1 | // SPDX-License-Identifier: GPL-2.0-or-later |
2 | |
3 | #include <linux/bitfield.h> |
4 | #include <linux/bits.h> |
5 | #include <linux/console.h> |
6 | #include <linux/delay.h> |
7 | #include <linux/io.h> |
8 | #include <linux/irq.h> |
9 | #include <linux/module.h> |
10 | #include <linux/of.h> |
11 | #include <linux/platform_device.h> |
12 | #include <linux/serial_core.h> |
13 | #include <linux/slab.h> |
14 | #include <linux/tty_flip.h> |
15 | #include <asm/serial.h> |
16 | |
17 | #define DRIVER_NAME "esp32s3-acm" |
18 | #define DEV_NAME "ttyGS" |
19 | #define UART_NR 4 |
20 | |
21 | #define ESP32S3_ACM_TX_FIFO_SIZE 64 |
22 | |
23 | #define USB_SERIAL_JTAG_EP1_REG 0x00 |
24 | #define USB_SERIAL_JTAG_EP1_CONF_REG 0x04 |
25 | #define USB_SERIAL_JTAG_WR_DONE BIT(0) |
26 | #define USB_SERIAL_JTAG_SERIAL_IN_EP_DATA_FREE BIT(1) |
27 | #define USB_SERIAL_JTAG_INT_ST_REG 0x0c |
28 | #define USB_SERIAL_JTAG_SERIAL_OUT_RECV_PKT_INT_ST BIT(2) |
29 | #define USB_SERIAL_JTAG_SERIAL_IN_EMPTY_INT_ST BIT(3) |
30 | #define USB_SERIAL_JTAG_INT_ENA_REG 0x10 |
31 | #define USB_SERIAL_JTAG_SERIAL_OUT_RECV_PKT_INT_ENA BIT(2) |
32 | #define USB_SERIAL_JTAG_SERIAL_IN_EMPTY_INT_ENA BIT(3) |
33 | #define USB_SERIAL_JTAG_INT_CLR_REG 0x14 |
34 | #define USB_SERIAL_JTAG_IN_EP1_ST_REG 0x2c |
35 | #define USB_SERIAL_JTAG_IN_EP1_WR_ADDR GENMASK(8, 2) |
36 | #define USB_SERIAL_JTAG_OUT_EP1_ST_REG 0x3c |
37 | #define USB_SERIAL_JTAG_OUT_EP1_REC_DATA_CNT GENMASK(22, 16) |
38 | |
39 | static const struct of_device_id esp32s3_acm_dt_ids[] = { |
40 | { |
41 | .compatible = "esp,esp32s3-acm" , |
42 | }, { /* sentinel */ } |
43 | }; |
44 | MODULE_DEVICE_TABLE(of, esp32s3_acm_dt_ids); |
45 | |
46 | static struct uart_port *esp32s3_acm_ports[UART_NR]; |
47 | |
48 | static void esp32s3_acm_write(struct uart_port *port, unsigned long reg, u32 v) |
49 | { |
50 | writel(val: v, addr: port->membase + reg); |
51 | } |
52 | |
53 | static u32 esp32s3_acm_read(struct uart_port *port, unsigned long reg) |
54 | { |
55 | return readl(addr: port->membase + reg); |
56 | } |
57 | |
58 | static u32 esp32s3_acm_tx_fifo_free(struct uart_port *port) |
59 | { |
60 | u32 status = esp32s3_acm_read(port, USB_SERIAL_JTAG_EP1_CONF_REG); |
61 | |
62 | return status & USB_SERIAL_JTAG_SERIAL_IN_EP_DATA_FREE; |
63 | } |
64 | |
65 | static u32 esp32s3_acm_tx_fifo_cnt(struct uart_port *port) |
66 | { |
67 | u32 status = esp32s3_acm_read(port, USB_SERIAL_JTAG_IN_EP1_ST_REG); |
68 | |
69 | return FIELD_GET(USB_SERIAL_JTAG_IN_EP1_WR_ADDR, status); |
70 | } |
71 | |
72 | static u32 esp32s3_acm_rx_fifo_cnt(struct uart_port *port) |
73 | { |
74 | u32 status = esp32s3_acm_read(port, USB_SERIAL_JTAG_OUT_EP1_ST_REG); |
75 | |
76 | return FIELD_GET(USB_SERIAL_JTAG_OUT_EP1_REC_DATA_CNT, status); |
77 | } |
78 | |
79 | /* return TIOCSER_TEMT when transmitter is not busy */ |
80 | static unsigned int esp32s3_acm_tx_empty(struct uart_port *port) |
81 | { |
