xref: /openbmc/u-boot/drivers/serial/ns16550.c (revision dffceb4b)
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 <dm.h>
9 #include <errno.h>
10 #include <fdtdec.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 #define UART_FCRVAL (UART_FCR_FIFO_EN |	\
23 		     UART_FCR_RXSR |	\
24 		     UART_FCR_TXSR)		/* Clear & enable FIFOs */
25 
26 #ifndef CONFIG_DM_SERIAL
27 #ifdef CONFIG_SYS_NS16550_PORT_MAPPED
28 #define serial_out(x, y)	outb(x, (ulong)y)
29 #define serial_in(y)		inb((ulong)y)
30 #elif defined(CONFIG_SYS_NS16550_MEM32) && (CONFIG_SYS_NS16550_REG_SIZE > 0)
31 #define serial_out(x, y)	out_be32(y, x)
32 #define serial_in(y)		in_be32(y)
33 #elif defined(CONFIG_SYS_NS16550_MEM32) && (CONFIG_SYS_NS16550_REG_SIZE < 0)
34 #define serial_out(x, y)	out_le32(y, x)
35 #define serial_in(y)		in_le32(y)
36 #else
37 #define serial_out(x, y)	writeb(x, y)
38 #define serial_in(y)		readb(y)
39 #endif
40 #endif /* !CONFIG_DM_SERIAL */
41 
42 #if defined(CONFIG_SOC_KEYSTONE)
43 #define UART_REG_VAL_PWREMU_MGMT_UART_DISABLE   0
44 #define UART_REG_VAL_PWREMU_MGMT_UART_ENABLE ((1 << 14) | (1 << 13) | (1 << 0))
45 #undef UART_MCRVAL
46 #ifdef CONFIG_SERIAL_HW_FLOW_CONTROL
47 #define UART_MCRVAL             (UART_MCR_RTS | UART_MCR_AFE)
48 #else
49 #define UART_MCRVAL             (UART_MCR_RTS)
50 #endif
51 #endif
52 
53 #ifndef CONFIG_SYS_NS16550_IER
54 #define CONFIG_SYS_NS16550_IER  0x00
55 #endif /* CONFIG_SYS_NS16550_IER */
56 
57 #ifdef CONFIG_DM_SERIAL
58 
59 #ifndef CONFIG_SYS_NS16550_CLK
60 #define CONFIG_SYS_NS16550_CLK  0
61 #endif
62 
63 static inline void serial_out_shift(void *addr, int shift, int value)
64 {
65 #ifdef CONFIG_SYS_NS16550_PORT_MAPPED
66 	outb(value, (ulong)addr);
67 #elif defined(CONFIG_SYS_NS16550_MEM32) && !defined(CONFIG_SYS_BIG_ENDIAN)
68 	out_le32(addr, value);
69 #elif defined(CONFIG_SYS_NS16550_MEM32) && defined(CONFIG_SYS_BIG_ENDIAN)
70 	out_be32(addr, value);
71 #elif defined(CONFIG_SYS_NS16550_MEM32)
72 	writel(value, addr);
73 #elif defined(CONFIG_SYS_BIG_ENDIAN)
74 	writeb(value, addr + (1 << shift) - 1);
75 #else
76 	writeb(value, addr);
77 #endif
78 }
79 
80 static inline int serial_in_shift(void *addr, int shift)
81 {
82 #ifdef CONFIG_SYS_NS16550_PORT_MAPPED
83 	return inb((ulong)addr);
84 #elif defined(CONFIG_SYS_NS16550_MEM32) && !defined(CONFIG_SYS_BIG_ENDIAN)
85 	return in_le32(addr);
86 #elif defined(CONFIG_SYS_NS16550_MEM32) && defined(CONFIG_SYS_BIG_ENDIAN)
87 	return in_be32(addr);
88 #elif defined(CONFIG_SYS_NS16550_MEM32)
89 	return readl(addr);
90 #elif defined(CONFIG_SYS_BIG_ENDIAN)
91 	return readb(addr + (1 << shift) - 1);
92 #else
93 	return readb(addr);
94 #endif
95 }
96 
97 static void ns16550_writeb(NS16550_t port, int offset, int value)
98 {
99 	struct ns16550_platdata *plat = port->plat;
100 	unsigned char *addr;
101 
102 	offset *= 1 << plat->reg_shift;
103 	addr = map_physmem(plat->base, 0, MAP_NOCACHE) + offset;
104 	/*
105 	 * As far as we know it doesn't make sense to support selection of
106 	 * these options at run-time, so use the existing CONFIG options.
