[U-Boot] [PATCH v3 03/10] dm: spi: add BCM63xx SPI driver

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

This driver is a simplified version of linux/drivers/spi/spi-bcm63xx.c
Instead of supporting both HW revisions of the controller in a single build,
support has been split by the selected config to save space.

Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
---
 v3: rename BCM6338 SPI driver to BCM6348
  switch to devfdt_get_addr_size_index()
 v2: no changes

 drivers/spi/Kconfig       |  21 +++
 drivers/spi/Makefile      |   1 +
 drivers/spi/bcm63xx_spi.c | 404 ++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 426 insertions(+)
 create mode 100644 drivers/spi/bcm63xx_spi.c

diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
index bef864f..0b408db 100644
--- a/drivers/spi/Kconfig
+++ b/drivers/spi/Kconfig
@@ -40,6 +40,27 @@ config ATMEL_SPI
 	  many AT32 (AVR32) and AT91 (ARM) chips. This driver can be
 	  used to access the SPI Flash, such as AT25DF321.
 
+choice
+	prompt "BCM63xx SPI driver"
+	depends on ARCH_BMIPS
+	optional
+
+config BCM6348_SPI
+	bool "BCM6348 SPI driver"
+	help
+	  Enable the BCM6348 SPI driver. This driver can be used to
+	  access the SPI NOR flash on platforms embedding this Broadcom
+	  SPI core.
+
+config BCM6358_SPI
+	bool "BCM6358 SPI driver"
+	help
+	  Enable the BCM6358 SPI driver. This driver can be used to
+	  access the SPI NOR flash on platforms embedding this Broadcom
+	  SPI core.
+
+endchoice
+
 config CADENCE_QSPI
 	bool "Cadence QSPI driver"
 	help
diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile
index c090562..2795a34 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-$(CONFIG_BCM6348_SPI)$(CONFIG_BCM6358_SPI) += bcm63xx_spi.o
 obj-$(CONFIG_CADENCE_QSPI) += cadence_qspi.o cadence_qspi_apb.o
 obj-$(CONFIG_CF_SPI) += cf_spi.o
 obj-$(CONFIG_DAVINCI_SPI) += davinci_spi.o
diff --git a/drivers/spi/bcm63xx_spi.c b/drivers/spi/bcm63xx_spi.c
new file mode 100644
index 0000000..d3aad70
--- /dev/null
+++ b/drivers/spi/bcm63xx_spi.c
@@ -0,0 +1,404 @@
+/*
+ * Copyright (C) 2017 Álvaro Fernández Rojas <noltari@gmail.com>
+ *
+ * Derived from linux/drivers/spi/spi-bcm63xx.c:
+ *	Copyright (C) 2009-2012 Florian Fainelli <florian@openwrt.org>
+ *	Copyright (C) 2010 Tanguy Bouzeloc <tanguy.bouzeloc@efixo.com>
+ *
+ * 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;
+
+#if defined(CONFIG_BCM6348_SPI)
+
+# define SPI_DT_ID		"brcm,bcm6348-spi"
+
+/* SPI Command register */
+# define SPI_CMD_REG		0x00
+
+/* SPI Interrupt registers */
+# define SPI_IR_STAT_REG	0x02
+# define SPI_IR_MASK_REG	0x04
+
+/* SPI Clock register */
+# define SPI_CLK_REG		0x06
+
+/* SPI Fill register */
+# define SPI_FILL_REG		0x07
+
+/* SPI Control register (8 bit) */
+# define SPI_CTL_REG		0x40
+# define SPI_CTL_BYTES_SHIFT	0
+# define SPI_CTL_BYTES_MASK	(0x3f << SPI_CTL_BYTES_SHIFT)
+# define SPI_CTL_TYPE_SHIFT	6
+# define SPI_CTL_TYPE_FD_RW	(0 << SPI_CTL_TYPE_SHIFT)
+# define SPI_CTL_TYPE_HD_W	(1 << SPI_CTL_TYPE_SHIFT)
+# define SPI_CTL_TYPE_HD_R	(2 << SPI_CTL_TYPE_SHIFT)
+
