1 // SPDX-License-Identifier: GPL-2.0
3 * Copyright (c) 2018, NVIDIA CORPORATION. All rights reserved.
6 #include <linux/console.h>
7 #include <linux/mailbox_client.h>
8 #include <linux/module.h>
10 #include <linux/platform_device.h>
11 #include <linux/serial.h>
12 #include <linux/serial_core.h>
13 #include <linux/slab.h>
14 #include <linux/tty.h>
15 #include <linux/tty_flip.h>
17 #define TCU_MBOX_BYTE(i, x) ((x) << (i * 8))
18 #define TCU_MBOX_BYTE_V(x, i) (((x) >> (i * 8)) & 0xff)
19 #define TCU_MBOX_NUM_BYTES(x) ((x) << 24)
20 #define TCU_MBOX_NUM_BYTES_V(x) (((x) >> 24) & 0x3)
23 struct uart_driver driver;
24 #if IS_ENABLED(CONFIG_SERIAL_TEGRA_TCU_CONSOLE)
25 struct console console;
27 struct uart_port port;
29 struct mbox_client tx_client, rx_client;
30 struct mbox_chan *tx, *rx;
33 static unsigned int tegra_tcu_uart_tx_empty(struct uart_port *port)
38 static void tegra_tcu_uart_set_mctrl(struct uart_port *port, unsigned int mctrl)
42 static unsigned int tegra_tcu_uart_get_mctrl(struct uart_port *port)
47 static void tegra_tcu_uart_stop_tx(struct uart_port *port)
51 static void tegra_tcu_write_one(struct tegra_tcu *tcu, u32 value,
56 value |= TCU_MBOX_NUM_BYTES(count);
57 msg = (void *)(unsigned long)value;
58 mbox_send_message(tcu->tx, msg);
59 mbox_flush(tcu->tx, 1000);
62 static void tegra_tcu_write(struct tegra_tcu *tcu, const char *s,
65 unsigned int written = 0, i = 0;
66 bool insert_nl = false;
71 value |= TCU_MBOX_BYTE(written++, '\n');
74 } else if (s[i] == '\n') {
75 value |= TCU_MBOX_BYTE(written++, '\r');
78 value |= TCU_MBOX_BYTE(written++, s[i++]);
82 tegra_tcu_write_one(tcu, value, 3);
88 tegra_tcu_write_one(tcu, value, written);
91 static void tegra_tcu_uart_start_tx(struct uart_port *port)
93 struct tegra_tcu *tcu = port->private_data;
94 struct tty_port *tport = &port->state->port;
99 count = kfifo_out_linear_ptr(&tport->xmit_fifo, &tail,
104 tegra_tcu_write(tcu, tail, count);
105 uart_xmit_advance(port, count);
108 uart_write_wakeup(port);
111 static void tegra_tcu_uart_stop_rx(struct uart_port *port)
115 static void tegra_tcu_uart_break_ctl(struct uart_port *port, int ctl)
119 static int tegra_tcu_uart_startup(struct uart_port *port)
124 static void tegra_tcu_uart_shutdown(struct uart_port *port)
128 static void tegra_tcu_uart_set_termios(struct uart_port *port,
129 struct ktermios *new,
130 const struct ktermios *old)
134 static const struct uart_ops tegra_tcu_uart_ops = {
135 .tx_empty = tegra_tcu_uart_tx_empty,
136 .set_mctrl = tegra_tcu_uart_set_mctrl,
137 .get_mctrl = tegra_tcu_uart_get_mctrl,
138 .stop_tx = tegra_tcu_uart_stop_tx,
139 .start_tx = tegra_tcu_uart_start_tx,
140 .stop_rx = tegra_tcu_uart_stop_rx,
141 .break_ctl = tegra_tcu_uart_break_ctl,
142 .startup = tegra_tcu_uart_startup,
143 .shutdown = tegra_tcu_uart_shutdown,
144 .set_termios = tegra_tcu_uart_set_termios,
147 #if IS_ENABLED(CONFIG_SERIAL_TEGRA_TCU_CONSOLE)
148 static void tegra_tcu_console_write(struct console *cons, const char *s,
151 struct tegra_tcu *tcu = container_of(cons, struct tegra_tcu, console);
153 tegra_tcu_write(tcu, s, count);
156 static int tegra_tcu_console_setup(struct console *cons, char *options)
162 static void tegra_tcu_receive(struct mbox_client *cl, void *msg)
164 struct tegra_tcu *tcu = container_of(cl, struct tegra_tcu, rx_client);
