1 files changed, 625 insertions, 0 deletions
diff --git a/drivers/tty/serial/tegra-utc.c b/drivers/tty/serial/tegra-utc.c
new file mode 100644
index 000000000000..39b14fe813c9
--- /dev/null
+++ b/drivers/tty/serial/tegra-utc.c
@@ -0,0 +1,625 @@
+// SPDX-License-Identifier: GPL-2.0-only
+// SPDX-FileCopyrightText: Copyright (c) 2025 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
+// NVIDIA Tegra UTC (UART Trace Controller) driver.
+
+#include <linux/bits.h>
+#include <linux/console.h>
+#include <linux/container_of.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/iopoll.h>
+#include <linux/kfifo.h>
+#include <linux/module.h>
+#include <linux/mod_devicetable.h>
+#include <linux/property.h>
+#include <linux/platform_device.h>
+#include <linux/serial.h>
+#include <linux/serial_core.h>
+#include <linux/slab.h>
+#include <linux/tty.h>
+#include <linux/tty_flip.h>
+#include <linux/types.h>
+
+#define TEGRA_UTC_ENABLE			0x000
+#define TEGRA_UTC_ENABLE_CLIENT_ENABLE		BIT(0)
+
+#define TEGRA_UTC_FIFO_THRESHOLD		0x008
+
+#define TEGRA_UTC_COMMAND			0x00c
+#define TEGRA_UTC_COMMAND_RESET			BIT(0)
+#define TEGRA_UTC_COMMAND_FLUSH			BIT(1)
+
+#define TEGRA_UTC_DATA				0x020
+
+#define TEGRA_UTC_FIFO_STATUS			0x100
+#define TEGRA_UTC_FIFO_EMPTY			BIT(0)
+#define TEGRA_UTC_FIFO_FULL			BIT(1)
+#define TEGRA_UTC_FIFO_REQ			BIT(2)
+#define TEGRA_UTC_FIFO_OVERFLOW			BIT(3)
+#define TEGRA_UTC_FIFO_TIMEOUT			BIT(4)
+
+#define TEGRA_UTC_FIFO_OCCUPANCY		0x104
+
+#define TEGRA_UTC_INTR_STATUS			0x108
+#define TEGRA_UTC_INTR_SET			0x10c
+#define TEGRA_UTC_INTR_MASK			0x110
+#define TEGRA_UTC_INTR_CLEAR			0x114
+#define TEGRA_UTC_INTR_EMPTY			BIT(0)
+#define TEGRA_UTC_INTR_FULL			BIT(1)
+#define TEGRA_UTC_INTR_REQ			BIT(2)
+#define TEGRA_UTC_INTR_OVERFLOW			BIT(3)
+#define TEGRA_UTC_INTR_TIMEOUT			BIT(4)
+
+#define TEGRA_UTC_UART_NR			16
+
+#define TEGRA_UTC_INTR_COMMON	(TEGRA_UTC_INTR_REQ | TEGRA_UTC_INTR_FULL | TEGRA_UTC_INTR_EMPTY)
+
+struct tegra_utc_port {
+#if IS_ENABLED(CONFIG_SERIAL_TEGRA_UTC_CONSOLE)
+	struct console console;
+#endif
+	struct uart_port port;
+
+	void __iomem *rx_base;
+	void __iomem *tx_base;
+
+	u32 tx_irqmask;
+	u32 rx_irqmask;
+
+	unsigned int fifosize;
+	u32 tx_threshold;
+	u32 rx_threshold;
+};
+
+static u32 tegra_utc_rx_readl(struct tegra_utc_port *tup, unsigned int offset)
+{
+	void __iomem *addr = tup->rx_base + offset;
+
+	return readl_relaxed(addr);
+}
+
+static void tegra_utc_rx_writel(struct tegra_utc_port *tup, u32 val, unsigned int offset)
+{
+	void __iomem *addr = tup->rx_base + offset;
+
+	writel_relaxed(val, addr);
+}
+
+static u32 tegra_utc_tx_readl(struct tegra_utc_port *tup, unsigned int offset)
+{
+	void __iomem *addr = tup->tx_base + offset;
+
+	return readl_relaxed(addr);
+}
+
+static void tegra_utc_tx_writel(struct tegra_utc_port *tup, u32 val, unsigned int offset)
+{
+	void __iomem *addr = tup->tx_base + offset;
+
+	writel_relaxed(val, addr);
+}
+
