1 // SPDX-License-Identifier: GPL-2.0
3 * Based on drivers/char/serial.c, by Linus Torvalds, Theodore Ts'o.
5 * Copyright (C) 2004 Infineon IFAP DC COM CPE
6 * Copyright (C) 2007 Felix Fietkau <nbd@openwrt.org>
7 * Copyright (C) 2007 John Crispin <john@phrozen.org>
8 * Copyright (C) 2010 Thomas Langer, <thomas.langer@lantiq.com>
11 #include <linux/clk.h>
12 #include <linux/console.h>
13 #include <linux/device.h>
14 #include <linux/gpio.h>
15 #include <linux/init.h>
17 #include <linux/ioport.h>
18 #include <linux/lantiq.h>
19 #include <linux/of_address.h>
20 #include <linux/of_irq.h>
21 #include <linux/of_platform.h>
22 #include <linux/serial.h>
23 #include <linux/serial_core.h>
24 #include <linux/slab.h>
25 #include <linux/sysrq.h>
26 #include <linux/tty.h>
27 #include <linux/tty_flip.h>
29 #define PORT_LTQ_ASC 111
31 #define UART_DUMMY_UER_RX 1
32 #define DRVNAME "lantiq,asc"
34 #define LTQ_ASC_TBUF (0x0020 + 3)
35 #define LTQ_ASC_RBUF (0x0024 + 3)
37 #define LTQ_ASC_TBUF 0x0020
38 #define LTQ_ASC_RBUF 0x0024
40 #define LTQ_ASC_FSTAT 0x0048
41 #define LTQ_ASC_WHBSTATE 0x0018
42 #define LTQ_ASC_STATE 0x0014
43 #define LTQ_ASC_IRNCR 0x00F8
44 #define LTQ_ASC_CLC 0x0000
45 #define LTQ_ASC_ID 0x0008
46 #define LTQ_ASC_PISEL 0x0004
47 #define LTQ_ASC_TXFCON 0x0044
48 #define LTQ_ASC_RXFCON 0x0040
49 #define LTQ_ASC_CON 0x0010
50 #define LTQ_ASC_BG 0x0050
51 #define LTQ_ASC_IRNREN 0x00F4
53 #define ASC_IRNREN_TX 0x1
54 #define ASC_IRNREN_RX 0x2
55 #define ASC_IRNREN_ERR 0x4
56 #define ASC_IRNREN_TX_BUF 0x8
57 #define ASC_IRNCR_TIR 0x1
58 #define ASC_IRNCR_RIR 0x2
59 #define ASC_IRNCR_EIR 0x4
61 #define ASCOPT_CSIZE 0x3
64 #define ASCCLC_DISS 0x2
65 #define ASCCLC_RMCMASK 0x0000FF00
66 #define ASCCLC_RMCOFFSET 8
67 #define ASCCON_M_8ASYNC 0x0
68 #define ASCCON_M_7ASYNC 0x2
69 #define ASCCON_ODD 0x00000020
70 #define ASCCON_STP 0x00000080
71 #define ASCCON_BRS 0x00000100
72 #define ASCCON_FDE 0x00000200
73 #define ASCCON_R 0x00008000
74 #define ASCCON_FEN 0x00020000
75 #define ASCCON_ROEN 0x00080000
76 #define ASCCON_TOEN 0x00100000
77 #define ASCSTATE_PE 0x00010000
78 #define ASCSTATE_FE 0x00020000
79 #define ASCSTATE_ROE 0x00080000
80 #define ASCSTATE_ANY (ASCSTATE_ROE|ASCSTATE_PE|ASCSTATE_FE)
81 #define ASCWHBSTATE_CLRREN 0x00000001
82 #define ASCWHBSTATE_SETREN 0x00000002
83 #define ASCWHBSTATE_CLRPE 0x00000004
84 #define ASCWHBSTATE_CLRFE 0x00000008
85 #define ASCWHBSTATE_CLRROE 0x00000020
86 #define ASCTXFCON_TXFEN 0x0001
87 #define ASCTXFCON_TXFFLU 0x0002
88 #define ASCTXFCON_TXFITLMASK 0x3F00
89 #define ASCTXFCON_TXFITLOFF 8
90 #define ASCRXFCON_RXFEN 0x0001
91 #define ASCRXFCON_RXFFLU 0x0002
92 #define ASCRXFCON_RXFITLMASK 0x3F00
93 #define ASCRXFCON_RXFITLOFF 8
94 #define ASCFSTAT_RXFFLMASK 0x003F
95 #define ASCFSTAT_TXFFLMASK 0x3F00
96 #define ASCFSTAT_TXFREEMASK 0x3F000000
