xref: /openbmc/u-boot/drivers/serial/ns16550.c (revision 4d93617d)
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 static inline void serial_out_shift(unsigned char *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_BIG_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_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(unsigned char *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_BIG_ENDIAN)
83 	return readb(addr + (1 << shift) - 1);
84 #else
85 	return readb(addr);
86 #endif
87 }
88 
89 static void ns16550_writeb(NS16550_t port, int offset, int value)
90 {
91 	struct ns16550_platdata *plat = port->plat;
92 	unsigned char *addr;
93 
94 	offset *= 1 << plat->reg_shift;
95 	addr = map_sysmem(plat->base, 0) + offset;
96 	/*
97 	 * As far as we know it doesn't make sense to support selection of
98 	 * these options at run-time, so use the existing CONFIG options.
99 	 */
100 	serial_out_shift(addr, plat->reg_shift, value);
101 }
102 
103 static int ns16550_readb(NS16550_t port, int offset)
104 {
105 	struct ns16550_platdata *plat = port->plat;
106 	unsigned char *addr;
107 
108 	offset *= 1 << plat->reg_shift;
109 	addr = map_sysmem(plat->base, 0) + offset;
110 
111 	return serial_in_shift(addr, plat->reg_shift);
112 }
113 
114 /* We can clean these up once everything is moved to driver model */
115 #define serial_out(value, addr)	\
116 	ns16550_writeb(com_port, addr - (unsigned char *)com_port, value)
117 #define serial_in(addr) \
118 	ns16550_readb(com_port, addr - (unsigned char *)com_port)
119 #endif
120 
121 static inline int calc_divisor(NS16550_t port, int clock, int baudrate)
122 {
123 	const unsigned int mode_x_div = 16;
124 
125 	return DIV_ROUND_CLOSEST(clock, mode_x_div * baudrate);
126 }
127 
128 int ns16550_calc_divisor(NS16550_t port, int clock, int baudrate)
129 {
130 #ifdef CONFIG_OMAP1510
131 	/* If can't cleanly clock 115200 set div to 1 */
132 	if ((clock == 12000000) && (baudrate == 115200)) {
133 		port->osc_12m_sel = OSC_12M_SEL;  /* enable 6.5 * divisor */
134 		return 1;			/* return 1 for base divisor */
135 	}
136 	port->osc_12m_sel = 0;			/* clear if previsouly set */
137 #endif
138 
139 	return calc_divisor(port, clock, baudrate);
140 }
141 
142 static void NS16550_setbrg(NS16550_t com_port, int baud_divisor)
143 {
144 	serial_out(UART_LCR_BKSE | UART_LCRVAL, &com_port->lcr);
145 	serial_out(baud_divisor & 0xff, &com_port->dll);
146 	serial_out((baud_divisor >> 8) & 0xff, &com_port->dlm);
147 	serial_out(UART_LCRVAL, &com_port->lcr);
148 }
149 
150 void NS16550_init(NS16550_t com_port, int baud_divisor)
151 {
152 #if (defined(CONFIG_SPL_BUILD) && \
153 		(defined(CONFIG_OMAP34XX) || defined(CONFIG_OMAP44XX)))
154 	/*
155 	 * On some OMAP3/OMAP4 devices when UART3 is configured for boot mode
156 	 * before SPL starts only THRE bit is set. We have to empty the
157 	 * transmitter before initialization starts.
