xref: /openbmc/u-boot/drivers/serial/ns16550.c (revision a7da6f8c)
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 static inline void serial_out_shift(void *addr, int shift, int value)
58 {
59 #ifdef CONFIG_SYS_NS16550_PORT_MAPPED
60 	outb(value, (ulong)addr);
61 #elif defined(CONFIG_SYS_NS16550_MEM32) && !defined(CONFIG_SYS_BIG_ENDIAN)
62 	out_le32(addr, value);
63 #elif defined(CONFIG_SYS_NS16550_MEM32) && defined(CONFIG_SYS_BIG_ENDIAN)
64 	out_be32(addr, value);
65 #elif defined(CONFIG_SYS_NS16550_MEM32)
66 	writel(value, addr);
67 #elif defined(CONFIG_SYS_BIG_ENDIAN)
68 	writeb(value, addr + (1 << shift) - 1);
69 #else
70 	writeb(value, addr);
71 #endif
72 }
73 
74 static inline int serial_in_shift(void *addr, int shift)
75 {
76 #ifdef CONFIG_SYS_NS16550_PORT_MAPPED
77 	return inb((ulong)addr);
78 #elif defined(CONFIG_SYS_NS16550_MEM32) && !defined(CONFIG_SYS_BIG_ENDIAN)
79 	return in_le32(addr);
80 #elif defined(CONFIG_SYS_NS16550_MEM32) && defined(CONFIG_SYS_BIG_ENDIAN)
81 	return in_be32(addr);
82 #elif defined(CONFIG_SYS_NS16550_MEM32)
83 	return readl(addr);
84 #elif defined(CONFIG_SYS_BIG_ENDIAN)
85 	return readb(addr + (1 << shift) - 1);
86 #else
87 	return readb(addr);
88 #endif
89 }
90 
91 #ifdef CONFIG_DM_SERIAL
92 
93 #ifndef CONFIG_SYS_NS16550_CLK
94 #define CONFIG_SYS_NS16550_CLK  0
95 #endif
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 = (unsigned char *)plat->base + offset;
104 
105 	/*
106 	 * As far as we know it doesn't make sense to support selection of
107 	 * these options at run-time, so use the existing CONFIG options.
108 	 */
109 	serial_out_shift(addr + plat->reg_offset, plat->reg_shift, value);
110 }
111 
112 static int ns16550_readb(NS16550_t port, int offset)
113 {
114 	struct ns16550_platdata *plat = port->plat;
115 	unsigned char *addr;
116 
117 	offset *= 1 << plat->reg_shift;
118 	addr = (unsigned char *)plat->base + offset;
119 
120 	return serial_in_shift(addr + plat->reg_offset, plat->reg_shift);
121 }
122 
123 /* We can clean these up once everything is moved to driver model */
124 #define serial_out(value, addr)	\
125 	ns16550_writeb(com_port, \
126 		(unsigned char *)addr - (unsigned char *)com_port, value)
127 #define serial_in(addr) \
128 	ns16550_readb(com_port, \
129 		(unsigned char *)addr - (unsigned char *)com_port)
130 #endif
131 
132 int ns16550_calc_divisor(NS16550_t port, int clock, int baudrate)
133 {
134 	const unsigned int mode_x_div = 16;
135 
136 	return DIV_ROUND_CLOSEST(clock, mode_x_div * baudrate);
137 }
138 
139 static void NS16550_setbrg(NS16550_t com_port, int baud_divisor)
140 {
141 	serial_out(UART_LCR_BKSE | UART_LCRVAL, &com_port->lcr);
142 	serial_out(baud_divisor & 0xff, &com_port->dll);
143 	serial_out((baud_divisor >> 8) & 0xff, &com_port->dlm);
144 	serial_out(UART_LCRVAL, &com_port->lcr);
145 }
146 
147 void NS16550_init(NS16550_t com_port, int baud_divisor)
148 {
149 #if (defined(CONFIG_SPL_BUILD) && \
150 		(defined(CONFIG_OMAP34XX) || defined(CONFIG_OMAP44XX)))
151 	/*
152 	 * On some OMAP3/OMAP4 devices when UART3 is configured for boot mode
153 	 * before SPL starts only THRE bit is set. We have to empty the
154 	 * transmitter before initialization starts.
