tashaboot: arm64 bringup, semihosting payload loader

consoles on the pl011 the dtb points at, walks the memory node and
chosen, loads an arm64 kernel Image over semihosting and jumps to it
with the documented register state. string functions, printf and
libfdt are vendored from lk (lk2nd) and u-boot so the libc surface is
the one those projects already proved. built and booted on qemu virt,
payload exits clean through semihosting.

1 files changed, 63 insertions, 0 deletions

diff --git a/lib/itoa.c b/lib/itoa.c
new file mode 100644
index 0000000..4fc2db6
--- /dev/null
+++ b/lib/itoa.c
@@ -0,0 +1,63 @@
+/* Copyright (c) 2012, The Linux Foundation. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ * * Redistributions of source code must retain the above copyright
+ *  notice, this list of conditions and the following disclaimer.
+ *  * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following
+ * disclaimer in the documentation and/or other materials provided
+ *  with the distribution.
+ *   * Neither the name of The Linux Foundation nor the names of its
+ * contributors may be used to endorse or promote products derived
+ * from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED "AS IS" AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS
+ * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
+ * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+ * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
+ * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN
+ * IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
+
+/* freestanding, no stdlib */
+#include <string.h>
+#include <ctype.h>
+
+int
+itoa(int num, unsigned char* str, int len, int base)
+{
+	int sum = num;
+	int i = 0;
+	int digit;
+
+	if (len == 0)
+		return -1;
+
+	do
+	{
+		digit = sum % base;
+
+		if (digit < 0xA)
+			str[i++] = '0' + digit;
+		else
+			str[i++] = 'A' + digit - 0xA;
+
+		sum /= base;
+
+	}while (sum && (i < (len - 1)));
+
+	if (i == (len - 1) && sum)
+		return -1;
+
+	str[i] = '\0';
+	strrev(str);
+
+	return 0;
+}