serial: add serial driver for BCM6345

It is based on linux/drivers/tty/serial/bcm63xx_uart.c

Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

3 files changed, 315 insertions, 0 deletions

diff --git a/drivers/serial/Kconfig b/drivers/serial/Kconfig
index 5832066..7249945 100644
--- a/drivers/serial/Kconfig
+++ b/drivers/serial/Kconfig
@@ -145,6 +145,14 @@ config DEBUG_UART_ATMEL
 	  will need to provide parameters to make this work. The driver will
 	  be available until the real driver-model serial is running.
 
+config DEBUG_UART_BCM6345
+	bool "BCM6345 UART"
+	depends on BCM6345_SERIAL
+	help
+	  Select this to enable a debug UART on BCM6345 SoCs. You
+	  will need to provide parameters to make this work. The driver will
+	  be available until the real driver model serial is running.
+
 config DEBUG_UART_NS16550
 	bool "ns16550"
 	help
@@ -350,6 +358,12 @@ config ATMEL_USART
 	  configured in the device tree, and input clock frequency can
 	  be got from the clk node.
 
+config BCM6345_SERIAL
+	bool "Support for BCM6345 UART"
+	depends on DM_SERIAL && ARCH_BMIPS
+	help
+	  Select this to enable UART on BCM6345 SoCs.
+
 config FSL_LPUART
 	bool "Freescale LPUART support"
 	help
diff --git a/drivers/serial/Makefile b/drivers/serial/Makefile
index 4382cf9..dca31b2 100644
--- a/drivers/serial/Makefile
+++ b/drivers/serial/Makefile
@@ -20,6 +20,7 @@ obj-$(CONFIG_ALTERA_JTAG_UART) += altera_jtag_uart.o
 obj-$(CONFIG_AR933X_UART) += serial_ar933x.o
 obj-$(CONFIG_ARM_DCC) += arm_dcc.o
 obj-$(CONFIG_ATMEL_USART) += atmel_usart.o
+obj-$(CONFIG_BCM6345_SERIAL) += serial_bcm6345.o
 obj-$(CONFIG_EFI_APP) += serial_efi.o
 obj-$(CONFIG_LPC32XX_HSUART) += lpc32xx_hsuart.o
 obj-$(CONFIG_MCFUART) += mcfuart.o
diff --git a/drivers/serial/serial_bcm6345.c b/drivers/serial/serial_bcm6345.c
new file mode 100644
index 0000000..db270e3
--- /dev/null
+++ b/drivers/serial/serial_bcm6345.c
@@ -0,0 +1,300 @@
+/*
+ * Copyright (C) 2017 Álvaro Fernández Rojas <noltari@gmail.com>
+ *
+ * Derived from linux/drivers/tty/serial/bcm63xx_uart.c:
+ *	Copyright (C) 2008 Maxime Bizon <mbizon@freebox.fr>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <clk.h>
+#include <debug_uart.h>
+#include <errno.h>
+#include <serial.h>
+#include <asm/io.h>
+#include <asm/types.h>
+#include <dm/device.h>
+
+/* UART Control register */
+#define UART_CTL_REG			0x0
+#define UART_CTL_RXTIMEOUT_MASK		0x1f
+#define UART_CTL_RXTIMEOUT_5		0x5
+#define UART_CTL_RSTRXFIFO_SHIFT	6
+#define UART_CTL_RSTRXFIFO_MASK		(1 << UART_CTL_RSTRXFIFO_SHIFT)
+#define UART_CTL_RSTTXFIFO_SHIFT	7
+#define UART_CTL_RSTTXFIFO_MASK		(1 << UART_CTL_RSTTXFIFO_SHIFT)
