xref: /OK3568_Linux_fs/u-boot/drivers/serial/ns16550.c (revision 4882a59341e53eb6f0b4789bf948001014eff981)
1 /*
2  * COM1 NS16550 support
3  * originally from linux source (arch/powerpc/boot/ns16550.c)
4  * modified to use CONFIG_SYS_ISA_MEM and new defines
5  */
6 
7 #include <common.h>
8 #include <clk.h>
9 #include <dm.h>
10 #include <errno.h>
11 #include <ns16550.h>
12 #include <serial.h>
13 #include <watchdog.h>
14 #include <linux/types.h>
15 #include <asm/io.h>
16 
17 DECLARE_GLOBAL_DATA_PTR;
18 
19 #define UART_LCRVAL UART_LCR_8N1		/* 8 data, 1 stop, no parity */
20 #define UART_MCRVAL (UART_MCR_DTR | \
21 		     UART_MCR_RTS)		/* RTS/DTR */
22 
23 #ifndef CONFIG_DM_SERIAL
24 #ifdef CONFIG_SYS_NS16550_PORT_MAPPED
25 #define serial_out(x, y)	outb(x, (ulong)y)
26 #define serial_in(y)		inb((ulong)y)
27 #elif defined(CONFIG_SYS_NS16550_MEM32) && (CONFIG_SYS_NS16550_REG_SIZE > 0)
28 #define serial_out(x, y)	out_be32(y, x)
29 #define serial_in(y)		in_be32(y)
30 #elif defined(CONFIG_SYS_NS16550_MEM32) && (CONFIG_SYS_NS16550_REG_SIZE < 0)
31 #define serial_out(x, y)	out_le32(y, x)
32 #define serial_in(y)		in_le32(y)
33 #else
34 #define serial_out(x, y)	writeb(x, y)
35 #define serial_in(y)		readb(y)
36 #endif
37 #endif /* !CONFIG_DM_SERIAL */
38 
39 #if defined(CONFIG_SOC_KEYSTONE)
40 #define UART_REG_VAL_PWREMU_MGMT_UART_DISABLE   0
41 #define UART_REG_VAL_PWREMU_MGMT_UART_ENABLE ((1 << 14) | (1 << 13) | (1 << 0))
42 #undef UART_MCRVAL
43 #ifdef CONFIG_SERIAL_HW_FLOW_CONTROL
44 #define UART_MCRVAL             (UART_MCR_RTS | UART_MCR_AFE)
45 #else
46 #define UART_MCRVAL             (UART_MCR_RTS)
47 #endif
48 #endif
49 
50 #ifndef CONFIG_SYS_NS16550_IER
51 #define CONFIG_SYS_NS16550_IER  0x00
52 #endif /* CONFIG_SYS_NS16550_IER */
53 
serial_out_shift(void * addr,int shift,int value)54 static inline void serial_out_shift(void *addr, int shift, int value)
55 {
56 #ifdef CONFIG_SYS_NS16550_PORT_MAPPED
57 	outb(value, (ulong)addr);
58 #elif defined(CONFIG_SYS_NS16550_MEM32) && !defined(CONFIG_SYS_BIG_ENDIAN)
59 	out_le32(addr, value);
60 #elif defined(CONFIG_SYS_NS16550_MEM32) && defined(CONFIG_SYS_BIG_ENDIAN)
61 	out_be32(addr, value);
62 #elif defined(CONFIG_SYS_NS16550_MEM32)
63 	writel(value, addr);
64 #elif defined(CONFIG_SYS_BIG_ENDIAN)
65 	writeb(value, addr + (1 << shift) - 1);
66 #else
67 	writeb(value, addr);
68 #endif
69 }
70 
serial_in_shift(void * addr,int shift)71 static inline int serial_in_shift(void *addr, int shift)
72 {
73 #ifdef CONFIG_SYS_NS16550_PORT_MAPPED
74 	return inb((ulong)addr);
75 #elif defined(CONFIG_SYS_NS16550_MEM32) && !defined(CONFIG_SYS_BIG_ENDIAN)
76 	return in_le32(addr);
77 #elif defined(CONFIG_SYS_NS16550_MEM32) && defined(CONFIG_SYS_BIG_ENDIAN)
78 	return in_be32(addr);
79 #elif defined(CONFIG_SYS_NS16550_MEM32)
80 	return readl(addr);
81 #elif defined(CONFIG_SYS_BIG_ENDIAN)
82 	return readb(addr + (1 << shift) - 1);
83 #else
84 	return readb(addr);
85 #endif
86 }
87 
88 #ifdef CONFIG_DM_SERIAL
89 
90 #ifndef CONFIG_SYS_NS16550_CLK
91 #define CONFIG_SYS_NS16550_CLK  0
92 #endif
93 
ns16550_writeb(NS16550_t port,int offset,int value)94 static void ns16550_writeb(NS16550_t port, int offset, int value)
95 {
96 	struct ns16550_platdata *plat = port->plat;
97 	unsigned char *addr;
98 
99 	offset *= 1 << plat->reg_shift;
100 	addr = (unsigned char *)plat->base + offset;
101 
102 	/*
103 	 * As far as we know it doesn't make sense to support selection of
104 	 * these options at run-time, so use the existing CONFIG options.
