1 files changed, 303 insertions, 0 deletions
diff --git a/drivers/tty/serial/tegra-tcu.c b/drivers/tty/serial/tegra-tcu.c
new file mode 100644
index 000000000..23500b342
--- /dev/null
+++ b/drivers/tty/serial/tegra-tcu.c
@@ -0,0 +1,303 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2018, NVIDIA CORPORATION.  All rights reserved.
+ */
+
+#include <linux/console.h>
+#include <linux/mailbox_client.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.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>
+
+#define TCU_MBOX_BYTE(i, x)			((x) << (i * 8))
+#define TCU_MBOX_BYTE_V(x, i)			(((x) >> (i * 8)) & 0xff)
+#define TCU_MBOX_NUM_BYTES(x)			((x) << 24)
+#define TCU_MBOX_NUM_BYTES_V(x)			(((x) >> 24) & 0x3)
+
+struct tegra_tcu {
+	struct uart_driver driver;
+#if IS_ENABLED(CONFIG_SERIAL_TEGRA_TCU_CONSOLE)
+	struct console console;
+#endif
+	struct uart_port port;
+
+	struct mbox_client tx_client, rx_client;
+	struct mbox_chan *tx, *rx;
+};
+
+static unsigned int tegra_tcu_uart_tx_empty(struct uart_port *port)
+{
+	return TIOCSER_TEMT;
+}
+
+static void tegra_tcu_uart_set_mctrl(struct uart_port *port, unsigned int mctrl)
+{
+}
+
+static unsigned int tegra_tcu_uart_get_mctrl(struct uart_port *port)
+{
+	return 0;
+}
+
+static void tegra_tcu_uart_stop_tx(struct uart_port *port)
+{
+}
+
+static void tegra_tcu_write_one(struct tegra_tcu *tcu, u32 value,
+				unsigned int count)
+{
+	void *msg;
+
+	value |= TCU_MBOX_NUM_BYTES(count);
+	msg = (void *)(unsigned long)value;
+	mbox_send_message(tcu->tx, msg);
+	mbox_flush(tcu->tx, 1000);
+}
+
+static void tegra_tcu_write(struct tegra_tcu *tcu, const char *s,
+			    unsigned int count)
+{
+	unsigned int written = 0, i = 0;
+	bool insert_nl = false;
+	u32 value = 0;
+
+	while (i < count) {
+		if (insert_nl) {
+			value |= TCU_MBOX_BYTE(written++, '\n');
+			insert_nl = false;
+			i++;
+		} else if (s[i] == '\n') {
+			value |= TCU_MBOX_BYTE(written++, '\r');
+			insert_nl = true;
+		} else {
+			value |= TCU_MBOX_BYTE(written++, s[i++]);
+		}
+
+		if (written == 3) {
+			tegra_tcu_write_one(tcu, value, 3);
+			value = written = 0;
+		}
+	}
+
+	if (written)
+		tegra_tcu_write_one(tcu, value, written);
+}
+
+static void tegra_tcu_uart_start_tx(struct uart_port *port)
+{
+	struct tegra_tcu *tcu = port->private_data;
+	struct circ_buf *xmit = &port->state->xmit;
+	unsigned long count;
+
+	for (;;) {
+		count = CIRC_CNT_TO_END(xmit->head, xmit->tail, UART_XMIT_SIZE);
+		if (!count)
+			break;
+
+		tegra_tcu_write(tcu, &xmit->buf[xmit->tail], count);
+		uart_xmit_advance(port, count);
+	}
+
+	uart_write_wakeup(port);
+}
+
+static void tegra_tcu_uart_stop_rx(struct uart_port *port)
+{
+}
+
+static void tegra_tcu_uart_break_ctl(struct uart_port *port, int ctl)
+{
+}
+
+static int tegra_tcu_uart_startup(struct uart_port *port)
+{
+	return 0;
+}
+
+static void tegra_tcu_uart_shutdown(struct uart_port *port)
+{
+}
+
+static void tegra_tcu_uart_set_termios(struct uart_port *port,
+				       struct ktermios *new,
+				       const struct ktermios *old)
+{
+}
+
+static const struct uart_ops tegra_tcu_uart_ops = {
+	.tx_empty = tegra_tcu_uart_tx_empty,
+	.set_mctrl = tegra_tcu_uart_set_mctrl,
+	.get_mctrl = tegra_tcu_uart_get_mctrl,
+	.stop_tx = tegra_tcu_uart_stop_tx,
+	.start_tx = tegra_tcu_uart_start_tx,
+	.stop_rx = tegra_tcu_uart_stop_rx,
+	.break_ctl = tegra_tcu_uart_break_ctl,
+	.startup = tegra_tcu_uart_startup,
+	.shutdown = tegra_tcu_uart_shutdown,
+	.set_termios = tegra_tcu_uart_set_termios,
+};
+
+#if IS_ENABLED(CONFIG_SERIAL_TEGRA_TCU_CONSOLE)
+static void tegra_tcu_console_write(struct console *cons, const char *s,
+				    unsigned int count)
+{
+	struct tegra_tcu *tcu = container_of(cons, struct tegra_tcu, console);
+
+	tegra_tcu_write(tcu, s, count);
+}
+
+static int tegra_tcu_console_setup(struct console *cons, char *options)
+{