+#define UART_CTL_STOPBITS_SHIFT		8
+#define UART_CTL_STOPBITS_MASK		(0xf << UART_CTL_STOPBITS_SHIFT)
+#define UART_CTL_STOPBITS_1		(0x7 << UART_CTL_STOPBITS_SHIFT)
+#define UART_CTL_BITSPERSYM_SHIFT	12
+#define UART_CTL_BITSPERSYM_MASK	(0x3 << UART_CTL_BITSPERSYM_SHIFT)
+#define UART_CTL_BITSPERSYM_8		(0x3 << UART_CTL_BITSPERSYM_SHIFT)
+#define UART_CTL_XMITBRK_SHIFT		14
+#define UART_CTL_XMITBRK_MASK		(1 << UART_CTL_XMITBRK_SHIFT)
+#define UART_CTL_RSVD_SHIFT		15
+#define UART_CTL_RSVD_MASK		(1 << UART_CTL_RSVD_SHIFT)
+#define UART_CTL_RXPAREVEN_SHIFT	16
+#define UART_CTL_RXPAREVEN_MASK		(1 << UART_CTL_RXPAREVEN_SHIFT)
+#define UART_CTL_RXPAREN_SHIFT		17
+#define UART_CTL_RXPAREN_MASK		(1 << UART_CTL_RXPAREN_SHIFT)
+#define UART_CTL_TXPAREVEN_SHIFT	18
+#define UART_CTL_TXPAREVEN_MASK		(1 << UART_CTL_TXPAREVEN_SHIFT)
+#define UART_CTL_TXPAREN_SHIFT		19
+#define UART_CTL_TXPAREN_MASK		(1 << UART_CTL_TXPAREN_SHIFT)
+#define UART_CTL_LOOPBACK_SHIFT		20
+#define UART_CTL_LOOPBACK_MASK		(1 << UART_CTL_LOOPBACK_SHIFT)
+#define UART_CTL_RXEN_SHIFT		21
+#define UART_CTL_RXEN_MASK		(1 << UART_CTL_RXEN_SHIFT)
+#define UART_CTL_TXEN_SHIFT		22
+#define UART_CTL_TXEN_MASK		(1 << UART_CTL_TXEN_SHIFT)
+#define UART_CTL_BRGEN_SHIFT		23
+#define UART_CTL_BRGEN_MASK		(1 << UART_CTL_BRGEN_SHIFT)
+
+/* UART Baudword register */
+#define UART_BAUD_REG			0x4
+
+/* UART FIFO Config register */
+#define UART_FIFO_CFG_REG		0x8
+#define UART_FIFO_CFG_RX_SHIFT		8
+#define UART_FIFO_CFG_RX_MASK		(0xf << UART_FIFO_CFG_RX_SHIFT)
+#define UART_FIFO_CFG_RX_4		(0x4 << UART_FIFO_CFG_RX_SHIFT)
+#define UART_FIFO_CFG_TX_SHIFT		12
+#define UART_FIFO_CFG_TX_MASK		(0xf << UART_FIFO_CFG_TX_SHIFT)
+#define UART_FIFO_CFG_TX_4		(0x4 << UART_FIFO_CFG_TX_SHIFT)
+
+/* UART Interrupt register */
+#define UART_IR_REG			0x10
+#define UART_IR_STAT(x)			(1 << (x))
+#define UART_IR_TXEMPTY			5
+#define UART_IR_RXOVER			7
+#define UART_IR_RXNOTEMPTY		11
+
+/* UART FIFO register */
+#define UART_FIFO_REG			0x14
+#define UART_FIFO_VALID_MASK		0xff
+#define UART_FIFO_FRAMEERR_SHIFT	8
+#define UART_FIFO_FRAMEERR_MASK		(1 << UART_FIFO_FRAMEERR_SHIFT)
+#define UART_FIFO_PARERR_SHIFT		9
+#define UART_FIFO_PARERR_MASK		(1 << UART_FIFO_PARERR_SHIFT)
+#define UART_FIFO_BRKDET_SHIFT		10
+#define UART_FIFO_BRKDET_MASK		(1 << UART_FIFO_BRKDET_SHIFT)
+#define UART_FIFO_ANYERR_MASK		(UART_FIFO_FRAMEERR_MASK |	\
+					UART_FIFO_PARERR_MASK |		\
+					UART_FIFO_BRKDET_MASK)
+
+struct bcm6345_serial_priv {
+	void __iomem *base;
+	ulong uartclk;
+};
+
+/* enable rx & tx operation on uart */
+static void bcm6345_serial_enable(void __iomem *base)