105 	 */
106 	serial_out_shift(addr + plat->reg_offset, plat->reg_shift, value);
107 }
108 
ns16550_readb(NS16550_t port,int offset)109 static int ns16550_readb(NS16550_t port, int offset)
110 {
111 	struct ns16550_platdata *plat = port->plat;
112 	unsigned char *addr;
113 
114 	offset *= 1 << plat->reg_shift;
115 	addr = (unsigned char *)plat->base + offset;
116 
117 	return serial_in_shift(addr + plat->reg_offset, plat->reg_shift);
118 }
119 
ns16550_getfcr(NS16550_t port)120 static u32 ns16550_getfcr(NS16550_t port)
121 {
122 	struct ns16550_platdata *plat = port->plat;
123 
124 	return plat->fcr;
125 }
126 
127 /* We can clean these up once everything is moved to driver model */
128 #define serial_out(value, addr)	\
129 	ns16550_writeb(com_port, \
130 		(unsigned char *)addr - (unsigned char *)com_port, value)
131 #define serial_in(addr) \
132 	ns16550_readb(com_port, \
133 		(unsigned char *)addr - (unsigned char *)com_port)
134 #else
ns16550_getfcr(NS16550_t port)135 static u32 ns16550_getfcr(NS16550_t port)
136 {
137 	return UART_FCR_DEFVAL;
138 }
139 #endif
140 
ns16550_calc_divisor(NS16550_t port,int clock,int baudrate)141 int ns16550_calc_divisor(NS16550_t port, int clock, int baudrate)
142 {
143 	const unsigned int mode_x_div = 16;
144 
145 	return DIV_ROUND_CLOSEST(clock, mode_x_div * baudrate);
146 }
147 
NS16550_setbrg(NS16550_t com_port,int baud_divisor)148 static void NS16550_setbrg(NS16550_t com_port, int baud_divisor)
149 {
150 	serial_out(UART_LCR_BKSE | UART_LCRVAL, &com_port->lcr);
151 	serial_out(baud_divisor & 0xff, &com_port->dll);
152 	serial_out((baud_divisor >> 8) & 0xff, &com_port->dlm);
153 	serial_out(UART_LCRVAL, &com_port->lcr);
154 }
155 
NS16550_init(NS16550_t com_port,int baud_divisor)156 void NS16550_init(NS16550_t com_port, int baud_divisor)
157 {
158 #if (defined(CONFIG_SPL_BUILD) && \
159 		(defined(CONFIG_OMAP34XX) || defined(CONFIG_OMAP44XX)))
160 	/*
161 	 * On some OMAP3/OMAP4 devices when UART3 is configured for boot mode
162 	 * before SPL starts only THRE bit is set. We have to empty the
163 	 * transmitter before initialization starts.
