[PATCH] ndelay() for x86

The implementation is not ideal.  Thats something to tidy up.

arch/i386/kernel/i386_ksyms.c

@@ -104,6 +104,7 @@ EXPORT_SYMBOL_NOVERS(__up_wakeup);
 /* Networking helper routines. */
 EXPORT_SYMBOL(csum_partial_copy_generic);
 /* Delay loops */
+EXPORT_SYMBOL(__ndelay);
 EXPORT_SYMBOL(__udelay);
 EXPORT_SYMBOL(__delay);
 EXPORT_SYMBOL(__const_udelay);

arch/i386/lib/delay.c

@@ -41,3 +41,8 @@ void __udelay(unsigned long usecs)
 {
 	__const_udelay(usecs * 0x000010c6);  /* 2**32 / 1000000 */
 }
+
+void __ndelay(unsigned long nsecs)
+{
+	__const_udelay(nsecs * 0x00005);  /* 2**32 / 1000000000 (rounded up) */
+}

include/asm-i386/delay.h

@@ -8,8 +8,10 @@
  */
  
 extern void __bad_udelay(void);
+extern void __bad_ndelay(void);
 
 extern void __udelay(unsigned long usecs);
+extern void __ndelay(unsigned long nsecs);
 extern void __const_udelay(unsigned long usecs);
 extern void __delay(unsigned long loops);
 
@@ -17,4 +19,8 @@ extern void __delay(unsigned long loops);
 	((n) > 20000 ? __bad_udelay() : __const_udelay((n) * 0x10c6ul)) : \
 	__udelay(n))
 	
+#define ndelay(n) (__builtin_constant_p(n) ? \
+	((n) > 20000 ? __bad_ndelay() : __const_udelay((n) * 5ul)) : \
+	__ndelay(n))
+
 #endif /* defined(_I386_DELAY_H) */