+{
+	setbits_be32(base + UART_CTL_REG, UART_CTL_BRGEN_MASK |
+		     UART_CTL_TXEN_MASK | UART_CTL_RXEN_MASK);
+}
+
+/* disable rx & tx operation on uart */
+static void bcm6345_serial_disable(void __iomem *base)
+{
+	clrbits_be32(base + UART_CTL_REG, UART_CTL_BRGEN_MASK |
+		     UART_CTL_TXEN_MASK | UART_CTL_RXEN_MASK);
+}
+
+/* clear all unread data in rx fifo and unsent data in tx fifo */
+static void bcm6345_serial_flush(void __iomem *base)
+{
+	/* empty rx and tx fifo */
+	setbits_be32(base + UART_CTL_REG, UART_CTL_RSTRXFIFO_MASK |
+		     UART_CTL_RSTTXFIFO_MASK);
+
+	/* read any pending char to make sure all irq status are cleared */
+	readl_be(base + UART_FIFO_REG);
+}
+
+static int bcm6345_serial_init(void __iomem *base, ulong clk, u32 baudrate)
+{
+	u32 val;
+
+	/* mask all irq and flush port */
+	bcm6345_serial_disable(base);
+	bcm6345_serial_flush(base);
+
+	/* set uart control config */
+	clrsetbits_be32(base + UART_CTL_REG,
+			/* clear rx timeout */
+			UART_CTL_RXTIMEOUT_MASK |
+			/* clear stop bits */
+			UART_CTL_STOPBITS_MASK |
+			/* clear bits per symbol */
+			UART_CTL_BITSPERSYM_MASK |
+			/* clear xmit break */
+			UART_CTL_XMITBRK_MASK |
+			/* clear reserved bit */
+			UART_CTL_RSVD_MASK |
+			/* disable parity */
+			UART_CTL_RXPAREN_MASK |
+			UART_CTL_TXPAREN_MASK |
+			/* disable loopback */
+			UART_CTL_LOOPBACK_MASK,
+			/* set timeout to 5 */
+			UART_CTL_RXTIMEOUT_5 |
+			/* set 8 bits/symbol */
+			UART_CTL_BITSPERSYM_8 |
+			/* set parity to even */
+			UART_CTL_RXPAREVEN_MASK |
+			UART_CTL_TXPAREVEN_MASK);
+
+	/* set uart fifo config */
+	clrsetbits_be32(base + UART_FIFO_CFG_REG,
+			/* clear fifo config */
+			UART_FIFO_CFG_RX_MASK |
+			UART_FIFO_CFG_TX_MASK,
+			/* set fifo config to 4 */
+			UART_FIFO_CFG_RX_4 |
+			UART_FIFO_CFG_TX_4);
+
+	/* set baud rate */
+	val = (clk / baudrate) / 16;
+	if (val & 0x1)
+		val = val;
+	else
+		val = val / 2 - 1;
+	writel_be(val, base + UART_BAUD_REG);
+
+	/* clear interrupts */
+	writel_be(0, base + UART_IR_REG);
+
+	/* enable uart */
+	bcm6345_serial_enable(base);
+
+	return 0;
+}
+
+static int bcm6345_serial_pending(struct udevice *dev, bool input)
+{
+	struct bcm6345_serial_priv *priv = dev_get_priv(dev);
+	u32 val = readl_be(priv->base + UART_IR_REG);
+
+	if (input)
+		return !!(val & UART_IR_STAT(UART_IR_RXNOTEMPTY));
+	else
+		return !(val & UART_IR_STAT(UART_IR_TXEMPTY));
+}
+
+static int bcm6345_serial_setbrg(struct udevice *dev, int baudrate)
+{
+	struct bcm6345_serial_priv *priv = dev_get_priv(dev);
+
+	return bcm6345_serial_init(priv->base, priv->uartclk, baudrate);
+}
+
