+	/* fifo operation */
+	if (tx && rx)
+		opcode = SPI_PP_FIFO_OP_CODE_RW;
+	else if (rx)
+		opcode = SPI_PP_FIFO_OP_CODE_R;
+	else if (tx)
+		opcode = SPI_PP_FIFO_OP_CODE_W;
+
+	if (opcode != SPI_PP_FIFO_OP_CODE_R)
+		step_size -= SPI_PP_FIFO_OP_SIZE;
+
+	/* dual mode */
+	if ((opcode == SPI_PP_FIFO_OP_CODE_R && plat->mode == SPI_RX_DUAL) ||
+	    (opcode == SPI_PP_FIFO_OP_CODE_W && plat->mode == SPI_TX_DUAL))
+		opcode |= SPI_PP_FIFO_OP_MBIT_MASK;
+
+	/* profile mode */
+	val = SPI_PFL_MODE_FILL_MASK |
+	      SPI_PFL_MODE_MDRDSZ_MASK |
+	      SPI_PFL_MODE_MDWRSZ_MASK;
+	if (plat->mode & SPI_3WIRE)
+		val |= SPI_PFL_MODE_3WIRE_MASK;
+	writel_be(val, priv->regs + SPI_PFL_MODE_REG(plat->cs));
+
+	/* transfer loop */
+	while (data_bytes > 0) {
+		size_t curr_step = min(step_size, data_bytes);
+
+		/* copy tx data */
+		if (tx) {
+			memcpy_toio(priv->regs + SPI_PP_FIFO_BASE +
+				    SPI_PP_FIFO_OP_SIZE, tx, curr_step);
+			tx += curr_step;
+		}
+
+		/* set fifo operation */
+		writew_be(opcode | (curr_step & SPI_PP_FIFO_OP_BYTES_MASK),
+			  priv->regs + SPI_PP_FIFO_OP_REG);
+
+		/* issue the transfer */
+		val = SPI_PP_CMD_OP_START;
+		val |= (plat->cs << SPI_PP_CMD_PFL_SHIFT) &
+		       SPI_PP_CMD_PFL_MASK;
+		val |= (!plat->cs << SPI_PP_CMD_SLAVE_SHIFT) &
+		       SPI_PP_CMD_SLAVE_MASK;
+		writel_be(val, priv->regs + SPI_PP_CMD_REG);
+
+		/* wait for completion */
+		do {
+			/* check ping-pong status */
+			val = readl_be(priv->regs + SPI_PP_STAT_REG);
+
+			/* transfer completed */
+			if (!(val & SPI_PP_STAT_SRCBUSY_MASK))
+				break;
+		} while (1);
+
+		/* copy rx data */
+		if (rx) {
+			memcpy_fromio(rx, priv->regs + SPI_PP_FIFO_BASE,
+				      curr_step);
+			rx += curr_step;
+		}
+
+		data_bytes -= curr_step;
+	}
+
+	if (flags & SPI_XFER_END)
+		bcm63xx_hsspi_release_cs(priv);
+
+	return 0;
+}
+
+static const struct dm_spi_ops bcm63xx_hsspi_ops = {
+	.cs_info = bcm63xx_hsspi_cs_info,
+	.set_mode = bcm63xx_hsspi_set_mode,
+	.set_speed = bcm63xx_hsspi_set_speed,
+	.xfer = bcm63xx_hsspi_xfer,
+};
+
+static const struct udevice_id bcm63xx_hsspi_ids[] = {
+	{ .compatible = "brcm,bcm6328-hsspi", },
+	{ /* sentinel */ }
+};
+
+static int bcm63xx_hsspi_child_pre_probe(struct udevice *dev)
+{
+	struct bcm63xx_hsspi_priv *priv = dev_get_priv(dev->parent);
+	struct dm_spi_slave_platdata *plat = dev_get_parent_platdata(dev);
+
+	/* check cs */
+	if (plat->cs >= priv->num_cs) {
+		error("no cs %u\n", plat->cs);
+		return -ENODEV;
+	}
+
+	/* cs polarity */
+	if (plat->mode & SPI_CS_HIGH)
+		priv->cs_pols |= BIT(plat->cs);
+	else
+		priv->cs_pols &= ~BIT(plat->cs);
+
+	return 0;
+}
+
+static int bcm63xx_hsspi_probe(struct udevice *dev)
+{
+	struct bcm63xx_hsspi_priv *priv = dev_get_priv(dev);
+	struct reset_ctl rst_ctl;
+	struct clk clk;
+	fdt_addr_t addr;
+	fdt_size_t size;
+	int ret;
+
+	addr = devfdt_get_addr_size_index(dev, 0, &size);
+	if (addr == FDT_ADDR_T_NONE)
+		return -EINVAL;
+
+	priv->regs = ioremap(addr, size);
+	priv->num_cs = fdtdec_get_uint(gd->fdt_blob, dev_of_offset(dev),
+				       "num-cs", 8);
+
+	/* enable clock */
+	ret = clk_get_by_name(dev, "hsspi", &clk);
+	if (ret < 0)
+		return ret;
+
+	ret = clk_enable(&clk);
+	if (ret < 0)
+		return ret;
+
+	ret = clk_free(&clk);
+	if (ret < 0)
+		return ret;
+
+	/* get clock rate */
+	ret = clk_get_by_name(dev, "pll", &clk);
+	if (ret < 0)
+		return ret;
+
+	priv->clk_rate = clk_get_rate(&clk);
+
+	ret = clk_free(&clk);
+	if (ret < 0)
+		return ret;
+
+	/* perform reset */
+	ret = reset_get_by_index(dev, 0, &rst_ctl);
+	if (ret < 0)
+		return ret;
+
+	ret = reset_deassert(&rst_ctl);
+	if (ret < 0)
+		return ret;
+
+	ret = reset_free(&rst_ctl);
+	if (ret < 0)
+		return ret;
+
+	/* initialize hardware */
+	writel_be(0, priv->regs + SPI_IR_MASK_REG);
+
+	/* clear pending interrupts */
+	writel_be(SPI_IR_CLEAR_ALL, priv->regs + SPI_IR_STAT_REG);
+
+	/* enable clk gate */
+	setbits_be32(priv->regs + SPI_CTL_REG, SPI_CTL_CLK_GATE_MASK);
+
+	/* read default cs polarities */
+	priv->cs_pols = readl_be(priv->regs + SPI_CTL_REG) &
+			SPI_CTL_CS_POL_MASK;
+
+	return 0;
+}
+
+U_BOOT_DRIVER(bcm63xx_hsspi) = {
+	.name = "bcm63xx_hsspi",
+	.id = UCLASS_SPI,
+	.of_match = bcm63xx_hsspi_ids,
+	.ops = &bcm63xx_hsspi_ops,
+	.priv_auto_alloc_size = sizeof(struct bcm63xx_hsspi_priv),
+	.child_pre_probe = bcm63xx_hsspi_child_pre_probe,
+	.probe = bcm63xx_hsspi_probe,
+};
-- 
2.1.4