+static void tegra_utc_enable_tx_irq(struct tegra_utc_port *tup)
+{
+	tup->tx_irqmask = TEGRA_UTC_INTR_REQ;
+
+	tegra_utc_tx_writel(tup, tup->tx_irqmask, TEGRA_UTC_INTR_MASK);
+	tegra_utc_tx_writel(tup, tup->tx_irqmask, TEGRA_UTC_INTR_SET);
+}
+
+static void tegra_utc_disable_tx_irq(struct tegra_utc_port *tup)
+{
+	tup->tx_irqmask = 0x0;
+
+	tegra_utc_tx_writel(tup, tup->tx_irqmask, TEGRA_UTC_INTR_MASK);
+	tegra_utc_tx_writel(tup, tup->tx_irqmask, TEGRA_UTC_INTR_SET);
+}
+
+static void tegra_utc_stop_tx(struct uart_port *port)
+{
+	struct tegra_utc_port *tup = container_of(port, struct tegra_utc_port, port);
+
+	tegra_utc_disable_tx_irq(tup);
+}
+
+static void tegra_utc_init_tx(struct tegra_utc_port *tup)
+{
+	/* Disable TX. */
+	tegra_utc_tx_writel(tup, 0x0, TEGRA_UTC_ENABLE);
+
+	/* Update the FIFO Threshold. */
+	tegra_utc_tx_writel(tup, tup->tx_threshold, TEGRA_UTC_FIFO_THRESHOLD);
+
+	/* Clear and mask all the interrupts. */
+	tegra_utc_tx_writel(tup, TEGRA_UTC_INTR_COMMON, TEGRA_UTC_INTR_CLEAR);
+	tegra_utc_disable_tx_irq(tup);
+
+	/* Enable TX. */
+	tegra_utc_tx_writel(tup, TEGRA_UTC_ENABLE_CLIENT_ENABLE, TEGRA_UTC_ENABLE);
+}
+
+static void tegra_utc_init_rx(struct tegra_utc_port *tup)
+{
+	tup->rx_irqmask = TEGRA_UTC_INTR_REQ | TEGRA_UTC_INTR_TIMEOUT;
+
+	tegra_utc_rx_writel(tup, TEGRA_UTC_COMMAND_RESET, TEGRA_UTC_COMMAND);
+	tegra_utc_rx_writel(tup, tup->rx_threshold, TEGRA_UTC_FIFO_THRESHOLD);
+
+	/* Clear all the pending interrupts. */
+	tegra_utc_rx_writel(tup, TEGRA_UTC_INTR_TIMEOUT | TEGRA_UTC_INTR_OVERFLOW |
+			    TEGRA_UTC_INTR_COMMON, TEGRA_UTC_INTR_CLEAR);
+	tegra_utc_rx_writel(tup, tup->rx_irqmask, TEGRA_UTC_INTR_MASK);
+	tegra_utc_rx_writel(tup, tup->rx_irqmask, TEGRA_UTC_INTR_SET);
+
+	/* Enable RX. */
+	tegra_utc_rx_writel(tup, TEGRA_UTC_ENABLE_CLIENT_ENABLE, TEGRA_UTC_ENABLE);
+}
+
+static bool tegra_utc_tx_chars(struct tegra_utc_port *tup)
+{
+	struct uart_port *port = &tup->port;
+	unsigned int pending;
+	u8 c;
+
+	pending = uart_port_tx(port, c,
+		     !(tegra_utc_tx_readl(tup, TEGRA_UTC_FIFO_STATUS) & TEGRA_UTC_FIFO_FULL),
+		     tegra_utc_tx_writel(tup, c, TEGRA_UTC_DATA));
+
+	return pending;
+}
+
+static void tegra_utc_rx_chars(struct tegra_utc_port *tup)
+{
+	struct tty_port *port = &tup->port.state->port;
+	unsigned int max_chars = 256;
+	u32 status;
+	int sysrq;
+	u32 ch;
+
+	while (max_chars--) {
+		status = tegra_utc_rx_readl(tup, TEGRA_UTC_FIFO_STATUS);
+		if (status & TEGRA_UTC_FIFO_EMPTY)
+			break;
+
+		ch = tegra_utc_rx_readl(tup, TEGRA_UTC_DATA);
+		tup->port.icount.rx++;
+
+		if (status & TEGRA_UTC_FIFO_OVERFLOW)
+			tup->port.icount.overrun++;
+
+		uart_port_unlock(&tup->port);
+		sysrq = uart_handle_sysrq_char(&tup->port, ch);
+		uart_port_lock(&tup->port);
+
+		if (!sysrq)
+			tty_insert_flip_char(port, ch, TTY_NORMAL);
+	}
+
+	tty_flip_buffer_push(port);
+}
+
+static irqreturn_t tegra_utc_isr(int irq, void *dev_id)
+{
+	struct tegra_utc_port *tup = dev_id;
