xref: /openbmc/u-boot/lib/tiny-printf.c (revision 2a046ff5)
1 // SPDX-License-Identifier: LGPL-2.1+
2 /*
3  * Tiny printf version for SPL
4  *
5  * Copied from:
6  * http://www.sparetimelabs.com/printfrevisited/printfrevisited.php
7  *
8  * Copyright (C) 2004,2008  Kustaa Nyholm
9  */
10 
11 #include <common.h>
12 #include <stdarg.h>
13 #include <serial.h>
14 #include <linux/ctype.h>
15 
16 struct printf_info {
17 	char *bf;	/* Digit buffer */
18 	char zs;	/* non-zero if a digit has been written */
19 	char *outstr;	/* Next output position for sprintf() */
20 
21 	/* Output a character */
22 	void (*putc)(struct printf_info *info, char ch);
23 };
24 
25 static void out(struct printf_info *info, char c)
26 {
27 	*info->bf++ = c;
28 }
29 
30 static void out_dgt(struct printf_info *info, char dgt)
31 {
32 	out(info, dgt + (dgt < 10 ? '0' : 'a' - 10));
33 	info->zs = 1;
34 }
35 
36 static void div_out(struct printf_info *info, unsigned long *num,
37 		    unsigned long div)
38 {
39 	unsigned char dgt = 0;
40 
41 	while (*num >= div) {
42 		*num -= div;
43 		dgt++;
44 	}
45 
46 	if (info->zs || dgt > 0)
47 		out_dgt(info, dgt);
48 }
49 
50 #ifdef CONFIG_SPL_NET_SUPPORT
51 static void string(struct printf_info *info, char *s)
52 {
53 	char ch;
54 
55 	while ((ch = *s++))
56 		out(info, ch);
57 }
58 
59 static const char hex_asc[] = "0123456789abcdef";
60 #define hex_asc_lo(x)	hex_asc[((x) & 0x0f)]
61 #define hex_asc_hi(x)	hex_asc[((x) & 0xf0) >> 4]
62 
63 static inline char *pack_hex_byte(char *buf, u8 byte)
64 {
65 	*buf++ = hex_asc_hi(byte);
66 	*buf++ = hex_asc_lo(byte);
67 	return buf;
68 }
69 
70 static void mac_address_string(struct printf_info *info, u8 *addr,
71 				bool separator)
72 {
73 	/* (6 * 2 hex digits), 5 colons and trailing zero */
74 	char mac_addr[6 * 3];
75 	char *p = mac_addr;
76 	int i;
77 
78 	for (i = 0; i < 6; i++) {
79 		p = pack_hex_byte(p, addr[i]);
80 		if (separator && i != 5)
81 			*p++ = ':';
82 	}
83 	*p = '\0';
84 
85 	string(info, mac_addr);
86 }
87 
88 static char *put_dec_trunc(char *buf, unsigned int q)
89 {
90 	unsigned int d3, d2, d1, d0;
91 	d1 = (q >> 4) & 0xf;
92 	d2 = (q >> 8) & 0xf;
93 	d3 = (q >> 12);
94 
95 	d0 = 6 * (d3 + d2 + d1) + (q & 0xf);
96 	q = (d0 * 0xcd) >> 11;
97 	d0 = d0 - 10 * q;
98 	*buf++ = d0 + '0'; /* least significant digit */
99 	d1 = q + 9 * d3 + 5 * d2 + d1;
100 	if (d1 != 0) {
101 		q = (d1 * 0xcd) >> 11;
102 		d1 = d1 - 10 * q;
103 		*buf++ = d1 + '0'; /* next digit */
104 
105 		d2 = q + 2 * d2;
106 		if ((d2 != 0) || (d3 != 0)) {
107 			q = (d2 * 0xd) >> 7;
108 			d2 = d2 - 10 * q;
109 			*buf++ = d2 + '0'; /* next digit */
110 
111 			d3 = q + 4 * d3;
112 			if (d3 != 0) {
113 				q = (d3 * 0xcd) >> 11;
114 				d3 = d3 - 10 * q;
115 				*buf++ = d3 + '0';  /* next digit */
116 				if (q != 0)
117 					*buf++ = q + '0'; /* most sign. digit */
118 			}
119 		}
120 	}
121 	return buf;
122 }