+# define bcm63xx_spi_wctl(v,a)	writeb_be(v, a);
+
+/* SPI TX Data registers */
+# define SPI_TX_DATA_REG	0x41
+# define SPI_TX_DATA_SIZE	0x3f
+
+/* SPI RX Data registers */
+# define SPI_RX_DATA_REG	0x80
+# define SPI_RX_DATA_SIZE	0x3f
+
+#elif defined(CONFIG_BCM6358_SPI)
+
+# define SPI_DT_ID		"brcm,bcm6358-spi"
+
+/* SPI Control register (16 bit) */
+# define SPI_CTL_REG		0x000
+# define SPI_CTL_BYTES_SHIFT	0
+# define SPI_CTL_BYTES_MASK	(0x3ff << SPI_CTL_BYTES_SHIFT)
+# define SPI_CTL_TYPE_SHIFT	14
+# define SPI_CTL_TYPE_FD_RW	(0 << SPI_CTL_TYPE_SHIFT)
+# define SPI_CTL_TYPE_HD_W	(1 << SPI_CTL_TYPE_SHIFT)
+# define SPI_CTL_TYPE_HD_R	(2 << SPI_CTL_TYPE_SHIFT)
+
+# define bcm63xx_spi_wctl(v,a)	writew_be(v, a);
+
+/* SPI TX Data registers */
+# define SPI_TX_DATA_REG	0x002
+# define SPI_TX_DATA_SIZE	0x21e
+
+/* SPI RX Data registers */
+# define SPI_RX_DATA_REG	0x400
+# define SPI_RX_DATA_SIZE	0x220
+
+/* SPI Command register */
+# define SPI_CMD_REG		0x700
+
+/* SPI Interrupt registers */
+# define SPI_IR_STAT_REG	0x702
+# define SPI_IR_MASK_REG	0x704
+
+/* SPI Clock register */
+# define SPI_CLK_REG		0x706
+
+/* SPI Fill register */
+# define SPI_FILL_REG		0x707
+
+#endif
+
+/* SPI Command register */
+#define SPI_CMD_OP_SHIFT	0
+#define SPI_CMD_OP_START	(0x3 << SPI_CMD_OP_SHIFT)
+#define SPI_CMD_SLAVE_SHIFT	4
+#define SPI_CMD_SLAVE_MASK	(0xf << SPI_CMD_SLAVE_SHIFT)
+#define SPI_CMD_PREPEND_SHIFT	8
+#define SPI_CMD_PREPEND_BYTES	0xf
+#define SPI_CMD_3WIRE_SHIFT	12
+#define SPI_CMD_3WIRE_MASK	(1 << SPI_CMD_3WIRE_SHIFT)
+
+/* SPI Interrupt registers */
+#define SPI_IR_DONE_SHIFT	0
+#define SPI_IR_DONE_MASK	(1 << SPI_IR_DONE_SHIFT)
+#define SPI_IR_RXOVER_SHIFT	1
+#define SPI_IR_RXOVER_MASK	(1 << SPI_IR_RXOVER_SHIFT)
+#define SPI_IR_TXUNDER_SHIFT	2
+#define SPI_IR_TXUNDER_MASK	(1 << SPI_IR_TXUNDER_SHIFT)
+#define SPI_IR_TXOVER_SHIFT	3
+#define SPI_IR_TXOVER_MASK	(1 << SPI_IR_TXOVER_SHIFT)
+#define SPI_IR_RXUNDER_SHIFT	4
+#define SPI_IR_RXUNDER_MASK	(1 << SPI_IR_RXUNDER_SHIFT)
+#define SPI_IR_CLEAR_MASK	(SPI_IR_DONE_MASK |\
+				 SPI_IR_RXOVER_MASK |\
+				 SPI_IR_TXUNDER_MASK |\
+				 SPI_IR_TXOVER_MASK |\
+				 SPI_IR_RXUNDER_MASK)
+
+/* SPI Clock register */
+#define SPI_CLK_SHIFT		0
+#define SPI_CLK_20MHZ		(0 << SPI_CLK_SHIFT)
+#define SPI_CLK_0_391MHZ	(1 << SPI_CLK_SHIFT)
+#define SPI_CLK_0_781MHZ	(2 << SPI_CLK_SHIFT)
+#define SPI_CLK_1_563MHZ	(3 << SPI_CLK_SHIFT)
+#define SPI_CLK_3_125MHZ	(4 << SPI_CLK_SHIFT)
+#define SPI_CLK_6_250MHZ	(5 << SPI_CLK_SHIFT)
+#define SPI_CLK_12_50MHZ	(6 << SPI_CLK_SHIFT)
+#define SPI_CLK_25MHZ		(7 << SPI_CLK_SHIFT)
+#define SPI_CLK_MASK		(7 << SPI_CLK_SHIFT)
+#define SPI_CLK_SSOFF_SHIFT	3
+#define SPI_CLK_SSOFF_2		(2 << SPI_CLK_SSOFF_SHIFT)
+#define SPI_CLK_SSOFF_MASK	(7 << SPI_CLK_SSOFF_SHIFT)
+#define SPI_CLK_BSWAP_SHIFT	7
+#define SPI_CLK_BSWAP_MASK	(1 << SPI_CLK_BSWAP_SHIFT)
+
+#define SPI_CLK_CNT		8
+static const unsigned bcm63xx_spi_freq_table[SPI_CLK_CNT][2] = {
+	{ 25000000, SPI_CLK_25MHZ },
+	{ 20000000, SPI_CLK_20MHZ },
+	{ 12500000, SPI_CLK_12_50MHZ },
+	{  6250000, SPI_CLK_6_250MHZ },
+	{  3125000, SPI_CLK_3_125MHZ },