97 #define ASCFSTAT_TXFREEOFF 24
99 static void lqasc_tx_chars(struct uart_port *port);
100 static struct ltq_uart_port *lqasc_port[MAXPORTS];
101 static struct uart_driver lqasc_reg;
102 static DEFINE_SPINLOCK(ltq_asc_lock);
104 struct ltq_uart_port {
105 struct uart_port port;
106 /* clock used to derive divider */
108 /* clock gating of the ASC core */
112 unsigned int err_irq;
115 static inline void asc_update_bits(u32 clear, u32 set, void __iomem *reg)
117 u32 tmp = __raw_readl(reg);
119 __raw_writel((tmp & ~clear) | set, reg);
123 ltq_uart_port *to_ltq_uart_port(struct uart_port *port)
125 return container_of(port, struct ltq_uart_port, port);
129 lqasc_stop_tx(struct uart_port *port)
135 lqasc_start_tx(struct uart_port *port)
138 spin_lock_irqsave(<q_asc_lock, flags);
139 lqasc_tx_chars(port);
140 spin_unlock_irqrestore(<q_asc_lock, flags);
145 lqasc_stop_rx(struct uart_port *port)
147 __raw_writel(ASCWHBSTATE_CLRREN, port->membase + LTQ_ASC_WHBSTATE);
151 lqasc_rx_chars(struct uart_port *port)
153 struct tty_port *tport = &port->state->port;
154 unsigned int ch = 0, rsr = 0, fifocnt;
156 fifocnt = __raw_readl(port->membase + LTQ_ASC_FSTAT) &
159 u8 flag = TTY_NORMAL;
160 ch = readb(port->membase + LTQ_ASC_RBUF);
161 rsr = (__raw_readl(port->membase + LTQ_ASC_STATE)
162 & ASCSTATE_ANY) | UART_DUMMY_UER_RX;
163 tty_flip_buffer_push(tport);
167 * Note that the error handling code is
168 * out of the main execution path
170 if (rsr & ASCSTATE_ANY) {
171 if (rsr & ASCSTATE_PE) {
172 port->icount.parity++;
173 asc_update_bits(0, ASCWHBSTATE_CLRPE,
174 port->membase + LTQ_ASC_WHBSTATE);
175 } else if (rsr & ASCSTATE_FE) {
176 port->icount.frame++;
177 asc_update_bits(0, ASCWHBSTATE_CLRFE,
178 port->membase + LTQ_ASC_WHBSTATE);
180 if (rsr & ASCSTATE_ROE) {
181 port->icount.overrun++;
182 asc_update_bits(0, ASCWHBSTATE_CLRROE,
183 port->membase + LTQ_ASC_WHBSTATE);
186 rsr &= port->read_status_mask;
188 if (rsr & ASCSTATE_PE)
190 else if (rsr & ASCSTATE_FE)
194 if ((rsr & port->ignore_status_mask) == 0)
195 tty_insert_flip_char(tport, ch, flag);
197 if (rsr & ASCSTATE_ROE)
199 * Overrun is special, since it's reported
200 * immediately, and doesn't affect the current
203 tty_insert_flip_char(tport, 0, TTY_OVERRUN);
207 tty_flip_buffer_push(tport);
213 lqasc_tx_chars(struct uart_port *port)
215 struct circ_buf *xmit = &port->state->xmit;
216 if (uart_tx_stopped(port)) {
221 while (((__raw_readl(port->membase + LTQ_ASC_FSTAT) &
222 ASCFSTAT_TXFREEMASK) >> ASCFSTAT_TXFREEOFF) != 0) {
224 writeb(port->x_char, port->membase + LTQ_ASC_TBUF);
230 if (uart_circ_empty(xmit))
233 writeb(port->state->xmit.buf[port->state->xmit.tail],
234 port->membase + LTQ_ASC_TBUF);
235 xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
239 if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
