[POWERPC] 4xx: Add early udbg support for 40x processors
This adds some basic real mode based early udbg support for 40x
in order to debug things more easily
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Josh Boyer <jwboyer@linux.vnet.ibm.com>
diff --git a/arch/powerpc/kernel/udbg_16550.c b/arch/powerpc/kernel/udbg_16550.c
index df740ea..cb01ebc 100644
--- a/arch/powerpc/kernel/udbg_16550.c
+++ b/arch/powerpc/kernel/udbg_16550.c
@@ -225,3 +225,36 @@
udbg_getc = udbg_44x_as1_getc;
}
#endif /* CONFIG_PPC_EARLY_DEBUG_44x */
+
+#ifdef CONFIG_PPC_EARLY_DEBUG_40x
+static void udbg_40x_real_putc(char c)
+{
+ if (udbg_comport) {
+ while ((real_readb(&udbg_comport->lsr) & LSR_THRE) == 0)
+ /* wait for idle */;
+ real_writeb(c, &udbg_comport->thr); eieio();
+ if (c == '\n')
+ udbg_40x_real_putc('\r');
+ }
+}
+
+static int udbg_40x_real_getc(void)
+{
+ if (udbg_comport) {
+ while ((real_readb(&udbg_comport->lsr) & LSR_DR) == 0)
+ ; /* wait for char */
+ return real_readb(&udbg_comport->rbr);
+ }
+ return -1;
+}
+
+void __init udbg_init_40x_realmode(void)
+{
+ udbg_comport = (struct NS16550 __iomem *)
+ CONFIG_PPC_EARLY_DEBUG_40x_PHYSADDR;
+
+ udbg_putc = udbg_40x_real_putc;
+ udbg_getc = udbg_40x_real_getc;
+ udbg_getc_poll = NULL;
+}
+#endif /* CONFIG_PPC_EARLY_DEBUG_40x */