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 <clock_legacy.h>
8 #include <common.h>
9 #include <clk.h>
10 #include <dm.h>
11 #include <errno.h>
12 #include <log.h>
13 #include <ns16550.h>
14 #include <reset.h>
15 #include <serial.h>
16 #include <watchdog.h>
17 #include <asm/global_data.h>
18 #include <linux/err.h>
19 #include <linux/types.h>
20 #include <asm/io.h>
21 
22 DECLARE_GLOBAL_DATA_PTR;
23 
24 #define UART_LCRVAL UART_LCR_8N1		/* 8 data, 1 stop, no parity */
25 #define UART_MCRVAL (UART_MCR_DTR | \
26 		     UART_MCR_RTS)		/* RTS/DTR */
27 
28 #if !CONFIG_IS_ENABLED(DM_SERIAL)
29 #ifdef CONFIG_SYS_NS16550_PORT_MAPPED
30 #define serial_out(x, y)	outb(x, (ulong)y)
31 #define serial_in(y)		inb((ulong)y)
32 #elif defined(CONFIG_SYS_NS16550_MEM32) && (CONFIG_SYS_NS16550_REG_SIZE > 0)
33 #define serial_out(x, y)	out_be32(y, x)
34 #define serial_in(y)		in_be32(y)
35 #elif defined(CONFIG_SYS_NS16550_MEM32) && (CONFIG_SYS_NS16550_REG_SIZE < 0)
36 #define serial_out(x, y)	out_le32(y, x)
37 #define serial_in(y)		in_le32(y)
38 #else
39 #define serial_out(x, y)	writeb(x, y)
40 #define serial_in(y)		readb(y)
41 #endif
42 #endif /* !CONFIG_DM_SERIAL */
43 
44 #if defined(CONFIG_SOC_KEYSTONE)
45 #define UART_REG_VAL_PWREMU_MGMT_UART_DISABLE   0
46 #define UART_REG_VAL_PWREMU_MGMT_UART_ENABLE ((1 << 14) | (1 << 13) | (1 << 0))
47 #undef UART_MCRVAL
48 #ifdef CONFIG_SERIAL_HW_FLOW_CONTROL
49 #define UART_MCRVAL             (UART_MCR_RTS | UART_MCR_AFE)
50 #else
51 #define UART_MCRVAL             (UART_MCR_RTS)
52 #endif
53 #endif
54 
55 #ifndef CONFIG_SYS_NS16550_IER
56 #define CONFIG_SYS_NS16550_IER  0x00
57 #endif /* CONFIG_SYS_NS16550_IER */
58 
serial_out_shift(void * addr,int shift,int value)59 static inline void serial_out_shift(void *addr, int shift, int value)
60 {
61 #ifdef CONFIG_SYS_NS16550_PORT_MAPPED
62 	outb(value, (ulong)addr);
63 #elif defined(CONFIG_SYS_NS16550_MEM32) && defined(CONFIG_SYS_LITTLE_ENDIAN)
64 	out_le32(addr, value);
65 #elif defined(CONFIG_SYS_NS16550_MEM32) && defined(CONFIG_SYS_BIG_ENDIAN)
66 	out_be32(addr, value);
67 #elif defined(CONFIG_SYS_NS16550_MEM32)
68 	writel(value, addr);
69 #elif defined(CONFIG_SYS_BIG_ENDIAN)
70 	writeb(value, addr + (1 << shift) - 1);
71 #else
72 	writeb(value, addr);
73 #endif
74 }
75 
serial_in_shift(void * addr,int shift)76 static inline int serial_in_shift(void *addr, int shift)
77 {
78 #ifdef CONFIG_SYS_NS16550_PORT_MAPPED
79 	return inb((ulong)addr);
80 #elif defined(CONFIG_SYS_NS16550_MEM32) && defined(CONFIG_SYS_LITTLE_ENDIAN)
81 	return in_le32(addr);
82 #elif defined(CONFIG_SYS_NS16550_MEM32) && defined(CONFIG_SYS_BIG_ENDIAN)
83 	return in_be32(addr);
84 #elif defined(CONFIG_SYS_NS16550_MEM32)
85 	return readl(addr);
86 #elif defined(CONFIG_SYS_BIG_ENDIAN)
87 	return readb(addr + (1 << shift) - 1);
88 #else
89 	return readb(addr);
90 #endif
91 }
92 
93 #if CONFIG_IS_ENABLED(DM_SERIAL)
94 
95 #ifndef CONFIG_SYS_NS16550_CLK
96 #define CONFIG_SYS_NS16550_CLK  0
97 #endif
98 
99 /*
100  * Use this #ifdef for now since many platforms don't define in(), out(),
101  * out_le32(), etc. but we don't have #defines to indicate this.