82 | return esp32s3_acm_tx_fifo_cnt(port) == 0 ? TIOCSER_TEMT : 0; |
83 | } |
84 | |
85 | static void esp32s3_acm_set_mctrl(struct uart_port *port, unsigned int mctrl) |
86 | { |
87 | } |
88 | |
89 | static unsigned int esp32s3_acm_get_mctrl(struct uart_port *port) |
90 | { |
91 | return TIOCM_CAR; |
92 | } |
93 | |
94 | static void esp32s3_acm_stop_tx(struct uart_port *port) |
95 | { |
96 | u32 int_ena; |
97 | |
98 | int_ena = esp32s3_acm_read(port, USB_SERIAL_JTAG_INT_ENA_REG); |
99 | int_ena &= ~USB_SERIAL_JTAG_SERIAL_IN_EMPTY_INT_ENA; |
100 | esp32s3_acm_write(port, USB_SERIAL_JTAG_INT_ENA_REG, v: int_ena); |
101 | } |
102 | |
103 | static void esp32s3_acm_rxint(struct uart_port *port) |
104 | { |
105 | struct tty_port *tty_port = &port->state->port; |
106 | u32 rx_fifo_cnt = esp32s3_acm_rx_fifo_cnt(port); |
107 | unsigned long flags; |
108 | u32 i; |
109 | |
110 | if (!rx_fifo_cnt) |
111 | return; |
112 | |
113 | spin_lock_irqsave(&port->lock, flags); |
114 | |
115 | for (i = 0; i < rx_fifo_cnt; ++i) { |
116 | u32 rx = esp32s3_acm_read(port, USB_SERIAL_JTAG_EP1_REG); |
117 | |
118 | ++port->icount.rx; |
119 | tty_insert_flip_char(port: tty_port, ch: rx, TTY_NORMAL); |
120 | } |
121 | spin_unlock_irqrestore(lock: &port->lock, flags); |
122 | |
123 | tty_flip_buffer_push(port: tty_port); |
124 | } |
125 | |
126 | static void esp32s3_acm_push(struct uart_port *port) |
127 | { |
128 | if (esp32s3_acm_tx_fifo_free(port)) |
129 | esp32s3_acm_write(port, USB_SERIAL_JTAG_EP1_CONF_REG, |
130 | USB_SERIAL_JTAG_WR_DONE); |
131 | } |
132 | |
133 | static void esp32s3_acm_put_char(struct uart_port *port, u8 c) |
134 | { |
135 | esp32s3_acm_write(port, USB_SERIAL_JTAG_EP1_REG, v: c); |
136 | } |
137 | |
138 | static void esp32s3_acm_put_char_sync(struct uart_port *port, u8 c) |
139 | { |
140 | unsigned long timeout = jiffies + HZ; |
141 | |
142 | while (!esp32s3_acm_tx_fifo_free(port)) { |
143 | if (time_after(jiffies, timeout)) { |
144 | dev_warn(port->dev, "timeout waiting for TX FIFO\n" ); |
145 | return; |
146 | } |
147 | cpu_relax(); |
148 | } |
149 | esp32s3_acm_put_char(port, c); |
150 | esp32s3_acm_push(port); |
151 | } |
152 | |
153 | static void esp32s3_acm_transmit_buffer(struct uart_port *port) |
154 | { |
155 | u32 tx_fifo_used; |
156 | unsigned int pending; |
157 | u8 ch; |
158 | |
159 | if (!esp32s3_acm_tx_fifo_free(port)) |
160 | return; |
161 | |
162 | tx_fifo_used = esp32s3_acm_tx_fifo_cnt(port); |
163 | pending = uart_port_tx_limited(port, ch, |
164 | ESP32S3_ACM_TX_FIFO_SIZE - tx_fifo_used, |
165 | true, esp32s3_acm_put_char(port, ch), |
166 | ({})); |
167 | if (pending) { |
168 | u32 int_ena; |
169 | |
170 | int_ena = esp32s3_acm_read(port, USB_SERIAL_JTAG_INT_ENA_REG); |
171 | int_ena |= USB_SERIAL_JTAG_SERIAL_IN_EMPTY_INT_ENA; |
172 | esp32s3_acm_write(port, USB_SERIAL_JTAG_INT_ENA_REG, v: int_ena); |
173 | } |
174 | esp32s3_acm_push(port); |
175 | } |
176 | |
