[PATCH] powerpc/powernv: Properly drop characters if console is closed

[Benjamin Herrenschmidt]

If the firmware returns an error such as "closed" (or hardware
error), we should drop characters.

Currently we only do that when a firmware compatible with OPAL v2
APIs is detected, in the code that calls opal_console_write_buffer_space(),
which didn't exist with OPAL v1 (or didn't work).

However, when enabling early debug consoles, the flag indicating
that v2 is supported isn't set yet, causing us, in case of errors
or closed console, to spin forever.

Signed-off-by: Benjamin Herrenschmidt <benh at kernel.crashing.org>
---
 arch/powerpc/platforms/powernv/opal.c |    7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/arch/powerpc/platforms/powernv/opal.c b/arch/powerpc/platforms/powernv/opal.c
index ade4463..12d9846 100644
--- a/arch/powerpc/platforms/powernv/opal.c
+++ b/arch/powerpc/platforms/powernv/opal.c
@@ -144,6 +144,13 @@ int opal_put_chars(uint32_t vtermno, const char *data, int total_len)
 				rc == OPAL_BUSY_EVENT || rc == OPAL_SUCCESS)) {
 		len = total_len;
 		rc = opal_console_write(vtermno, &len, data);
+
+		/* Closed or other error drop */
+		if (rc != OPAL_SUCCESS && rc != OPAL_BUSY &&
+		    rc != OPAL_BUSY_EVENT) {
+			written = total_len;
+			break;
+		}
 		if (rc == OPAL_SUCCESS) {
 			total_len -= len;
 			data += len;