102  *
103  * TODO(sjg@chromium.org): Add CONFIG options to indicate what I/O is available
104  * on a platform
105  */
106 #ifdef CONFIG_NS16550_DYNAMIC
serial_out_dynamic(struct ns16550_plat * plat,u8 * addr,int value)107 static void serial_out_dynamic(struct ns16550_plat *plat, u8 *addr,
108 			       int value)
109 {
110 	if (plat->flags & NS16550_FLAG_IO) {
111 		outb(value, addr);
112 	} else if (plat->reg_width == 4) {
113 		if (plat->flags & NS16550_FLAG_ENDIAN) {
114 			if (plat->flags & NS16550_FLAG_BE)
115 				out_be32(addr, value);
116 			else
117 				out_le32(addr, value);
118 		} else {
119 			writel(value, addr);
120 		}
121 	} else if (plat->flags & NS16550_FLAG_BE) {
122 		writeb(value, addr + (1 << plat->reg_shift) - 1);
123 	} else {
124 		writeb(value, addr);
125 	}
126 }
127 
serial_in_dynamic(struct ns16550_plat * plat,u8 * addr)128 static int serial_in_dynamic(struct ns16550_plat *plat, u8 *addr)
129 {
130 	if (plat->flags & NS16550_FLAG_IO) {
131 		return inb(addr);
132 	} else if (plat->reg_width == 4) {
133 		if (plat->flags & NS16550_FLAG_ENDIAN) {
134 			if (plat->flags & NS16550_FLAG_BE)
135 				return in_be32(addr);
136 			else
137 				return in_le32(addr);
138 		} else {
139 			return readl(addr);
140 		}
141 	} else if (plat->flags & NS16550_FLAG_BE) {
142 		return readb(addr + (1 << plat->reg_shift) - 1);
143 	} else {
144 		return readb(addr);
145 	}
146 }
147 #else
serial_out_dynamic(struct ns16550_plat * plat,u8 * addr,int value)148 static inline void serial_out_dynamic(struct ns16550_plat *plat, u8 *addr,
149 				      int value)
150 {
151 }
152 
serial_in_dynamic(struct ns16550_plat * plat,u8 * addr)153 static inline int serial_in_dynamic(struct ns16550_plat *plat, u8 *addr)
154 {
155 	return 0;
156 }
157 
158 #endif /* CONFIG_NS16550_DYNAMIC */
159 
ns16550_writeb(struct ns16550 * port,int offset,int value)160 static void ns16550_writeb(struct ns16550 *port, int offset, int value)
161 {
162 	struct ns16550_plat *plat = port->plat;
163 	unsigned char *addr;
164 
165 	offset *= 1 << plat->reg_shift;
166 	addr = (unsigned char *)plat->base + offset + plat->reg_offset;
167 
168 	if (IS_ENABLED(CONFIG_NS16550_DYNAMIC))
169 		serial_out_dynamic(plat, addr, value);
170 	else
171 		serial_out_shift(addr, plat->reg_shift, value);
172 }
173 
ns16550_readb(struct ns16550 * port,int offset)174 static int ns16550_readb(struct ns16550 *port, int offset)
175 {
176 	struct ns16550_plat *plat = port->plat;
177 	unsigned char *addr;
178 
179 	offset *= 1 << plat->reg_shift;
180 	addr = (unsigned char *)plat->base + offset + plat->reg_offset;
181 
182 	if (IS_ENABLED(CONFIG_NS16550_DYNAMIC))
183 		return serial_in_dynamic(plat, addr);
184 	else