164 	 */
165 	if ((serial_in(&com_port->lsr) & (UART_LSR_TEMT | UART_LSR_THRE))
166 	     == UART_LSR_THRE) {
167 		if (baud_divisor != -1)
168 			NS16550_setbrg(com_port, baud_divisor);
169 		serial_out(0, &com_port->mdr1);
170 	}
171 #endif
172 
173 	while (!(serial_in(&com_port->lsr) & UART_LSR_TEMT))
174 		;
175 
176 	serial_out(CONFIG_SYS_NS16550_IER, &com_port->ier);
177 #if defined(CONFIG_ARCH_OMAP2PLUS)
178 	serial_out(0x7, &com_port->mdr1);	/* mode select reset TL16C750*/
179 #endif
180 	serial_out(UART_MCRVAL, &com_port->mcr);
181 	serial_out(ns16550_getfcr(com_port), &com_port->fcr);
182 	if (baud_divisor != -1)
183 		NS16550_setbrg(com_port, baud_divisor);
184 #if defined(CONFIG_ARCH_OMAP2PLUS) || defined(CONFIG_SOC_DA8XX)
185 	/* /16 is proper to hit 115200 with 48MHz */
186 	serial_out(0, &com_port->mdr1);
187 #endif
188 #if defined(CONFIG_SOC_KEYSTONE)
189 	serial_out(UART_REG_VAL_PWREMU_MGMT_UART_ENABLE, &com_port->regC);
190 #endif
191 }
192 
193 #ifndef CONFIG_NS16550_MIN_FUNCTIONS
NS16550_reinit(NS16550_t com_port,int baud_divisor)194 void NS16550_reinit(NS16550_t com_port, int baud_divisor)
195 {
196 	serial_out(CONFIG_SYS_NS16550_IER, &com_port->ier);
197 	NS16550_setbrg(com_port, 0);
198 	serial_out(UART_MCRVAL, &com_port->mcr);
199 	serial_out(ns16550_getfcr(com_port), &com_port->fcr);
200 	NS16550_setbrg(com_port, baud_divisor);
201 }
202 #endif /* CONFIG_NS16550_MIN_FUNCTIONS */
203 
NS16550_putc(NS16550_t com_port,char c)204 void NS16550_putc(NS16550_t com_port, char c)
205 {
206 	while ((serial_in(&com_port->lsr) & UART_LSR_THRE) == 0)
207 		;
208 	serial_out(c, &com_port->thr);
209 
210 	/*
211 	 * Call watchdog_reset() upon newline. This is done here in putc
212 	 * since the environment code uses a single puts() to print the complete
213 	 * environment upon "printenv". So we can't put this watchdog call
214 	 * in puts().
215 	 */
216 	if (c == '\n')
217 		WATCHDOG_RESET();
218 }
219 
220 #ifndef CONFIG_NS16550_MIN_FUNCTIONS
NS16550_getc(NS16550_t com_port)221 char NS16550_getc(NS16550_t com_port)
222 {
223 	while ((serial_in(&com_port->lsr) & UART_LSR_DR) == 0) {
224 #if !defined(CONFIG_SPL_BUILD) && defined(CONFIG_USB_TTY)
225 		extern void usbtty_poll(void);
226 		usbtty_poll();
227 #endif
228 		WATCHDOG_RESET();
229 	}
230 	return serial_in(&com_port->rbr);
231 }
232 
NS16550_tstc(NS16550_t com_port)233 int NS16550_tstc(NS16550_t com_port)
234 {
235 	return (serial_in(&com_port->lsr) & UART_LSR_DR) != 0;
236 }
237 
238 #endif /* CONFIG_NS16550_MIN_FUNCTIONS */
239 
240 #ifdef CONFIG_DEBUG_UART_NS16550
241 
242 #include <debug_uart.h>
243 
_debug_uart_init(void)244 static inline void _debug_uart_init(void)
245 {
246 	struct NS16550 *com_port = (struct NS16550 *)CONFIG_DEBUG_UART_BASE;
247 	int baud_divisor;
248 
249 	if (gd && gd->flags & GD_FLG_DISABLE_CONSOLE)
250 		return;
251 
252 	if (gd && gd->serial.using_pre_serial)
253 		return;
254 
255 	/*
256 	 * We copy the code from above because it is already horribly messy.
257 	 * Trying to refactor to nicely remove the duplication doesn't seem
258 	 * feasible. The better fix is to move all users of this driver to
259 	 * driver model.