107 	 */
108 	serial_out_shift(addr, plat->reg_shift, value);
109 }
110 
111 static int ns16550_readb(NS16550_t port, int offset)
112 {
113 	struct ns16550_platdata *plat = port->plat;
114 	unsigned char *addr;
115 
116 	offset *= 1 << plat->reg_shift;
117 	addr = map_physmem(plat->base, 0, MAP_NOCACHE) + offset;
118 
119 	return serial_in_shift(addr, plat->reg_shift);
120 }
121 
122 /* We can clean these up once everything is moved to driver model */
123 #define serial_out(value, addr)	\
124 	ns16550_writeb(com_port, \
125 		(unsigned char *)addr - (unsigned char *)com_port, value)
126 #define serial_in(addr) \
127 	ns16550_readb(com_port, \
128 		(unsigned char *)addr - (unsigned char *)com_port)
129 #endif
130 
131 static inline int calc_divisor(NS16550_t port, int clock, int baudrate)
132 {
133 	const unsigned int mode_x_div = 16;
134 
135 	return DIV_ROUND_CLOSEST(clock, mode_x_div * baudrate);
136 }
137 
138 int ns16550_calc_divisor(NS16550_t port, int clock, int baudrate)
139 {
140 #ifdef CONFIG_OMAP1510
141 	/* If can't cleanly clock 115200 set div to 1 */
142 	if ((clock == 12000000) && (baudrate == 115200)) {
143 		port->osc_12m_sel = OSC_12M_SEL;  /* enable 6.5 * divisor */
144 		return 1;			/* return 1 for base divisor */
145 	}
146 	port->osc_12m_sel = 0;			/* clear if previsouly set */
147 #endif
148 
149 	return calc_divisor(port, clock, baudrate);
150 }
151 
152 static void NS16550_setbrg(NS16550_t com_port, int baud_divisor)
153 {
154 	serial_out(UART_LCR_BKSE | UART_LCRVAL, &com_port->lcr);
155 	serial_out(baud_divisor & 0xff, &com_port->dll);
156 	serial_out((baud_divisor >> 8) & 0xff, &com_port->dlm);
157 	serial_out(UART_LCRVAL, &com_port->lcr);
158 }
159 
160 void NS16550_init(NS16550_t com_port, int baud_divisor)
161 {
162 #if (defined(CONFIG_SPL_BUILD) && \
163 		(defined(CONFIG_OMAP34XX) || defined(CONFIG_OMAP44XX)))
164 	/*
165 	 * On some OMAP3/OMAP4 devices when UART3 is configured for boot mode
166 	 * before SPL starts only THRE bit is set. We have to empty the
167 	 * transmitter before initialization starts.
