From ac4ac788fdadc6b703ff3322de07dee442e08e1c Mon Sep 17 00:00:00 2001 From: Nicholas Piggin Date: Tue, 1 May 2018 00:55:50 +1000 Subject: [PATCH] powerpc/powernv: move opal console flushing to udbg OPAL console writes do not have to synchronously flush firmware / hardware buffers unless they are going through the udbg path. Remove the unconditional flushing from opal_put_chars. Flush if there was no space in the buffer as an optimisation (callers loop waiting for success in that case). udbg flushing is moved to udbg_opal_putc. Signed-off-by: Nicholas Piggin Signed-off-by: Michael Ellerman --- arch/powerpc/platforms/powernv/opal.c | 12 +++++++----- drivers/tty/hvc/hvc_opal.c | 5 +++++ 2 files changed, 12 insertions(+), 5 deletions(-) diff --git a/arch/powerpc/platforms/powernv/opal.c b/arch/powerpc/platforms/powernv/opal.c index e184727..cf02e60 100644 --- a/arch/powerpc/platforms/powernv/opal.c +++ b/arch/powerpc/platforms/powernv/opal.c @@ -400,12 +400,14 @@ int opal_put_chars(uint32_t vtermno, const char *data, int total_len) out: spin_unlock_irqrestore(&opal_write_lock, flags); - /* This is a bit nasty but we need that for the console to - * flush when there aren't any interrupts. We will clean - * things a bit later to limit that to synchronous path - * such as the kernel console and xmon/udbg + /* In the -EAGAIN case, callers loop, so we have to flush the console + * here in case they have interrupts off (and we don't want to wait + * for async flushing if we can make immediate progress here). If + * necessary the API could be made entirely non-flushing if the + * callers had a ->flush API to use. */ - opal_flush_console(vtermno); + if (written == -EAGAIN) + opal_flush_console(vtermno); return written; } diff --git a/drivers/tty/hvc/hvc_opal.c b/drivers/tty/hvc/hvc_opal.c index 9645c00..958c61c 100644 --- a/drivers/tty/hvc/hvc_opal.c +++ b/drivers/tty/hvc/hvc_opal.c @@ -275,6 +275,11 @@ static void udbg_opal_putc(char c) count = hvc_opal_hvsi_put_chars(termno, &c, 1); break; } + + /* This is needed for the cosole to flush + * when there aren't any interrupts. + */ + opal_flush_console(termno); } while(count == 0 || count == -EAGAIN); } -- 2.7.4