+	unsigned int handled = 0;
+	u32 status;
+
+	uart_port_lock(&tup->port);
+
+	/* Process RX_REQ and RX_TIMEOUT interrupts. */
+	do {
+		status = tegra_utc_rx_readl(tup, TEGRA_UTC_INTR_STATUS) & tup->rx_irqmask;
+		if (status) {
+			tegra_utc_rx_writel(tup, tup->rx_irqmask, TEGRA_UTC_INTR_CLEAR);
+			tegra_utc_rx_chars(tup);
+			handled = 1;
+		}
+	} while (status);
+
+	/* Process TX_REQ interrupt. */
+	do {
+		status = tegra_utc_tx_readl(tup, TEGRA_UTC_INTR_STATUS) & tup->tx_irqmask;
+		if (status) {
+			tegra_utc_tx_writel(tup, tup->tx_irqmask, TEGRA_UTC_INTR_CLEAR);
+			tegra_utc_tx_chars(tup);
+			handled = 1;
+		}
+	} while (status);
+
+	uart_port_unlock(&tup->port);
+
+	return IRQ_RETVAL(handled);
+}
+
+static unsigned int tegra_utc_tx_empty(struct uart_port *port)
+{
+	struct tegra_utc_port *tup = container_of(port, struct tegra_utc_port, port);
+
+	return tegra_utc_tx_readl(tup, TEGRA_UTC_FIFO_OCCUPANCY) ? 0 : TIOCSER_TEMT;
+}
+
+static void tegra_utc_set_mctrl(struct uart_port *port, unsigned int mctrl)
+{
+}
+
+static unsigned int tegra_utc_get_mctrl(struct uart_port *port)
+{
+	return 0;
+}
+
+static void tegra_utc_start_tx(struct uart_port *port)
+{
+	struct tegra_utc_port *tup = container_of(port, struct tegra_utc_port, port);
+
+	if (tegra_utc_tx_chars(tup))
+		tegra_utc_enable_tx_irq(tup);
+}
+
+static void tegra_utc_stop_rx(struct uart_port *port)
+{
+	struct tegra_utc_port *tup = container_of(port, struct tegra_utc_port, port);
+
+	tup->rx_irqmask = 0x0;
+	tegra_utc_rx_writel(tup, tup->rx_irqmask, TEGRA_UTC_INTR_MASK);
+	tegra_utc_rx_writel(tup, tup->rx_irqmask, TEGRA_UTC_INTR_SET);
+}
+
+static void tegra_utc_hw_init(struct tegra_utc_port *tup)
+{
+	tegra_utc_init_tx(tup);
+	tegra_utc_init_rx(tup);
+}
+
+static int tegra_utc_startup(struct uart_port *port)
+{
+	struct tegra_utc_port *tup = container_of(port, struct tegra_utc_port, port);
+	int ret;
+
+	tegra_utc_hw_init(tup);
+
+	/* Interrupt is dedicated to this UTC client. */
+	ret = request_irq(port->irq, tegra_utc_isr, 0, dev_name(port->dev), tup);
+	if (ret < 0)
+		dev_err(port->dev, "failed to register interrupt handler\n");
+
+	return ret;
+}
+
+static void tegra_utc_shutdown(struct uart_port *port)
+{
+	struct tegra_utc_port *tup = container_of(port, struct tegra_utc_port, port);
+
+	tegra_utc_rx_writel(tup, 0x0, TEGRA_UTC_ENABLE);
+	free_irq(port->irq, tup);
+}
+
+static void tegra_utc_set_termios(struct uart_port *port, struct ktermios *termios,
+				  const struct ktermios *old)
+{
+	/* The Tegra UTC clients supports only 8-N-1 configuration without HW flow control */
+	termios->c_cflag &= ~(CSIZE | CSTOPB | PARENB | PARODD);
+	termios->c_cflag &= ~(CMSPAR | CRTSCTS);
+	termios->c_cflag |= CS8 | CLOCAL;
+}
+
+#ifdef CONFIG_CONSOLE_POLL
+
+static int tegra_utc_poll_init(struct uart_port *port)
+{
+	struct tegra_utc_port *tup = container_of(port, struct tegra_utc_port, port);
+
+	tegra_utc_hw_init(tup);
+	return 0;
+}
+