168 	 */
169 	if ((serial_in(&com_port->lsr) & (UART_LSR_TEMT | UART_LSR_THRE))
170 	     == UART_LSR_THRE) {
171 		if (baud_divisor != -1)
172 			NS16550_setbrg(com_port, baud_divisor);
173 		serial_out(0, &com_port->mdr1);
174 	}
175 #endif
176 
177 	while (!(serial_in(&com_port->lsr) & UART_LSR_TEMT))
178 		;
179 
180 	serial_out(CONFIG_SYS_NS16550_IER, &com_port->ier);
181 #if defined(CONFIG_OMAP) || defined(CONFIG_AM33XX) || \
182 			defined(CONFIG_TI81XX) || defined(CONFIG_AM43XX)
183 	serial_out(0x7, &com_port->mdr1);	/* mode select reset TL16C750*/
184 #endif
185 	serial_out(UART_MCRVAL, &com_port->mcr);
186 	serial_out(UART_FCRVAL, &com_port->fcr);
187 	if (baud_divisor != -1)
188 		NS16550_setbrg(com_port, baud_divisor);
189 #if defined(CONFIG_OMAP) || \
190 	defined(CONFIG_AM33XX) || defined(CONFIG_SOC_DA8XX) || \
191 	defined(CONFIG_TI81XX) || defined(CONFIG_AM43XX)
192 
193 	/* /16 is proper to hit 115200 with 48MHz */
194 	serial_out(0, &com_port->mdr1);
195 #endif /* CONFIG_OMAP */
196 #if defined(CONFIG_SOC_KEYSTONE)
197 	serial_out(UART_REG_VAL_PWREMU_MGMT_UART_ENABLE, &com_port->regC);
198 #endif
199 }
200 
201 #ifndef CONFIG_NS16550_MIN_FUNCTIONS
202 void NS16550_reinit(NS16550_t com_port, int baud_divisor)
203 {
204 	serial_out(CONFIG_SYS_NS16550_IER, &com_port->ier);
205 	NS16550_setbrg(com_port, 0);
206 	serial_out(UART_MCRVAL, &com_port->mcr);
207 	serial_out(UART_FCRVAL, &com_port->fcr);
208 	NS16550_setbrg(com_port, baud_divisor);
209 }
210 #endif /* CONFIG_NS16550_MIN_FUNCTIONS */
211 
212 void NS16550_putc(NS16550_t com_port, char c)
213 {
214 	while ((serial_in(&com_port->lsr) & UART_LSR_THRE) == 0)
215 		;
216 	serial_out(c, &com_port->thr);
217 
218 	/*
219 	 * Call watchdog_reset() upon newline. This is done here in putc
220 	 * since the environment code uses a single puts() to print the complete
221 	 * environment upon "printenv". So we can't put this watchdog call
222 	 * in puts().
223 	 */
224 	if (c == '\n')
225 		WATCHDOG_RESET();
226 }
227 
228 #ifndef CONFIG_NS16550_MIN_FUNCTIONS
229 char NS16550_getc(NS16550_t com_port)
230 {
231 	while ((serial_in(&com_port->lsr) & UART_LSR_DR) == 0) {
232 #if !defined(CONFIG_SPL_BUILD) && defined(CONFIG_USB_TTY)
233 		extern void usbtty_poll(void);
234 		usbtty_poll();
235 #endif
236 		WATCHDOG_RESET();
237 	}
238 	return serial_in(&com_port->rbr);
239 }
240 
241 int NS16550_tstc(NS16550_t com_port)
242 {
243 	return (serial_in(&com_port->lsr) & UART_LSR_DR) != 0;
244 }
245 
246 #endif /* CONFIG_NS16550_MIN_FUNCTIONS */
247 
248 #ifdef CONFIG_DEBUG_UART_NS16550
249 
250 #include <debug_uart.h>
251 
252 #define serial_dout(reg, value)	\
253 	serial_out_shift((char *)com_port + \
254 		((char *)reg - (char *)com_port) * \
255 			(1 << CONFIG_DEBUG_UART_SHIFT), \
256 		CONFIG_DEBUG_UART_SHIFT, value)
257 #define serial_din(reg) \
258 	serial_in_shift((char *)com_port + \
259 		((char *)reg - (char *)com_port) * \
260 			(1 << CONFIG_DEBUG_UART_SHIFT), \
261 		CONFIG_DEBUG_UART_SHIFT)
262 
263 static inline void _debug_uart_init(void)
264 {
265 	struct NS16550 *com_port = (struct NS16550 *)CONFIG_DEBUG_UART_BASE;
266 	int baud_divisor;
267 
268 	/*
269 	 * We copy the code from above because it is already horribly messy.