155 	 */
156 	if ((serial_in(&com_port->lsr) & (UART_LSR_TEMT | UART_LSR_THRE))
157 	     == UART_LSR_THRE) {
158 		if (baud_divisor != -1)
159 			NS16550_setbrg(com_port, baud_divisor);
160 		serial_out(0, &com_port->mdr1);
161 	}
162 #endif
163 
164 	while (!(serial_in(&com_port->lsr) & UART_LSR_TEMT))
165 		;
166 
167 	serial_out(CONFIG_SYS_NS16550_IER, &com_port->ier);
168 #if defined(CONFIG_OMAP) || defined(CONFIG_AM33XX) || \
169 			defined(CONFIG_TI81XX) || defined(CONFIG_AM43XX)
170 	serial_out(0x7, &com_port->mdr1);	/* mode select reset TL16C750*/
171 #endif
172 	serial_out(UART_MCRVAL, &com_port->mcr);
173 	serial_out(UART_FCRVAL, &com_port->fcr);
174 	if (baud_divisor != -1)
175 		NS16550_setbrg(com_port, baud_divisor);
176 #if defined(CONFIG_OMAP) || \
177 	defined(CONFIG_AM33XX) || defined(CONFIG_SOC_DA8XX) || \
178 	defined(CONFIG_TI81XX) || defined(CONFIG_AM43XX)
179 
180 	/* /16 is proper to hit 115200 with 48MHz */
181 	serial_out(0, &com_port->mdr1);
182 #endif /* CONFIG_OMAP */
183 #if defined(CONFIG_SOC_KEYSTONE)
184 	serial_out(UART_REG_VAL_PWREMU_MGMT_UART_ENABLE, &com_port->regC);
185 #endif
186 }
187 
188 #ifndef CONFIG_NS16550_MIN_FUNCTIONS
189 void NS16550_reinit(NS16550_t com_port, int baud_divisor)
190 {
191 	serial_out(CONFIG_SYS_NS16550_IER, &com_port->ier);
192 	NS16550_setbrg(com_port, 0);
193 	serial_out(UART_MCRVAL, &com_port->mcr);
194 	serial_out(UART_FCRVAL, &com_port->fcr);
195 	NS16550_setbrg(com_port, baud_divisor);
196 }
197 #endif /* CONFIG_NS16550_MIN_FUNCTIONS */
198 
199 void NS16550_putc(NS16550_t com_port, char c)
200 {
201 	while ((serial_in(&com_port->lsr) & UART_LSR_THRE) == 0)
202 		;
203 	serial_out(c, &com_port->thr);
204 
205 	/*
206 	 * Call watchdog_reset() upon newline. This is done here in putc
207 	 * since the environment code uses a single puts() to print the complete
208 	 * environment upon "printenv". So we can't put this watchdog call
209 	 * in puts().
