xref: /openbmc/u-boot/drivers/serial/ns16550.c (revision c6832a96)
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 static void ns16550_writeb(NS16550_t port, int offset, int value)
59 {
60 	struct ns16550_platdata *plat = port->plat;
61 	unsigned char *addr;
62 
63 	offset *= 1 << plat->reg_shift;
64 	addr = map_sysmem(plat->base, 0) + offset;
65 	/*
66 	 * As far as we know it doesn't make sense to support selection of
67 	 * these options at run-time, so use the existing CONFIG options.
68 	 */
69 #ifdef CONFIG_SYS_NS16550_PORT_MAPPED
70 	outb(value, (ulong)addr);
71 #elif defined(CONFIG_SYS_NS16550_MEM32) && !defined(CONFIG_SYS_BIG_ENDIAN)
72 	out_le32(addr, value);
73 #elif defined(CONFIG_SYS_NS16550_MEM32) && defined(CONFIG_SYS_BIG_ENDIAN)
74 	out_be32(addr, value);
75 #elif defined(CONFIG_SYS_BIG_ENDIAN)
76 	writeb(value, addr + (1 << plat->reg_shift) - 1);
77 #else
78 	writeb(value, addr);
79 #endif
80 }
81 
82 static int ns16550_readb(NS16550_t port, int offset)
83 {
84 	struct ns16550_platdata *plat = port->plat;
85 	unsigned char *addr;
86 
87 	offset *= 1 << plat->reg_shift;
88 	addr = map_sysmem(plat->base, 0) + offset;
89 #ifdef CONFIG_SYS_NS16550_PORT_MAPPED
90 	return inb((ulong)addr);
91 #elif defined(CONFIG_SYS_NS16550_MEM32) && !defined(CONFIG_SYS_BIG_ENDIAN)
92 	return in_le32(addr);
93 #elif defined(CONFIG_SYS_NS16550_MEM32) && defined(CONFIG_SYS_BIG_ENDIAN)
94 	return in_be32(addr);
95 #elif defined(CONFIG_SYS_BIG_ENDIAN)
96 	return readb(addr + (1 << plat->reg_shift) - 1);
97 #else
98 	return readb(addr);
99 #endif
100 }
101 
102 /* We can clean these up once everything is moved to driver model */
103 #define serial_out(value, addr)	\
104 	ns16550_writeb(com_port, addr - (unsigned char *)com_port, value)
105 #define serial_in(addr) \
106 	ns16550_readb(com_port, addr - (unsigned char *)com_port)
107 #endif
108 
109 int ns16550_calc_divisor(NS16550_t port, int clock, int baudrate)
110 {
111 	const unsigned int mode_x_div = 16;
112 
113 #ifdef CONFIG_OMAP1510
114 	/* If can't cleanly clock 115200 set div to 1 */
115 	if ((clock == 12000000) && (baudrate == 115200)) {
116 		port->osc_12m_sel = OSC_12M_SEL;  /* enable 6.5 * divisor */
117 		return 1;			/* return 1 for base divisor */
118 	}
119 	port->osc_12m_sel = 0;			/* clear if previsouly set */
120 #endif
121 
122 	return DIV_ROUND_CLOSEST(clock, mode_x_div * baudrate);
123 }
124 
125 static void NS16550_setbrg(NS16550_t com_port, int baud_divisor)
126 {
127 	serial_out(UART_LCR_BKSE | UART_LCRVAL, &com_port->lcr);
128 	serial_out(baud_divisor & 0xff, &com_port->dll);
129 	serial_out((baud_divisor >> 8) & 0xff, &com_port->dlm);
130 	serial_out(UART_LCRVAL, &com_port->lcr);
131 }
132 
133 void NS16550_init(NS16550_t com_port, int baud_divisor)
134 {
135 #if (defined(CONFIG_SPL_BUILD) && defined(CONFIG_OMAP34XX))
136 	/*
137 	 * On some OMAP3 devices when UART3 is configured for boot mode before
138 	 * SPL starts only THRE bit is set. We have to empty the transmitter
139 	 * before initialization starts.
140 	 */
141 	if ((serial_in(&com_port->lsr) & (UART_LSR_TEMT | UART_LSR_THRE))
142 	     == UART_LSR_THRE) {
143 		if (baud_divisor != -1)
144 			NS16550_setbrg(com_port, baud_divisor);
145 		serial_out(0, &com_port->mdr1);
146 	}
147 #endif
148 
149 	while (!(serial_in(&com_port->lsr) & UART_LSR_TEMT))
150 		;
151 
152 	serial_out(CONFIG_SYS_NS16550_IER, &com_port->ier);
153 #if defined(CONFIG_OMAP) || defined(CONFIG_AM33XX) || \
154 			defined(CONFIG_TI81XX) || defined(CONFIG_AM43XX)
155 	serial_out(0x7, &com_port->mdr1);	/* mode select reset TL16C750*/
156 #endif
157 	NS16550_setbrg(com_port, 0);
158 	serial_out(UART_MCRVAL, &com_port->mcr);
159 	serial_out(UART_FCRVAL, &com_port->fcr);
160 	if (baud_divisor != -1)
161 		NS16550_setbrg(com_port, baud_divisor);
162 #if defined(CONFIG_OMAP) || \
163 	defined(CONFIG_AM33XX) || defined(CONFIG_SOC_DA8XX) || \
164 	defined(CONFIG_TI81XX) || defined(CONFIG_AM43XX)
165 
166 	/* /16 is proper to hit 115200 with 48MHz */
167 	serial_out(0, &com_port->mdr1);
168 #endif /* CONFIG_OMAP */
169 #if defined(CONFIG_SOC_KEYSTONE)
170 	serial_out(UART_REG_VAL_PWREMU_MGMT_UART_ENABLE, &com_port->regC);
171 #endif
172 }
173 
174 #ifndef CONFIG_NS16550_MIN_FUNCTIONS
175 void NS16550_reinit(NS16550_t com_port, int baud_divisor)
176 {
177 	serial_out(CONFIG_SYS_NS16550_IER, &com_port->ier);
178 	NS16550_setbrg(com_port, 0);
179 	serial_out(UART_MCRVAL, &com_port->mcr);
180 	serial_out(UART_FCRVAL, &com_port->fcr);
181 	NS16550_setbrg(com_port, baud_divisor);
182 }
183 #endif /* CONFIG_NS16550_MIN_FUNCTIONS */
184 
185 void NS16550_putc(NS16550_t com_port, char c)
186 {
187 	while ((serial_in(&com_port->lsr) & UART_LSR_THRE) == 0)
188 		;
189 	serial_out(c, &com_port->thr);
190 
191 	/*
192 	 * Call watchdog_reset() upon newline. This is done here in putc
193 	 * since the environment code uses a single puts() to print the complete
194 	 * environment upon "printenv". So we can't put this watchdog call
195 	 * in puts().