260 	 */
261 	baud_divisor = ns16550_calc_divisor(com_port, CONFIG_DEBUG_UART_CLOCK,
262 					    CONFIG_BAUDRATE);
263 	serial_dout(&com_port->ier, CONFIG_SYS_NS16550_IER);
264 	serial_dout(&com_port->mcr, UART_MCRVAL);
265 	serial_dout(&com_port->fcr, UART_FCR_DEFVAL);
266 
267 	serial_dout(&com_port->lcr, UART_LCR_BKSE | UART_LCRVAL);
268 	serial_dout(&com_port->dll, baud_divisor & 0xff);
269 	serial_dout(&com_port->dlm, (baud_divisor >> 8) & 0xff);
270 	serial_dout(&com_port->lcr, UART_LCRVAL);
271 }
272 
_debug_uart_putc(int ch)273 static inline void _debug_uart_putc(int ch)
274 {
275 	struct NS16550 *com_port;
276 
277 	if (gd && gd->flags & GD_FLG_DISABLE_CONSOLE)
278 		return;
279 
280 	if (gd && gd->serial.addr)
281 		com_port = (struct NS16550 *)gd->serial.addr;
282 	else
283 		com_port = (struct NS16550 *)CONFIG_DEBUG_UART_BASE;
284 
285 	while (!(serial_din(&com_port->lsr) & UART_LSR_THRE))
286 		;
287 	serial_dout(&com_port->thr, ch);
288 }
289 
_debug_uart_getc(void)290 static inline int _debug_uart_getc(void)
291 {
292 	struct NS16550 *com_port;
293 
294 	if (gd && gd->flags & GD_FLG_DISABLE_CONSOLE)
295 		return 0;
296 
297 	if (gd && gd->serial.addr)
298 		com_port = (struct NS16550 *)gd->serial.addr;
299 	else
300 		com_port = (struct NS16550 *)CONFIG_DEBUG_UART_BASE;
301 
302 	while (!(serial_din(&com_port->lsr) & UART_LSR_DR))
303 		;
304 
305 	return serial_din(&com_port->rbr);
306 }
307 
_debug_uart_tstc(int input)308 static inline int _debug_uart_tstc(int input)
309 {
310 	struct NS16550 *com_port;
311 
312 	if (gd && gd->flags & GD_FLG_DISABLE_CONSOLE)
313 		return 0;
314 
315 	if (gd && gd->serial.addr)
316 		com_port = (struct NS16550 *)gd->serial.addr;
317 	else
318 		com_port = (struct NS16550 *)CONFIG_DEBUG_UART_BASE;
319 
320 	if (input)
321 		return serial_din(&com_port->lsr) & UART_LSR_DR ? 1 : 0;
322 	else
323 		return serial_din(&com_port->lsr) & UART_LSR_THRE ? 0 : 1;
324 }
325 
_debug_uart_clrc(void)326 static inline int _debug_uart_clrc(void)
327 {
328 	struct NS16550 *com_port;
329 
330 	if (gd && gd->flags & GD_FLG_DISABLE_CONSOLE)
331 		return 0;
332 
333 	if (gd && gd->serial.addr)
334 		com_port = (struct NS16550 *)gd->serial.addr;
335 	else
336 		com_port = (struct NS16550 *)CONFIG_DEBUG_UART_BASE;
337 
338 	serial_dout(&com_port->fcr, UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT);
339 
340 	return 0;
341 }
342 
_debug_uart_flushc(void)343 static inline int _debug_uart_flushc(void)
344 {
345 	struct NS16550 *com_port;
346 
347 	if (gd && gd->flags & GD_FLG_DISABLE_CONSOLE)
348 		return 0;
349 
350 	if (gd && gd->serial.addr)
351 		com_port = (struct NS16550 *)gd->serial.addr;
352 	else
353 		com_port = (struct NS16550 *)CONFIG_DEBUG_UART_BASE;
354 
355 	/*
356 	 * Wait fifo flush.