158 	 */
159 	if ((serial_in(&com_port->lsr) & (UART_LSR_TEMT | UART_LSR_THRE))
160 	     == UART_LSR_THRE) {
161 		if (baud_divisor != -1)
162 			NS16550_setbrg(com_port, baud_divisor);
163 		serial_out(0, &com_port->mdr1);
164 	}
165 #endif
166 
167 	while (!(serial_in(&com_port->lsr) & UART_LSR_TEMT))
168 		;
169 
170 	serial_out(CONFIG_SYS_NS16550_IER, &com_port->ier);
171 #if defined(CONFIG_OMAP) || defined(CONFIG_AM33XX) || \
172 			defined(CONFIG_TI81XX) || defined(CONFIG_AM43XX)
173 	serial_out(0x7, &com_port->mdr1);	/* mode select reset TL16C750*/
174 #endif
175 	NS16550_setbrg(com_port, 0);
176 	serial_out(UART_MCRVAL, &com_port->mcr);
177 	serial_out(UART_FCRVAL, &com_port->fcr);
178 	if (baud_divisor != -1)
179 		NS16550_setbrg(com_port, baud_divisor);
180 #if defined(CONFIG_OMAP) || \
181 	defined(CONFIG_AM33XX) || defined(CONFIG_SOC_DA8XX) || \
182 	defined(CONFIG_TI81XX) || defined(CONFIG_AM43XX)
183 
184 	/* /16 is proper to hit 115200 with 48MHz */
185 	serial_out(0, &com_port->mdr1);
186 #endif /* CONFIG_OMAP */
187 #if defined(CONFIG_SOC_KEYSTONE)
188 	serial_out(UART_REG_VAL_PWREMU_MGMT_UART_ENABLE, &com_port->regC);
189 #endif
190 }
191 
192 #ifndef CONFIG_NS16550_MIN_FUNCTIONS
193 void NS16550_reinit(NS16550_t com_port, int baud_divisor)
194 {
195 	serial_out(CONFIG_SYS_NS16550_IER, &com_port->ier);
196 	NS16550_setbrg(com_port, 0);
197 	serial_out(UART_MCRVAL, &com_port->mcr);
198 	serial_out(UART_FCRVAL, &com_port->fcr);
199 	NS16550_setbrg(com_port, baud_divisor);
200 }
201 #endif /* CONFIG_NS16550_MIN_FUNCTIONS */
202 
203 void NS16550_putc(NS16550_t com_port, char c)
204 {
205 	while ((serial_in(&com_port->lsr) & UART_LSR_THRE) == 0)
206 		;
207 	serial_out(c, &com_port->thr);
208 
209 	/*
210 	 * Call watchdog_reset() upon newline. This is done here in putc
211 	 * since the environment code uses a single puts() to print the complete
212 	 * environment upon "printenv". So we can't put this watchdog call
213 	 * in puts().
214 	 */
215 	if (c == '\n')
216 		WATCHDOG_RESET();
217 }
218 
219 #ifndef CONFIG_NS16550_MIN_FUNCTIONS
220 char NS16550_getc(NS16550_t com_port)
221 {
222 	while ((serial_in(&com_port->lsr) & UART_LSR_DR) == 0) {
223 #if !defined(CONFIG_SPL_BUILD) && defined(CONFIG_USB_TTY)
224 		extern void usbtty_poll(void);
225 		usbtty_poll();
226 #endif
227 		WATCHDOG_RESET();
228 	}
229 	return serial_in(&com_port->rbr);
230 }
231 
232 int NS16550_tstc(NS16550_t com_port)
233 {
234 	return (serial_in(&com_port->lsr) & UART_LSR_DR) != 0;
235 }
236 
237 #endif /* CONFIG_NS16550_MIN_FUNCTIONS */
238 
239 #ifdef CONFIG_DEBUG_UART_NS16550
240 
241 #include <debug_uart.h>
242 
243 void debug_uart_init(void)
244 {
245 	struct NS16550 *com_port = (struct NS16550 *)CONFIG_DEBUG_UART_BASE;
246 	int baud_divisor;
247 
248 	/*
249 	 * We copy the code from above because it is already horribly messy.
250 	 * Trying to refactor to nicely remove the duplication doesn't seem
251 	 * feasible. The better fix is to move all users of this driver to
252 	 * driver model.
253 	 */
254 	baud_divisor = calc_divisor(com_port, CONFIG_DEBUG_UART_CLOCK,
255 				    CONFIG_BAUDRATE);
256 
257 	serial_out_shift(&com_port->ier, 0, CONFIG_SYS_NS16550_IER);
258 	serial_out_shift(&com_port->mcr, 0, UART_MCRVAL);
259 	serial_out_shift(&com_port->fcr, 0, UART_FCRVAL);
260 
261 	serial_out_shift(&com_port->lcr, 0, UART_LCR_BKSE | UART_LCRVAL);
262 	serial_out_shift(&com_port->dll, 0, baud_divisor & 0xff);
263 	serial_out_shift(&com_port->dlm, 0, (baud_divisor >> 8) & 0xff);
264 	serial_out_shift(&com_port->lcr, 0, UART_LCRVAL);
265 }
266 
267 static inline void _debug_uart_putc(int ch)
268 {
269 	struct NS16550 *com_port = (struct NS16550 *)CONFIG_DEBUG_UART_BASE;
270 
271 	while (!(serial_in_shift(&com_port->lsr, 0) & UART_LSR_THRE))
272 		;
273 	serial_out_shift(&com_port->thr, 0, ch);
274 }
275 
276 DEBUG_UART_FUNCS
277 
278 #endif
279 
280 #ifdef CONFIG_DM_SERIAL
281 static int ns16550_serial_putc(struct udevice *dev, const char ch)
282 {
283 	struct NS16550 *const com_port = dev_get_priv(dev);
284 
285 	if (!(serial_in(&com_port->lsr) & UART_LSR_THRE))
286 		return -EAGAIN;
287 	serial_out(ch, &com_port->thr);
288 
289 	/*
290 	 * Call watchdog_reset() upon newline. This is done here in putc
291 	 * since the environment code uses a single puts() to print the complete
292 	 * environment upon "printenv". So we can't put this watchdog call
293 	 * in puts().