+static int bcm6345_serial_putc(struct udevice *dev, const char ch)
+{
+	struct bcm6345_serial_priv *priv = dev_get_priv(dev);
+	u32 val;
+
+	val = readl_be(priv->base + UART_IR_REG);
+	if (!(val & UART_IR_STAT(UART_IR_TXEMPTY)))
+		return -EAGAIN;
+
+	writel_be(ch, priv->base + UART_FIFO_REG);
+
+	return 0;
+}
+
+static int bcm6345_serial_getc(struct udevice *dev)
+{
+	struct bcm6345_serial_priv *priv = dev_get_priv(dev);
+	u32 val;
+
+	val = readl_be(priv->base + UART_IR_REG);
+	if (val & UART_IR_STAT(UART_IR_RXOVER))
+		setbits_be32(priv->base + UART_CTL_REG,
+			     UART_CTL_RSTRXFIFO_MASK);
+	if (!(val & UART_IR_STAT(UART_IR_RXNOTEMPTY)))
+		return -EAGAIN;
+
+	val = readl_be(priv->base + UART_FIFO_REG);
+	if (val & UART_FIFO_ANYERR_MASK)
+		return -EAGAIN;
+
+	return val & UART_FIFO_VALID_MASK;
+}
+
+static int bcm6345_serial_probe(struct udevice *dev)
+{
+	struct bcm6345_serial_priv *priv = dev_get_priv(dev);
+	struct clk clk;
+	fdt_addr_t addr;
+	fdt_size_t size;
+	int ret;
+
+	/* get address */
+	addr = dev_get_addr_size_index(dev, 0, &size);
+	if (addr == FDT_ADDR_T_NONE)
+		return -EINVAL;
+
+	priv->base = ioremap(addr, size);
+
+	/* get clock rate */
+	ret = clk_get_by_index(dev, 0, &clk);
+	if (ret < 0)
+		return ret;
+	priv->uartclk = clk_get_rate(&clk) / 2;
+	clk_free(&clk);
+
+	/* initialize serial */
+	return bcm6345_serial_init(priv->base, priv->uartclk, CONFIG_BAUDRATE);
+}
+
+static const struct dm_serial_ops bcm6345_serial_ops = {
+	.putc = bcm6345_serial_putc,
+	.pending = bcm6345_serial_pending,
+	.getc = bcm6345_serial_getc,
+	.setbrg = bcm6345_serial_setbrg,
+};
+
+static const struct udevice_id bcm6345_serial_ids[] = {
+	{ .compatible = "brcm,bcm6345-uart" },
+	{ /* sentinel */ }
+};
+
+U_BOOT_DRIVER(bcm6345_serial) = {
+	.name = "bcm6345-uart",
+	.id = UCLASS_SERIAL,
+	.of_match = bcm6345_serial_ids,
+	.probe = bcm6345_serial_probe,
+	.priv_auto_alloc_size = sizeof(struct bcm6345_serial_priv),
+	.ops = &bcm6345_serial_ops,
+	.flags = DM_FLAG_PRE_RELOC,
+};
+
+#ifdef CONFIG_DEBUG_UART_BCM6345
+static inline void _debug_uart_init(void)
+{
+	void __iomem *base = (void __iomem *)CONFIG_DEBUG_UART_BASE;
+
+	bcm6345_serial_init(base, CONFIG_DEBUG_UART_CLOCK, CONFIG_BAUDRATE);
+}
+
+static inline void wait_xfered(void __iomem *base)
+{
+	do {
+		u32 val = readl_be(base + UART_IR_REG);
+		if (val & UART_IR_STAT(UART_IR_TXEMPTY))
+			break;
+	} while (1);
+}
+
+static inline void _debug_uart_putc(int ch)
+{
+	void __iomem *base = (void __iomem *)CONFIG_DEBUG_UART_BASE;
+
+	wait_xfered(base);
+	writel_be(ch, base + UART_FIFO_REG);
+	wait_xfered(base);
+}
+
+DEBUG_UART_FUNCS
+#endif