+	{  1563000, SPI_CLK_1_563MHZ },
+	{   781000, SPI_CLK_0_781MHZ },
+	{   391000, SPI_CLK_0_391MHZ }
+};
+
+struct bcm63xx_spi_priv {
+	void __iomem *regs;
+	uint8_t num_cs;
+	size_t tx_bytes;
+};
+
+static int bcm63xx_spi_cs_info(struct udevice *bus, uint cs,
+			   struct spi_cs_info *info)
+{
+	struct bcm63xx_spi_priv *priv = dev_get_priv(bus);
+
+	if (cs >= priv->num_cs) {
+		error("no cs %u\n", cs);
+		return -ENODEV;
+	}
+
+	return 0;
+}
+
+static int bcm63xx_spi_set_mode(struct udevice *bus, uint mode)
+{
+	struct bcm63xx_spi_priv *priv = dev_get_priv(bus);
+
+	if (mode & SPI_LSB_FIRST)
+		setbits_8(priv->regs + SPI_CLK_REG, SPI_CLK_BSWAP_MASK);
+	else
+		clrbits_8(priv->regs + SPI_CLK_REG, SPI_CLK_BSWAP_MASK);
+
+	return 0;
+}
+
+static int bcm63xx_spi_set_speed(struct udevice *bus, uint speed)
+{
+	struct bcm63xx_spi_priv *priv = dev_get_priv(bus);
+	uint8_t clk_cfg;
+	int i;
+
+	/* default to lowest clock configuration */
+	clk_cfg = SPI_CLK_0_391MHZ;
+
+	/* find the closest clock configuration */
+	for (i = 0; i < SPI_CLK_CNT; i++) {
+		if (speed >= bcm63xx_spi_freq_table[i][0]) {
+			clk_cfg = bcm63xx_spi_freq_table[i][1];
+			break;
+		}
+	}
+
+	/* write clock configuration */
+	clrsetbits_8(priv->regs + SPI_CLK_REG,
+		     SPI_CLK_SSOFF_MASK | SPI_CLK_MASK,
+		     clk_cfg | SPI_CLK_SSOFF_2);
+
+	return 0;
+}
+
+/*
+ * BCM63xx SPI driver doesn't allow keeping CS active between transfers since
+ * they are HW controlled.
+ * 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.
+ *
+ * This implementation takes advantage of the prepend mechanism and combines
+ * multiple transfers into a single one where possible (single/multiple write
+ * transfer(s) followed by a final read/write transfer).
+ * However, it's not possible to buffer reads, which means that read transfers
+ * should always be done as the final ones.
+ * On the other hand, take into account that combining write transfers into
+ * a single one is just buffering and doesn't require prepend mechanism.
+ */
+static int bcm63xx_spi_xfer(struct udevice *dev, unsigned int bitlen,
+		const void *dout, void *din, unsigned long flags)
+{
+	struct bcm63xx_spi_priv *priv = dev_get_priv(dev->parent);
+	size_t data_bytes = bitlen / 8;
+
+	if (flags & SPI_XFER_BEGIN) {
+		/* clear prepends */
+		priv->tx_bytes = 0;
+
+		/* initialize hardware */
+		writeb_be(0, priv->regs + SPI_IR_MASK_REG);
+	}
+
+	if (din) {
+		/* buffering reads not possible since cs is hw controlled */
+		if (!(flags & SPI_XFER_END)) {
+			error("unable to buffer reads\n");
+			return -EINVAL;
+		}
+
+		/* check rx size */
+		 if (data_bytes > SPI_RX_DATA_SIZE) {
+			error("max rx bytes exceeded\n");
+			return -EMSGSIZE;
+		}
+	}
+
+	if (dout) {
+		/* check tx size */
+		if (priv->tx_bytes + data_bytes > SPI_TX_DATA_SIZE) {
+			error("max tx bytes exceeded\n");
+			return -EMSGSIZE;
+		}
+
+		/* copy tx data */
+		memcpy_toio(priv->regs + SPI_TX_DATA_REG + priv->tx_bytes,
+			    dout, data_bytes);
+		priv->tx_bytes += data_bytes;
+	}
+
+	if (flags & SPI_XFER_END) {
+		struct dm_spi_slave_platdata *plat =
