[U-Boot] [PATCH v2 04/14] serial: add serial driver for BCM6345

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

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

Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
---
 v2: Introduce changes suggested by Daniel Schwierzeck:
  - Remove unneeded defines.
  - Fix incorrect multi-line comment.

 drivers/serial/Kconfig          |  14 +++
 drivers/serial/Makefile         |   1 +
 drivers/serial/serial_bcm6345.c | 267 ++++++++++++++++++++++++++++++++++++++++
 3 files changed, 282 insertions(+)
 create mode 100644 drivers/serial/serial_bcm6345.c

diff --git a/drivers/serial/Kconfig b/drivers/serial/Kconfig
index c0ec2ec..ca776d8 100644
--- a/drivers/serial/Kconfig
+++ b/drivers/serial/Kconfig
@@ -134,6 +134,14 @@ 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
@@ -339,6 +347,12 @@ 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
+	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..fa1e3e3
--- /dev/null
+++ b/drivers/serial/serial_bcm6345.c
@@ -0,0 +1,267 @@
+/*
+ * 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_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_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 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)
+{
+	u32 val;
+
+	val = __raw_readl(base + UART_CTL_REG);
+	val |= (UART_CTL_BRGEN_MASK | UART_CTL_TXEN_MASK | UART_CTL_RXEN_MASK);
+	__raw_writel(val, base + UART_CTL_REG);
+}
+
+/*
+ * disable rx & tx operation on uart
+ */
+static void bcm6345_serial_disable(void __iomem *base)
+{
+	u32 val;
+
+	val = __raw_readl(base + UART_CTL_REG);
+	val &= ~(UART_CTL_BRGEN_MASK | UART_CTL_TXEN_MASK |
+		 UART_CTL_RXEN_MASK);
+	__raw_writel(val, base + UART_CTL_REG);
+}
+
+/*
+ * clear all unread data in rx fifo and unsent data in tx fifo
+ */
+static void bcm6345_serial_flush(void __iomem *base)
+{
+	u32 val;
+
+	/* empty rx and tx fifo */
+	val = __raw_readl(base + UART_CTL_REG);
+	val |= UART_CTL_RSTRXFIFO_MASK | UART_CTL_RSTTXFIFO_MASK;
+	__raw_writel(val, base + UART_CTL_REG);
+
+	/* read any pending char to make sure all irq status are cleared */
+	__raw_readl(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 bits per sym and stop bits */
+	val = __raw_readl(base + UART_CTL_REG);
+	val &= ~UART_CTL_BITSPERSYM_MASK;
+	val |= (3 << UART_CTL_BITSPERSYM_SHIFT);
+	val &= ~UART_CTL_STOPBITS_MASK;
+	val |= UART_CTL_STOPBITS_1;
+	__raw_writel(val, base + UART_CTL_REG);
+
+	/* set baud rate */
+	val = (clk / baudrate) / 16;
+	if (val & 0x1)
+		val = val;
+	else
+		val = val / 2 - 1;
+	__raw_writel(val, base + UART_BAUD_REG);
+
+	/* clear interrupts */
+	__raw_writel(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 = __raw_readl(priv->base + UART_IR_REG);
+
+	if (input)
+		return (val & UART_IR_STAT(UART_IR_RXNOTEMPTY)) ? 1 : 0;
+	else
+		return (val & UART_IR_STAT(UART_IR_TXEMPTY)) ? 0 : 1;
+}
+
+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 = __raw_readl(priv->base + UART_IR_REG);
+	if (!(val & UART_IR_STAT(UART_IR_TXEMPTY)))
+		return -EAGAIN;
+
+	__raw_writel(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 = __raw_readl(priv->base + UART_IR_REG);
+	if (val & UART_IR_STAT(UART_IR_RXOVER)) {
+		/* fifo reset is required to clear interrupt */
+		val = __raw_readl(priv->base + UART_CTL_REG);
+		val |= UART_CTL_RSTRXFIFO_MASK;
+		__raw_writel(val, priv->base + UART_CTL_REG);
+	}
+	if (!(val & UART_IR_STAT(UART_IR_RXNOTEMPTY)))
+		return -EAGAIN;
+
+	val = __raw_readl(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_of_match[] = {
+	{ .compatible = "brcm,bcm6345-uart" },
+	{ /* sentinel */ }
+};
+
+U_BOOT_DRIVER(bcm6345_serial) = {
+	.name = "bcm6345-uart",
+	.id = UCLASS_SERIAL,
+	.of_match = bcm6345_serial_of_match,
+	.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 = __raw_readl(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);
+	__raw_writel(ch, base + UART_FIFO_REG);
+	wait_xfered(base);
+}
+
+DEBUG_UART_FUNCS
+#endif
-- 
2.1.4