1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Copyright (c) 2018, NVIDIA CORPORATION. All rights reserved.
4 */
5
6 #include <linux/console.h>
7 #include <linux/mailbox_client.h>
8 #include <linux/module.h>
9 #include <linux/of.h>
10 #include <linux/of_device.h>
11 #include <linux/platform_device.h>
12 #include <linux/serial.h>
13 #include <linux/serial_core.h>
14 #include <linux/slab.h>
15 #include <linux/tty.h>
16 #include <linux/tty_flip.h>
17
18 #define TCU_MBOX_BYTE(i, x) ((x) << (i * 8))
19 #define TCU_MBOX_BYTE_V(x, i) (((x) >> (i * 8)) & 0xff)
20 #define TCU_MBOX_NUM_BYTES(x) ((x) << 24)
21 #define TCU_MBOX_NUM_BYTES_V(x) (((x) >> 24) & 0x3)
22
23 struct tegra_tcu {
24 struct uart_driver driver;
25 #if IS_ENABLED(CONFIG_SERIAL_TEGRA_TCU_CONSOLE)
26 struct console console;
27 #endif
28 struct uart_port port;
29
30 struct mbox_client tx_client, rx_client;
31 struct mbox_chan *tx, *rx;
32 };
33
tegra_tcu_uart_tx_empty(struct uart_port * port)34 static unsigned int tegra_tcu_uart_tx_empty(struct uart_port *port)
35 {
36 return TIOCSER_TEMT;
37 }
38
tegra_tcu_uart_set_mctrl(struct uart_port * port,unsigned int mctrl)39 static void tegra_tcu_uart_set_mctrl(struct uart_port *port, unsigned int mctrl)
40 {
41 }
42
tegra_tcu_uart_get_mctrl(struct uart_port * port)43 static unsigned int tegra_tcu_uart_get_mctrl(struct uart_port *port)
44 {
45 return 0;
46 }
47
tegra_tcu_uart_stop_tx(struct uart_port * port)48 static void tegra_tcu_uart_stop_tx(struct uart_port *port)
49 {
50 }
51
tegra_tcu_write_one(struct tegra_tcu * tcu,u32 value,unsigned int count)52 static void tegra_tcu_write_one(struct tegra_tcu *tcu, u32 value,
53 unsigned int count)
54 {
55 void *msg;
56
57 value |= TCU_MBOX_NUM_BYTES(count);
58 msg = (void *)(unsigned long)value;
59 mbox_send_message(tcu->tx, msg);
60 mbox_flush(tcu->tx, 1000);
61 }
62
tegra_tcu_write(struct tegra_tcu * tcu,const char * s,unsigned int count)63 static void tegra_tcu_write(struct tegra_tcu *tcu, const char *s,
64 unsigned int count)
65 {
66 unsigned int written = 0, i = 0;
67 bool insert_nl = false;
68 u32 value = 0;
69
70 while (i < count) {
71 if (insert_nl) {
72 value |= TCU_MBOX_BYTE(written++, '\n');
73 insert_nl = false;
74 i++;
75 } else if (s[i] == '\n') {
76 value |= TCU_MBOX_BYTE(written++, '\r');
77 insert_nl = true;
78 } else {
79 value |= TCU_MBOX_BYTE(written++, s[i++]);
80 }
81
82 if (written == 3) {
83 tegra_tcu_write_one(tcu, value, 3);
84 value = written = 0;
85 }
86 }
87
88 if (written)
89 tegra_tcu_write_one(tcu, value, written);
90 }
91
tegra_tcu_uart_start_tx(struct uart_port * port)92 static void tegra_tcu_uart_start_tx(struct uart_port *port)
93 {
94 struct tegra_tcu *tcu = port->private_data;
95 struct circ_buf *xmit = &port->state->xmit;
96 unsigned long count;
97
98 for (;;) {
99 count = CIRC_CNT_TO_END(xmit->head, xmit->tail, UART_XMIT_SIZE);
100 if (!count)
101 break;
102
103 tegra_tcu_write(tcu, &xmit->buf[xmit->tail], count);