210 	 */
211 	if (c == '\n')
212 		WATCHDOG_RESET();
213 }
214 
215 #ifndef CONFIG_NS16550_MIN_FUNCTIONS
216 char NS16550_getc(NS16550_t com_port)
217 {
218 	while ((serial_in(&com_port->lsr) & UART_LSR_DR) == 0) {
219 #if !defined(CONFIG_SPL_BUILD) && defined(CONFIG_USB_TTY)
220 		extern void usbtty_poll(void);
221 		usbtty_poll();
222 #endif
223 		WATCHDOG_RESET();
224 	}
225 	return serial_in(&com_port->rbr);
226 }
227 
228 int NS16550_tstc(NS16550_t com_port)
229 {
230 	return (serial_in(&com_port->lsr) & UART_LSR_DR) != 0;
231 }
232 
233 #endif /* CONFIG_NS16550_MIN_FUNCTIONS */
234 
235 #ifdef CONFIG_DEBUG_UART_NS16550
236 
237 #include <debug_uart.h>
238 
239 #define serial_dout(reg, value)	\
240 	serial_out_shift((char *)com_port + \
241 		((char *)reg - (char *)com_port) * \
242 			(1 << CONFIG_DEBUG_UART_SHIFT), \
243 		CONFIG_DEBUG_UART_SHIFT, value)
244 #define serial_din(reg) \
245 	serial_in_shift((char *)com_port + \
246 		((char *)reg - (char *)com_port) * \
247 			(1 << CONFIG_DEBUG_UART_SHIFT), \
248 		CONFIG_DEBUG_UART_SHIFT)
249 
250 static inline void _debug_uart_init(void)
251 {
252 	struct NS16550 *com_port = (struct NS16550 *)CONFIG_DEBUG_UART_BASE;
253 	int baud_divisor;
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_FCRVAL);
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 
273 static inline void _debug_uart_putc(int ch)
274 {
275 	struct NS16550 *com_port = (struct NS16550 *)CONFIG_DEBUG_UART_BASE;
276 
277 	while (!(serial_din(&com_port->lsr) & UART_LSR_THRE))
278 		;
279 	serial_dout(&com_port->thr, ch);
280 }
281 
282 DEBUG_UART_FUNCS
283 
284 #endif
285 
286 #ifdef CONFIG_DM_SERIAL
287 static int ns16550_serial_putc(struct udevice *dev, const char ch)
288 {
289 	struct NS16550 *const com_port = dev_get_priv(dev);
290 
291 	if (!(serial_in(&com_port->lsr) & UART_LSR_THRE))
292 		return -EAGAIN;
293 	serial_out(ch, &com_port->thr);
294 
295 	/*
296 	 * Call watchdog_reset() upon newline. This is done here in putc
297 	 * since the environment code uses a single puts() to print the complete
298 	 * environment upon "printenv". So we can't put this watchdog call
299 	 * in puts().
300 	 */
301 	if (ch == '\n')
302 		WATCHDOG_RESET();
303 
304 	return 0;
305 }
306 
307 static int ns16550_serial_pending(struct udevice *dev, bool input)
308 {
309 	struct NS16550 *const com_port = dev_get_priv(dev);
310 
311 	if (input)
312 		return serial_in(&com_port->lsr) & UART_LSR_DR ? 1 : 0;
313 	else
314 		return serial_in(&com_port->lsr) & UART_LSR_THRE ? 0 : 1;
315 }
316 
317 static int ns16550_serial_getc(struct udevice *dev)
318 {
319 	struct NS16550 *const com_port = dev_get_priv(dev);
320 
321 	if (!(serial_in(&com_port->lsr) & UART_LSR_DR))
322 		return -EAGAIN;
323 
324 	return serial_in(&com_port->rbr);
325 }
326 
327 static int ns16550_serial_setbrg(struct udevice *dev, int baudrate)
328 {
329 	struct NS16550 *const com_port = dev_get_priv(dev);
330 	struct ns16550_platdata *plat = com_port->plat;
331 	int clock_divisor;
332 
333 	clock_divisor = ns16550_calc_divisor(com_port, plat->clock, baudrate);
334 
335 	NS16550_setbrg(com_port, clock_divisor);
336 
337 	return 0;
338 }
339 
340 int ns16550_serial_probe(struct udevice *dev)
341 {
342 	struct NS16550 *const com_port = dev_get_priv(dev);
343 