123 
124 static void ip4_addr_string(struct printf_info *info, u8 *addr)
125 {
126 	/* (4 * 3 decimal digits), 3 dots and trailing zero */
127 	char ip4_addr[4 * 4];
128 	char temp[3];	/* hold each IP quad in reverse order */
129 	char *p = ip4_addr;
130 	int i, digits;
131 
132 	for (i = 0; i < 4; i++) {
133 		digits = put_dec_trunc(temp, addr[i]) - temp;
134 		/* reverse the digits in the quad */
135 		while (digits--)
136 			*p++ = temp[digits];
137 		if (i != 3)
138 			*p++ = '.';
139 	}
140 	*p = '\0';
141 
142 	string(info, ip4_addr);
143 }
144 #endif
145 
146 /*
147  * Show a '%p' thing.  A kernel extension is that the '%p' is followed
148  * by an extra set of characters that are extended format
149  * specifiers.
150  *
151  * Right now we handle:
152  *
153  * - 'M' For a 6-byte MAC address, it prints the address in the
154  *       usual colon-separated hex notation.
155  * - 'm' Same as above except there is no colon-separator.
156  * - 'I4'for IPv4 addresses printed in the usual way (dot-separated
157  *       decimal).
158  */
159 
160 static void pointer(struct printf_info *info, const char *fmt, void *ptr)
161 {
162 #ifdef DEBUG
163 	unsigned long num = (uintptr_t)ptr;
164 	unsigned long div;
165 #endif
166 
167 	switch (*fmt) {
168 #ifdef DEBUG
169 	case 'a':
170 
171 		switch (fmt[1]) {
172 		case 'p':
173 		default:
174 			num = *(phys_addr_t *)ptr;
175 			break;
176 		}
177 		break;
178 #endif
179 #ifdef CONFIG_SPL_NET_SUPPORT
180 	case 'm':
181 		return mac_address_string(info, ptr, false);
182 	case 'M':
183 		return mac_address_string(info, ptr, true);
184 	case 'I':
185 		if (fmt[1] == '4')
186 			return ip4_addr_string(info, ptr);
187 #endif
188 	default:
189 		break;
190 	}
191 #ifdef DEBUG
192 	div = 1UL << (sizeof(long) * 8 - 4);
193 	for (; div; div /= 0x10)
194 		div_out(info, &num, div);
195 #endif
196 }
197 
198 static int _vprintf(struct printf_info *info, const char *fmt, va_list va)
199 {
200 	char ch;
201 	char *p;
202 	unsigned long num;
203 	char buf[12];
204 	unsigned long div;
205 
206 	while ((ch = *(fmt++))) {
207 		if (ch != '%') {
208 			info->putc(info, ch);
209 		} else {
210 			bool lz = false;
211 			int width = 0;
212 			bool islong = false;
213 
214 			ch = *(fmt++);
215 			if (ch == '-')
216 				ch = *(fmt++);
217 
218 			if (ch == '0') {
219 				ch = *(fmt++);
220 				lz = 1;
221 			}
222 
223 			if (ch >= '0' && ch <= '9') {
224 				width = 0;
225 				while (ch >= '0' && ch <= '9') {
226 					width = (width * 10) + ch - '0';
227 					ch = *fmt++;
228 				}
229 			}
230 			if (ch == 'l') {
231 				ch = *(fmt++);
232 				islong = true;
233 			}
234 
235 			info->bf = buf;
236 			p = info->bf;
237 			info->zs = 0;
238 
239 			switch (ch) {
240 			case '\0':
241 				goto abort;
242 			case 'u':
243 			case 'd':
244 				div = 1000000000;
245 				if (islong) {
246 					num = va_arg(va, unsigned long);
