lib/tiny-printf.c: Add tiny printf function for space limited environments

This patch adds a small printf() version that supports all basic formats.
Its intented to be used in U-Boot SPL versions on platforms with very
limited internal RAM sizes.

To enable it, just define CONFIG_USE_TINY_PRINTF in your defconfig. This
will result in the SPL using this tiny function and the main U-Boot
still using the full-blown printf() function.

This code was copied from:
http://www.sparetimelabs.com/printfrevisited
With mostly only coding style related changes so that its checkpatch
clean.

The size reduction is about 2.5KiB. Here a comparison for the db-mv784mp-gp
(Marvell AXP) SPL:

Without this patch:
  58963   18536    1928   79427   13643 ./spl/u-boot-spl

With this patch:
  56542   18536    1956   77034   12cea ./spl/u-boot-spl

Note:
To make it possible to compile tiny-printf.c instead of vsprintf.c when
CONFIG_USE_TINY_PRINTF is defined, the functions printf() and vprintf() are
moved from common/console.c into vsprintf.c in this patch.

Signed-off-by: Stefan Roese <sr@denx.de>
Cc: Simon Glass <sjg@chromium.org>
Cc: Hans de Goede <hdegoede@redhat.com>
Cc: Tom Rini <trini@konsulko.com>
Cc: Albert Aribaud <albert.u.boot@aribaud.net>

1 files changed, 36 insertions, 0 deletions

diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index 4c82837cc4..dd8380b418 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -861,6 +861,42 @@ int sprintf(char *buf, const char *fmt, ...)
 	return i;
 }
 
+int printf(const char *fmt, ...)
+{
+	va_list args;
+	uint i;
+	char printbuffer[CONFIG_SYS_PBSIZE];
+
+	va_start(args, fmt);
+
+	/*
+	 * For this to work, printbuffer must be larger than
+	 * anything we ever want to print.
+	 */
+	i = vscnprintf(printbuffer, sizeof(printbuffer), fmt, args);
+	va_end(args);
+
+	/* Print the string */
+	puts(printbuffer);
+	return i;
+}
+
+int vprintf(const char *fmt, va_list args)
+{
+	uint i;
+	char printbuffer[CONFIG_SYS_PBSIZE];
+
+	/*
+	 * For this to work, printbuffer must be larger than
+	 * anything we ever want to print.
+	 */
+	i = vscnprintf(printbuffer, sizeof(printbuffer), fmt, args);
+
+	/* Print the string */
+	puts(printbuffer);
+	return i;
+}
+
 static void panic_finish(void) __attribute__ ((noreturn));
 
 static void panic_finish(void)