185 		return serial_in_shift(addr, plat->reg_shift);
186 }
187 
ns16550_getfcr(struct ns16550 * port)188 static u32 ns16550_getfcr(struct ns16550 *port)
189 {
190 	struct ns16550_plat *plat = port->plat;
191 
192 	return plat->fcr;
193 }
194 
195 /* We can clean these up once everything is moved to driver model */
196 #define serial_out(value, addr)	\
197 	ns16550_writeb(com_port, \
198 		(unsigned char *)addr - (unsigned char *)com_port, value)
199 #define serial_in(addr) \
200 	ns16550_readb(com_port, \
201 		(unsigned char *)addr - (unsigned char *)com_port)
202 #else
ns16550_getfcr(struct ns16550 * port)203 static u32 ns16550_getfcr(struct ns16550 *port)
204 {
205 	return UART_FCR_DEFVAL;
206 }
207 #endif
208 
ns16550_calc_divisor(struct ns16550 * port,int clock,int baudrate)209 int ns16550_calc_divisor(struct ns16550 *port, int clock, int baudrate)
210 {
211 	const unsigned int mode_x_div = 16;
212 
213 	return DIV_ROUND_CLOSEST(clock, mode_x_div * baudrate);
214 }
215 
ns16550_setbrg(struct ns16550 * com_port,int baud_divisor)216 static void ns16550_setbrg(struct ns16550 *com_port, int baud_divisor)
217 {
218 	/* to keep serial format, read lcr before writing BKSE */
219 	int lcr_val = serial_in(&com_port->lcr) & ~UART_LCR_BKSE;
220 
221 	serial_out(UART_LCR_BKSE | lcr_val, &com_port->lcr);
222 	serial_out(baud_divisor & 0xff, &com_port->dll);
223 	serial_out((baud_divisor >> 8) & 0xff, &com_port->dlm);
224 	serial_out(lcr_val, &com_port->lcr);
225 }
226 
ns16550_init(struct ns16550 * com_port,int baud_divisor)227 void ns16550_init(struct ns16550 *com_port, int baud_divisor)
228 {
229 #if (defined(CONFIG_SPL_BUILD) && \
230 		(defined(CONFIG_OMAP34XX) || defined(CONFIG_OMAP44XX)))
231 	/*
232 	 * On some OMAP3/OMAP4 devices when UART3 is configured for boot mode
233 	 * before SPL starts only THRE bit is set. We have to empty the
234 	 * transmitter before initialization starts.
235 	 */
236 	if ((serial_in(&com_port->lsr) & (UART_LSR_TEMT | UART_LSR_THRE))
237 	     == UART_LSR_THRE) {
238 		if (baud_divisor != -1)
239 			ns16550_setbrg(com_port, baud_divisor);
240 		else {
241 			// Re-use old baud rate divisor to flush transmit reg.
242 			const int dll = serial_in(&com_port->dll);
243 			const int dlm = serial_in(&com_port->dlm);
244 			const int divisor = dll | (dlm << 8);
245 			ns16550_setbrg(com_port, divisor);
246 		}
247 		serial_out(0, &com_port->mdr1);
248 	}
249 #endif
250 
251 	while (!(serial_in(&com_port->lsr) & UART_LSR_TEMT))
252 		;
253 
254 	serial_out(CONFIG_SYS_NS16550_IER, &com_port->ier);
255 #if defined(CONFIG_ARCH_OMAP2PLUS) || defined(CONFIG_OMAP_SERIAL)
256 	serial_out(0x7, &com_port->mdr1);	/* mode select reset TL16C750*/
257 #endif
258 