240 uart_write_wakeup(port);
244 lqasc_tx_int(int irq, void *_port)
247 struct uart_port *port = (struct uart_port *)_port;
248 spin_lock_irqsave(<q_asc_lock, flags);
249 __raw_writel(ASC_IRNCR_TIR, port->membase + LTQ_ASC_IRNCR);
250 spin_unlock_irqrestore(<q_asc_lock, flags);
251 lqasc_start_tx(port);
256 lqasc_err_int(int irq, void *_port)
259 struct uart_port *port = (struct uart_port *)_port;
260 spin_lock_irqsave(<q_asc_lock, flags);
261 /* clear any pending interrupts */
262 asc_update_bits(0, ASCWHBSTATE_CLRPE | ASCWHBSTATE_CLRFE |
263 ASCWHBSTATE_CLRROE, port->membase + LTQ_ASC_WHBSTATE);
264 spin_unlock_irqrestore(<q_asc_lock, flags);
269 lqasc_rx_int(int irq, void *_port)
272 struct uart_port *port = (struct uart_port *)_port;
273 spin_lock_irqsave(<q_asc_lock, flags);
274 __raw_writel(ASC_IRNCR_RIR, port->membase + LTQ_ASC_IRNCR);
275 lqasc_rx_chars(port);
276 spin_unlock_irqrestore(<q_asc_lock, flags);
281 lqasc_tx_empty(struct uart_port *port)
284 status = __raw_readl(port->membase + LTQ_ASC_FSTAT) &
286 return status ? 0 : TIOCSER_TEMT;
290 lqasc_get_mctrl(struct uart_port *port)
292 return TIOCM_CTS | TIOCM_CAR | TIOCM_DSR;
296 lqasc_set_mctrl(struct uart_port *port, u_int mctrl)
301 lqasc_break_ctl(struct uart_port *port, int break_state)
306 lqasc_startup(struct uart_port *port)
308 struct ltq_uart_port *ltq_port = to_ltq_uart_port(port);
311 if (!IS_ERR(ltq_port->clk))
312 clk_prepare_enable(ltq_port->clk);
313 port->uartclk = clk_get_rate(ltq_port->freqclk);
315 asc_update_bits(ASCCLC_DISS | ASCCLC_RMCMASK, (1 << ASCCLC_RMCOFFSET),
316 port->membase + LTQ_ASC_CLC);
318 __raw_writel(0, port->membase + LTQ_ASC_PISEL);
320 ((TXFIFO_FL << ASCTXFCON_TXFITLOFF) & ASCTXFCON_TXFITLMASK) |
321 ASCTXFCON_TXFEN | ASCTXFCON_TXFFLU,
322 port->membase + LTQ_ASC_TXFCON);
324 ((RXFIFO_FL << ASCRXFCON_RXFITLOFF) & ASCRXFCON_RXFITLMASK)
325 | ASCRXFCON_RXFEN | ASCRXFCON_RXFFLU,
326 port->membase + LTQ_ASC_RXFCON);
327 /* make sure other settings are written to hardware before
328 * setting enable bits
331 asc_update_bits(0, ASCCON_M_8ASYNC | ASCCON_FEN | ASCCON_TOEN |
332 ASCCON_ROEN, port->membase + LTQ_ASC_CON);
334 retval = request_irq(ltq_port->tx_irq, lqasc_tx_int,
337 pr_err("failed to request lqasc_tx_int\n");
341 retval = request_irq(ltq_port->rx_irq, lqasc_rx_int,
344 pr_err("failed to request lqasc_rx_int\n");
348 retval = request_irq(ltq_port->err_irq, lqasc_err_int,
351 pr_err("failed to request lqasc_err_int\n");
355 __raw_writel(ASC_IRNREN_RX | ASC_IRNREN_ERR | ASC_IRNREN_TX,
356 port->membase + LTQ_ASC_IRNREN);
360 free_irq(ltq_port->rx_irq, port);
362 free_irq(ltq_port->tx_irq, port);
367 lqasc_shutdown(struct uart_port *port)
369 struct ltq_uart_port *ltq_port = to_ltq_uart_port(port);
370 free_irq(ltq_port->tx_irq, port);