294 	 */
295 	if (ch == '\n')
296 		WATCHDOG_RESET();
297 
298 	return 0;
299 }
300 
301 static int ns16550_serial_pending(struct udevice *dev, bool input)
302 {
303 	struct NS16550 *const com_port = dev_get_priv(dev);
304 
305 	if (input)
306 		return serial_in(&com_port->lsr) & UART_LSR_DR ? 1 : 0;
307 	else
308 		return serial_in(&com_port->lsr) & UART_LSR_THRE ? 0 : 1;
309 }
310 
311 static int ns16550_serial_getc(struct udevice *dev)
312 {
313 	struct NS16550 *const com_port = dev_get_priv(dev);
314 
315 	if (!(serial_in(&com_port->lsr) & UART_LSR_DR))
316 		return -EAGAIN;
317 
318 	return serial_in(&com_port->rbr);
319 }
320 
321 static int ns16550_serial_setbrg(struct udevice *dev, int baudrate)
322 {
323 	struct NS16550 *const com_port = dev_get_priv(dev);
324 	struct ns16550_platdata *plat = com_port->plat;
325 	int clock_divisor;
326 
327 	clock_divisor = ns16550_calc_divisor(com_port, plat->clock, baudrate);
328 
329 	NS16550_setbrg(com_port, clock_divisor);
330 
331 	return 0;
332 }
333 
334 int ns16550_serial_probe(struct udevice *dev)
335 {
336 	struct NS16550 *const com_port = dev_get_priv(dev);
337 
338 	com_port->plat = dev_get_platdata(dev);
339 	NS16550_init(com_port, -1);
340 
341 	return 0;
342 }
343 
344 #ifdef CONFIG_OF_CONTROL
345 int ns16550_serial_ofdata_to_platdata(struct udevice *dev)
346 {
347 	struct ns16550_platdata *plat = dev->platdata;
348 	fdt_addr_t addr;
349 
350 	/* try Processor Local Bus device first */
351 	addr = fdtdec_get_addr(gd->fdt_blob, dev->of_offset, "reg");
352 #ifdef CONFIG_PCI
353 	if (addr == FDT_ADDR_T_NONE) {
354 		/* then try pci device */
355 		struct fdt_pci_addr pci_addr;
356 		u32 bar;
357 		int ret;
358 
359 		/* we prefer to use a memory-mapped register */
360 		ret = fdtdec_get_pci_addr(gd->fdt_blob, dev->of_offset,
361 					  FDT_PCI_SPACE_MEM32, "reg",
362 					  &pci_addr);
363 		if (ret) {
364 			/* try if there is any i/o-mapped register */
365 			ret = fdtdec_get_pci_addr(gd->fdt_blob,
366 						  dev->of_offset,
367 						  FDT_PCI_SPACE_IO,
368 						  "reg", &pci_addr);
369 			if (ret)
370 				return ret;
371 		}
372 
373 		ret = fdtdec_get_pci_bar32(gd->fdt_blob, dev->of_offset,
374 					   &pci_addr, &bar);
375 		if (ret)
376 			return ret;
377 
378 		addr = bar;
379 	}
380 #endif
381 
382 	if (addr == FDT_ADDR_T_NONE)
383 		return -EINVAL;
384 
385 	plat->base = addr;
386 	plat->reg_shift = fdtdec_get_int(gd->fdt_blob, dev->of_offset,
387 					 "reg-shift", 1);
388 
389 	return 0;
390 }
391 #endif
392 
393 const struct dm_serial_ops ns16550_serial_ops = {
394 	.putc = ns16550_serial_putc,
395 	.pending = ns16550_serial_pending,
396 	.getc = ns16550_serial_getc,
397 	.setbrg = ns16550_serial_setbrg,
398 };
399 #endif /* CONFIG_DM_SERIAL */
400