357 	 *
358 	 * UART_USR: bit2 trans_fifo_empty:
359 	 *	0 = Transmit FIFO is not empty
360 	 *	1 = Transmit FIFO is empty
361 	 */
362 	while (!(serial_din(&com_port->rbr + 0x1f) & 0x04))
363 		;
364 
365 	return 0;
366 }
367 
368 /* should use gd->baudrate, it can be updated by env callback: on_baudrate() */
_debug_uart_setbrg(void)369 static inline int _debug_uart_setbrg(void)
370 {
371 	struct NS16550 *com_port;
372 	int baud_divisor;
373 
374 	if (gd && gd->flags & GD_FLG_DISABLE_CONSOLE)
375 		return 0;
376 
377 	if (gd && gd->serial.addr) {
378 		com_port = (struct NS16550 *)gd->serial.addr;
379 		baud_divisor = ns16550_calc_divisor(com_port,
380 			CONFIG_DEBUG_UART_CLOCK, gd->baudrate);
381 	} else {
382 		com_port = (struct NS16550 *)CONFIG_DEBUG_UART_BASE;
383 		baud_divisor = ns16550_calc_divisor(com_port,
384 			CONFIG_DEBUG_UART_CLOCK, CONFIG_BAUDRATE);
385 	}
386 
387 	serial_dout(&com_port->lcr, UART_LCR_BKSE | UART_LCRVAL);
388 	serial_dout(&com_port->dll, baud_divisor & 0xff);
389 	serial_dout(&com_port->dlm, (baud_divisor >> 8) & 0xff);
390 	serial_dout(&com_port->lcr, UART_LCRVAL);
391 
392 	return 0;
393 }
394 
395 DEBUG_UART_FUNCS
396 
397 #endif
398 
399 #ifdef CONFIG_DEBUG_UART_OMAP
400 
401 #include <debug_uart.h>
402 
_debug_uart_init(void)403 static inline void _debug_uart_init(void)
404 {
405 	struct NS16550 *com_port = (struct NS16550 *)CONFIG_DEBUG_UART_BASE;
406 	int baud_divisor;
407 
408 	baud_divisor = ns16550_calc_divisor(com_port, CONFIG_DEBUG_UART_CLOCK,
409 					    CONFIG_BAUDRATE);
410 	serial_dout(&com_port->ier, CONFIG_SYS_NS16550_IER);
411 	serial_dout(&com_port->mdr1, 0x7);
412 	serial_dout(&com_port->mcr, UART_MCRVAL);
413 	serial_dout(&com_port->fcr, UART_FCR_DEFVAL);
414 
415 	serial_dout(&com_port->lcr, UART_LCR_BKSE | UART_LCRVAL);
416 	serial_dout(&com_port->dll, baud_divisor & 0xff);
417 	serial_dout(&com_port->dlm, (baud_divisor >> 8) & 0xff);
418 	serial_dout(&com_port->lcr, UART_LCRVAL);
419 	serial_dout(&com_port->mdr1, 0x0);
420 }
421 
_debug_uart_putc(int ch)422 static inline void _debug_uart_putc(int ch)
423 {
424 	struct NS16550 *com_port = (struct NS16550 *)CONFIG_DEBUG_UART_BASE;
425 
426 	while (!(serial_din(&com_port->lsr) & UART_LSR_THRE))
427 		;
428 	serial_dout(&com_port->thr, ch);
429 }
430 
431 DEBUG_UART_FUNCS
432 
433 #endif
434 
435 #ifdef CONFIG_DM_SERIAL
ns16550_serial_putc(struct udevice * dev,const char ch)436 static int ns16550_serial_putc(struct udevice *dev, const char ch)
437 {
438 	struct NS16550 *const com_port = dev_get_priv(dev);
439 
440 	/*
441 	 * Use fifo function.
442 	 *
443 	 * UART_USR: bit1 trans_fifo_not_full:
444 	 *	0 = Transmit FIFO is full;
445 	 *	1 = Transmit FIFO is not full;
446 	 */
447 	while (!(serial_in(&com_port->rbr + 0x1f) & 0x02))
448 		;
449 	serial_out(ch, &com_port->thr);
450 
451 	/*
452 	 * Call watchdog_reset() upon newline. This is done here in putc
453 	 * since the environment code uses a single puts() to print the complete
454 	 * environment upon "printenv". So we can't put this watchdog call
455 	 * in puts().