270 	 * Trying to refactor to nicely remove the duplication doesn't seem
271 	 * feasible. The better fix is to move all users of this driver to
272 	 * driver model.
273 	 */
274 	baud_divisor = calc_divisor(com_port, CONFIG_DEBUG_UART_CLOCK,
275 				    CONFIG_BAUDRATE);
276 	serial_dout(&com_port->ier, CONFIG_SYS_NS16550_IER);
277 	serial_dout(&com_port->mcr, UART_MCRVAL);
278 	serial_dout(&com_port->fcr, UART_FCRVAL);
279 
280 	serial_dout(&com_port->lcr, UART_LCR_BKSE | UART_LCRVAL);
281 	serial_dout(&com_port->dll, baud_divisor & 0xff);
282 	serial_dout(&com_port->dlm, (baud_divisor >> 8) & 0xff);
283 	serial_dout(&com_port->lcr, UART_LCRVAL);
284 }
285 
286 static inline void _debug_uart_putc(int ch)
287 {
288 	struct NS16550 *com_port = (struct NS16550 *)CONFIG_DEBUG_UART_BASE;
289 
290 	while (!(serial_din(&com_port->lsr) & UART_LSR_THRE))
291 		;
292 	serial_dout(&com_port->thr, ch);
293 }
294 
295 DEBUG_UART_FUNCS
296 
297 #endif
298 
299 #ifdef CONFIG_DM_SERIAL
300 static int ns16550_serial_putc(struct udevice *dev, const char ch)
301 {
302 	struct NS16550 *const com_port = dev_get_priv(dev);
303 
304 	if (!(serial_in(&com_port->lsr) & UART_LSR_THRE))
305 		return -EAGAIN;
306 	serial_out(ch, &com_port->thr);
307 
308 	/*
309 	 * Call watchdog_reset() upon newline. This is done here in putc
310 	 * since the environment code uses a single puts() to print the complete
311 	 * environment upon "printenv". So we can't put this watchdog call
312 	 * in puts().
313 	 */
314 	if (ch == '\n')
315 		WATCHDOG_RESET();
316 
317 	return 0;
318 }
319 
320 static int ns16550_serial_pending(struct udevice *dev, bool input)
321 {
322 	struct NS16550 *const com_port = dev_get_priv(dev);
323 
324 	if (input)
325 		return serial_in(&com_port->lsr) & UART_LSR_DR ? 1 : 0;
326 	else
327 		return serial_in(&com_port->lsr) & UART_LSR_THRE ? 0 : 1;
328 }
329 
330 static int ns16550_serial_getc(struct udevice *dev)
331 {
332 	struct NS16550 *const com_port = dev_get_priv(dev);
333 
334 	if (!(serial_in(&com_port->lsr) & UART_LSR_DR))
335 		return -EAGAIN;
336 
337 	return serial_in(&com_port->rbr);
338 }
339 
340 static int ns16550_serial_setbrg(struct udevice *dev, int baudrate)
341 {
342 	struct NS16550 *const com_port = dev_get_priv(dev);
343 	struct ns16550_platdata *plat = com_port->plat;
344 	int clock_divisor;
345 
346 	clock_divisor = ns16550_calc_divisor(com_port, plat->clock, baudrate);
347 
348 	NS16550_setbrg(com_port, clock_divisor);
349 
350 	return 0;
351 }
352 
353 int ns16550_serial_probe(struct udevice *dev)
354 {
355 	struct NS16550 *const com_port = dev_get_priv(dev);
356 
357 	com_port->plat = dev_get_platdata(dev);
358 	NS16550_init(com_port, -1);
359 
360 	return 0;
361 }
362 
363 #if CONFIG_IS_ENABLED(OF_CONTROL)
364 int ns16550_serial_ofdata_to_platdata(struct udevice *dev)
365 {
