start trying to boot on visionfive 2

+ Not bootable quite yet. Among other things, I couldn't
  get the current starfive u-boot fork to boot, so
  try adding support for booting with precompiled u-boot
  via the `go` command. Initial testing with qemu shows that
  this should be possible, and if it works, might be useful
  in the (far) future with other slightly janky SBCs.

  Also, NS16550 is 8250-based, and I'm really only using the base
  8250, so rename and add visionfive 2 uart to list of compatibles.
  Visionfive 2 is still completely untested.

2 files changed, 17 insertions, 2 deletions

diff --git a/include/kmi/debug.h b/include/kmi/debug.h
index deca4ca..4079048 100644
--- a/include/kmi/debug.h
+++ b/include/kmi/debug.h
@@ -320,8 +320,8 @@
 #if defined(DEBUG)
 /** Serial devices supported. */
 enum serial_dev {
-	/** NS16550A and compatible. Currently the only supported serial device. */
-	NS16550A,
+	/** 8250 and compatible. Currently the only supported serial device. */
+	UART_8250,
 };
 
 /**
diff --git a/include/kmi/string.h b/include/kmi/string.h
index 2b26a2d..f72299b 100644
--- a/include/kmi/string.h
+++ b/include/kmi/string.h
@@ -215,6 +215,21 @@ void *memmove(void *dst, const void *src, size_t num);
  */
 int memcmp(const void *ptr1, const void *ptr2, size_t num);
 
+/**
+ * Try to convert string \p s into a corresponding
+ * \c uintptr_t. Handles decimal, octal and hex,
+ * assuming hex starts with \c 0x or \c 0X and octal with
+ * \c 0, otherwise assumes decimal. Allows \c + and \c - in
+ * decimal.
+ *
+ * Note that u-boot likes to skip leading \c 0x when using hex,
+ * so if you're passing u-boot variables make sure to check prefixes.
+ *
+ * @param s String to convert to pointer.
+ * @return Corresponding pointer value.
+ */
+uintptr_t strtouintptr(const char *s);
+
 /* Honorable mentions:
  *
  * char *strerror(int err);