[POWERPC] Get default baud rate in udbg_scc

On powermac, when open firmware is set to use the SCC for console, this
causes the low level udbg early console to read back the speed and
re-use it instead of hard coding 57600 bps. This doesn't (yet) pass the
detected speed all the way to pmac_zilog though.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>

1 files changed, 12 insertions, 2 deletions

diff --git a/arch/powerpc/platforms/powermac/udbg_scc.c b/arch/powerpc/platforms/powermac/udbg_scc.c
index ce1a235855f7..379db05b0082 100644
--- a/arch/powerpc/platforms/powermac/udbg_scc.c
+++ b/arch/powerpc/platforms/powermac/udbg_scc.c
@@ -111,8 +111,6 @@ void udbg_scc_init(int force_scc)
         pmac_call_feature(PMAC_FTR_SCC_ENABLE, ch,
                           PMAC_SCC_ASYNC | PMAC_SCC_FLAG_XMON, 1);
 
-
-        /* Setup for 57600 8N1 */
         if (ch == ch_a)
                 addr += 0x20;
         sccc = ioremap(addr & PAGE_MASK, PAGE_SIZE) ;
@@ -125,9 +123,21 @@ void udbg_scc_init(int force_scc)
                 x = in_8(sccc);
         out_8(sccc, 0x09);              /* reset A or B side */
         out_8(sccc, 0xc0);
+
+        /* If SCC was the OF output port, read the BRG value, else
+         * Setup for 57600 8N1
+         */
+        if (ch_def != NULL) {
+                out_8(sccc, 13);
+                scc_inittab[1] = in_8(sccc);
+                out_8(sccc, 12);
+                scc_inittab[3] = in_8(sccc);
+        }
+
         for (i = 0; i < sizeof(scc_inittab); ++i)
                 out_8(sccc, scc_inittab[i]);
 
+
         udbg_putc = udbg_scc_putc;
         udbg_getc = udbg_scc_getc;
         udbg_getc_poll = udbg_scc_getc_poll;