366 	struct ns16550_platdata *plat = dev->platdata;
367 	fdt_addr_t addr;
368 
369 	/* try Processor Local Bus device first */
370 	addr = dev_get_addr(dev);
371 #if defined(CONFIG_PCI) && defined(CONFIG_DM_PCI)
372 	if (addr == FDT_ADDR_T_NONE) {
373 		/* then try pci device */
374 		struct fdt_pci_addr pci_addr;
375 		u32 bar;
376 		int ret;
377 
378 		/* we prefer to use a memory-mapped register */
379 		ret = fdtdec_get_pci_addr(gd->fdt_blob, dev->of_offset,
380 					  FDT_PCI_SPACE_MEM32, "reg",
381 					  &pci_addr);
382 		if (ret) {
383 			/* try if there is any i/o-mapped register */
384 			ret = fdtdec_get_pci_addr(gd->fdt_blob,
385 						  dev->of_offset,
386 						  FDT_PCI_SPACE_IO,
387 						  "reg", &pci_addr);
388 			if (ret)
389 				return ret;
390 		}
391 
392 		ret = fdtdec_get_pci_bar32(dev, &pci_addr, &bar);
393 		if (ret)
394 			return ret;
395 
396 		addr = bar;
397 	}
398 #endif
399 
400 	if (addr == FDT_ADDR_T_NONE)
401 		return -EINVAL;
402 
403 	plat->base = addr;
404 	plat->reg_shift = fdtdec_get_int(gd->fdt_blob, dev->of_offset,
405 					 "reg-shift", 0);
406 	plat->clock = fdtdec_get_int(gd->fdt_blob, dev->of_offset,
407 				     "clock-frequency",
408 				     CONFIG_SYS_NS16550_CLK);
409 	if (!plat->clock) {
410 		debug("ns16550 clock not defined\n");
411 		return -EINVAL;
412 	}
413 
414 	return 0;
415 }
416 #endif
417 
418 const struct dm_serial_ops ns16550_serial_ops = {
419 	.putc = ns16550_serial_putc,
420 	.pending = ns16550_serial_pending,
421 	.getc = ns16550_serial_getc,
422 	.setbrg = ns16550_serial_setbrg,
423 };
424 
425 #if CONFIG_IS_ENABLED(OF_CONTROL)
426 /*
427  * Please consider existing compatible strings before adding a new
428  * one to keep this table compact. Or you may add a generic "ns16550"
429  * compatible string to your dts.
430  */
431 static const struct udevice_id ns16550_serial_ids[] = {
432 	{ .compatible = "ns16550" },
433 	{ .compatible = "ns16550a" },
434 	{ .compatible = "nvidia,tegra20-uart" },
435 	{ .compatible = "snps,dw-apb-uart" },
436 	{ .compatible = "ti,omap2-uart" },
437 	{ .compatible = "ti,omap3-uart" },
438 	{ .compatible = "ti,omap4-uart" },
439 	{ .compatible = "ti,am3352-uart" },
440 	{ .compatible = "ti,am4372-uart" },
441 	{ .compatible = "ti,dra742-uart" },
442 	{}
443 };
444 #endif
445 
446 #if CONFIG_IS_ENABLED(SERIAL_PRESENT)
447 U_BOOT_DRIVER(ns16550_serial) = {
448 	.name	= "ns16550_serial",
449 	.id	= UCLASS_SERIAL,
450 #if CONFIG_IS_ENABLED(OF_CONTROL)
451 	.of_match = ns16550_serial_ids,
452 	.ofdata_to_platdata = ns16550_serial_ofdata_to_platdata,
453 	.platdata_auto_alloc_size = sizeof(struct ns16550_platdata),
454 #endif
455 	.priv_auto_alloc_size = sizeof(struct NS16550),
456 	.probe = ns16550_serial_probe,
457 	.ops	= &ns16550_serial_ops,
458 	.flags	= DM_FLAG_PRE_RELOC,
459 };
460 #endif
461 #endif /* CONFIG_DM_SERIAL */
462