+	return 0;
+}
+#endif
+
+static void tegra_tcu_receive(struct mbox_client *cl, void *msg)
+{
+	struct tegra_tcu *tcu = container_of(cl, struct tegra_tcu, rx_client);
+	struct tty_port *port = &tcu->port.state->port;
+	u32 value = (u32)(unsigned long)msg;
+	unsigned int num_bytes, i;
+
+	num_bytes = TCU_MBOX_NUM_BYTES_V(value);
+
+	for (i = 0; i < num_bytes; i++)
+		tty_insert_flip_char(port, TCU_MBOX_BYTE_V(value, i),
+				     TTY_NORMAL);
+
+	tty_flip_buffer_push(port);
+}
+
+static int tegra_tcu_probe(struct platform_device *pdev)
+{
+	struct uart_port *port;
+	struct tegra_tcu *tcu;
+	int err;
+
+	tcu = devm_kzalloc(&pdev->dev, sizeof(*tcu), GFP_KERNEL);
+	if (!tcu)
+		return -ENOMEM;
+
+	tcu->tx_client.dev = &pdev->dev;
+	tcu->rx_client.dev = &pdev->dev;
+	tcu->rx_client.rx_callback = tegra_tcu_receive;
+
+	tcu->tx = mbox_request_channel_byname(&tcu->tx_client, "tx");
+	if (IS_ERR(tcu->tx)) {
+		err = PTR_ERR(tcu->tx);
+		dev_err(&pdev->dev, "failed to get tx mailbox: %d\n", err);
+		return err;
+	}
+
+#if IS_ENABLED(CONFIG_SERIAL_TEGRA_TCU_CONSOLE)
+	/* setup the console */
+	strcpy(tcu->console.name, "ttyTCU");
+	tcu->console.device = uart_console_device;
+	tcu->console.flags = CON_PRINTBUFFER | CON_ANYTIME;
+	tcu->console.index = -1;
+	tcu->console.write = tegra_tcu_console_write;
+	tcu->console.setup = tegra_tcu_console_setup;
+	tcu->console.data = &tcu->driver;
+#endif
+
+	/* setup the driver */
+	tcu->driver.owner = THIS_MODULE;
+	tcu->driver.driver_name = "tegra-tcu";
+	tcu->driver.dev_name = "ttyTCU";
+#if IS_ENABLED(CONFIG_SERIAL_TEGRA_TCU_CONSOLE)
+	tcu->driver.cons = &tcu->console;
+#endif
+	tcu->driver.nr = 1;
+
+	err = uart_register_driver(&tcu->driver);
+	if (err) {
+		dev_err(&pdev->dev, "failed to register UART driver: %d\n",
+			err);
+		goto free_tx;
+	}
+
+	/* setup the port */
+	port = &tcu->port;
+	spin_lock_init(&port->lock);
+	port->dev = &pdev->dev;
+	port->type = PORT_TEGRA_TCU;
+	port->ops = &tegra_tcu_uart_ops;
+	port->fifosize = 1;
+	port->iotype = UPIO_MEM;
+	port->flags = UPF_BOOT_AUTOCONF;
+	port->private_data = tcu;
+
+	err = uart_add_one_port(&tcu->driver, port);
+	if (err) {
+		dev_err(&pdev->dev, "failed to add UART port: %d\n", err);
+		goto unregister_uart;
+	}
+
+	/*
+	 * Request RX channel after creating port to ensure tcu->port
+	 * is ready for any immediate incoming bytes.
+	 */
+	tcu->rx = mbox_request_channel_byname(&tcu->rx_client, "rx");
+	if (IS_ERR(tcu->rx)) {
+		err = PTR_ERR(tcu->rx);
+		dev_err(&pdev->dev, "failed to get rx mailbox: %d\n", err);
+		goto remove_uart_port;
+	}
+
+	platform_set_drvdata(pdev, tcu);
+#if IS_ENABLED(CONFIG_SERIAL_TEGRA_TCU_CONSOLE)
+	register_console(&tcu->console);
+#endif
+
+	return 0;
+
+remove_uart_port:
+	uart_remove_one_port(&tcu->driver, &tcu->port);
+unregister_uart:
+	uart_unregister_driver(&tcu->driver);
+free_tx:
+	mbox_free_channel(tcu->tx);
+
+	return err;
+}
+
+static int tegra_tcu_remove(struct platform_device *pdev)
+{
+	struct tegra_tcu *tcu = platform_get_drvdata(pdev);
+
+#if IS_ENABLED(CONFIG_SERIAL_TEGRA_TCU_CONSOLE)
+	unregister_console(&tcu->console);
+#endif
+	mbox_free_channel(tcu->rx);
+	uart_remove_one_port(&tcu->driver, &tcu->port);
+	uart_unregister_driver(&tcu->driver);
+	mbox_free_channel(tcu->tx);
+
+	return 0;
+}
+
+static const struct of_device_id tegra_tcu_match[] = {
+	{ .compatible = "nvidia,tegra194-tcu" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, tegra_tcu_match);
+
+static struct platform_driver tegra_tcu_driver = {
+	.driver = {
+		.name = "tegra-tcu",
+		.of_match_table = tegra_tcu_match,
+	},
+	.probe = tegra_tcu_probe,
+	.remove = tegra_tcu_remove,
+};
+module_platform_driver(tegra_tcu_driver);
+
+MODULE_AUTHOR("Mikko Perttunen <mperttunen@nvidia.com>");
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("NVIDIA Tegra Combined UART driver");