196 	 */
197 	if (c == '\n')
198 		WATCHDOG_RESET();
199 }
200 
201 #ifndef CONFIG_NS16550_MIN_FUNCTIONS
202 char NS16550_getc(NS16550_t com_port)
203 {
204 	while ((serial_in(&com_port->lsr) & UART_LSR_DR) == 0) {
205 #if !defined(CONFIG_SPL_BUILD) && defined(CONFIG_USB_TTY)
206 		extern void usbtty_poll(void);
207 		usbtty_poll();
208 #endif
209 		WATCHDOG_RESET();
210 	}
211 	return serial_in(&com_port->rbr);
212 }
213 
214 int NS16550_tstc(NS16550_t com_port)
215 {
216 	return (serial_in(&com_port->lsr) & UART_LSR_DR) != 0;
217 }
218 
219 #endif /* CONFIG_NS16550_MIN_FUNCTIONS */
220 
221 #ifdef CONFIG_DM_SERIAL
222 static int ns16550_serial_putc(struct udevice *dev, const char ch)
223 {
224 	struct NS16550 *const com_port = dev_get_priv(dev);
225 
226 	if (!(serial_in(&com_port->lsr) & UART_LSR_THRE))
227 		return -EAGAIN;
228 	serial_out(ch, &com_port->thr);
229 
230 	/*
231 	 * Call watchdog_reset() upon newline. This is done here in putc
232 	 * since the environment code uses a single puts() to print the complete
233 	 * environment upon "printenv". So we can't put this watchdog call
234 	 * in puts().
235 	 */
236 	if (ch == '\n')
237 		WATCHDOG_RESET();
238 
239 	return 0;
240 }
241 
242 static int ns16550_serial_pending(struct udevice *dev, bool input)
243 {
244 	struct NS16550 *const com_port = dev_get_priv(dev);
245 
246 	if (input)
247 		return serial_in(&com_port->lsr) & UART_LSR_DR ? 1 : 0;
248 	else
249 		return serial_in(&com_port->lsr) & UART_LSR_THRE ? 0 : 1;
250 }
251 
252 static int ns16550_serial_getc(struct udevice *dev)
253 {
254 	struct NS16550 *const com_port = dev_get_priv(dev);
255 
256 	if (!(serial_in(&com_port->lsr) & UART_LSR_DR))
257 		return -EAGAIN;
258 
259 	return serial_in(&com_port->rbr);
260 }
261 
262 static int ns16550_serial_setbrg(struct udevice *dev, int baudrate)
263 {
264 	struct NS16550 *const com_port = dev_get_priv(dev);
265 	struct ns16550_platdata *plat = com_port->plat;
266 	int clock_divisor;
267 
268 	clock_divisor = ns16550_calc_divisor(com_port, plat->clock, baudrate);
269 
270 	NS16550_setbrg(com_port, clock_divisor);
271 
272 	return 0;
273 }
274 
275 int ns16550_serial_probe(struct udevice *dev)
276 {
277 	struct NS16550 *const com_port = dev_get_priv(dev);
278 
279 	com_port->plat = dev_get_platdata(dev);
280 	NS16550_init(com_port, -1);
281 
282 	return 0;
283 }
284 
285 #ifdef CONFIG_OF_CONTROL
286 int ns16550_serial_ofdata_to_platdata(struct udevice *dev)
287 {
288 	struct ns16550_platdata *plat = dev->platdata;
289 	fdt_addr_t addr;
290 
291 	addr = fdtdec_get_addr(gd->fdt_blob, dev->of_offset, "reg");
292 	if (addr == FDT_ADDR_T_NONE)
293 		return -EINVAL;
294 
295 	plat->base = addr;
296 	plat->reg_shift = fdtdec_get_int(gd->fdt_blob, dev->of_offset,
297 					 "reg-shift", 1);
298 
299 	return 0;
300 }
301 #endif
302 
303 const struct dm_serial_ops ns16550_serial_ops = {
304 	.putc = ns16550_serial_putc,
305 	.pending = ns16550_serial_pending,
306 	.getc = ns16550_serial_getc,
307 	.setbrg = ns16550_serial_setbrg,
308 };
309 #endif /* CONFIG_DM_SERIAL */
310