1 // SPDX-License-Identifier: GPL-2.0+
3 * High Speed Serial Ports on NXP LPC32xx SoC
8 * Copyright (C) 2010 NXP Semiconductors
9 * Copyright (C) 2012 Roland Stigge
12 #include <linux/module.h>
13 #include <linux/ioport.h>
14 #include <linux/init.h>
15 #include <linux/console.h>
16 #include <linux/sysrq.h>
17 #include <linux/tty.h>
18 #include <linux/tty_flip.h>
19 #include <linux/serial_core.h>
20 #include <linux/serial.h>
21 #include <linux/platform_device.h>
22 #include <linux/delay.h>
23 #include <linux/nmi.h>
25 #include <linux/irq.h>
27 #include <linux/sizes.h>
28 #include <linux/soc/nxp/lpc32xx-misc.h>
31 * High Speed UART register offsets
33 #define LPC32XX_HSUART_FIFO(x) ((x) + 0x00)
34 #define LPC32XX_HSUART_LEVEL(x) ((x) + 0x04)
35 #define LPC32XX_HSUART_IIR(x) ((x) + 0x08)
36 #define LPC32XX_HSUART_CTRL(x) ((x) + 0x0C)
37 #define LPC32XX_HSUART_RATE(x) ((x) + 0x10)
39 #define LPC32XX_HSU_BREAK_DATA (1 << 10)
40 #define LPC32XX_HSU_ERROR_DATA (1 << 9)
41 #define LPC32XX_HSU_RX_EMPTY (1 << 8)
43 #define LPC32XX_HSU_TX_LEV(n) (((n) >> 8) & 0xFF)
44 #define LPC32XX_HSU_RX_LEV(n) ((n) & 0xFF)
46 #define LPC32XX_HSU_TX_INT_SET (1 << 6)
47 #define LPC32XX_HSU_RX_OE_INT (1 << 5)
48 #define LPC32XX_HSU_BRK_INT (1 << 4)
49 #define LPC32XX_HSU_FE_INT (1 << 3)
50 #define LPC32XX_HSU_RX_TIMEOUT_INT (1 << 2)
51 #define LPC32XX_HSU_RX_TRIG_INT (1 << 1)
52 #define LPC32XX_HSU_TX_INT (1 << 0)
54 #define LPC32XX_HSU_HRTS_INV (1 << 21)
55 #define LPC32XX_HSU_HRTS_TRIG_8B (0x0 << 19)
56 #define LPC32XX_HSU_HRTS_TRIG_16B (0x1 << 19)
57 #define LPC32XX_HSU_HRTS_TRIG_32B (0x2 << 19)
58 #define LPC32XX_HSU_HRTS_TRIG_48B (0x3 << 19)
59 #define LPC32XX_HSU_HRTS_EN (1 << 18)
60 #define LPC32XX_HSU_TMO_DISABLED (0x0 << 16)
61 #define LPC32XX_HSU_TMO_INACT_4B (0x1 << 16)
62 #define LPC32XX_HSU_TMO_INACT_8B (0x2 << 16)
63 #define LPC32XX_HSU_TMO_INACT_16B (0x3 << 16)
64 #define LPC32XX_HSU_HCTS_INV (1 << 15)
65 #define LPC32XX_HSU_HCTS_EN (1 << 14)
66 #define LPC32XX_HSU_OFFSET(n) ((n) << 9)
67 #define LPC32XX_HSU_BREAK (1 << 8)
68 #define LPC32XX_HSU_ERR_INT_EN (1 << 7)
69 #define LPC32XX_HSU_RX_INT_EN (1 << 6)
70 #define LPC32XX_HSU_TX_INT_EN (1 << 5)
71 #define LPC32XX_HSU_RX_TL1B (0x0 << 2)
72 #define LPC32XX_HSU_RX_TL4B (0x1 << 2)
73 #define LPC32XX_HSU_RX_TL8B (0x2 << 2)
74 #define LPC32XX_HSU_RX_TL16B (0x3 << 2)
75 #define LPC32XX_HSU_RX_TL32B (0x4 << 2)
76 #define LPC32XX_HSU_RX_TL48B (0x5 << 2)
77 #define LPC32XX_HSU_TX_TLEMPTY (0x0 << 0)
78 #define LPC32XX_HSU_TX_TL0B (0x0 << 0)
79 #define LPC32XX_HSU_TX_TL4B (0x1 << 0)
80 #define LPC32XX_HSU_TX_TL8B (0x2 << 0)
81 #define LPC32XX_HSU_TX_TL16B (0x3 << 0)
83 #define LPC32XX_MAIN_OSC_FREQ 13000000
85 #define MODNAME "lpc32xx_hsuart"
87 struct lpc32xx_hsuart_port {
88 struct uart_port port;
91 #define FIFO_READ_LIMIT 128
93 #define LPC32XX_TTY_NAME "ttyTX"
