xref: /openbmc/u-boot/drivers/serial/ns16550.c (revision ed09a554)
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 <mapmem.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 #ifdef CONFIG_DM_SERIAL
59 
60 static inline void serial_out_shift(unsigned char *addr, int shift, int value)
61 {
62 #ifdef CONFIG_SYS_NS16550_PORT_MAPPED
63 	outb(value, (ulong)addr);
64 #elif defined(CONFIG_SYS_NS16550_MEM32) && !defined(CONFIG_SYS_BIG_ENDIAN)
65 	out_le32(addr, value);
66 #elif defined(CONFIG_SYS_NS16550_MEM32) && defined(CONFIG_SYS_BIG_ENDIAN)
67 	out_be32(addr, value);
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(unsigned char *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_BIG_ENDIAN)
84 	return readb(addr + (1 << shift) - 1);
85 #else
86 	return readb(addr);
87 #endif
88 }
89 
90 static void ns16550_writeb(NS16550_t port, int offset, int value)
91 {
92 	struct ns16550_platdata *plat = port->plat;
93 	unsigned char *addr;
94 
95 	offset *= 1 << plat->reg_shift;
96 	addr = map_sysmem(plat->base, 0) + offset;
97 	/*
98 	 * As far as we know it doesn't make sense to support selection of
99 	 * these options at run-time, so use the existing CONFIG options.
100 	 */
101 	serial_out_shift(addr, plat->reg_shift, value);
102 }
103 
104 static int ns16550_readb(NS16550_t port, int offset)
105 {
106 	struct ns16550_platdata *plat = port->plat;
107 	unsigned char *addr;
108 
109 	offset *= 1 << plat->reg_shift;
110 	addr = map_sysmem(plat->base, 0) + offset;
111 
112 	return serial_in_shift(addr, plat->reg_shift);
113 }
114 
115 /* We can clean these up once everything is moved to driver model */
116 #define serial_out(value, addr)	\
117 	ns16550_writeb(com_port, addr - (unsigned char *)com_port, value)
118 #define serial_in(addr) \
119 	ns16550_readb(com_port, addr - (unsigned char *)com_port)
120 #endif
121 
122 static inline int calc_divisor(NS16550_t port, int clock, int baudrate)
123 {
124 	const unsigned int mode_x_div = 16;
125 
126 	return DIV_ROUND_CLOSEST(clock, mode_x_div * baudrate);
127 }
128 
129 int ns16550_calc_divisor(NS16550_t port, int clock, int baudrate)
130 {
131 #ifdef CONFIG_OMAP1510
132 	/* If can't cleanly clock 115200 set div to 1 */
133 	if ((clock == 12000000) && (baudrate == 115200)) {
134 		port->osc_12m_sel = OSC_12M_SEL;  /* enable 6.5 * divisor */
135 		return 1;			/* return 1 for base divisor */
136 	}
137 	port->osc_12m_sel = 0;			/* clear if previsouly set */
138 #endif
139 
140 	return calc_divisor(port, clock, baudrate);
141 }
142 
143 static void NS16550_setbrg(NS16550_t com_port, int baud_divisor)
144 {
145 	serial_out(UART_LCR_BKSE | UART_LCRVAL, &com_port->lcr);
146 	serial_out(baud_divisor & 0xff, &com_port->dll);
147 	serial_out((baud_divisor >> 8) & 0xff, &com_port->dlm);
148 	serial_out(UART_LCRVAL, &com_port->lcr);
149 }
150 
151 void NS16550_init(NS16550_t com_port, int baud_divisor)
152 {
153 #if (defined(CONFIG_SPL_BUILD) && \
154 		(defined(CONFIG_OMAP34XX) || defined(CONFIG_OMAP44XX)))
155 	/*
156 	 * On some OMAP3/OMAP4 devices when UART3 is configured for boot mode
157 	 * before SPL starts only THRE bit is set. We have to empty the
158 	 * transmitter before initialization starts.