259 	serial_out(UART_MCRVAL, &com_port->mcr);
260 	serial_out(ns16550_getfcr(com_port), &com_port->fcr);
261 	/* initialize serial config to 8N1 before writing baudrate */
262 	serial_out(UART_LCRVAL, &com_port->lcr);
263 	if (baud_divisor != -1)
264 		ns16550_setbrg(com_port, baud_divisor);
265 #if defined(CONFIG_ARCH_OMAP2PLUS) || defined(CONFIG_SOC_DA8XX) || \
266 	defined(CONFIG_OMAP_SERIAL)
267 	/* /16 is proper to hit 115200 with 48MHz */
268 	serial_out(0, &com_port->mdr1);
269 #endif
270 #if defined(CONFIG_SOC_KEYSTONE)
271 	serial_out(UART_REG_VAL_PWREMU_MGMT_UART_ENABLE, &com_port->regC);
272 #endif
273 }
274 
275 #ifndef CONFIG_NS16550_MIN_FUNCTIONS
ns16550_reinit(struct ns16550 * com_port,int baud_divisor)276 void ns16550_reinit(struct ns16550 *com_port, int baud_divisor)
277 {
278 	serial_out(CONFIG_SYS_NS16550_IER, &com_port->ier);
279 	ns16550_setbrg(com_port, 0);
280 	serial_out(UART_MCRVAL, &com_port->mcr);
281 	serial_out(ns16550_getfcr(com_port), &com_port->fcr);
282 	ns16550_setbrg(com_port, baud_divisor);
283 }
284 #endif /* CONFIG_NS16550_MIN_FUNCTIONS */
285 
ns16550_putc(struct ns16550 * com_port,char c)286 void ns16550_putc(struct ns16550 *com_port, char c)
287 {
288 	while ((serial_in(&com_port->lsr) & UART_LSR_THRE) == 0)
289 		;
290 	serial_out(c, &com_port->thr);
291 
292 	/*
293 	 * Call watchdog_reset() upon newline. This is done here in putc
294 	 * since the environment code uses a single puts() to print the complete
295 	 * environment upon "printenv". So we can't put this watchdog call
296 	 * in puts().
297 	 */
298 	if (c == '\n')
299 		WATCHDOG_RESET();
300 }
301 
302 #ifndef CONFIG_NS16550_MIN_FUNCTIONS
ns16550_getc(struct ns16550 * com_port)303 char ns16550_getc(struct ns16550 *com_port)
304 {
305 	while ((serial_in(&com_port->lsr) & UART_LSR_DR) == 0) {
306 #if !defined(CONFIG_SPL_BUILD) && defined(CONFIG_USB_TTY)
307 		extern void usbtty_poll(void);
308 		usbtty_poll();
309 #endif
310 		WATCHDOG_RESET();
311 	}
312 	return serial_in(&com_port->rbr);
313 }
314 
ns16550_tstc(struct ns16550 * com_port)315 int ns16550_tstc(struct ns16550 *com_port)
316 {
317 	return (serial_in(&com_port->lsr) & UART_LSR_DR) != 0;
318 }
319 
320 #endif /* CONFIG_NS16550_MIN_FUNCTIONS */
321 
322 #ifdef CONFIG_DEBUG_UART_NS16550
323 
324 #include <debug_uart.h>
325 
_debug_uart_init(void)326 static inline void _debug_uart_init(void)
327 {
328 	struct ns16550 *com_port = (struct ns16550 *)CONFIG_DEBUG_UART_BASE;
329 	int baud_divisor;
330 
331 	/*
332 	 * We copy the code from above because it is already horribly messy.
333 	 * Trying to refactor to nicely remove the duplication doesn't seem
334 	 * feasible. The better fix is to move all users of this driver to
335 	 * driver model.