+			dev_get_parent_platdata(dev);
+		uint16_t val = 0;
+		uint8_t irq;
+
+		/* determine control config */
+		if (dout && !din) {
+			/* buffered write transfers */
+			val |= (priv->tx_bytes << SPI_CTL_BYTES_SHIFT);
+			val |= SPI_CTL_TYPE_HD_W;
+			priv->tx_bytes = 0;
+		} else {
+			if (dout && din && (flags & SPI_XFER_ONCE)) {
+				/* full duplex read/write */
+				val |= (data_bytes << SPI_CTL_BYTES_SHIFT);
+				val |= SPI_CTL_TYPE_FD_RW;
+				priv->tx_bytes = 0;
+			} else {
+				/* prepended write transfer */
+				val |= (data_bytes << SPI_CTL_BYTES_SHIFT);
+				val |= SPI_CTL_TYPE_HD_R;
+				if (priv->tx_bytes > SPI_CMD_PREPEND_BYTES) {
+					error("max prepend bytes exceeded\n");
+					return -EMSGSIZE;
+				}
+			}
+		}
+		bcm63xx_spi_wctl(val, priv->regs + SPI_CTL_REG);
+
+		/* clear interrupts */
+		writeb_be(SPI_IR_CLEAR_MASK, priv->regs + SPI_IR_STAT_REG);
+
+		/* issue the transfer */
+		val = SPI_CMD_OP_START;
+		val |= (plat->cs << SPI_CMD_SLAVE_SHIFT) & SPI_CMD_SLAVE_MASK;
+		val |= (priv->tx_bytes << SPI_CMD_PREPEND_SHIFT);
+		if (plat->mode & SPI_3WIRE)
+			val |= SPI_CMD_3WIRE_MASK;
+		writew_be(val, priv->regs + SPI_CMD_REG);
+
+		/* enable interrupts */
+		writeb_be(SPI_IR_DONE_MASK, priv->regs + SPI_IR_MASK_REG);
+
+		do {
+			/* read interupts */
+			irq = readb_be(priv->regs + SPI_IR_STAT_REG);
+
+			/* transfer completed */
+			if (irq & SPI_IR_DONE_MASK)
+				break;
+		} while (1);
+
+		/* copy rx data */
+		if (din)
+			memcpy_fromio(din, priv->regs + SPI_RX_DATA_REG,
+				      data_bytes);
+	}
+
+	return 0;
+}
+
+static const struct dm_spi_ops bcm63xx_spi_ops = {
+	.cs_info = bcm63xx_spi_cs_info,
+	.set_mode = bcm63xx_spi_set_mode,
+	.set_speed = bcm63xx_spi_set_speed,
+	.xfer = bcm63xx_spi_xfer,
+};
+
+static const struct udevice_id bcm63xx_spi_ids[] = {
+	{ .compatible = SPI_DT_ID, },
+	{ /* sentinel */ }
+};
+
+static int bcm63xx_spi_child_pre_probe(struct udevice *dev)
+{
+	struct bcm63xx_spi_priv *priv = dev_get_priv(dev->parent);
+	struct spi_slave *slave = dev_get_parent_priv(dev);
+	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;
+	}
+
+	/* max read/write sizes */
+	slave->max_read_size = SPI_RX_DATA_SIZE;
+	slave->max_write_size = SPI_TX_DATA_SIZE;
+
+	return 0;
+}
+
+static int bcm63xx_spi_probe(struct udevice *dev)
+{
+	struct bcm63xx_spi_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_index(dev, 0, &clk);
+	if (ret < 0)
+		return ret;
+	clk_enable(&clk);
+	clk_free(&clk);
+
+	/* perform reset */
+	ret = reset_get_by_index(dev, 0, &rst_ctl);
+	if (ret < 0)
+		return ret;
+	reset_deassert(&rst_ctl);
+	reset_free(&rst_ctl);
+
+	/* initialize hardware */
+	writeb_be(0, priv->regs + SPI_IR_MASK_REG);
+
+	/* set fill register */
+	writeb_be(0xff, priv->regs + SPI_FILL_REG);
+
+	return 0;
+}
+
+U_BOOT_DRIVER(bcm63xx_spi) = {
+	.name = "bcm63xx_spi",
+	.id = UCLASS_SPI,
+	.of_match = bcm63xx_spi_ids,
+	.ops = &bcm63xx_spi_ops,
+	.priv_auto_alloc_size = sizeof(struct bcm63xx_spi_priv),
+	.child_pre_probe = bcm63xx_spi_child_pre_probe,
+	.probe = bcm63xx_spi_probe,
+};
-- 
2.1.4