+static int tegra_utc_get_poll_char(struct uart_port *port)
+{
+	struct tegra_utc_port *tup = container_of(port, struct tegra_utc_port, port);
+
+	if (tegra_utc_rx_readl(tup, TEGRA_UTC_FIFO_STATUS) & TEGRA_UTC_FIFO_EMPTY)
+		return NO_POLL_CHAR;
+
+	return tegra_utc_rx_readl(tup, TEGRA_UTC_DATA);
+}
+
+static void tegra_utc_put_poll_char(struct uart_port *port, unsigned char ch)
+{
+	struct tegra_utc_port *tup = container_of(port, struct tegra_utc_port, port);
+	u32 val;
+
+	read_poll_timeout_atomic(tegra_utc_tx_readl, val, !(val & TEGRA_UTC_FIFO_FULL),
+				 0, USEC_PER_SEC, false, tup, TEGRA_UTC_FIFO_STATUS);
+
+	tegra_utc_tx_writel(tup, ch, TEGRA_UTC_DATA);
+}
+
+#endif
+
+static const struct uart_ops tegra_utc_uart_ops = {
+	.tx_empty = tegra_utc_tx_empty,
+	.set_mctrl = tegra_utc_set_mctrl,
+	.get_mctrl = tegra_utc_get_mctrl,
+	.stop_tx = tegra_utc_stop_tx,
+	.start_tx = tegra_utc_start_tx,
+	.stop_rx = tegra_utc_stop_rx,
+	.startup = tegra_utc_startup,
+	.shutdown = tegra_utc_shutdown,
+	.set_termios = tegra_utc_set_termios,
+#ifdef CONFIG_CONSOLE_POLL
+	.poll_init = tegra_utc_poll_init,
+	.poll_get_char = tegra_utc_get_poll_char,
+	.poll_put_char = tegra_utc_put_poll_char,
+#endif
+};
+
+#if IS_ENABLED(CONFIG_SERIAL_TEGRA_UTC_CONSOLE)
+#define TEGRA_UTC_DEFAULT_FIFO_THRESHOLD	4
+#define TEGRA_UTC_EARLYCON_MAX_BURST_SIZE	128
+
+static void tegra_utc_putc(struct uart_port *port, unsigned char c)
+{
+	writel(c, port->membase + TEGRA_UTC_DATA);
+}
+
+static void tegra_utc_early_write(struct console *con, const char *s, unsigned int n)
+{
+	struct earlycon_device *dev = con->data;
+
+	while (n) {
+		u32 burst_size = TEGRA_UTC_EARLYCON_MAX_BURST_SIZE;
+
+		burst_size -= readl(dev->port.membase + TEGRA_UTC_FIFO_OCCUPANCY);
+		if (n < burst_size)
+			burst_size = n;
+
+		uart_console_write(&dev->port, s, burst_size, tegra_utc_putc);
+
+		n -= burst_size;
+		s += burst_size;
+	}
+}
+
+static int __init tegra_utc_early_console_setup(struct earlycon_device *device, const char *opt)
+{
+	if (!device->port.membase)
+		return -ENODEV;
+
+	/* Configure TX */
+	writel(TEGRA_UTC_COMMAND_FLUSH | TEGRA_UTC_COMMAND_RESET,
+		device->port.membase + TEGRA_UTC_COMMAND);
+	writel(TEGRA_UTC_DEFAULT_FIFO_THRESHOLD, device->port.membase + TEGRA_UTC_FIFO_THRESHOLD);
+
+	/* Clear and mask all the interrupts. */
+	writel(TEGRA_UTC_INTR_COMMON, device->port.membase + TEGRA_UTC_INTR_CLEAR);
+
+	writel(0x0, device->port.membase + TEGRA_UTC_INTR_MASK);
+	writel(0x0, device->port.membase + TEGRA_UTC_INTR_SET);
+
+	/* Enable TX. */
+	writel(TEGRA_UTC_ENABLE_CLIENT_ENABLE, device->port.membase + TEGRA_UTC_ENABLE);
+
+	device->con->write = tegra_utc_early_write;
+
+	return 0;
+}
+OF_EARLYCON_DECLARE(tegra_utc, "nvidia,tegra264-utc", tegra_utc_early_console_setup);
+
+static void tegra_utc_console_putchar(struct uart_port *port, unsigned char ch)
+{
+	struct tegra_utc_port *tup = container_of(port, struct tegra_utc_port, port);
+