371 free_irq(ltq_port->rx_irq, port);
372 free_irq(ltq_port->err_irq, port);
374 __raw_writel(0, port->membase + LTQ_ASC_CON);
375 asc_update_bits(ASCRXFCON_RXFEN, ASCRXFCON_RXFFLU,
376 port->membase + LTQ_ASC_RXFCON);
377 asc_update_bits(ASCTXFCON_TXFEN, ASCTXFCON_TXFFLU,
378 port->membase + LTQ_ASC_TXFCON);
379 if (!IS_ERR(ltq_port->clk))
380 clk_disable_unprepare(ltq_port->clk);
384 lqasc_set_termios(struct uart_port *port,
385 struct ktermios *new, struct ktermios *old)
389 unsigned int divisor;
391 unsigned int con = 0;
394 cflag = new->c_cflag;
395 iflag = new->c_iflag;
397 switch (cflag & CSIZE) {
399 con = ASCCON_M_7ASYNC;
405 new->c_cflag &= ~ CSIZE;
407 con = ASCCON_M_8ASYNC;
411 cflag &= ~CMSPAR; /* Mark/Space parity is not supported */
416 if (cflag & PARENB) {
417 if (!(cflag & PARODD))
423 port->read_status_mask = ASCSTATE_ROE;
425 port->read_status_mask |= ASCSTATE_FE | ASCSTATE_PE;
427 port->ignore_status_mask = 0;
429 port->ignore_status_mask |= ASCSTATE_FE | ASCSTATE_PE;
431 if (iflag & IGNBRK) {
433 * If we're ignoring parity and break indicators,
434 * ignore overruns too (for real raw support).
437 port->ignore_status_mask |= ASCSTATE_ROE;
440 if ((cflag & CREAD) == 0)
441 port->ignore_status_mask |= UART_DUMMY_UER_RX;
443 /* set error signals - framing, parity and overrun, enable receiver */
444 con |= ASCCON_FEN | ASCCON_TOEN | ASCCON_ROEN;
446 spin_lock_irqsave(<q_asc_lock, flags);
449 asc_update_bits(0, con, port->membase + LTQ_ASC_CON);
451 /* Set baud rate - take a divider of 2 into account */
452 baud = uart_get_baud_rate(port, new, old, 0, port->uartclk / 16);
453 divisor = uart_get_divisor(port, baud);
454 divisor = divisor / 2 - 1;
456 /* disable the baudrate generator */
457 asc_update_bits(ASCCON_R, 0, port->membase + LTQ_ASC_CON);
459 /* make sure the fractional divider is off */
460 asc_update_bits(ASCCON_FDE, 0, port->membase + LTQ_ASC_CON);
462 /* set up to use divisor of 2 */
463 asc_update_bits(ASCCON_BRS, 0, port->membase + LTQ_ASC_CON);
465 /* now we can write the new baudrate into the register */
466 __raw_writel(divisor, port->membase + LTQ_ASC_BG);
468 /* turn the baudrate generator back on */
469 asc_update_bits(0, ASCCON_R, port->membase + LTQ_ASC_CON);
472 __raw_writel(ASCWHBSTATE_SETREN, port->membase + LTQ_ASC_WHBSTATE);
474 spin_unlock_irqrestore(<q_asc_lock, flags);
476 /* Don't rewrite B0 */
477 if (tty_termios_baud_rate(new))
478 tty_termios_encode_baud_rate(new, baud, baud);
480 uart_update_timeout(port, cflag, baud);
484 lqasc_type(struct uart_port *port)
486 if (port->type == PORT_LTQ_ASC)
493 lqasc_release_port(struct uart_port *port)
495 struct platform_device *pdev = to_platform_device(port->dev);
497 if (port->flags & UPF_IOREMAP) {
498 devm_iounmap(&pdev->dev, port->membase);
499 port->membase = NULL;