159 	 */
160 	if ((serial_in(&com_port->lsr) & (UART_LSR_TEMT | UART_LSR_THRE))
161 	     == UART_LSR_THRE) {
162 		if (baud_divisor != -1)
163 			NS16550_setbrg(com_port, baud_divisor);
164 		serial_out(0, &com_port->mdr1);
165 	}
166 #endif
167 
168 	while (!(serial_in(&com_port->lsr) & UART_LSR_TEMT))
169 		;
170 
171 	serial_out(CONFIG_SYS_NS16550_IER, &com_port->ier);
172 #if defined(CONFIG_OMAP) || defined(CONFIG_AM33XX) || \
173 			defined(CONFIG_TI81XX) || defined(CONFIG_AM43XX)
174 	serial_out(0x7, &com_port->mdr1);	/* mode select reset TL16C750*/
175 #endif
176 	NS16550_setbrg(com_port, 0);
177 	serial_out(UART_MCRVAL, &com_port->mcr);
178 	serial_out(UART_FCRVAL, &com_port->fcr);
179 	if (baud_divisor != -1)
180 		NS16550_setbrg(com_port, baud_divisor);
181 #if defined(CONFIG_OMAP) || \
182 	defined(CONFIG_AM33XX) || defined(CONFIG_SOC_DA8XX) || \
183 	defined(CONFIG_TI81XX) || defined(CONFIG_AM43XX)
184 
185 	/* /16 is proper to hit 115200 with 48MHz */
186 	serial_out(0, &com_port->mdr1);
187 #endif /* CONFIG_OMAP */
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
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(UART_FCRVAL, &com_port->fcr);
200 	NS16550_setbrg(com_port, baud_divisor);
201 }
202 #endif /* CONFIG_NS16550_MIN_FUNCTIONS */
203 
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
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 
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 
244 void debug_uart_init(void)
245 {
246 	struct NS16550 *com_port = (struct NS16550 *)CONFIG_DEBUG_UART_BASE;
247 	int baud_divisor;
248 
249 	/*
250 	 * We copy the code from above because it is already horribly messy.
251 	 * Trying to refactor to nicely remove the duplication doesn't seem
252 	 * feasible. The better fix is to move all users of this driver to
253 	 * driver model.
254 	 */
255 	baud_divisor = calc_divisor(com_port, CONFIG_DEBUG_UART_CLOCK,
256 				    CONFIG_BAUDRATE);
257 
258 	serial_out_shift(&com_port->ier, 0, CONFIG_SYS_NS16550_IER);
259 	serial_out_shift(&com_port->mcr, 0, UART_MCRVAL);
260 	serial_out_shift(&com_port->fcr, 0, UART_FCRVAL);
261 
262 	serial_out_shift(&com_port->lcr, 0, UART_LCR_BKSE | UART_LCRVAL);
263 	serial_out_shift(&com_port->dll, 0, baud_divisor & 0xff);
264 	serial_out_shift(&com_port->dlm, 0, (baud_divisor >> 8) & 0xff);
265 	serial_out_shift(&com_port->lcr, 0, UART_LCRVAL);
266 }
267 
268 static inline void _debug_uart_putc(int ch)
269 {
270 	struct NS16550 *com_port = (struct NS16550 *)CONFIG_DEBUG_UART_BASE;
271 
272 	while (!(serial_in_shift(&com_port->lsr, 0) & UART_LSR_THRE))
273 		;
274 	serial_out_shift(&com_port->thr, 0, ch);
275 }
276 
277 DEBUG_UART_FUNCS
278 
279 #endif
280 
281 #ifdef CONFIG_DM_SERIAL
282 static int ns16550_serial_putc(struct udevice *dev, const char ch)
283 {
284 	struct NS16550 *const com_port = dev_get_priv(dev);
285 
286 	if (!(serial_in(&com_port->lsr) & UART_LSR_THRE))
287 		return -EAGAIN;
288 	serial_out(ch, &com_port->thr);
289 
290 	/*
291 	 * Call watchdog_reset() upon newline. This is done here in putc
292 	 * since the environment code uses a single puts() to print the complete
293 	 * environment upon "printenv". So we can't put this watchdog call
294 	 * in puts().