336 	 */
337 	baud_divisor = ns16550_calc_divisor(com_port, CONFIG_DEBUG_UART_CLOCK,
338 					    CONFIG_BAUDRATE);
339 	serial_dout(&com_port->ier, CONFIG_SYS_NS16550_IER);
340 	serial_dout(&com_port->mcr, UART_MCRVAL);
341 	serial_dout(&com_port->fcr, UART_FCR_DEFVAL);
342 
343 	serial_dout(&com_port->lcr, UART_LCR_BKSE | UART_LCRVAL);
344 	serial_dout(&com_port->dll, baud_divisor & 0xff);
345 	serial_dout(&com_port->dlm, (baud_divisor >> 8) & 0xff);
346 	serial_dout(&com_port->lcr, UART_LCRVAL);
347 }
348 
NS16550_read_baud_divisor(struct ns16550 * com_port)349 static inline int NS16550_read_baud_divisor(struct ns16550 *com_port)
350 {
351 	int ret;
352 
353 	serial_dout(&com_port->lcr, UART_LCR_BKSE | UART_LCRVAL);
354 	ret = serial_din(&com_port->dll) & 0xff;
355 	ret |= (serial_din(&com_port->dlm) & 0xff) << 8;
356 	serial_dout(&com_port->lcr, UART_LCRVAL);
357 
358 	return ret;
359 }
360 
_debug_uart_putc(int ch)361 static inline void _debug_uart_putc(int ch)
362 {
363 	struct ns16550 *com_port = (struct ns16550 *)CONFIG_DEBUG_UART_BASE;
364 
365 	while (!(serial_din(&com_port->lsr) & UART_LSR_THRE)) {
366 #ifdef CONFIG_DEBUG_UART_NS16550_CHECK_ENABLED
367 		if (!NS16550_read_baud_divisor(com_port))
368 			return;
369 #endif
370 	}
371 	serial_dout(&com_port->thr, ch);
372 }
373 
374 DEBUG_UART_FUNCS
375 
376 #endif
377 
378 #if CONFIG_IS_ENABLED(DM_SERIAL)
ns16550_serial_putc(struct udevice * dev,const char ch)379 static int ns16550_serial_putc(struct udevice *dev, const char ch)
380 {
381 	struct ns16550 *const com_port = dev_get_priv(dev);
382 
383 	if (!(serial_in(&com_port->lsr) & UART_LSR_THRE))
384 		return -EAGAIN;
385 	serial_out(ch, &com_port->thr);
386 
387 	/*
388 	 * Call watchdog_reset() upon newline. This is done here in putc
389 	 * since the environment code uses a single puts() to print the complete
390 	 * environment upon "printenv". So we can't put this watchdog call
391 	 * in puts().
392 	 */
393 	if (ch == '\n')
394 		WATCHDOG_RESET();
395 
396 	return 0;
397 }
398 
ns16550_serial_pending(struct udevice * dev,bool input)399 static int ns16550_serial_pending(struct udevice *dev, bool input)
400 {
401 	struct ns16550 *const com_port = dev_get_priv(dev);
402 
403 	if (input)
404 		return (serial_in(&com_port->lsr) & UART_LSR_DR) ? 1 : 0;
405 	else
406 		return (serial_in(&com_port->lsr) & UART_LSR_THRE) ? 0 : 1;
407 }
408 
ns16550_serial_getc(struct udevice * dev)409 static int ns16550_serial_getc(struct udevice *dev)
410 {
411 	struct ns16550 *const com_port = dev_get_priv(dev);
412 
413 	if (!(serial_in(&com_port->lsr) & UART_LSR_DR))
414 		return -EAGAIN;
415 
416 	return serial_in(&com_port->rbr);
417 }
418 
ns16550_serial_setbrg(struct udevice * dev,int baudrate)419 static int ns16550_serial_setbrg(struct udevice *dev, int baudrate)
420 {
421 	struct ns16550 *const com_port = dev_get_priv(dev);
422 	struct ns16550_plat *plat = com_port->plat;
423 	int clock_divisor;
424 
425 	clock_divisor = ns16550_calc_divisor(com_port, plat->clock, baudrate);
426 
427 	ns16550_setbrg(com_port, clock_divisor);
428 
429 	return 0;
430 }
431 
ns16550_serial_setconfig(struct udevice * dev,uint serial_config)432 static int ns16550_serial_setconfig(struct udevice *dev, uint serial_config)
433 {
434 	struct ns16550 *const com_port = dev_get_priv(dev);
435 	int lcr_val = UART_LCR_WLS_8;
436 	uint parity = SERIAL_GET_PARITY(serial_config);
437 	uint bits = SERIAL_GET_BITS(serial_config);
438 	uint stop = SERIAL_GET_STOP(serial_config);
439 
440 	/*
441 	 * only parity config is implemented, check if other serial settings
442 	 * are the default one.
