xref: /openbmc/u-boot/drivers/serial/ns16550.c (revision e9c847c3)
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 <fdtdec.h>
12 #include <ns16550.h>
13 #include <serial.h>
14 #include <watchdog.h>
15 #include <linux/types.h>
16 #include <asm/io.h>
17 
18 DECLARE_GLOBAL_DATA_PTR;
19 
20 #define UART_LCRVAL UART_LCR_8N1		/* 8 data, 1 stop, no parity */
21 #define UART_MCRVAL (UART_MCR_DTR | \
22 		     UART_MCR_RTS)		/* RTS/DTR */
23 #define UART_FCRVAL (UART_FCR_FIFO_EN |	\
24 		     UART_FCR_RXSR |	\
25 		     UART_FCR_TXSR)		/* Clear & enable FIFOs */
26 
27 #ifndef CONFIG_DM_SERIAL
28 #ifdef CONFIG_SYS_NS16550_PORT_MAPPED
29 #define serial_out(x, y)	outb(x, (ulong)y)
30 #define serial_in(y)		inb((ulong)y)
31 #elif defined(CONFIG_SYS_NS16550_MEM32) && (CONFIG_SYS_NS16550_REG_SIZE > 0)
32 #define serial_out(x, y)	out_be32(y, x)
33 #define serial_in(y)		in_be32(y)
34 #elif defined(CONFIG_SYS_NS16550_MEM32) && (CONFIG_SYS_NS16550_REG_SIZE < 0)
35 #define serial_out(x, y)	out_le32(y, x)
36 #define serial_in(y)		in_le32(y)
37 #else
38 #define serial_out(x, y)	writeb(x, y)
39 #define serial_in(y)		readb(y)
40 #endif
41 #endif /* !CONFIG_DM_SERIAL */
42 
43 #if defined(CONFIG_SOC_KEYSTONE)
44 #define UART_REG_VAL_PWREMU_MGMT_UART_DISABLE   0
45 #define UART_REG_VAL_PWREMU_MGMT_UART_ENABLE ((1 << 14) | (1 << 13) | (1 << 0))
46 #undef UART_MCRVAL
47 #ifdef CONFIG_SERIAL_HW_FLOW_CONTROL
48 #define UART_MCRVAL             (UART_MCR_RTS | UART_MCR_AFE)
49 #else
50 #define UART_MCRVAL             (UART_MCR_RTS)
51 #endif
52 #endif
53 
54 #ifndef CONFIG_SYS_NS16550_IER
55 #define CONFIG_SYS_NS16550_IER  0x00
56 #endif /* CONFIG_SYS_NS16550_IER */
57 
58 static inline void serial_out_shift(void *addr, int shift, int value)
59 {
60 #ifdef CONFIG_SYS_NS16550_PORT_MAPPED
61 	outb(value, (ulong)addr);
62 #elif defined(CONFIG_SYS_NS16550_MEM32) && !defined(CONFIG_SYS_BIG_ENDIAN)
63 	out_le32(addr, value);
64 #elif defined(CONFIG_SYS_NS16550_MEM32) && defined(CONFIG_SYS_BIG_ENDIAN)
65 	out_be32(addr, value);
66 #elif defined(CONFIG_SYS_NS16550_MEM32)
67 	writel(value, addr);
68 #elif defined(CONFIG_SYS_BIG_ENDIAN)
69 	writeb(value, addr + (1 << shift) - 1);
70 #else
71 	writeb(value, addr);
72 #endif
73 }
74 
75 static inline int serial_in_shift(void *addr, int shift)
76 {
77 #ifdef CONFIG_SYS_NS16550_PORT_MAPPED
78 	return inb((ulong)addr);
79 #elif defined(CONFIG_SYS_NS16550_MEM32) && !defined(CONFIG_SYS_BIG_ENDIAN)
80 	return in_le32(addr);
81 #elif defined(CONFIG_SYS_NS16550_MEM32) && defined(CONFIG_SYS_BIG_ENDIAN)
82 	return in_be32(addr);
83 #elif defined(CONFIG_SYS_NS16550_MEM32)
84 	return readl(addr);
85 #elif defined(CONFIG_SYS_BIG_ENDIAN)
86 	return readb(addr + (1 << shift) - 1);
87 #else
88 	return readb(addr);
89 #endif
90 }
91 
92 #ifdef CONFIG_DM_SERIAL
93 
94 #ifndef CONFIG_SYS_NS16550_CLK
95 #define CONFIG_SYS_NS16550_CLK  0
96 #endif
97 
98 static void ns16550_writeb(NS16550_t port, int offset, int value)
99 {
100 	struct ns16550_platdata *plat = port->plat;
101 	unsigned char *addr;
102 
103 	offset *= 1 << plat->reg_shift;
104 	addr = (unsigned char *)plat->base + offset;
105 
106 	/*
107 	 * As far as we know it doesn't make sense to support selection of
108 	 * these options at run-time, so use the existing CONFIG options.