94 static struct lpc32xx_hsuart_port lpc32xx_hs_ports[MAX_PORTS];
96 #ifdef CONFIG_SERIAL_HS_LPC32XX_CONSOLE
97 static void wait_for_xmit_empty(struct uart_port *port)
99 unsigned int timeout = 10000;
102 if (LPC32XX_HSU_TX_LEV(readl(LPC32XX_HSUART_LEVEL(
103 port->membase))) == 0)
111 static void wait_for_xmit_ready(struct uart_port *port)
113 unsigned int timeout = 10000;
116 if (LPC32XX_HSU_TX_LEV(readl(LPC32XX_HSUART_LEVEL(
117 port->membase))) < 32)
125 static void lpc32xx_hsuart_console_putchar(struct uart_port *port, unsigned char ch)
127 wait_for_xmit_ready(port);
128 writel((u32)ch, LPC32XX_HSUART_FIFO(port->membase));
131 static void lpc32xx_hsuart_console_write(struct console *co, const char *s,
134 struct lpc32xx_hsuart_port *up = &lpc32xx_hs_ports[co->index];
138 touch_nmi_watchdog();
139 local_irq_save(flags);
142 else if (oops_in_progress)
143 locked = spin_trylock(&up->port.lock);
145 spin_lock(&up->port.lock);
147 uart_console_write(&up->port, s, count, lpc32xx_hsuart_console_putchar);
148 wait_for_xmit_empty(&up->port);
151 spin_unlock(&up->port.lock);
152 local_irq_restore(flags);
155 static int __init lpc32xx_hsuart_console_setup(struct console *co,
158 struct uart_port *port;
164 if (co->index >= MAX_PORTS)
167 port = &lpc32xx_hs_ports[co->index].port;
172 uart_parse_options(options, &baud, &parity, &bits, &flow);
174 lpc32xx_loopback_set(port->mapbase, 0); /* get out of loopback mode */
176 return uart_set_options(port, co, baud, parity, bits, flow);
179 static struct uart_driver lpc32xx_hsuart_reg;
180 static struct console lpc32xx_hsuart_console = {
181 .name = LPC32XX_TTY_NAME,
182 .write = lpc32xx_hsuart_console_write,
183 .device = uart_console_device,
184 .setup = lpc32xx_hsuart_console_setup,
185 .flags = CON_PRINTBUFFER,
187 .data = &lpc32xx_hsuart_reg,
190 static int __init lpc32xx_hsuart_console_init(void)
192 register_console(&lpc32xx_hsuart_console);
195 console_initcall(lpc32xx_hsuart_console_init);
197 #define LPC32XX_HSUART_CONSOLE (&lpc32xx_hsuart_console)
199 #define LPC32XX_HSUART_CONSOLE NULL
202 static struct uart_driver lpc32xx_hs_reg = {
203 .owner = THIS_MODULE,
204 .driver_name = MODNAME,
205 .dev_name = LPC32XX_TTY_NAME,
207 .cons = LPC32XX_HSUART_CONSOLE,
209 static int uarts_registered;
211 static unsigned int __serial_get_clock_div(unsigned long uartclk,
214 u32 div, goodrate, hsu_rate, l_hsu_rate, comprate;
217 /* Find the closest divider to get the desired clock rate */
218 div = uartclk / rate;
219 goodrate = hsu_rate = (div / 14) - 1;
224 l_hsu_rate = hsu_rate + 3;
225 rate_diff = 0xFFFFFFFF;
227 while (hsu_rate < l_hsu_rate) {
228 comprate = uartclk / ((hsu_rate + 1) * 14);
229 if (abs(comprate - rate) < rate_diff) {
231 rate_diff = abs(comprate - rate);
242 static void __serial_uart_flush(struct uart_port *port)
246 while ((readl(LPC32XX_HSUART_LEVEL(port->membase)) > 0) &&