104 xmit->tail = (xmit->tail + count) & (UART_XMIT_SIZE - 1);
105 }
106
107 uart_write_wakeup(port);
108 }
109
tegra_tcu_uart_stop_rx(struct uart_port * port)110 static void tegra_tcu_uart_stop_rx(struct uart_port *port)
111 {
112 }
113
tegra_tcu_uart_break_ctl(struct uart_port * port,int ctl)114 static void tegra_tcu_uart_break_ctl(struct uart_port *port, int ctl)
115 {
116 }
117
tegra_tcu_uart_startup(struct uart_port * port)118 static int tegra_tcu_uart_startup(struct uart_port *port)
119 {
120 return 0;
121 }
122
tegra_tcu_uart_shutdown(struct uart_port * port)123 static void tegra_tcu_uart_shutdown(struct uart_port *port)
124 {
125 }
126
tegra_tcu_uart_set_termios(struct uart_port * port,struct ktermios * new,struct ktermios * old)127 static void tegra_tcu_uart_set_termios(struct uart_port *port,
128 struct ktermios *new,
129 struct ktermios *old)
130 {
131 }
132
133 static const struct uart_ops tegra_tcu_uart_ops = {
134 .tx_empty = tegra_tcu_uart_tx_empty,
135 .set_mctrl = tegra_tcu_uart_set_mctrl,
136 .get_mctrl = tegra_tcu_uart_get_mctrl,
137 .stop_tx = tegra_tcu_uart_stop_tx,
138 .start_tx = tegra_tcu_uart_start_tx,
139 .stop_rx = tegra_tcu_uart_stop_rx,
140 .break_ctl = tegra_tcu_uart_break_ctl,
141 .startup = tegra_tcu_uart_startup,
142 .shutdown = tegra_tcu_uart_shutdown,
143 .set_termios = tegra_tcu_uart_set_termios,
144 };
145
146 #if IS_ENABLED(CONFIG_SERIAL_TEGRA_TCU_CONSOLE)
tegra_tcu_console_write(struct console * cons,const char * s,unsigned int count)147 static void tegra_tcu_console_write(struct console *cons, const char *s,
148 unsigned int count)
149 {
150 struct tegra_tcu *tcu = container_of(cons, struct tegra_tcu, console);
151
152 tegra_tcu_write(tcu, s, count);
153 }
154
tegra_tcu_console_setup(struct console * cons,char * options)155 static int tegra_tcu_console_setup(struct console *cons, char *options)
156 {
157 return 0;
158 }
159 #endif
160
tegra_tcu_receive(struct mbox_client * cl,void * msg)161 static void tegra_tcu_receive(struct mbox_client *cl, void *msg)
162 {
163 struct tegra_tcu *tcu = container_of(cl, struct tegra_tcu, rx_client);
164 struct tty_port *port = &tcu->port.state->port;
165 u32 value = (u32)(unsigned long)msg;
166 unsigned int num_bytes, i;
167
168 num_bytes = TCU_MBOX_NUM_BYTES_V(value);
169
170 for (i = 0; i < num_bytes; i++)
171 tty_insert_flip_char(port, TCU_MBOX_BYTE_V(value, i),
172 TTY_NORMAL);
173
174 tty_flip_buffer_push(port);
175 }
176
tegra_tcu_probe(struct platform_device * pdev)177 static int tegra_tcu_probe(struct platform_device *pdev)
178 {
179 struct uart_port *port;
180 struct tegra_tcu *tcu;
181 int err;
182
183 tcu = devm_kzalloc(&pdev->dev, sizeof(*tcu), GFP_KERNEL);
184 if (!tcu)
185 return -ENOMEM;
186
187 tcu->tx_client.dev = &pdev->dev;
188 tcu->rx_client.dev = &pdev->dev;
189 tcu->rx_client.rx_callback = tegra_tcu_receive;
190
191 tcu->tx = mbox_request_channel_byname(&tcu->tx_client, "tx");
192 if (IS_ERR(tcu->tx)) {
193 err = PTR_ERR(tcu->tx);