109 	 */
110 	serial_out_shift(addr + plat->reg_offset, plat->reg_shift, value);
111 }
112 
113 static int ns16550_readb(NS16550_t port, int offset)
114 {
115 	struct ns16550_platdata *plat = port->plat;
116 	unsigned char *addr;
117 
118 	offset *= 1 << plat->reg_shift;
119 	addr = (unsigned char *)plat->base + offset;
120 
121 	return serial_in_shift(addr + plat->reg_offset, plat->reg_shift);
122 }
123 
124 /* We can clean these up once everything is moved to driver model */
125 #define serial_out(value, addr)	\
126 	ns16550_writeb(com_port, \
127 		(unsigned char *)addr - (unsigned char *)com_port, value)
128 #define serial_in(addr) \
129 	ns16550_readb(com_port, \
130 		(unsigned char *)addr - (unsigned char *)com_port)
131 #endif
132 
133 int ns16550_calc_divisor(NS16550_t port, int clock, int baudrate)
134 {
135 	const unsigned int mode_x_div = 16;
136 
137 	return DIV_ROUND_CLOSEST(clock, mode_x_div * baudrate);
138 }
139 
140 static void NS16550_setbrg(NS16550_t com_port, int baud_divisor)
141 {
142 	serial_out(UART_LCR_BKSE | UART_LCRVAL, &com_port->lcr);
143 	serial_out(baud_divisor & 0xff, &com_port->dll);
144 	serial_out((baud_divisor >> 8) & 0xff, &com_port->dlm);
145 	serial_out(UART_LCRVAL, &com_port->lcr);
146 }
147 
148 void NS16550_init(NS16550_t com_port, int baud_divisor)
149 {
150 #if (defined(CONFIG_SPL_BUILD) && \
151 		(defined(CONFIG_OMAP34XX) || defined(CONFIG_OMAP44XX)))
152 	/*
153 	 * On some OMAP3/OMAP4 devices when UART3 is configured for boot mode
154 	 * before SPL starts only THRE bit is set. We have to empty the
155 	 * transmitter before initialization starts.