504 lqasc_request_port(struct uart_port *port)
506 struct platform_device *pdev = to_platform_device(port->dev);
507 struct resource *res;
510 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
512 dev_err(&pdev->dev, "cannot obtain I/O memory region");
515 size = resource_size(res);
517 res = devm_request_mem_region(&pdev->dev, res->start,
518 size, dev_name(&pdev->dev));
520 dev_err(&pdev->dev, "cannot request I/O memory region");
524 if (port->flags & UPF_IOREMAP) {
525 port->membase = devm_ioremap_nocache(&pdev->dev,
526 port->mapbase, size);
527 if (port->membase == NULL)
534 lqasc_config_port(struct uart_port *port, int flags)
536 if (flags & UART_CONFIG_TYPE) {
537 port->type = PORT_LTQ_ASC;
538 lqasc_request_port(port);
543 lqasc_verify_port(struct uart_port *port,
544 struct serial_struct *ser)
547 if (ser->type != PORT_UNKNOWN && ser->type != PORT_LTQ_ASC)
549 if (ser->irq < 0 || ser->irq >= NR_IRQS)
551 if (ser->baud_base < 9600)
556 static const struct uart_ops lqasc_pops = {
557 .tx_empty = lqasc_tx_empty,
558 .set_mctrl = lqasc_set_mctrl,
559 .get_mctrl = lqasc_get_mctrl,
560 .stop_tx = lqasc_stop_tx,
561 .start_tx = lqasc_start_tx,
562 .stop_rx = lqasc_stop_rx,
563 .break_ctl = lqasc_break_ctl,
564 .startup = lqasc_startup,
565 .shutdown = lqasc_shutdown,
566 .set_termios = lqasc_set_termios,
568 .release_port = lqasc_release_port,
569 .request_port = lqasc_request_port,
570 .config_port = lqasc_config_port,
571 .verify_port = lqasc_verify_port,
575 lqasc_console_putchar(struct uart_port *port, int ch)
583 fifofree = (__raw_readl(port->membase + LTQ_ASC_FSTAT)
584 & ASCFSTAT_TXFREEMASK) >> ASCFSTAT_TXFREEOFF;
585 } while (fifofree == 0);
586 writeb(ch, port->membase + LTQ_ASC_TBUF);
589 static void lqasc_serial_port_write(struct uart_port *port, const char *s,
594 spin_lock_irqsave(<q_asc_lock, flags);
595 uart_console_write(port, s, count, lqasc_console_putchar);
596 spin_unlock_irqrestore(<q_asc_lock, flags);
600 lqasc_console_write(struct console *co, const char *s, u_int count)
602 struct ltq_uart_port *ltq_port;
604 if (co->index >= MAXPORTS)
607 ltq_port = lqasc_port[co->index];
611 lqasc_serial_port_write(<q_port->port, s, count);
615 lqasc_console_setup(struct console *co, char *options)
617 struct ltq_uart_port *ltq_port;
618 struct uart_port *port;
624 if (co->index >= MAXPORTS)
627 ltq_port = lqasc_port[co->index];
631 port = <q_port->port;
633 if (!IS_ERR(ltq_port->clk))
634 clk_prepare_enable(ltq_port->clk);
636 port->uartclk = clk_get_rate(ltq_port->freqclk);
639 uart_parse_options(options, &baud, &parity, &bits, &flow);
640 return uart_set_options(port, co, baud, parity, bits, flow);
643 static struct console lqasc_console = {
645 .write = lqasc_console_write,
646 .device = uart_console_device,
647 .setup = lqasc_console_setup,
648 .flags = CON_PRINTBUFFER,