177 | static void esp32s3_acm_txint(struct uart_port *port) |
178 | { |
179 | esp32s3_acm_transmit_buffer(port); |
180 | } |
181 | |
182 | static irqreturn_t esp32s3_acm_int(int irq, void *dev_id) |
183 | { |
184 | struct uart_port *port = dev_id; |
185 | u32 status; |
186 | |
187 | status = esp32s3_acm_read(port, USB_SERIAL_JTAG_INT_ST_REG); |
188 | esp32s3_acm_write(port, USB_SERIAL_JTAG_INT_CLR_REG, v: status); |
189 | |
190 | if (status & USB_SERIAL_JTAG_SERIAL_OUT_RECV_PKT_INT_ST) |
191 | esp32s3_acm_rxint(port); |
192 | if (status & USB_SERIAL_JTAG_SERIAL_IN_EMPTY_INT_ST) |
193 | esp32s3_acm_txint(port); |
194 | |
195 | return IRQ_RETVAL(status); |
196 | } |
197 | |
198 | static void esp32s3_acm_start_tx(struct uart_port *port) |
199 | { |
200 | esp32s3_acm_transmit_buffer(port); |
201 | } |
202 | |
203 | static void esp32s3_acm_stop_rx(struct uart_port *port) |
204 | { |
205 | u32 int_ena; |
206 | |
207 | int_ena = esp32s3_acm_read(port, USB_SERIAL_JTAG_INT_ENA_REG); |
208 | int_ena &= ~USB_SERIAL_JTAG_SERIAL_OUT_RECV_PKT_INT_ENA; |
209 | esp32s3_acm_write(port, USB_SERIAL_JTAG_INT_ENA_REG, v: int_ena); |
210 | } |
211 | |
212 | static int esp32s3_acm_startup(struct uart_port *port) |
213 | { |
214 | int ret; |
215 | |
216 | ret = request_irq(irq: port->irq, handler: esp32s3_acm_int, flags: 0, DRIVER_NAME, dev: port); |
217 | if (ret) |
218 | return ret; |
219 | esp32s3_acm_write(port, USB_SERIAL_JTAG_INT_ENA_REG, |
220 | USB_SERIAL_JTAG_SERIAL_OUT_RECV_PKT_INT_ENA); |
221 | |
222 | return 0; |
223 | } |
224 | |
225 | static void esp32s3_acm_shutdown(struct uart_port *port) |
226 | { |
227 | esp32s3_acm_write(port, USB_SERIAL_JTAG_INT_ENA_REG, v: 0); |
228 | free_irq(port->irq, port); |
229 | } |
230 | |
231 | static void esp32s3_acm_set_termios(struct uart_port *port, |
232 | struct ktermios *termios, |
233 | const struct ktermios *old) |
234 | { |
235 | } |
236 | |
237 | static const char *esp32s3_acm_type(struct uart_port *port) |
238 | { |
239 | return "ESP32S3 ACM" ; |
240 | } |
241 | |
242 | /* configure/auto-configure the port */ |
243 | static void esp32s3_acm_config_port(struct uart_port *port, int flags) |
244 | { |
245 | if (flags & UART_CONFIG_TYPE) |
246 | port->type = PORT_GENERIC; |
247 | } |
248 | |
249 | #ifdef CONFIG_CONSOLE_POLL |
250 | static void esp32s3_acm_poll_put_char(struct uart_port *port, unsigned char c) |
251 | { |
252 | esp32s3_acm_put_char_sync(port, c); |
253 | } |
254 | |
255 | static int esp32s3_acm_poll_get_char(struct uart_port *port) |
256 | { |
257 | if (esp32s3_acm_rx_fifo_cnt(port)) |
258 | return esp32s3_acm_read(port, USB_SERIAL_JTAG_EP1_REG); |
259 | else |
260 | return NO_POLL_CHAR; |
261 | } |
262 | #endif |
263 | |
264 | static const struct uart_ops esp32s3_acm_pops = { |
265 | .tx_empty = esp32s3_acm_tx_empty, |
266 | .set_mctrl = esp32s3_acm_set_mctrl, |
267 | .get_mctrl = esp32s3_acm_get_mctrl, |
268 | .stop_tx = esp32s3_acm_stop_tx, |
269 | .start_tx = esp32s3_acm_start_tx, |
