tiny-printf: Handle formatting of %p with an extra Kconfig

The formatting with %pa / %pap behaves like %x, which results in an
incorrect value being output. To improve this, a new fine-tuning
Kconfig SPL_USE_TINY_PRINTF_POINTER_SUPPORT for pointer formatting
has been added. If it is enabled, the output of %pa / %pap should
be correct, and if it is disabled, the pointer formatting is
completely unsupported. In addition to indicate unsupported formatting,
'?' will be output. This allows enabling pointer formatting only
when needed. For SPL_NET it is selected by default. Then it also
supports the formatting with %pm, %pM and %pI4.

In summery this level of %p support for tiny printf is possible now:

1) The standard tiny printf won't have support for pointer formatting.
   So it doesn't print misleading values for %pa, instead '?' will be
   output:
   %p   => ?
   %pa  => ?a
   %pap => ?ap

2) If SPL_USE_TINY_PRINTF_POINTER_SUPPORT is enabled or DEBUG is defined
   tiny printf supports formatting %p and %pa / %pap.

3) If SPL_NET is enabled the support of pointers is extended
   for %pm, %pM and %pI4.

Signed-off-by: Christoph Niedermaier <[email protected]>

2 files changed, 32 insertions, 24 deletions

diff --git a/lib/Kconfig b/lib/Kconfig
index b2aecd8a49e..cdf8f7ee0e8 100644
--- a/lib/Kconfig
+++ b/lib/Kconfig
@@ -253,6 +253,14 @@ config VPL_USE_TINY_PRINTF
 
 	  The supported format specifiers are %c, %s, %u/%d and %x.
 
+config SPL_USE_TINY_PRINTF_POINTER_SUPPORT
+	bool "Extend tiny printf with the pointer formatting %p"
+	depends on SPL_USE_TINY_PRINTF
+	help
+	  This option enables the formatting of pointers %p. It supports
+	  %p and %pa / %pap. If this option is selected by SPL_NET
+	  it also supports the formatting with %pm, %pM and %pI4.
+
 config PANIC_HANG
 	bool "Do not reset the system on fatal error"
 	help
diff --git a/lib/tiny-printf.c b/lib/tiny-printf.c
index 2a7a4d286c0..411ae6189f2 100644
--- a/lib/tiny-printf.c
+++ b/lib/tiny-printf.c
@@ -141,7 +141,7 @@ static void ip4_addr_string(struct printf_info *info, u8 *addr)
 
 	string(info, ip4_addr);
 }
-#endif
+#endif /* CONFIG_SPL_NET */
 
 /*
  * Show a '%p' thing.  A kernel extension is that the '%p' is followed
@@ -157,18 +157,14 @@ static void ip4_addr_string(struct printf_info *info, u8 *addr)
  *       decimal).
  */
 
-static void __maybe_unused pointer(struct printf_info *info, const char *fmt,
-				   void *ptr)
+#if defined(CONFIG_SPL_USE_TINY_PRINTF_POINTER_SUPPORT) || defined(DEBUG)
+static void pointer(struct printf_info *info, const char *fmt, void *ptr)
 {
-#ifdef DEBUG
 	unsigned long num = (uintptr_t)ptr;
 	unsigned long div;
-#endif
 
 	switch (*fmt) {
-#ifdef DEBUG
 	case 'a':
-
 		switch (fmt[1]) {
 		case 'p':
 		default:
@@ -176,7 +172,6 @@ static void __maybe_unused pointer(struct printf_info *info, const char *fmt,
 			break;
 		}
 		break;
-#endif
 #ifdef CONFIG_SPL_NET
 	case 'm':
 		return mac_address_string(info, ptr, false);
@@ -185,16 +180,22 @@ static void __maybe_unused pointer(struct printf_info *info, const char *fmt,
 	case 'I':
 		if (fmt[1] == '4')
 			return ip4_addr_string(info, ptr);
+#else
+	case 'm':
+	case 'M':
+	case 'I':
+		out(info, '?');
+		return;
 #endif
 	default:
 		break;
 	}
-#ifdef DEBUG
+
 	div = 1UL << (sizeof(long) * 8 - 4);
 	for (; div; div /= 0x10)
 		div_out(info, &num, div);
-#endif
 }
+#endif
 
 static int _vprintf(struct printf_info *info, const char *fmt, va_list va)
 {
@@ -269,21 +270,18 @@ static int _vprintf(struct printf_info *info, const char *fmt, va_list va)
 						div_out(info, &num, div);
 				}
 				break;
+#if defined(CONFIG_SPL_USE_TINY_PRINTF_POINTER_SUPPORT) || defined(DEBUG)
 			case 'p':
-				if (CONFIG_IS_ENABLED(NET) ||
-				    CONFIG_IS_ENABLED(NET_LWIP) || _DEBUG) {
-					pointer(info, fmt, va_arg(va, void *));
-					/*
-					 * Skip this because it pulls in _ctype which is
-					 * 256 bytes, and we don't generally implement
-					 * pointer anyway
-					 */
-					while (isalnum(fmt[0]))
-						fmt++;
-					break;
-				}
-				islong = true;
-				fallthrough;
+				pointer(info, fmt, va_arg(va, void *));
+				/*
+				 * Skip this because it pulls in _ctype which is
+				 * 256 bytes, and we don't generally implement
+				 * pointer anyway
+				 */
+				while (isalnum(fmt[0]))
+					fmt++;
+				break;
+#endif
 			case 'x':
 			case 'X':
 				if (islong) {
@@ -310,7 +308,9 @@ static int _vprintf(struct printf_info *info, const char *fmt, va_list va)
 				break;
 			case '%':
 				out(info, '%');
+				break;
 			default:
+				out(info, '?');
 				break;
 			}