165 struct tty_port *port = &tcu->port.state->port;
166 u32 value = (u32)(unsigned long)msg;
167 unsigned int num_bytes, i;
169 num_bytes = TCU_MBOX_NUM_BYTES_V(value);
171 for (i = 0; i < num_bytes; i++)
172 tty_insert_flip_char(port, TCU_MBOX_BYTE_V(value, i),
175 tty_flip_buffer_push(port);
178 static int tegra_tcu_probe(struct platform_device *pdev)
180 struct uart_port *port;
181 struct tegra_tcu *tcu;
184 tcu = devm_kzalloc(&pdev->dev, sizeof(*tcu), GFP_KERNEL);
188 tcu->tx_client.dev = &pdev->dev;
189 tcu->rx_client.dev = &pdev->dev;
190 tcu->rx_client.rx_callback = tegra_tcu_receive;
192 tcu->tx = mbox_request_channel_byname(&tcu->tx_client, "tx");
193 if (IS_ERR(tcu->tx)) {
194 err = PTR_ERR(tcu->tx);
195 dev_err(&pdev->dev, "failed to get tx mailbox: %d\n", err);
199 #if IS_ENABLED(CONFIG_SERIAL_TEGRA_TCU_CONSOLE)
200 /* setup the console */
201 strcpy(tcu->console.name, "ttyTCU");
202 tcu->console.device = uart_console_device;
203 tcu->console.flags = CON_PRINTBUFFER | CON_ANYTIME;
204 tcu->console.index = -1;
205 tcu->console.write = tegra_tcu_console_write;
206 tcu->console.setup = tegra_tcu_console_setup;
207 tcu->console.data = &tcu->driver;
210 /* setup the driver */
211 tcu->driver.owner = THIS_MODULE;
212 tcu->driver.driver_name = "tegra-tcu";
213 tcu->driver.dev_name = "ttyTCU";
214 #if IS_ENABLED(CONFIG_SERIAL_TEGRA_TCU_CONSOLE)
215 tcu->driver.cons = &tcu->console;
219 err = uart_register_driver(&tcu->driver);
221 dev_err(&pdev->dev, "failed to register UART driver: %d\n",
228 spin_lock_init(&port->lock);
229 port->dev = &pdev->dev;
230 port->type = PORT_TEGRA_TCU;
231 port->ops = &tegra_tcu_uart_ops;
233 port->iotype = UPIO_MEM;
234 port->flags = UPF_BOOT_AUTOCONF;
235 port->private_data = tcu;
237 err = uart_add_one_port(&tcu->driver, port);
239 dev_err(&pdev->dev, "failed to add UART port: %d\n", err);
240 goto unregister_uart;
244 * Request RX channel after creating port to ensure tcu->port
245 * is ready for any immediate incoming bytes.
247 tcu->rx = mbox_request_channel_byname(&tcu->rx_client, "rx");
248 if (IS_ERR(tcu->rx)) {
249 err = PTR_ERR(tcu->rx);
250 dev_err(&pdev->dev, "failed to get rx mailbox: %d\n", err);
251 goto remove_uart_port;
254 platform_set_drvdata(pdev, tcu);
255 #if IS_ENABLED(CONFIG_SERIAL_TEGRA_TCU_CONSOLE)
256 register_console(&tcu->console);
262 uart_remove_one_port(&tcu->driver, &tcu->port);
264 uart_unregister_driver(&tcu->driver);
266 mbox_free_channel(tcu->tx);
271 static void tegra_tcu_remove(struct platform_device *pdev)
273 struct tegra_tcu *tcu = platform_get_drvdata(pdev);
275 #if IS_ENABLED(CONFIG_SERIAL_TEGRA_TCU_CONSOLE)
276 unregister_console(&tcu->console);
278 mbox_free_channel(tcu->rx);
279 uart_remove_one_port(&tcu->driver, &tcu->port);
280 uart_unregister_driver(&tcu->driver);
281 mbox_free_channel(tcu->tx);
284 static const struct of_device_id tegra_tcu_match[] = {
285 { .compatible = "nvidia,tegra194-tcu" },
288 MODULE_DEVICE_TABLE(of, tegra_tcu_match);
290 static struct platform_driver tegra_tcu_driver = {
293 .of_match_table = tegra_tcu_match,
295 .probe = tegra_tcu_probe,
296 .remove_new = tegra_tcu_remove,
298 module_platform_driver(tegra_tcu_driver);
300 MODULE_AUTHOR("Mikko Perttunen <mperttunen@nvidia.com>");
301 MODULE_LICENSE("GPL v2");
302 MODULE_DESCRIPTION("NVIDIA Tegra Combined UART driver");