270 | .stop_rx = esp32s3_acm_stop_rx, |
271 | .startup = esp32s3_acm_startup, |
272 | .shutdown = esp32s3_acm_shutdown, |
273 | .set_termios = esp32s3_acm_set_termios, |
274 | .type = esp32s3_acm_type, |
275 | .config_port = esp32s3_acm_config_port, |
276 | #ifdef CONFIG_CONSOLE_POLL |
277 | .poll_put_char = esp32s3_acm_poll_put_char, |
278 | .poll_get_char = esp32s3_acm_poll_get_char, |
279 | #endif |
280 | }; |
281 | |
282 | static void esp32s3_acm_string_write(struct uart_port *port, const char *s, |
283 | unsigned int count) |
284 | { |
285 | uart_console_write(port, s, count, putchar: esp32s3_acm_put_char_sync); |
286 | } |
287 | |
288 | static void |
289 | esp32s3_acm_console_write(struct console *co, const char *s, unsigned int count) |
290 | { |
291 | struct uart_port *port = esp32s3_acm_ports[co->index]; |
292 | unsigned long flags; |
293 | bool locked = true; |
294 | |
295 | if (port->sysrq) |
296 | locked = false; |
297 | else if (oops_in_progress) |
298 | locked = spin_trylock_irqsave(&port->lock, flags); |
299 | else |
300 | spin_lock_irqsave(&port->lock, flags); |
301 | |
302 | esp32s3_acm_string_write(port, s, count); |
303 | |
304 | if (locked) |
305 | spin_unlock_irqrestore(lock: &port->lock, flags); |
306 | } |
307 | |
308 | static struct uart_driver esp32s3_acm_reg; |
309 | static struct console esp32s3_acm_console = { |
310 | .name = DEV_NAME, |
311 | .write = esp32s3_acm_console_write, |
312 | .device = uart_console_device, |
313 | .flags = CON_PRINTBUFFER, |
314 | .index = -1, |
315 | .data = &esp32s3_acm_reg, |
316 | }; |
317 | |
318 | static void esp32s3_acm_earlycon_write(struct console *con, const char *s, |
319 | unsigned int n) |
320 | { |
321 | struct earlycon_device *dev = con->data; |
322 | |
323 | uart_console_write(port: &dev->port, s, count: n, putchar: esp32s3_acm_put_char_sync); |
324 | } |
325 | |
326 | #ifdef CONFIG_CONSOLE_POLL |
327 | static int esp32s3_acm_earlycon_read(struct console *con, char *s, unsigned int n) |
328 | { |
329 | struct earlycon_device *dev = con->data; |
330 | unsigned int num_read = 0; |
331 | |
332 | while (num_read < n) { |
333 | int c = esp32s3_acm_poll_get_char(port: &dev->port); |
334 | |
335 | if (c == NO_POLL_CHAR) |
336 | break; |
337 | s[num_read++] = c; |
338 | } |
339 | return num_read; |
340 | } |
341 | #endif |
342 | |
343 | static int __init esp32s3_acm_early_console_setup(struct earlycon_device *device, |
344 | const char *options) |
345 | { |
346 | if (!device->port.membase) |
347 | return -ENODEV; |
348 | |
349 | device->con->write = esp32s3_acm_earlycon_write; |
350 | #ifdef CONFIG_CONSOLE_POLL |
351 | device->con->read = esp32s3_acm_earlycon_read; |
352 | #endif |
353 | return 0; |
354 | } |
355 | |
356 | OF_EARLYCON_DECLARE(esp32s3acm, "esp,esp32s3-acm" , |
357 | esp32s3_acm_early_console_setup); |
358 | |
359 | static struct uart_driver esp32s3_acm_reg = { |
360 | .owner = THIS_MODULE, |