247 (cnt++ < FIFO_READ_LIMIT))
248 readl(LPC32XX_HSUART_FIFO(port->membase));
251 static void __serial_lpc32xx_rx(struct uart_port *port)
253 struct tty_port *tport = &port->state->port;
254 unsigned int tmp, flag;
256 /* Read data from FIFO and push into terminal */
257 tmp = readl(LPC32XX_HSUART_FIFO(port->membase));
258 while (!(tmp & LPC32XX_HSU_RX_EMPTY)) {
262 if (tmp & LPC32XX_HSU_ERROR_DATA) {
264 writel(LPC32XX_HSU_FE_INT,
265 LPC32XX_HSUART_IIR(port->membase));
266 port->icount.frame++;
268 tty_insert_flip_char(tport, 0, TTY_FRAME);
271 tty_insert_flip_char(tport, (tmp & 0xFF), flag);
273 tmp = readl(LPC32XX_HSUART_FIFO(port->membase));
276 tty_flip_buffer_push(tport);
279 static bool serial_lpc32xx_tx_ready(struct uart_port *port)
281 u32 level = readl(LPC32XX_HSUART_LEVEL(port->membase));
283 return LPC32XX_HSU_TX_LEV(level) < 64;
286 static void __serial_lpc32xx_tx(struct uart_port *port)
290 uart_port_tx(port, ch,
291 serial_lpc32xx_tx_ready(port),
292 writel(ch, LPC32XX_HSUART_FIFO(port->membase)));
295 static irqreturn_t serial_lpc32xx_interrupt(int irq, void *dev_id)
297 struct uart_port *port = dev_id;
298 struct tty_port *tport = &port->state->port;
301 spin_lock(&port->lock);
303 /* Read UART status and clear latched interrupts */
304 status = readl(LPC32XX_HSUART_IIR(port->membase));
306 if (status & LPC32XX_HSU_BRK_INT) {
308 writel(LPC32XX_HSU_BRK_INT, LPC32XX_HSUART_IIR(port->membase));
310 uart_handle_break(port);
314 if (status & LPC32XX_HSU_FE_INT)
315 writel(LPC32XX_HSU_FE_INT, LPC32XX_HSUART_IIR(port->membase));
317 if (status & LPC32XX_HSU_RX_OE_INT) {
318 /* Receive FIFO overrun */
319 writel(LPC32XX_HSU_RX_OE_INT,
320 LPC32XX_HSUART_IIR(port->membase));
321 port->icount.overrun++;
322 tty_insert_flip_char(tport, 0, TTY_OVERRUN);
323 tty_flip_buffer_push(tport);
327 if (status & (LPC32XX_HSU_RX_TIMEOUT_INT | LPC32XX_HSU_RX_TRIG_INT))
328 __serial_lpc32xx_rx(port);
330 /* Transmit data request? */
331 if ((status & LPC32XX_HSU_TX_INT) && (!uart_tx_stopped(port))) {
332 writel(LPC32XX_HSU_TX_INT, LPC32XX_HSUART_IIR(port->membase));
333 __serial_lpc32xx_tx(port);
336 spin_unlock(&port->lock);
341 /* port->lock is not held. */
342 static unsigned int serial_lpc32xx_tx_empty(struct uart_port *port)
344 unsigned int ret = 0;
346 if (LPC32XX_HSU_TX_LEV(readl(LPC32XX_HSUART_LEVEL(port->membase))) == 0)
352 /* port->lock held by caller. */
353 static void serial_lpc32xx_set_mctrl(struct uart_port *port,
356 /* No signals are supported on HS UARTs */
359 /* port->lock is held by caller and interrupts are disabled. */
360 static unsigned int serial_lpc32xx_get_mctrl(struct uart_port *port)
362 /* No signals are supported on HS UARTs */
363 return TIOCM_CAR | TIOCM_DSR | TIOCM_CTS;
366 /* port->lock held by caller. */
367 static void serial_lpc32xx_stop_tx(struct uart_port *port)