194 dev_err(&pdev->dev, "failed to get tx mailbox: %d\n", err);
195 return err;
196 }
197
198 tcu->rx = mbox_request_channel_byname(&tcu->rx_client, "rx");
199 if (IS_ERR(tcu->rx)) {
200 err = PTR_ERR(tcu->rx);
201 dev_err(&pdev->dev, "failed to get rx mailbox: %d\n", err);
202 goto free_tx;
203 }
204
205 #if IS_ENABLED(CONFIG_SERIAL_TEGRA_TCU_CONSOLE)
206 /* setup the console */
207 strcpy(tcu->console.name, "ttyTCU");
208 tcu->console.device = uart_console_device;
209 tcu->console.flags = CON_PRINTBUFFER | CON_ANYTIME;
210 tcu->console.index = -1;
211 tcu->console.write = tegra_tcu_console_write;
212 tcu->console.setup = tegra_tcu_console_setup;
213 tcu->console.data = &tcu->driver;
214 #endif
215
216 /* setup the driver */
217 tcu->driver.owner = THIS_MODULE;
218 tcu->driver.driver_name = "tegra-tcu";
219 tcu->driver.dev_name = "ttyTCU";
220 #if IS_ENABLED(CONFIG_SERIAL_TEGRA_TCU_CONSOLE)
221 tcu->driver.cons = &tcu->console;
222 #endif
223 tcu->driver.nr = 1;
224
225 err = uart_register_driver(&tcu->driver);
226 if (err) {
227 dev_err(&pdev->dev, "failed to register UART driver: %d\n",
228 err);
229 goto free_rx;
230 }
231
232 /* setup the port */
233 port = &tcu->port;
234 spin_lock_init(&port->lock);
235 port->dev = &pdev->dev;
236 port->type = PORT_TEGRA_TCU;
237 port->ops = &tegra_tcu_uart_ops;
238 port->fifosize = 1;
239 port->iotype = UPIO_MEM;
240 port->flags = UPF_BOOT_AUTOCONF;
241 port->private_data = tcu;
242
243 err = uart_add_one_port(&tcu->driver, port);
244 if (err) {
245 dev_err(&pdev->dev, "failed to add UART port: %d\n", err);
246 goto unregister_uart;
247 }
248
249 platform_set_drvdata(pdev, tcu);
250 #if IS_ENABLED(CONFIG_SERIAL_TEGRA_TCU_CONSOLE)
251 register_console(&tcu->console);
252 #endif
253
254 return 0;
255
256 unregister_uart:
257 uart_unregister_driver(&tcu->driver);
258 free_rx:
259 mbox_free_channel(tcu->rx);
260 free_tx:
261 mbox_free_channel(tcu->tx);
262
263 return err;
264 }
265
tegra_tcu_remove(struct platform_device * pdev)266 static int tegra_tcu_remove(struct platform_device *pdev)
267 {
268 struct tegra_tcu *tcu = platform_get_drvdata(pdev);
269
270 #if IS_ENABLED(CONFIG_SERIAL_TEGRA_TCU_CONSOLE)
271 unregister_console(&tcu->console);
272 #endif
273 uart_remove_one_port(&tcu->driver, &tcu->port);
274 uart_unregister_driver(&tcu->driver);
275 mbox_free_channel(tcu->rx);
276 mbox_free_channel(tcu->tx);
277
278 return 0;
279 }
280
281 static const struct of_device_id tegra_tcu_match[] = {
282 { .compatible = "nvidia,tegra194-tcu" },
283 { }
284 };
285
286 static struct platform_driver tegra_tcu_driver = {
287 .driver = {
288 .name = "tegra-tcu",
289 .of_match_table = tegra_tcu_match,
290 },
291 .probe = tegra_tcu_probe,
292 .remove = tegra_tcu_remove,
293 };
294 module_platform_driver(tegra_tcu_driver);
295
296 MODULE_AUTHOR("Mikko Perttunen <mperttunen@nvidia.com>");
297 MODULE_LICENSE("GPL v2");
298 MODULE_DESCRIPTION("NVIDIA Tegra Combined UART driver");
299