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authorDavid Gibson <david@gibson.dropbear.id.au>2007-05-08 12:59:31 +1000
committerPaul Mackerras <paulus@samba.org>2007-05-08 14:47:33 +1000
commitd9b55a03611ff2e2e54fb4e1ad2648d5eb870fa3 (patch)
tree5704be539afcd6f29b1f5751476c8b4f53673bff /arch/powerpc/kernel/udbg_16550.c
parentf6dfc80554b27da11dbb36ebae166b23ec3aa9ca (diff)
[POWERPC] Early serial debug support for PPC44x
This adds support for early serial debugging via the built in port on IBM/AMCC PowerPC 44x CPUs. It uses a bolted TLB entry in address space 1 for the UART's mapping, allowing robust debugging both before and after the initialization of the MMU. Signed-off-by: David Gibson <dwg@au1.ibm.com> Signed-off-by: Paul Mackerras <paulus@samba.org>
Diffstat (limited to 'arch/powerpc/kernel/udbg_16550.c')
-rw-r--r--arch/powerpc/kernel/udbg_16550.c23
1 files changed, 23 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/udbg_16550.c b/arch/powerpc/kernel/udbg_16550.c
index a963f657222..7afab5bcd61 100644
--- a/arch/powerpc/kernel/udbg_16550.c
+++ b/arch/powerpc/kernel/udbg_16550.c
@@ -191,3 +191,26 @@ void udbg_init_pas_realmode(void)
udbg_getc_poll = NULL;
}
#endif /* CONFIG_PPC_MAPLE */
+
+#ifdef CONFIG_PPC_EARLY_DEBUG_44x
+#include <platforms/44x/44x.h>
+
+static void udbg_44x_as1_putc(char c)
+{
+ if (udbg_comport) {
+ while ((as1_readb(&udbg_comport->lsr) & LSR_THRE) == 0)
+ /* wait for idle */;
+ as1_writeb(c, &udbg_comport->thr); eieio();
+ if (c == '\n')
+ udbg_44x_as1_putc('\r');
+ }
+}
+
+void __init udbg_init_44x_as1(void)
+{
+ udbg_comport =
+ (volatile struct NS16550 __iomem *)PPC44x_EARLY_DEBUG_VIRTADDR;
+
+ udbg_putc = udbg_44x_as1_putc;
+}
+#endif /* CONFIG_PPC_EARLY_DEBUG_44x */