156 	 */
157 	if ((serial_in(&com_port->lsr) & (UART_LSR_TEMT | UART_LSR_THRE))
158 	     == UART_LSR_THRE) {
159 		if (baud_divisor != -1)
160 			NS16550_setbrg(com_port, baud_divisor);
161 		serial_out(0, &com_port->mdr1);
162 	}
163 #endif
164 
165 	while (!(serial_in(&com_port->lsr) & UART_LSR_TEMT))
166 		;
167 
168 	serial_out(CONFIG_SYS_NS16550_IER, &com_port->ier);
169 #if defined(CONFIG_OMAP) || defined(CONFIG_AM33XX) || \
170 			defined(CONFIG_TI81XX) || defined(CONFIG_AM43XX)
171 	serial_out(0x7, &com_port->mdr1);	/* mode select reset TL16C750*/
172 #endif
173 	serial_out(UART_MCRVAL, &com_port->mcr);
174 	serial_out(UART_FCRVAL, &com_port->fcr);
175 	if (baud_divisor != -1)
176 		NS16550_setbrg(com_port, baud_divisor);
177 #if defined(CONFIG_OMAP) || \
178 	defined(CONFIG_AM33XX) || defined(CONFIG_SOC_DA8XX) || \
179 	defined(CONFIG_TI81XX) || defined(CONFIG_AM43XX)
180 
181 	/* /16 is proper to hit 115200 with 48MHz */
182 	serial_out(0, &com_port->mdr1);
183 #endif /* CONFIG_OMAP */
184 #if defined(CONFIG_SOC_KEYSTONE)
185 	serial_out(UART_REG_VAL_PWREMU_MGMT_UART_ENABLE, &com_port->regC);
186 #endif
187 }
188 
189 #ifndef CONFIG_NS16550_MIN_FUNCTIONS
190 void NS16550_reinit(NS16550_t com_port, int baud_divisor)
191 {
192 	serial_out(CONFIG_SYS_NS16550_IER, &com_port->ier);
193 	NS16550_setbrg(com_port, 0);
194 	serial_out(UART_MCRVAL, &com_port->mcr);
195 	serial_out(UART_FCRVAL, &com_port->fcr);
196 	NS16550_setbrg(com_port, baud_divisor);
197 }
198 #endif /* CONFIG_NS16550_MIN_FUNCTIONS */
199 
200 void NS16550_putc(NS16550_t com_port, char c)
201 {
202 	while ((serial_in(&com_port->lsr) & UART_LSR_THRE) == 0)
203 		;
204 	serial_out(c, &com_port->thr);
205 
206 	/*
207 	 * Call watchdog_reset() upon newline. This is done here in putc
208 	 * since the environment code uses a single puts() to print the complete
209 	 * environment upon "printenv". So we can't put this watchdog call
210 	 * in puts().
211 	 */
212 	if (c == '\n')
213 		WATCHDOG_RESET();
214 }
215 
216 #ifndef CONFIG_NS16550_MIN_FUNCTIONS
217 char NS16550_getc(NS16550_t com_port)
218 {
219 	while ((serial_in(&com_port->lsr) & UART_LSR_DR) == 0) {
220 #if !defined(CONFIG_SPL_BUILD) && defined(CONFIG_USB_TTY)
221 		extern void usbtty_poll(void);
222 		usbtty_poll();
223 #endif
224 		WATCHDOG_RESET();
225 	}
226 	return serial_in(&com_port->rbr);
227 }
228 
229 int NS16550_tstc(NS16550_t com_port)
230 {
231 	return (serial_in(&com_port->lsr) & UART_LSR_DR) != 0;
232 }
233 
234 #endif /* CONFIG_NS16550_MIN_FUNCTIONS */
235 
236 #ifdef CONFIG_DEBUG_UART_NS16550
237 
238 #include <debug_uart.h>
239 
240 #define serial_dout(reg, value)	\
241 	serial_out_shift((char *)com_port + \
242 		((char *)reg - (char *)com_port) * \
243 			(1 << CONFIG_DEBUG_UART_SHIFT), \
244 		CONFIG_DEBUG_UART_SHIFT, value)
245 #define serial_din(reg) \
246 	serial_in_shift((char *)com_port + \
247 		((char *)reg - (char *)com_port) * \
248 			(1 << CONFIG_DEBUG_UART_SHIFT), \
249 		CONFIG_DEBUG_UART_SHIFT)
250 
251 static inline void _debug_uart_init(void)
252 {
253 	struct NS16550 *com_port = (struct NS16550 *)CONFIG_DEBUG_UART_BASE;
254 	int baud_divisor;
255 
256 	/*
257 	 * We copy the code from above because it is already horribly messy.
258 	 * Trying to refactor to nicely remove the duplication doesn't seem
259 	 * feasible. The better fix is to move all users of this driver to
260 	 * driver model.