443 	 */
444 	if (bits != SERIAL_8_BITS || stop != SERIAL_ONE_STOP)
445 		return -ENOTSUPP; /* not supported in driver*/
446 
447 	switch (parity) {
448 	case SERIAL_PAR_NONE:
449 		/* no bits to add */
450 		break;
451 	case SERIAL_PAR_ODD:
452 		lcr_val |= UART_LCR_PEN;
453 		break;
454 	case SERIAL_PAR_EVEN:
455 		lcr_val |= UART_LCR_PEN | UART_LCR_EPS;
456 		break;
457 	default:
458 		return -ENOTSUPP; /* not supported in driver*/
459 	}
460 
461 	serial_out(lcr_val, &com_port->lcr);
462 	return 0;
463 }
464 
ns16550_serial_getinfo(struct udevice * dev,struct serial_device_info * info)465 static int ns16550_serial_getinfo(struct udevice *dev,
466 				  struct serial_device_info *info)
467 {
468 	struct ns16550 *const com_port = dev_get_priv(dev);
469 	struct ns16550_plat *plat = com_port->plat;
470 
471 	info->type = SERIAL_CHIP_16550_COMPATIBLE;
472 #ifdef CONFIG_SYS_NS16550_PORT_MAPPED
473 	info->addr_space = SERIAL_ADDRESS_SPACE_IO;
474 #else
475 	info->addr_space = SERIAL_ADDRESS_SPACE_MEMORY;
476 #endif
477 	info->addr = plat->base;
478 	info->reg_width = plat->reg_width;
479 	info->reg_shift = plat->reg_shift;
480 	info->reg_offset = plat->reg_offset;
481 	info->clock = plat->clock;
482 
483 	return 0;
484 }
485 
ns16550_serial_assign_base(struct ns16550_plat * plat,fdt_addr_t base)486 static int ns16550_serial_assign_base(struct ns16550_plat *plat, fdt_addr_t base)
487 {
488 	if (base == FDT_ADDR_T_NONE)
489 		return -EINVAL;
490 
491 #ifdef CONFIG_SYS_NS16550_PORT_MAPPED
492 	plat->base = base;
493 #else
494 	plat->base = (unsigned long)map_physmem(base, 0, MAP_NOCACHE);
495 #endif
496 
497 	return 0;
498 }
499 
ns16550_serial_probe(struct udevice * dev)500 int ns16550_serial_probe(struct udevice *dev)
501 {
502 	struct ns16550_plat *plat = dev_get_plat(dev);
503 	struct ns16550 *const com_port = dev_get_priv(dev);
504 	struct reset_ctl_bulk reset_bulk;
505 	fdt_addr_t addr;
506 	int ret;
507 
508 	/*
509 	 * If we are on PCI bus, either directly attached to a PCI root port,
510 	 * or via a PCI bridge, assign plat->base before probing hardware.
511 	 */
512 	if (device_is_on_pci_bus(dev)) {
513 		addr = devfdt_get_addr_pci(dev);
514 		ret = ns16550_serial_assign_base(plat, addr);
515 		if (ret)
516 			return ret;
517 	}
518 
519 	ret = reset_get_bulk(dev, &reset_bulk);
520 	if (!ret)
521 		reset_deassert_bulk(&reset_bulk);
522 
523 	com_port->plat = dev_get_plat(dev);
524 	ns16550_init(com_port, -1);
525 
526 	return 0;
527 }
528 
529 #if CONFIG_IS_ENABLED(OF_CONTROL)
530 enum {
531 	PORT_NS16550 = 0,
532 	PORT_JZ4780,
533 };
534 #endif
535 
536 #if CONFIG_IS_ENABLED(OF_CONTROL) && !CONFIG_IS_ENABLED(OF_PLATDATA)
ns16550_serial_of_to_plat(struct udevice * dev)537 int ns16550_serial_of_to_plat(struct udevice *dev)
538 {
539 	struct ns16550_plat *plat = dev_get_plat(dev);
540 	const u32 port_type = dev_get_driver_data(dev);
541 	fdt_addr_t addr;
542 	struct clk clk;
543 	int err;
544 
545 	addr = dev_read_addr(dev);
546 	err = ns16550_serial_assign_base(plat, addr);