654 lqasc_console_init(void)
656 register_console(&lqasc_console);
659 console_initcall(lqasc_console_init);
661 static void lqasc_serial_early_console_write(struct console *co,
665 struct earlycon_device *dev = co->data;
667 lqasc_serial_port_write(&dev->port, s, count);
671 lqasc_serial_early_console_setup(struct earlycon_device *device,
674 if (!device->port.membase)
677 device->con->write = lqasc_serial_early_console_write;
680 OF_EARLYCON_DECLARE(lantiq, DRVNAME, lqasc_serial_early_console_setup);
682 static struct uart_driver lqasc_reg = {
683 .owner = THIS_MODULE,
684 .driver_name = DRVNAME,
685 .dev_name = "ttyLTQ",
689 .cons = &lqasc_console,
693 lqasc_probe(struct platform_device *pdev)
695 struct device_node *node = pdev->dev.of_node;
696 struct ltq_uart_port *ltq_port;
697 struct uart_port *port;
698 struct resource *mmres, irqres[3];
702 mmres = platform_get_resource(pdev, IORESOURCE_MEM, 0);
703 ret = of_irq_to_resource_table(node, irqres, 3);
704 if (!mmres || (ret != 3)) {
706 "failed to get memory/irq for serial port\n");
711 line = of_alias_get_id(node, "serial");
713 if (IS_ENABLED(CONFIG_LANTIQ)) {
714 if (mmres->start == CPHYSADDR(LTQ_EARLY_ASC))
719 dev_err(&pdev->dev, "failed to get alias id, errno %d\n",
725 if (lqasc_port[line]) {
726 dev_err(&pdev->dev, "port %d already allocated\n", line);
730 ltq_port = devm_kzalloc(&pdev->dev, sizeof(struct ltq_uart_port),
735 port = <q_port->port;
737 port->iotype = SERIAL_IO_MEM;
738 port->flags = UPF_BOOT_AUTOCONF | UPF_IOREMAP;
739 port->ops = &lqasc_pops;
741 port->type = PORT_LTQ_ASC,
743 port->dev = &pdev->dev;
744 /* unused, just to be backward-compatible */
745 port->irq = irqres[0].start;
746 port->mapbase = mmres->start;
748 if (IS_ENABLED(CONFIG_LANTIQ) && !IS_ENABLED(CONFIG_COMMON_CLK))
749 ltq_port->freqclk = clk_get_fpi();
751 ltq_port->freqclk = devm_clk_get(&pdev->dev, "freq");
754 if (IS_ERR(ltq_port->freqclk)) {
755 pr_err("failed to get fpi clk\n");
759 /* not all asc ports have clock gates, lets ignore the return code */
760 if (IS_ENABLED(CONFIG_LANTIQ) && !IS_ENABLED(CONFIG_COMMON_CLK))
761 ltq_port->clk = clk_get(&pdev->dev, NULL);
763 ltq_port->clk = devm_clk_get(&pdev->dev, "asc");
765 ltq_port->tx_irq = irqres[0].start;
766 ltq_port->rx_irq = irqres[1].start;
767 ltq_port->err_irq = irqres[2].start;
769 lqasc_port[line] = ltq_port;
770 platform_set_drvdata(pdev, ltq_port);
772 ret = uart_add_one_port(&lqasc_reg, port);
777 static const struct of_device_id ltq_asc_match[] = {
778 { .compatible = DRVNAME },
782 static struct platform_driver lqasc_driver = {
785 .of_match_table = ltq_asc_match,
794 ret = uart_register_driver(&lqasc_reg);
798 ret = platform_driver_probe(&lqasc_driver, lqasc_probe);
800 uart_unregister_driver(&lqasc_reg);
804 device_initcall(init_lqasc);