[U-Boot] [RFC] tiny-printf: Add support for %p format

[Vignesh R]

Add support for %p, %pa[p], %pM, %pm and %pI4 formats to tiny-printf.
%pM and %pI4 are widely used by SPL networking stack and is required if
networking support is desired in SPL.

Before this patch:
$ size spl/u-boot-spl
   text	   data	    bss	    dec	    hex	filename
  99325	   4899	 218584	 322808	  4ecf8	spl/u-boot-spl

After this patch (with CONFIG_SPL_NET_SUPPORT):
$ size spl/u-boot-spl
   text	   data	    bss	    dec	    hex	filename
  99714	   4899	 218584	 323197	  4ee7d	spl/u-boot-spl

So, this patch adds ~390 bytes to code size.

If CONFIG_SPL_NET_SUPPORT is not enabled then only %p, %pa, %pap are
supported, this adds ~90 bytes to code size.

Compiler used is:
arm-linux-gnueabihf-gcc (Linaro GCC 6.2-2016.11) 6.2.1 20161016

Signed-off-by: Vignesh R <vigneshr at ti.com>
---
 lib/tiny-printf.c | 148 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 148 insertions(+)

diff --git a/lib/tiny-printf.c b/lib/tiny-printf.c
index 6def8f98aa41..e524ffb657e6 100644
--- a/lib/tiny-printf.c
+++ b/lib/tiny-printf.c
@@ -12,6 +12,7 @@
 #include <common.h>
 #include <stdarg.h>
 #include <serial.h>
+#include <linux/ctype.h>
 
 struct printf_info {
 	char *bf;	/* Digit buffer */
@@ -52,6 +53,148 @@ static void div_out(struct printf_info *info, unsigned long *num,
 		out_dgt(info, dgt);
 }
 
+#ifdef CONFIG_SPL_NET_SUPPORT
+static void string(struct printf_info *info, char *s)
+{
+	char ch;
+
+	while ((ch = *s++))
+		out(info, ch);
+}
+
+static const char hex_asc[] = "0123456789abcdef";
+#define hex_asc_lo(x)	hex_asc[((x) & 0x0f)]
+#define hex_asc_hi(x)	hex_asc[((x) & 0xf0) >> 4]
+
+static inline char *pack_hex_byte(char *buf, u8 byte)
+{
+	*buf++ = hex_asc_hi(byte);
+	*buf++ = hex_asc_lo(byte);
+	return buf;
+}
+
+static void mac_address_string(struct printf_info *info, u8 *addr,
+				bool separator)
+{
+	/* (6 * 2 hex digits), 5 colons and trailing zero */
+	char mac_addr[6 * 3];
+	char *p = mac_addr;
+	int i;
+
+	for (i = 0; i < 6; i++) {
+		p = pack_hex_byte(p, addr[i]);
+		if (separator && i != 5)
+			*p++ = ':';
+	}
+	*p = '\0';
+
+	string(info, mac_addr);
+}
+
+static char *put_dec_trunc(char *buf, unsigned int q)
+{
+	unsigned int d3, d2, d1, d0;
+	d1 = (q >> 4) & 0xf;
+	d2 = (q >> 8) & 0xf;
+	d3 = (q >> 12);
+
+	d0 = 6 * (d3 + d2 + d1) + (q & 0xf);
+	q = (d0 * 0xcd) >> 11;
+	d0 = d0 - 10 * q;
+	*buf++ = d0 + '0'; /* least significant digit */
+	d1 = q + 9 * d3 + 5 * d2 + d1;
+	if (d1 != 0) {
+		q = (d1 * 0xcd) >> 11;
+		d1 = d1 - 10 * q;
+		*buf++ = d1 + '0'; /* next digit */
+
+		d2 = q + 2 * d2;
+		if ((d2 != 0) || (d3 != 0)) {
+			q = (d2 * 0xd) >> 7;
+			d2 = d2 - 10 * q;
+			*buf++ = d2 + '0'; /* next digit */
+
+			d3 = q + 4 * d3;
+			if (d3 != 0) {
+				q = (d3 * 0xcd) >> 11;
+				d3 = d3 - 10 * q;
+				*buf++ = d3 + '0';  /* next digit */
+				if (q != 0)
+					*buf++ = q + '0'; /* most sign. digit */
+			}
+		}
+	}
+	return buf;
+}
+
+static void ip4_addr_string(struct printf_info *info, u8 *addr)
+{
+	/* (4 * 3 decimal digits), 3 dots and trailing zero */
+	char ip4_addr[4 * 4];
+	char temp[3];	/* hold each IP quad in reverse order */
+	char *p = ip4_addr;
+	int i, digits;
+
+	for (i = 0; i < 4; i++) {
+		digits = put_dec_trunc(temp, addr[i]) - temp;
+		/* reverse the digits in the quad */
+		while (digits--)
+			*p++ = temp[digits];
+		if (i != 3)
+			*p++ = '.';
+	}
+	*p = '\0';
+
+	string(info, ip4_addr);
+}
+#endif
+
+/*
+ * Show a '%p' thing.  A kernel extension is that the '%p' is followed
+ * by an extra set of characters that are extended format
+ * specifiers.
+ *
+ * Right now we handle:
+ *
+ * - 'M' For a 6-byte MAC address, it prints the address in the
+ *       usual colon-separated hex notation.
+ * - 'm' Same as above except there is no colon-separator.
+ * - 'I4'for IPv4 addresses printed in the usual way (dot-separated
+ *       decimal).
+ */
+
+static void pointer(struct printf_info *info, const char *fmt, void *ptr)
+{
+	unsigned long num = (uintptr_t)ptr;
+	unsigned long div;
+
+	switch (*fmt) {
+	case 'a':
+
+		switch (fmt[1]) {
+		case 'p':
+		default:
+			num = *(phys_addr_t *)ptr;
+			break;
+		}
+		break;
+#ifdef CONFIG_SPL_NET_SUPPORT
+	case 'm':
+		return mac_address_string(info, ptr, false);
+	case 'M':
+		return mac_address_string(info, ptr, true);
+	case 'I':
+		if (fmt[1] == '4')
+			return ip4_addr_string(info, ptr);
+#endif
+	default:
+		break;
+	}
+	div = 1UL << (sizeof(long) * 8 - 4);
+	for (; div; div /= 0x10)
+		div_out(info, &num, div);
+}
+
 static int _vprintf(struct printf_info *info, const char *fmt, va_list va)
 {
 	char ch;
@@ -144,6 +287,11 @@ static int _vprintf(struct printf_info *info, const char *fmt, va_list va)
 			case 's':
 				p = va_arg(va, char*);
 				break;
+			case 'p':
+				pointer(info, fmt, va_arg(va, void *));
+				while (isalnum(fmt[0]))
+					fmt++;
+				break;
 			case '%':
 				out(info, '%');
 			default:
-- 
2.11.0