+	tegra_utc_tx_writel(tup, ch, TEGRA_UTC_DATA);
+}
+
+static void tegra_utc_console_write_atomic(struct console *cons, struct nbcon_write_context *wctxt)
+{
+	struct tegra_utc_port *tup = container_of(cons, struct tegra_utc_port, console);
+	unsigned int len;
+	char *outbuf;
+
+	if (!nbcon_enter_unsafe(wctxt))
+		return;
+
+	outbuf = wctxt->outbuf;
+	len = wctxt->len;
+
+	while (len) {
+		u32 burst_size = tup->fifosize;
+
+		burst_size -= tegra_utc_tx_readl(tup, TEGRA_UTC_FIFO_OCCUPANCY);
+		if (len < burst_size)
+			burst_size = len;
+
+		uart_console_write(&tup->port, outbuf, burst_size, tegra_utc_console_putchar);
+
+		outbuf += burst_size;
+		len -= burst_size;
+	};
+
+	nbcon_exit_unsafe(wctxt);
+}
+
+static void tegra_utc_console_write_thread(struct console *cons, struct nbcon_write_context *wctxt)
+{
+	struct tegra_utc_port *tup = container_of(cons, struct tegra_utc_port, console);
+	unsigned int len = READ_ONCE(wctxt->len);
+	unsigned int i;
+	u32 val;
+
+	for (i = 0; i < len; i++) {
+		if (!nbcon_enter_unsafe(wctxt))
+			break;
+
+		read_poll_timeout_atomic(tegra_utc_tx_readl, val, !(val & TEGRA_UTC_FIFO_FULL),
+					 0, USEC_PER_SEC, false, tup, TEGRA_UTC_FIFO_STATUS);
+		uart_console_write(&tup->port, wctxt->outbuf + i, 1, tegra_utc_console_putchar);
+
+		if (!nbcon_exit_unsafe(wctxt))
+			break;
+	}
+}
+
+static void tegra_utc_console_device_lock(struct console *cons, unsigned long *flags)
+{
+	struct tegra_utc_port *tup = container_of(cons, struct tegra_utc_port, console);
+	struct uart_port *port = &tup->port;
+
+	__uart_port_lock_irqsave(port, flags);
+}
+
+static void tegra_utc_console_device_unlock(struct console *cons, unsigned long flags)
+{
+	struct tegra_utc_port *tup = container_of(cons, struct tegra_utc_port, console);
+	struct uart_port *port = &tup->port;
+
+	__uart_port_unlock_irqrestore(port, flags);
+}
+
+static int tegra_utc_console_setup(struct console *cons, char *options)
+{
+	struct tegra_utc_port *tup = container_of(cons, struct tegra_utc_port, console);
+
+	tegra_utc_init_tx(tup);
+
+	return 0;
+}
+#endif
+
+static struct uart_driver tegra_utc_driver = {
+	.driver_name	= "tegra-utc",
+	.dev_name	= "ttyUTC",
+	.nr		= TEGRA_UTC_UART_NR,
+};
+
+static int tegra_utc_setup_port(struct device *dev, struct tegra_utc_port *tup)
+{
+	tup->port.dev			= dev;
+	tup->port.fifosize		= tup->fifosize;
+	tup->port.flags			= UPF_BOOT_AUTOCONF;
+	tup->port.iotype		= UPIO_MEM;
+	tup->port.ops			= &tegra_utc_uart_ops;
+	tup->port.type			= PORT_TEGRA_TCU;
+	tup->port.private_data		= tup;
+
+#if IS_ENABLED(CONFIG_SERIAL_TEGRA_UTC_CONSOLE)
+	strscpy(tup->console.name, "ttyUTC", sizeof(tup->console.name));
+	tup->console.write_atomic	= tegra_utc_console_write_atomic;
+	tup->console.write_thread	= tegra_utc_console_write_thread;
+	tup->console.device_lock	= tegra_utc_console_device_lock;
+	tup->console.device_unlock	= tegra_utc_console_device_unlock;
+	tup->console.device		= uart_console_device;