261 	 */
262 	baud_divisor = ns16550_calc_divisor(com_port, CONFIG_DEBUG_UART_CLOCK,
263 					    CONFIG_BAUDRATE);
264 	serial_dout(&com_port->ier, CONFIG_SYS_NS16550_IER);
265 	serial_dout(&com_port->mcr, UART_MCRVAL);
266 	serial_dout(&com_port->fcr, UART_FCRVAL);
267 
268 	serial_dout(&com_port->lcr, UART_LCR_BKSE | UART_LCRVAL);
269 	serial_dout(&com_port->dll, baud_divisor & 0xff);
270 	serial_dout(&com_port->dlm, (baud_divisor >> 8) & 0xff);
271 	serial_dout(&com_port->lcr, UART_LCRVAL);
272 }
273 
274 static inline void _debug_uart_putc(int ch)
275 {
276 	struct NS16550 *com_port = (struct NS16550 *)CONFIG_DEBUG_UART_BASE;
277 
278 	while (!(serial_din(&com_port->lsr) & UART_LSR_THRE))
279 		;
280 	serial_dout(&com_port->thr, ch);
281 }
282 
283 DEBUG_UART_FUNCS
284 
285 #endif
286 
287 #ifdef CONFIG_DM_SERIAL
288 static int ns16550_serial_putc(struct udevice *dev, const char ch)
289 {
290 	struct NS16550 *const com_port = dev_get_priv(dev);
291 
292 	if (!(serial_in(&com_port->lsr) & UART_LSR_THRE))
293 		return -EAGAIN;
294 	serial_out(ch, &com_port->thr);
295 
296 	/*
297 	 * Call watchdog_reset() upon newline. This is done here in putc
298 	 * since the environment code uses a single puts() to print the complete
299 	 * environment upon "printenv". So we can't put this watchdog call
300 	 * in puts().
301 	 */
302 	if (ch == '\n')
303 		WATCHDOG_RESET();
304 
305 	return 0;
306 }
307 
308 static int ns16550_serial_pending(struct udevice *dev, bool input)
309 {
310 	struct NS16550 *const com_port = dev_get_priv(dev);
311 
312 	if (input)
313 		return serial_in(&com_port->lsr) & UART_LSR_DR ? 1 : 0;
314 	else
315 		return serial_in(&com_port->lsr) & UART_LSR_THRE ? 0 : 1;
316 }
317 
318 static int ns16550_serial_getc(struct udevice *dev)
319 {
320 	struct NS16550 *const com_port = dev_get_priv(dev);
321 
322 	if (!(serial_in(&com_port->lsr) & UART_LSR_DR))
323 		return -EAGAIN;
324 
325 	return serial_in(&com_port->rbr);
326 }
327 
328 static int ns16550_serial_setbrg(struct udevice *dev, int baudrate)
329 {
330 	struct NS16550 *const com_port = dev_get_priv(dev);
331 	struct ns16550_platdata *plat = com_port->plat;
332 	int clock_divisor;
333 
334 	clock_divisor = ns16550_calc_divisor(com_port, plat->clock, baudrate);
335 
336 	NS16550_setbrg(com_port, clock_divisor);
337 
338 	return 0;
339 }
340 
341 int ns16550_serial_probe(struct udevice *dev)
342 {
343 	struct NS16550 *const com_port = dev_get_priv(dev);
344 
345 	com_port->plat = dev_get_platdata(dev);
346 	NS16550_init(com_port, -1);
347 
348 	return 0;
349 }
350 
351 #if CONFIG_IS_ENABLED(OF_CONTROL) && !CONFIG_IS_ENABLED(OF_PLATDATA)
352 int ns16550_serial_ofdata_to_platdata(struct udevice *dev)
353 {
354 	struct ns16550_platdata *plat = dev->platdata;
355 	fdt_addr_t addr;
356 	struct clk clk;
357 	int err;
358 
359 	/* try Processor Local Bus device first */
360 	addr = dev_get_addr(dev);
361 #if defined(CONFIG_PCI) && defined(CONFIG_DM_PCI)
362 	if (addr == FDT_ADDR_T_NONE) {
363 		/* then try pci device */
364 		struct fdt_pci_addr pci_addr;
365 		u32 bar;
366 		int ret;
367 