456 	 */
457 	if (ch == '\n')
458 		WATCHDOG_RESET();
459 
460 	return 0;
461 }
462 
ns16550_serial_pending(struct udevice * dev,bool input)463 static int ns16550_serial_pending(struct udevice *dev, bool input)
464 {
465 	struct NS16550 *const com_port = dev_get_priv(dev);
466 
467 	if (input)
468 		return serial_in(&com_port->lsr) & UART_LSR_DR ? 1 : 0;
469 	else
470 		return serial_in(&com_port->lsr) & UART_LSR_THRE ? 0 : 1;
471 }
472 
ns16550_serial_getc(struct udevice * dev)473 static int ns16550_serial_getc(struct udevice *dev)
474 {
475 	struct NS16550 *const com_port = dev_get_priv(dev);
476 
477 	if (!(serial_in(&com_port->lsr) & UART_LSR_DR))
478 		return -EAGAIN;
479 
480 	return serial_in(&com_port->rbr);
481 }
482 
ns16550_serial_setbrg(struct udevice * dev,int baudrate)483 static int ns16550_serial_setbrg(struct udevice *dev, int baudrate)
484 {
485 	struct NS16550 *const com_port = dev_get_priv(dev);
486 	struct ns16550_platdata *plat = com_port->plat;
487 	int clock_divisor;
488 
489 	clock_divisor = ns16550_calc_divisor(com_port, plat->clock, baudrate);
490 
491 	NS16550_setbrg(com_port, clock_divisor);
492 
493 	return 0;
494 }
495 
ns16550_serial_clear(struct udevice * dev)496 static int ns16550_serial_clear(struct udevice *dev)
497 {
498 	struct NS16550 *const com_port = dev_get_priv(dev);
499 
500 	serial_out(UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT, &com_port->fcr);
501 
502 	return 0;
503 }
504 
ns16550_serial_probe(struct udevice * dev)505 int ns16550_serial_probe(struct udevice *dev)
506 {
507 	struct NS16550 *const com_port = dev_get_priv(dev);
508 
509 	com_port->plat = dev_get_platdata(dev);
510 	NS16550_init(com_port, -1);
511 
512 	return 0;
513 }
514 
515 #if CONFIG_IS_ENABLED(OF_CONTROL)
516 enum {
517 	PORT_NS16550 = 0,
518 	PORT_JZ4780,
519 };
520 #endif
521 
522 #if CONFIG_IS_ENABLED(OF_CONTROL) && !CONFIG_IS_ENABLED(OF_PLATDATA)
ns16550_serial_ofdata_to_platdata(struct udevice * dev)523 int ns16550_serial_ofdata_to_platdata(struct udevice *dev)
524 {
525 	struct ns16550_platdata *plat = dev->platdata;
526 	const u32 port_type = dev_get_driver_data(dev);
527 	fdt_addr_t addr;
528 	struct clk clk;
529 	int err;
530 
531 	/* try Processor Local Bus device first */
532 	addr = dev_read_addr(dev);
533 #if defined(CONFIG_PCI) && CONFIG_IS_ENABLED(DM_PCI)
534 	if (addr == FDT_ADDR_T_NONE) {
535 		/* then try pci device */
536 		struct fdt_pci_addr pci_addr;
537 		u32 bar;
538 		int ret;
539 
540 		/* we prefer to use a memory-mapped register */
541 		ret = fdtdec_get_pci_addr(gd->fdt_blob, dev_of_offset(dev),
542 					  FDT_PCI_SPACE_MEM32, "reg",
543 					  &pci_addr);
544 		if (ret) {
545 			/* try if there is any i/o-mapped register */
546 			ret = fdtdec_get_pci_addr(gd->fdt_blob,
547 						  dev_of_offset(dev),
548 						  FDT_PCI_SPACE_IO,
549 						  "reg", &pci_addr);
550 			if (ret)
551 				return ret;
552 		}
553 
554 		ret = fdtdec_get_pci_bar32(dev, &pci_addr, &bar);
555 		if (ret)
556 			return ret;
557 
558 		addr = bar;
559 	}
560 #endif
561 
562 	if (addr == FDT_ADDR_T_NONE)
563 		return -EINVAL;