+	tup->console.setup		= tegra_utc_console_setup;
+	tup->console.flags		= CON_PRINTBUFFER | CON_NBCON;
+	tup->console.data		= &tegra_utc_driver;
+#endif
+
+	return uart_read_port_properties(&tup->port);
+}
+
+static int tegra_utc_register_port(struct tegra_utc_port *tup)
+{
+	int ret;
+
+	ret = uart_add_one_port(&tegra_utc_driver, &tup->port);
+	if (ret)
+		return ret;
+
+#if IS_ENABLED(CONFIG_SERIAL_TEGRA_UTC_CONSOLE)
+	register_console(&tup->console);
+#endif
+
+	return 0;
+}
+
+static int tegra_utc_probe(struct platform_device *pdev)
+{
+	const unsigned int *soc_fifosize;
+	struct device *dev = &pdev->dev;
+	struct tegra_utc_port *tup;
+	int ret;
+
+	tup = devm_kzalloc(dev, sizeof(*tup), GFP_KERNEL);
+	if (!tup)
+		return -ENOMEM;
+
+	ret = device_property_read_u32(dev, "tx-threshold", &tup->tx_threshold);
+	if (ret)
+		return dev_err_probe(dev, ret, "missing %s property\n", "tx-threshold");
+
+	ret = device_property_read_u32(dev, "rx-threshold", &tup->rx_threshold);
+	if (ret)
+		return dev_err_probe(dev, ret, "missing %s property\n", "rx-threshold");
+
+	soc_fifosize = device_get_match_data(dev);
+	tup->fifosize = *soc_fifosize;
+
+	tup->tx_base = devm_platform_ioremap_resource_byname(pdev, "tx");
+	if (IS_ERR(tup->tx_base))
+		return PTR_ERR(tup->tx_base);
+
+	tup->rx_base = devm_platform_ioremap_resource_byname(pdev, "rx");
+	if (IS_ERR(tup->rx_base))
+		return PTR_ERR(tup->rx_base);
+
+	ret = tegra_utc_setup_port(dev, tup);
+	if (ret)
+		dev_err_probe(dev, ret, "failed to setup uart port\n");
+
+	platform_set_drvdata(pdev, tup);
+
+	return tegra_utc_register_port(tup);
+}
+
+static void tegra_utc_remove(struct platform_device *pdev)
+{
+	struct tegra_utc_port *tup = platform_get_drvdata(pdev);
+
+#if IS_ENABLED(CONFIG_SERIAL_TEGRA_UTC_CONSOLE)
+	unregister_console(&tup->console);
+#endif
+	uart_remove_one_port(&tegra_utc_driver, &tup->port);
+}
+
+static const unsigned int tegra264_utc_soc = 128;
+
+static const struct of_device_id tegra_utc_of_match[] = {
+	{ .compatible = "nvidia,tegra264-utc", .data = &tegra264_utc_soc },
+	{}
+};
+MODULE_DEVICE_TABLE(of, tegra_utc_of_match);
+
+static struct platform_driver tegra_utc_platform_driver = {
+	.probe = tegra_utc_probe,
+	.remove = tegra_utc_remove,
+	.driver = {
+		.name = "tegra-utc",
+		.of_match_table = tegra_utc_of_match,
+	},
+};
+
+static int __init tegra_utc_init(void)
+{
+	int ret;
+
+	ret = uart_register_driver(&tegra_utc_driver);
+	if (ret)
+		return ret;
+
+	ret = platform_driver_register(&tegra_utc_platform_driver);
+	if (ret)
+		uart_unregister_driver(&tegra_utc_driver);
+
+	return ret;
+}
+module_init(tegra_utc_init);
+
+static void __exit tegra_utc_exit(void)
+{
+	platform_driver_unregister(&tegra_utc_platform_driver);
+	uart_unregister_driver(&tegra_utc_driver);
+}
+module_exit(tegra_utc_exit);
+
+MODULE_AUTHOR("Kartik Rajput <kkartik@nvidia.com>");
+MODULE_DESCRIPTION("Tegra UART Trace Controller");
+MODULE_LICENSE("GPL");