547 	if (err && !device_is_on_pci_bus(dev))
548 		return err;
549 
550 	plat->reg_offset = dev_read_u32_default(dev, "reg-offset", 0);
551 	plat->reg_shift = dev_read_u32_default(dev, "reg-shift", 0);
552 	plat->reg_width = dev_read_u32_default(dev, "reg-io-width", 1);
553 
554 	err = clk_get_by_index(dev, 0, &clk);
555 	if (!err) {
556 		err = clk_get_rate(&clk);
557 		if (!IS_ERR_VALUE(err))
558 			plat->clock = err;
559 	} else if (err != -ENOENT && err != -ENODEV && err != -ENOSYS) {
560 		debug("ns16550 failed to get clock\n");
561 		return err;
562 	}
563 
564 	if (!plat->clock)
565 		plat->clock = dev_read_u32_default(dev, "clock-frequency",
566 						   CONFIG_SYS_NS16550_CLK);
567 	if (!plat->clock)
568 		plat->clock = CONFIG_SYS_NS16550_CLK;
569 	if (!plat->clock) {
570 		debug("ns16550 clock not defined\n");
571 		return -EINVAL;
572 	}
573 
574 	plat->fcr = UART_FCR_DEFVAL;
575 	if (port_type == PORT_JZ4780)
576 		plat->fcr |= UART_FCR_UME;
577 
578 	return 0;
579 }
580 #endif
581 
582 const struct dm_serial_ops ns16550_serial_ops = {
583 	.putc = ns16550_serial_putc,
584 	.pending = ns16550_serial_pending,
585 	.getc = ns16550_serial_getc,
586 	.setbrg = ns16550_serial_setbrg,
587 	.setconfig = ns16550_serial_setconfig,
588 	.getinfo = ns16550_serial_getinfo,
589 };
590 
591 #if CONFIG_IS_ENABLED(OF_CONTROL) && !CONFIG_IS_ENABLED(OF_PLATDATA)
592 /*
593  * Please consider existing compatible strings before adding a new
594  * one to keep this table compact. Or you may add a generic "ns16550"
595  * compatible string to your dts.
596  */
597 static const struct udevice_id ns16550_serial_ids[] = {
598 	{ .compatible = "ns16550",		.data = PORT_NS16550 },
599 	{ .compatible = "ns16550a",		.data = PORT_NS16550 },
600 	{ .compatible = "ingenic,jz4780-uart",	.data = PORT_JZ4780  },
601 	{ .compatible = "nvidia,tegra20-uart",	.data = PORT_NS16550 },
602 	{ .compatible = "snps,dw-apb-uart",	.data = PORT_NS16550 },
603 	{}
604 };
605 #endif /* OF_CONTROL && !OF_PLATDATA */
606 
607 #if CONFIG_IS_ENABLED(SERIAL_PRESENT)
608 
609 /* TODO(sjg@chromium.org): Integrate this into a macro like CONFIG_IS_ENABLED */
610 #if !defined(CONFIG_TPL_BUILD) || defined(CONFIG_TPL_DM_SERIAL)
611 U_BOOT_DRIVER(ns16550_serial) = {
612 	.name	= "ns16550_serial",
613 	.id	= UCLASS_SERIAL,
614 #if CONFIG_IS_ENABLED(OF_CONTROL) && !CONFIG_IS_ENABLED(OF_PLATDATA)
615 	.of_match = ns16550_serial_ids,
616 	.of_to_plat = ns16550_serial_of_to_plat,
617 	.plat_auto	= sizeof(struct ns16550_plat),
618 #endif
619 	.priv_auto	= sizeof(struct ns16550),
620 	.probe = ns16550_serial_probe,
621 	.ops	= &ns16550_serial_ops,
622 #if !CONFIG_IS_ENABLED(OF_CONTROL)
623 	.flags	= DM_FLAG_PRE_RELOC,
624 #endif
625 };
626 
627 DM_DRIVER_ALIAS(ns16550_serial, rockchip_rk3328_uart)
628 DM_DRIVER_ALIAS(ns16550_serial, rockchip_rk3368_uart)
629 DM_DRIVER_ALIAS(ns16550_serial, ti_da830_uart)
630 #endif
631 #endif /* SERIAL_PRESENT */
632 
633 #endif /* CONFIG_DM_SERIAL */
634