From nobody Wed Nov 5 02:08:11 2025 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) client-ip=208.118.235.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zohomail.com; spf=pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org Return-Path: Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) by mx.zohomail.com with SMTPS id 1532955834371606.4844762794937; Mon, 30 Jul 2018 06:03:54 -0700 (PDT) Received: from localhost ([::1]:52520 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fk7q5-0006l4-Cb for importer@patchew.org; Mon, 30 Jul 2018 09:03:53 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:39503) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fk7p0-0006RK-5t for qemu-devel@nongnu.org; Mon, 30 Jul 2018 09:02:50 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fk7ov-0002fa-Dj for qemu-devel@nongnu.org; Mon, 30 Jul 2018 09:02:46 -0400 Received: from xavier.telenet-ops.be ([2a02:1800:120:4::f00:14]:35842) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1fk7ov-0002eF-6f for qemu-devel@nongnu.org; Mon, 30 Jul 2018 09:02:41 -0400 Received: from ramsan.of.borg ([84.194.111.163]) by xavier.telenet-ops.be with bizsmtp id H12c1y00p3XaVaC0112ciW; Mon, 30 Jul 2018 15:02:38 +0200 Received: from rox.of.borg ([192.168.97.57]) by ramsan.of.borg with esmtp (Exim 4.86_2) (envelope-from ) id 1fk7op-0004gI-VS; Mon, 30 Jul 2018 15:02:35 +0200 Received: from geert by rox.of.borg with local (Exim 4.90_1) (envelope-from ) id 1fk7op-0007ov-TS; Mon, 30 Jul 2018 15:02:35 +0200 From: Geert Uytterhoeven To: Peter Maydell Date: Mon, 30 Jul 2018 15:02:34 +0200 Message-Id: <20180730130234.30020-1-geert+renesas@glider.be> X-Mailer: git-send-email 2.17.1 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x X-Received-From: 2a02:1800:120:4::f00:14 Subject: [Qemu-devel] [PATCH QEMU] hw/char/sh_serial: Add timeout handling to unbreak serial input X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Geert Uytterhoeven , linux-sh@vger.kernel.org, qemu-devel@nongnu.org, linux-renesas-soc@vger.kernel.org, Ulrich Hecht Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail: RSF_0 Z_629925259 SPT_0 Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" As of commit 18e8cf159177100e ("serial: sh-sci: increase RX FIFO trigger defaults for (H)SCIF") in Linux v4.11-rc1, the serial console on the QEMU SH4 target is broken: it delays serial input until enough data has been received. Since aformentioned commit, the Linux SCIF driver programs the Receive FIFO Data Count Trigger bits in the FIFO Control Register, to postpone generating a receive interrupt until: 1. At least the receive trigger count of bytes of data are available in the receive FIFO, OR 2. No further data has been received for at least 15 etu after the last received data. While QEMU implements the former, it does not implement the latter. Hence the receive interrupt is not generated until the former condition is met. Fix this by adding basic timeout handling. As the QEMU SCIF emulation ignores any serial speed programming, the timeout value used conforms to a default speed of 9600 bps, which is fine for any interative console. Reported-by: Rob Landley Signed-off-by: Geert Uytterhoeven Tested-by: Rich Felker Tested-by: Rob Landley Tested-by: Ulrich Hecht --- hw/char/sh_serial.c | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) diff --git a/hw/char/sh_serial.c b/hw/char/sh_serial.c index 373a40595fd975d1..12831561a6c8b137 100644 --- a/hw/char/sh_serial.c +++ b/hw/char/sh_serial.c @@ -29,6 +29,7 @@ #include "hw/sh4/sh.h" #include "chardev/char-fe.h" #include "qapi/error.h" +#include "qemu/timer.h" =20 //#define DEBUG_SERIAL =20 @@ -63,6 +64,8 @@ typedef struct { int rtrg; =20 CharBackend chr; + QEMUTimer *fifo_timeout_timer; + uint64_t etu; /* Elementary Time Unit (ns) */ =20 qemu_irq eri; qemu_irq rxi; @@ -314,6 +317,16 @@ static int sh_serial_can_receive1(void *opaque) return sh_serial_can_receive(s); } =20 +static void sh_serial_timeout_int(void *opaque) +{ + sh_serial_state *s =3D opaque; + + s->flags |=3D SH_SERIAL_FLAG_RDF; + if (s->scr & (1 << 6) && s->rxi) { + qemu_set_irq(s->rxi, 1); + } +} + static void sh_serial_receive1(void *opaque, const uint8_t *buf, int size) { sh_serial_state *s =3D opaque; @@ -330,8 +343,12 @@ static void sh_serial_receive1(void *opaque, const uin= t8_t *buf, int size) if (s->rx_cnt >=3D s->rtrg) { s->flags |=3D SH_SERIAL_FLAG_RDF; if (s->scr & (1 << 6) && s->rxi) { + timer_del(s->fifo_timeout_timer); qemu_set_irq(s->rxi, 1); } + } else { + timer_mod(s->fifo_timeout_timer, + qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) + 15 * s->et= u); } } } @@ -402,6 +419,9 @@ void sh_serial_init(MemoryRegion *sysmem, sh_serial_event, NULL, s, NULL, true); } =20 + s->fifo_timeout_timer =3D timer_new_ns(QEMU_CLOCK_VIRTUAL, + sh_serial_timeout_int, s); + s->etu =3D NANOSECONDS_PER_SECOND / 9600; s->eri =3D eri_source; s->rxi =3D rxi_source; s->txi =3D txi_source; --=20 2.17.1