368 		/* we prefer to use a memory-mapped register */
369 		ret = fdtdec_get_pci_addr(gd->fdt_blob, dev->of_offset,
370 					  FDT_PCI_SPACE_MEM32, "reg",
371 					  &pci_addr);
372 		if (ret) {
373 			/* try if there is any i/o-mapped register */
374 			ret = fdtdec_get_pci_addr(gd->fdt_blob,
375 						  dev->of_offset,
376 						  FDT_PCI_SPACE_IO,
377 						  "reg", &pci_addr);
378 			if (ret)
379 				return ret;
380 		}
381 
382 		ret = fdtdec_get_pci_bar32(dev, &pci_addr, &bar);
383 		if (ret)
384 			return ret;
385 
386 		addr = bar;
387 	}
388 #endif
389 
390 	if (addr == FDT_ADDR_T_NONE)
391 		return -EINVAL;
392 
393 #ifdef CONFIG_SYS_NS16550_PORT_MAPPED
394 	plat->base = addr;
395 #else
396 	plat->base = (unsigned long)map_physmem(addr, 0, MAP_NOCACHE);
397 #endif
398 
399 	plat->reg_offset = fdtdec_get_int(gd->fdt_blob, dev->of_offset,
400 				     "reg-offset", 0);
401 	plat->reg_shift = fdtdec_get_int(gd->fdt_blob, dev->of_offset,
402 					 "reg-shift", 0);
403 
404 	err = clk_get_by_index(dev, 0, &clk);
405 	if (!err) {
406 		err = clk_get_rate(&clk);
407 		if (!IS_ERR_VALUE(err))
408 			plat->clock = err;
409 	} else if (err != -ENOENT && err != -ENODEV && err != -ENOSYS) {
410 		debug("ns16550 failed to get clock\n");
411 		return err;
412 	}
413 
414 	if (!plat->clock)
415 		plat->clock = fdtdec_get_int(gd->fdt_blob, dev->of_offset,
416 					     "clock-frequency",
417 					     CONFIG_SYS_NS16550_CLK);
418 	if (!plat->clock) {
419 		debug("ns16550 clock not defined\n");
420 		return -EINVAL;
421 	}
422 
423 	return 0;
424 }
425 #endif
426 
427 const struct dm_serial_ops ns16550_serial_ops = {
428 	.putc = ns16550_serial_putc,
429 	.pending = ns16550_serial_pending,
430 	.getc = ns16550_serial_getc,
431 	.setbrg = ns16550_serial_setbrg,
432 };
433 
434 #if !CONFIG_IS_ENABLED(OF_PLATDATA)
435 #if CONFIG_IS_ENABLED(OF_CONTROL)
436 /*
437  * Please consider existing compatible strings before adding a new
438  * one to keep this table compact. Or you may add a generic "ns16550"
439  * compatible string to your dts.
440  */
441 static const struct udevice_id ns16550_serial_ids[] = {
442 	{ .compatible = "ns16550" },
443 	{ .compatible = "ns16550a" },
444 	{ .compatible = "nvidia,tegra20-uart" },
445 	{ .compatible = "snps,dw-apb-uart" },
446 	{ .compatible = "ti,omap2-uart" },
447 	{ .compatible = "ti,omap3-uart" },
448 	{ .compatible = "ti,omap4-uart" },
449 	{ .compatible = "ti,am3352-uart" },
450 	{ .compatible = "ti,am4372-uart" },
451 	{ .compatible = "ti,dra742-uart" },
452 	{}
453 };
454 #endif
455 
456 #if CONFIG_IS_ENABLED(SERIAL_PRESENT)
457 U_BOOT_DRIVER(ns16550_serial) = {
458 	.name	= "ns16550_serial",
459 	.id	= UCLASS_SERIAL,
460 #if CONFIG_IS_ENABLED(OF_CONTROL)
461 	.of_match = ns16550_serial_ids,
462 	.ofdata_to_platdata = ns16550_serial_ofdata_to_platdata,
463 	.platdata_auto_alloc_size = sizeof(struct ns16550_platdata),
464 #endif
465 	.priv_auto_alloc_size = sizeof(struct NS16550),
466 	.probe = ns16550_serial_probe,
467 	.ops	= &ns16550_serial_ops,
468 	.flags	= DM_FLAG_PRE_RELOC,
469 };
470 #endif
471 #endif /* !OF_PLATDATA */
472 #endif /* CONFIG_DM_SERIAL */
473