371 tmp = readl(LPC32XX_HSUART_CTRL(port->membase));
372 tmp &= ~LPC32XX_HSU_TX_INT_EN;
373 writel(tmp, LPC32XX_HSUART_CTRL(port->membase));
376 /* port->lock held by caller. */
377 static void serial_lpc32xx_start_tx(struct uart_port *port)
381 __serial_lpc32xx_tx(port);
382 tmp = readl(LPC32XX_HSUART_CTRL(port->membase));
383 tmp |= LPC32XX_HSU_TX_INT_EN;
384 writel(tmp, LPC32XX_HSUART_CTRL(port->membase));
387 /* port->lock held by caller. */
388 static void serial_lpc32xx_stop_rx(struct uart_port *port)
392 tmp = readl(LPC32XX_HSUART_CTRL(port->membase));
393 tmp &= ~(LPC32XX_HSU_RX_INT_EN | LPC32XX_HSU_ERR_INT_EN);
394 writel(tmp, LPC32XX_HSUART_CTRL(port->membase));
396 writel((LPC32XX_HSU_BRK_INT | LPC32XX_HSU_RX_OE_INT |
397 LPC32XX_HSU_FE_INT), LPC32XX_HSUART_IIR(port->membase));
400 /* port->lock is not held. */
401 static void serial_lpc32xx_break_ctl(struct uart_port *port,
407 spin_lock_irqsave(&port->lock, flags);
408 tmp = readl(LPC32XX_HSUART_CTRL(port->membase));
409 if (break_state != 0)
410 tmp |= LPC32XX_HSU_BREAK;
412 tmp &= ~LPC32XX_HSU_BREAK;
413 writel(tmp, LPC32XX_HSUART_CTRL(port->membase));
414 spin_unlock_irqrestore(&port->lock, flags);
417 /* port->lock is not held. */
418 static int serial_lpc32xx_startup(struct uart_port *port)
424 spin_lock_irqsave(&port->lock, flags);
426 __serial_uart_flush(port);
428 writel((LPC32XX_HSU_TX_INT | LPC32XX_HSU_FE_INT |
429 LPC32XX_HSU_BRK_INT | LPC32XX_HSU_RX_OE_INT),
430 LPC32XX_HSUART_IIR(port->membase));
432 writel(0xFF, LPC32XX_HSUART_RATE(port->membase));
435 * Set receiver timeout, HSU offset of 20, no break, no interrupts,
436 * and default FIFO trigger levels
438 tmp = LPC32XX_HSU_TX_TL8B | LPC32XX_HSU_RX_TL32B |
439 LPC32XX_HSU_OFFSET(20) | LPC32XX_HSU_TMO_INACT_4B;
440 writel(tmp, LPC32XX_HSUART_CTRL(port->membase));
442 lpc32xx_loopback_set(port->mapbase, 0); /* get out of loopback mode */
444 spin_unlock_irqrestore(&port->lock, flags);
446 retval = request_irq(port->irq, serial_lpc32xx_interrupt,
449 writel((tmp | LPC32XX_HSU_RX_INT_EN | LPC32XX_HSU_ERR_INT_EN),
450 LPC32XX_HSUART_CTRL(port->membase));
455 /* port->lock is not held. */
456 static void serial_lpc32xx_shutdown(struct uart_port *port)
461 spin_lock_irqsave(&port->lock, flags);
463 tmp = LPC32XX_HSU_TX_TL8B | LPC32XX_HSU_RX_TL32B |
464 LPC32XX_HSU_OFFSET(20) | LPC32XX_HSU_TMO_INACT_4B;
465 writel(tmp, LPC32XX_HSUART_CTRL(port->membase));
467 lpc32xx_loopback_set(port->mapbase, 1); /* go to loopback mode */
469 spin_unlock_irqrestore(&port->lock, flags);
471 free_irq(port->irq, port);
474 /* port->lock is not held. */
475 static void serial_lpc32xx_set_termios(struct uart_port *port,
476 struct ktermios *termios,
477 const struct ktermios *old)
480 unsigned int baud, quot;
483 /* Always 8-bit, no parity, 1 stop bit */
484 termios->c_cflag &= ~(CSIZE | CSTOPB | PARENB | PARODD);
485 termios->c_cflag |= CS8;