564 
565 #ifdef CONFIG_SYS_NS16550_PORT_MAPPED
566 	plat->base = addr;
567 #else
568 	plat->base = (unsigned long)map_physmem(addr, 0, MAP_NOCACHE);
569 #endif
570 
571 	plat->reg_offset = dev_read_u32_default(dev, "reg-offset", 0);
572 	plat->reg_shift = dev_read_u32_default(dev, "reg-shift", 0);
573 
574 	err = clk_get_by_index(dev, 0, &clk);
575 	if (!err) {
576 		err = clk_get_rate(&clk);
577 		if (!IS_ERR_VALUE(err))
578 			plat->clock = err;
579 	} else if (err != -ENOENT && err != -ENODEV && err != -ENOSYS) {
580 		printf("ns16550 failed to get clock, err=%d\n", err);
581 		return err;
582 	}
583 
584 	if (!plat->clock)
585 		plat->clock = dev_read_u32_default(dev, "clock-frequency",
586 						   CONFIG_SYS_NS16550_CLK);
587 	if (!plat->clock) {
588 		debug("ns16550 clock not defined\n");
589 		return -EINVAL;
590 	}
591 
592 	plat->fcr = UART_FCR_DEFVAL;
593 	if (port_type == PORT_JZ4780)
594 		plat->fcr |= UART_FCR_UME;
595 
596 	return 0;
597 }
598 #endif
599 
600 const struct dm_serial_ops ns16550_serial_ops = {
601 	.putc = ns16550_serial_putc,
602 	.pending = ns16550_serial_pending,
603 	.getc = ns16550_serial_getc,
604 	.setbrg = ns16550_serial_setbrg,
605 	.clear = ns16550_serial_clear,
606 };
607 
608 #if CONFIG_IS_ENABLED(SERIAL_PRESENT)
609 #if CONFIG_IS_ENABLED(OF_CONTROL) && !CONFIG_IS_ENABLED(OF_PLATDATA)
610 /*
611  * Please consider existing compatible strings before adding a new
612  * one to keep this table compact. Or you may add a generic "ns16550"
613  * compatible string to your dts.
614  */
615 static const struct udevice_id ns16550_serial_ids[] = {
616 	{ .compatible = "ns16550",		.data = PORT_NS16550 },
617 	{ .compatible = "ns16550a",		.data = PORT_NS16550 },
618 	{ .compatible = "ingenic,jz4780-uart",	.data = PORT_JZ4780  },
619 	{ .compatible = "nvidia,tegra20-uart",	.data = PORT_NS16550 },
620 	{ .compatible = "snps,dw-apb-uart",	.data = PORT_NS16550 },
621 	{ .compatible = "ti,omap2-uart",	.data = PORT_NS16550 },
622 	{ .compatible = "ti,omap3-uart",	.data = PORT_NS16550 },
623 	{ .compatible = "ti,omap4-uart",	.data = PORT_NS16550 },
624 	{ .compatible = "ti,am3352-uart",	.data = PORT_NS16550 },
625 	{ .compatible = "ti,am4372-uart",	.data = PORT_NS16550 },
626 	{ .compatible = "ti,dra742-uart",	.data = PORT_NS16550 },
627 	{}
628 };
629 #endif /* OF_CONTROL && !OF_PLATDATA */
630 
631 /* TODO(sjg@chromium.org): Integrate this into a macro like CONFIG_IS_ENABLED */
632 #if !defined(CONFIG_TPL_BUILD) || defined(CONFIG_TPL_DM_SERIAL)
633 U_BOOT_DRIVER(ns16550_serial) = {
634 	.name	= "ns16550_serial",
635 	.id	= UCLASS_SERIAL,
636 #if CONFIG_IS_ENABLED(OF_CONTROL) && !CONFIG_IS_ENABLED(OF_PLATDATA)
637 	.of_match = ns16550_serial_ids,
638 	.ofdata_to_platdata = ns16550_serial_ofdata_to_platdata,
639 	.platdata_auto_alloc_size = sizeof(struct ns16550_platdata),
640 #endif
641 	.priv_auto_alloc_size = sizeof(struct NS16550),
642 	.probe = ns16550_serial_probe,
643 	.ops	= &ns16550_serial_ops,
644 	.flags	= DM_FLAG_PRE_RELOC,
645 };
646 #endif
647 #endif /* SERIAL_PRESENT */
648 
649 #endif /* CONFIG_DM_SERIAL */
650