295 	 */
296 	if (ch == '\n')
297 		WATCHDOG_RESET();
298 
299 	return 0;
300 }
301 
302 static int ns16550_serial_pending(struct udevice *dev, bool input)
303 {
304 	struct NS16550 *const com_port = dev_get_priv(dev);
305 
306 	if (input)
307 		return serial_in(&com_port->lsr) & UART_LSR_DR ? 1 : 0;
308 	else
309 		return serial_in(&com_port->lsr) & UART_LSR_THRE ? 0 : 1;
310 }
311 
312 static int ns16550_serial_getc(struct udevice *dev)
313 {
314 	struct NS16550 *const com_port = dev_get_priv(dev);
315 
316 	if (!(serial_in(&com_port->lsr) & UART_LSR_DR))
317 		return -EAGAIN;
318 
319 	return serial_in(&com_port->rbr);
320 }
321 
322 static int ns16550_serial_setbrg(struct udevice *dev, int baudrate)
323 {
324 	struct NS16550 *const com_port = dev_get_priv(dev);
325 	struct ns16550_platdata *plat = com_port->plat;
326 	int clock_divisor;
327 
328 	clock_divisor = ns16550_calc_divisor(com_port, plat->clock, baudrate);
329 
330 	NS16550_setbrg(com_port, clock_divisor);
331 
332 	return 0;
333 }
334 
335 int ns16550_serial_probe(struct udevice *dev)
336 {
337 	struct NS16550 *const com_port = dev_get_priv(dev);
338 
339 	com_port->plat = dev_get_platdata(dev);
340 	NS16550_init(com_port, -1);
341 
342 	return 0;
343 }
344 
345 #ifdef CONFIG_OF_CONTROL
346 int ns16550_serial_ofdata_to_platdata(struct udevice *dev)
347 {
348 	struct ns16550_platdata *plat = dev->platdata;
349 	fdt_addr_t addr;
350 
351 	/* try Processor Local Bus device first */
352 	addr = fdtdec_get_addr(gd->fdt_blob, dev->of_offset, "reg");
353 #ifdef CONFIG_PCI
354 	if (addr == FDT_ADDR_T_NONE) {
355 		/* then try pci device */
356 		struct fdt_pci_addr pci_addr;
357 		u32 bar;
358 		int ret;
359 
360 		/* we prefer to use a memory-mapped register */
361 		ret = fdtdec_get_pci_addr(gd->fdt_blob, dev->of_offset,
362 					  FDT_PCI_SPACE_MEM32, "reg",
363 					  &pci_addr);
364 		if (ret) {
365 			/* try if there is any i/o-mapped register */
366 			ret = fdtdec_get_pci_addr(gd->fdt_blob,
367 						  dev->of_offset,
368 						  FDT_PCI_SPACE_IO,
369 						  "reg", &pci_addr);
370 			if (ret)
371 				return ret;
372 		}
373 
374 		ret = fdtdec_get_pci_bar32(gd->fdt_blob, dev->of_offset,
375 					   &pci_addr, &bar);
376 		if (ret)
377 			return ret;
378 
379 		addr = bar;
380 	}
381 #endif
382 
383 	if (addr == FDT_ADDR_T_NONE)
384 		return -EINVAL;
385 
386 	plat->base = addr;
387 	plat->reg_shift = fdtdec_get_int(gd->fdt_blob, dev->of_offset,
388 					 "reg-shift", 1);
389 
390 	return 0;
391 }
392 #endif
393 
394 const struct dm_serial_ops ns16550_serial_ops = {
395 	.putc = ns16550_serial_putc,
396 	.pending = ns16550_serial_pending,
397 	.getc = ns16550_serial_getc,
398 	.setbrg = ns16550_serial_setbrg,
399 };
400 #endif /* CONFIG_DM_SERIAL */
401