487 termios->c_cflag &= ~(HUPCL | CMSPAR | CLOCAL | CRTSCTS);
489 baud = uart_get_baud_rate(port, termios, old, 0,
492 quot = __serial_get_clock_div(port->uartclk, baud);
494 spin_lock_irqsave(&port->lock, flags);
496 /* Ignore characters? */
497 tmp = readl(LPC32XX_HSUART_CTRL(port->membase));
498 if ((termios->c_cflag & CREAD) == 0)
499 tmp &= ~(LPC32XX_HSU_RX_INT_EN | LPC32XX_HSU_ERR_INT_EN);
501 tmp |= LPC32XX_HSU_RX_INT_EN | LPC32XX_HSU_ERR_INT_EN;
502 writel(tmp, LPC32XX_HSUART_CTRL(port->membase));
504 writel(quot, LPC32XX_HSUART_RATE(port->membase));
506 uart_update_timeout(port, termios->c_cflag, baud);
508 spin_unlock_irqrestore(&port->lock, flags);
510 /* Don't rewrite B0 */
511 if (tty_termios_baud_rate(termios))
512 tty_termios_encode_baud_rate(termios, baud, baud);
515 static const char *serial_lpc32xx_type(struct uart_port *port)
520 static void serial_lpc32xx_release_port(struct uart_port *port)
522 if ((port->iotype == UPIO_MEM32) && (port->mapbase)) {
523 if (port->flags & UPF_IOREMAP) {
524 iounmap(port->membase);
525 port->membase = NULL;
528 release_mem_region(port->mapbase, SZ_4K);
532 static int serial_lpc32xx_request_port(struct uart_port *port)
536 if ((port->iotype == UPIO_MEM32) && (port->mapbase)) {
539 if (!request_mem_region(port->mapbase, SZ_4K, MODNAME))
541 else if (port->flags & UPF_IOREMAP) {
542 port->membase = ioremap(port->mapbase, SZ_4K);
543 if (!port->membase) {
544 release_mem_region(port->mapbase, SZ_4K);
553 static void serial_lpc32xx_config_port(struct uart_port *port, int uflags)
557 ret = serial_lpc32xx_request_port(port);
560 port->type = PORT_UART00;
563 __serial_uart_flush(port);
565 writel((LPC32XX_HSU_TX_INT | LPC32XX_HSU_FE_INT |
566 LPC32XX_HSU_BRK_INT | LPC32XX_HSU_RX_OE_INT),
567 LPC32XX_HSUART_IIR(port->membase));
569 writel(0xFF, LPC32XX_HSUART_RATE(port->membase));
571 /* Set receiver timeout, HSU offset of 20, no break, no interrupts,
572 and default FIFO trigger levels */
573 writel(LPC32XX_HSU_TX_TL8B | LPC32XX_HSU_RX_TL32B |
574 LPC32XX_HSU_OFFSET(20) | LPC32XX_HSU_TMO_INACT_4B,
575 LPC32XX_HSUART_CTRL(port->membase));
578 static int serial_lpc32xx_verify_port(struct uart_port *port,
579 struct serial_struct *ser)
583 if (ser->type != PORT_UART00)
589 static const struct uart_ops serial_lpc32xx_pops = {
590 .tx_empty = serial_lpc32xx_tx_empty,
591 .set_mctrl = serial_lpc32xx_set_mctrl,
592 .get_mctrl = serial_lpc32xx_get_mctrl,
593 .stop_tx = serial_lpc32xx_stop_tx,
594 .start_tx = serial_lpc32xx_start_tx,
595 .stop_rx = serial_lpc32xx_stop_rx,
596 .break_ctl = serial_lpc32xx_break_ctl,
597 .startup = serial_lpc32xx_startup,
598 .shutdown = serial_lpc32xx_shutdown,
599 .set_termios = serial_lpc32xx_set_termios,
600 .type = serial_lpc32xx_type,
601 .release_port = serial_lpc32xx_release_port,
602 .request_port = serial_lpc32xx_request_port,
