From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pl0-x242.google.com (mail-pl0-x242.google.com [IPv6:2607:f8b0:400e:c01::242]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 40KK0w0RWmzDrbT for ; Mon, 9 Apr 2018 15:41:19 +1000 (AEST) Received: by mail-pl0-x242.google.com with SMTP id t20-v6so1648064ply.9 for ; Sun, 08 Apr 2018 22:41:19 -0700 (PDT) From: Nicholas Piggin To: linuxppc-dev@lists.ozlabs.org Cc: Nicholas Piggin Subject: [PATCH 4/6] powerpc/powernv: move opal console flushing to udbg Date: Mon, 9 Apr 2018 15:40:54 +1000 Message-Id: <20180409054056.27292-5-npiggin@gmail.com> In-Reply-To: <20180409054056.27292-1-npiggin@gmail.com> References: <20180409054056.27292-1-npiggin@gmail.com> List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , 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 --- 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 a045c446a910..b05500a70f58 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 2ed07ca6389e..af122ad7f06d 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); } -- 2.17.0