361 | .driver_name = DRIVER_NAME, |
362 | .dev_name = DEV_NAME, |
363 | .nr = ARRAY_SIZE(esp32s3_acm_ports), |
364 | .cons = &esp32s3_acm_console, |
365 | }; |
366 | |
367 | static int esp32s3_acm_probe(struct platform_device *pdev) |
368 | { |
369 | struct device_node *np = pdev->dev.of_node; |
370 | struct uart_port *port; |
371 | struct resource *res; |
372 | int ret; |
373 | |
374 | port = devm_kzalloc(dev: &pdev->dev, size: sizeof(*port), GFP_KERNEL); |
375 | if (!port) |
376 | return -ENOMEM; |
377 | |
378 | ret = of_alias_get_id(np, stem: "serial" ); |
379 | if (ret < 0) { |
380 | dev_err(&pdev->dev, "failed to get alias id, errno %d\n" , ret); |
381 | return ret; |
382 | } |
383 | if (ret >= UART_NR) { |
384 | dev_err(&pdev->dev, "driver limited to %d serial ports\n" , |
385 | UART_NR); |
386 | return -ENOMEM; |
387 | } |
388 | |
389 | port->line = ret; |
390 | |
391 | res = platform_get_resource(pdev, IORESOURCE_MEM, 0); |
392 | if (!res) |
393 | return -ENODEV; |
394 | |
395 | port->mapbase = res->start; |
396 | port->membase = devm_ioremap_resource(dev: &pdev->dev, res); |
397 | if (IS_ERR(ptr: port->membase)) |
398 | return PTR_ERR(ptr: port->membase); |
399 | |
400 | port->dev = &pdev->dev; |
401 | port->type = PORT_GENERIC; |
402 | port->iotype = UPIO_MEM; |
403 | port->irq = platform_get_irq(pdev, 0); |
404 | port->ops = &esp32s3_acm_pops; |
405 | port->flags = UPF_BOOT_AUTOCONF; |
406 | port->has_sysrq = 1; |
407 | port->fifosize = ESP32S3_ACM_TX_FIFO_SIZE; |
408 | |
409 | esp32s3_acm_ports[port->line] = port; |
410 | |
411 | platform_set_drvdata(pdev, data: port); |
412 | |
413 | return uart_add_one_port(reg: &esp32s3_acm_reg, port); |
414 | } |
415 | |
416 | static void esp32s3_acm_remove(struct platform_device *pdev) |
417 | { |
418 | struct uart_port *port = platform_get_drvdata(pdev); |
419 | |
420 | uart_remove_one_port(reg: &esp32s3_acm_reg, port); |
421 | } |
422 | |
423 | |
424 | static struct platform_driver esp32s3_acm_driver = { |
425 | .probe = esp32s3_acm_probe, |
426 | .remove_new = esp32s3_acm_remove, |
427 | .driver = { |
428 | .name = DRIVER_NAME, |
429 | .of_match_table = esp32s3_acm_dt_ids, |
430 | }, |
431 | }; |
432 | |
433 | static int __init esp32s3_acm_init(void) |
434 | { |
435 | int ret; |
436 | |
437 | ret = uart_register_driver(uart: &esp32s3_acm_reg); |
438 | if (ret) |
439 | return ret; |
440 | |
441 | ret = platform_driver_register(&esp32s3_acm_driver); |
442 | if (ret) |
443 | uart_unregister_driver(uart: &esp32s3_acm_reg); |
444 | |
445 | return ret; |
446 | } |
447 | |
448 | static void __exit esp32s3_acm_exit(void) |
449 | { |
450 | platform_driver_unregister(&esp32s3_acm_driver); |
451 | uart_unregister_driver(uart: &esp32s3_acm_reg); |
452 | } |
453 | |
454 | module_init(esp32s3_acm_init); |
455 | module_exit(esp32s3_acm_exit); |
456 | |
457 | MODULE_AUTHOR("Max Filippov <jcmvbkbc@gmail.com>" ); |
458 | MODULE_LICENSE("GPL" ); |
459 | |