603 .config_port = serial_lpc32xx_config_port,
604 .verify_port = serial_lpc32xx_verify_port,
608 * Register a set of serial devices attached to a platform device
610 static int serial_hs_lpc32xx_probe(struct platform_device *pdev)
612 struct lpc32xx_hsuart_port *p = &lpc32xx_hs_ports[uarts_registered];
614 struct resource *res;
616 if (uarts_registered >= MAX_PORTS) {
618 "Error: Number of possible ports exceeded (%d)!\n",
619 uarts_registered + 1);
623 memset(p, 0, sizeof(*p));
625 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
628 "Error getting mem resource for HS UART port %d\n",
632 p->port.mapbase = res->start;
633 p->port.membase = NULL;
635 ret = platform_get_irq(pdev, 0);
640 p->port.iotype = UPIO_MEM32;
641 p->port.uartclk = LPC32XX_MAIN_OSC_FREQ;
642 p->port.regshift = 2;
643 p->port.flags = UPF_BOOT_AUTOCONF | UPF_FIXED_PORT | UPF_IOREMAP;
644 p->port.dev = &pdev->dev;
645 p->port.ops = &serial_lpc32xx_pops;
646 p->port.line = uarts_registered++;
647 spin_lock_init(&p->port.lock);
649 /* send port to loopback mode by default */
650 lpc32xx_loopback_set(p->port.mapbase, 1);
652 ret = uart_add_one_port(&lpc32xx_hs_reg, &p->port);
654 platform_set_drvdata(pdev, p);
660 * Remove serial ports registered against a platform device.
662 static int serial_hs_lpc32xx_remove(struct platform_device *pdev)
664 struct lpc32xx_hsuart_port *p = platform_get_drvdata(pdev);
666 uart_remove_one_port(&lpc32xx_hs_reg, &p->port);
673 static int serial_hs_lpc32xx_suspend(struct platform_device *pdev,
676 struct lpc32xx_hsuart_port *p = platform_get_drvdata(pdev);
678 uart_suspend_port(&lpc32xx_hs_reg, &p->port);
683 static int serial_hs_lpc32xx_resume(struct platform_device *pdev)
685 struct lpc32xx_hsuart_port *p = platform_get_drvdata(pdev);
687 uart_resume_port(&lpc32xx_hs_reg, &p->port);
692 #define serial_hs_lpc32xx_suspend NULL
693 #define serial_hs_lpc32xx_resume NULL
696 static const struct of_device_id serial_hs_lpc32xx_dt_ids[] = {
697 { .compatible = "nxp,lpc3220-hsuart" },
701 MODULE_DEVICE_TABLE(of, serial_hs_lpc32xx_dt_ids);
703 static struct platform_driver serial_hs_lpc32xx_driver = {
704 .probe = serial_hs_lpc32xx_probe,
705 .remove = serial_hs_lpc32xx_remove,
706 .suspend = serial_hs_lpc32xx_suspend,
707 .resume = serial_hs_lpc32xx_resume,
710 .of_match_table = serial_hs_lpc32xx_dt_ids,
714 static int __init lpc32xx_hsuart_init(void)
718 ret = uart_register_driver(&lpc32xx_hs_reg);
722 ret = platform_driver_register(&serial_hs_lpc32xx_driver);
724 uart_unregister_driver(&lpc32xx_hs_reg);
729 static void __exit lpc32xx_hsuart_exit(void)
731 platform_driver_unregister(&serial_hs_lpc32xx_driver);
732 uart_unregister_driver(&lpc32xx_hs_reg);
735 module_init(lpc32xx_hsuart_init);
736 module_exit(lpc32xx_hsuart_exit);
740 MODULE_DESCRIPTION("NXP LPC32XX High Speed UART driver");
741 MODULE_LICENSE("GPL");