[PATCH] check comport existence for udbg

[Mattias Engdegård]

If no serial port is detected in the OF device tree, udbg_putc() will still
attempt to talk to an imaginary uart at physical address 0. This will likely
lead to a hang in udbg_putc(). This trivial patch prevents this by not
creating the ioremapping in that case.

--- chrp_setup.c~	Tue Jun 17 17:43:50 2003
+++ chrp_setup.c	Tue Jun 24 17:37:05 2003
@@ -207,7 +207,9 @@
 #endif

 	/* Map the uart for udbg. */
-	comport = (void *)__ioremap(naca->serialPortAddr, 16, _PAGE_NO_CACHE);
+	if (naca->serialPortAddr)
+		comport = (void *)__ioremap(naca->serialPortAddr, 16,
+					    _PAGE_NO_CACHE);
 	udbg_init_uart(comport);

 	ppc_md.udbg_putc = udbg_putc;

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