344 	com_port->plat = dev_get_platdata(dev);
345 	NS16550_init(com_port, -1);
346 
347 	return 0;
348 }
349 
350 #if CONFIG_IS_ENABLED(OF_CONTROL)
351 int ns16550_serial_ofdata_to_platdata(struct udevice *dev)
352 {
353 	struct ns16550_platdata *plat = dev->platdata;
354 	fdt_addr_t addr;
355 
356 	/* try Processor Local Bus device first */
357 	addr = dev_get_addr(dev);
358 #if defined(CONFIG_PCI) && defined(CONFIG_DM_PCI)
359 	if (addr == FDT_ADDR_T_NONE) {
360 		/* then try pci device */
361 		struct fdt_pci_addr pci_addr;
362 		u32 bar;
363 		int ret;
364 
365 		/* we prefer to use a memory-mapped register */
366 		ret = fdtdec_get_pci_addr(gd->fdt_blob, dev->of_offset,
367 					  FDT_PCI_SPACE_MEM32, "reg",
368 					  &pci_addr);
369 		if (ret) {
370 			/* try if there is any i/o-mapped register */
371 			ret = fdtdec_get_pci_addr(gd->fdt_blob,
372 						  dev->of_offset,
373 						  FDT_PCI_SPACE_IO,
374 						  "reg", &pci_addr);
375 			if (ret)
376 				return ret;
377 		}
378 
379 		ret = fdtdec_get_pci_bar32(dev, &pci_addr, &bar);
380 		if (ret)
381 			return ret;
382 
383 		addr = bar;
384 	}
385 #endif
386 
387 	if (addr == FDT_ADDR_T_NONE)
388 		return -EINVAL;
389 
390 #ifdef CONFIG_SYS_NS16550_PORT_MAPPED
391 	plat->base = addr;
392 #else
393 	plat->base = (unsigned long)map_physmem(addr, 0, MAP_NOCACHE);
394 #endif
395 
396 	plat->reg_offset = fdtdec_get_int(gd->fdt_blob, dev->of_offset,
397 				     "reg-offset", 0);
398 	plat->reg_shift = fdtdec_get_int(gd->fdt_blob, dev->of_offset,
399 					 "reg-shift", 0);
400 	plat->clock = fdtdec_get_int(gd->fdt_blob, dev->of_offset,
401 				     "clock-frequency",
402 				     CONFIG_SYS_NS16550_CLK);
403 	if (!plat->clock) {
404 		debug("ns16550 clock not defined\n");
405 		return -EINVAL;
406 	}
407 
408 	return 0;
409 }
410 #endif
411 
412 const struct dm_serial_ops ns16550_serial_ops = {
413 	.putc = ns16550_serial_putc,
414 	.pending = ns16550_serial_pending,
415 	.getc = ns16550_serial_getc,
416 	.setbrg = ns16550_serial_setbrg,
417 };
418 
419 #if CONFIG_IS_ENABLED(OF_CONTROL)
420 /*
421  * Please consider existing compatible strings before adding a new
422  * one to keep this table compact. Or you may add a generic "ns16550"
423  * compatible string to your dts.
424  */
425 static const struct udevice_id ns16550_serial_ids[] = {
426 	{ .compatible = "ns16550" },
427 	{ .compatible = "ns16550a" },
428 	{ .compatible = "nvidia,tegra20-uart" },
429 	{ .compatible = "snps,dw-apb-uart" },
430 	{ .compatible = "ti,omap2-uart" },
431 	{ .compatible = "ti,omap3-uart" },
432 	{ .compatible = "ti,omap4-uart" },
433 	{ .compatible = "ti,am3352-uart" },
434 	{ .compatible = "ti,am4372-uart" },
435 	{ .compatible = "ti,dra742-uart" },
436 	{}
437 };
438 #endif
439 
440 #if CONFIG_IS_ENABLED(SERIAL_PRESENT)
441 U_BOOT_DRIVER(ns16550_serial) = {
442 	.name	= "ns16550_serial",
443 	.id	= UCLASS_SERIAL,
444 #if CONFIG_IS_ENABLED(OF_CONTROL)
445 	.of_match = ns16550_serial_ids,
446 	.ofdata_to_platdata = ns16550_serial_ofdata_to_platdata,
447 	.platdata_auto_alloc_size = sizeof(struct ns16550_platdata),
448 #endif
449 	.priv_auto_alloc_size = sizeof(struct NS16550),
450 	.probe = ns16550_serial_probe,
451 	.ops	= &ns16550_serial_ops,
452 	.flags	= DM_FLAG_PRE_RELOC,
453 };
454 #endif
455 #endif /* CONFIG_DM_SERIAL */
456