247 					if (sizeof(long) > 4)
248 						div *= div * 10;
249 				} else {
250 					num = va_arg(va, unsigned int);
251 				}
252 
253 				if (ch == 'd') {
254 					if (islong && (long)num < 0) {
255 						num = -(long)num;
256 						out(info, '-');
257 					} else if (!islong && (int)num < 0) {
258 						num = -(int)num;
259 						out(info, '-');
260 					}
261 				}
262 				if (!num) {
263 					out_dgt(info, 0);
264 				} else {
265 					for (; div; div /= 10)
266 						div_out(info, &num, div);
267 				}
268 				break;
269 			case 'x':
270 				if (islong) {
271 					num = va_arg(va, unsigned long);
272 					div = 1UL << (sizeof(long) * 8 - 4);
273 				} else {
274 					num = va_arg(va, unsigned int);
275 					div = 0x10000000;
276 				}
277 				if (!num) {
278 					out_dgt(info, 0);
279 				} else {
280 					for (; div; div /= 0x10)
281 						div_out(info, &num, div);
282 				}
283 				break;
284 			case 'c':
285 				out(info, (char)(va_arg(va, int)));
286 				break;
287 			case 's':
288 				p = va_arg(va, char*);
289 				break;
290 			case 'p':
291 				pointer(info, fmt, va_arg(va, void *));
292 				while (isalnum(fmt[0]))
293 					fmt++;
294 				break;
295 			case '%':
296 				out(info, '%');
297 			default:
298 				break;
299 			}
300 
301 			*info->bf = 0;
302 			info->bf = p;
303 			while (*info->bf++ && width > 0)
304 				width--;
305 			while (width-- > 0)
306 				info->putc(info, lz ? '0' : ' ');
307 			if (p) {
308 				while ((ch = *p++))
309 					info->putc(info, ch);
310 			}
311 		}
312 	}
313 
314 abort:
315 	return 0;
316 }
317 
318 #if CONFIG_IS_ENABLED(PRINTF)
319 static void putc_normal(struct printf_info *info, char ch)
320 {
321 	putc(ch);
322 }
323 
324 int vprintf(const char *fmt, va_list va)
325 {
326 	struct printf_info info;
327 
328 	info.putc = putc_normal;
329 	return _vprintf(&info, fmt, va);
330 }
331 
332 int printf(const char *fmt, ...)
333 {
334 	struct printf_info info;
335 
336 	va_list va;
337 	int ret;
338 
339 	info.putc = putc_normal;
340 	va_start(va, fmt);
341 	ret = _vprintf(&info, fmt, va);
342 	va_end(va);
343 
344 	return ret;
345 }
346 #endif
347 
348 static void putc_outstr(struct printf_info *info, char ch)
349 {
350 	*info->outstr++ = ch;
351 }
352 
353 int sprintf(char *buf, const char *fmt, ...)
354 {
355 	struct printf_info info;
356 	va_list va;
357 	int ret;
358 
359 	va_start(va, fmt);
360 	info.outstr = buf;
361 	info.putc = putc_outstr;
362 	ret = _vprintf(&info, fmt, va);
363 	va_end(va);
364 	*info.outstr = '\0';
365 
366 	return ret;
367 }
368 
369 /* Note that size is ignored */
370 int snprintf(char *buf, size_t size, const char *fmt, ...)
371 {
372 	struct printf_info info;
373 	va_list va;
374 	int ret;
375 
376 	va_start(va, fmt);
377 	info.outstr = buf;
378 	info.putc = putc_outstr;
379 	ret = _vprintf(&info, fmt, va);
380 	va_end(va);
381 	*info.outstr = '\0';
382 
383 	return ret;
384 }
385