From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.4 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 439B3C54FD5 for ; Wed, 25 Mar 2020 02:33:45 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 0D61420714 for ; Wed, 25 Mar 2020 02:33:44 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="E2eRhKyf" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0D61420714 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:58380 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jGvrU-0005tf-79 for qemu-devel@archiver.kernel.org; Tue, 24 Mar 2020 22:33:44 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:43696) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jGvqd-0005Mj-FH for qemu-devel@nongnu.org; Tue, 24 Mar 2020 22:32:52 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1jGvqb-0005VT-If for qemu-devel@nongnu.org; Tue, 24 Mar 2020 22:32:50 -0400 Received: from us-smtp-delivery-74.mimecast.com ([216.205.24.74]:37825) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1jGvqb-0005UP-9q for qemu-devel@nongnu.org; Tue, 24 Mar 2020 22:32:49 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1585103567; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=tfvdA6fl0nGiCwzGaUVcG2y7t0dMnDN1knHz/pUXHD8=; b=E2eRhKyfMxcIhqm1tMJScAXAelLaZqGfUxR2dtq+wgNYBwBg1Qwk5KwWeMNfBy3ERELQ9P BUUIlPsO8QzZXJ2ajdhGUJgHmyOqJP0+tj5l/vcH3YqIfr5B8Gcoj1/xJQWmBs82HL+T/T adv/pG3q8NAxlKL6jNYovTY/aohPkkE= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-223-yI709ja9MEezamytUEt5IQ-1; Tue, 24 Mar 2020 22:32:46 -0400 X-MC-Unique: yI709ja9MEezamytUEt5IQ-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id DCA331005513; Wed, 25 Mar 2020 02:32:44 +0000 (UTC) Received: from localhost.localdomain (vpn2-54-53.bne.redhat.com [10.64.54.53]) by smtp.corp.redhat.com (Postfix) with ESMTPS id C759B5C241; Wed, 25 Mar 2020 02:32:42 +0000 (UTC) Subject: Re: [PATCH v3] hw/char/pl011: Enable TxFIFO and async transmission From: Gavin Shan To: qemu-devel@nongnu.org, qemu-arm@nongnu.org References: <20200311040923.29115-1-gshan@redhat.com> Message-ID: <4c32dbe0-7d96-5e60-addc-b1bf43e17f47@redhat.com> Date: Wed, 25 Mar 2020 13:32:39 +1100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.2.0 MIME-Version: 1.0 In-Reply-To: <20200311040923.29115-1-gshan@redhat.com> Content-Language: en-US X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: quoted-printable X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 216.205.24.74 X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: peter.maydell@linaro.org, philmd@redhat.com, marcandre.lureau@gmail.com, pbonzini@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 3/11/20 3:09 PM, Gavin Shan wrote: > The depth of TxFIFO can be 1 or 16 depending on LCR[4]. The TxFIFO is > disabled when its depth is 1. It's nice to have TxFIFO enabled if > possible because more characters can be piled and transmitted at once, > which would have less overhead. Besides, we can be blocked because of > qemu_chr_fe_write_all(), which isn't nice. >=20 > This enables TxFIFO if possible. On ther other hand, the asynchronous > transmission is enabled if needed, as we did in hw/char/cadence_uart.c >=20 > Signed-off-by: Gavin Shan > --- > v3: Use PL011() to do data type conversion > Return G_SOURCE_REMOVE when the backend is disconnected in pl011_xmi= t() > Drop parenthesis in the condition validating @size in pl011_write_fi= fo() > --- > hw/char/pl011.c | 105 +++++++++++++++++++++++++++++++++++++--- > include/hw/char/pl011.h | 3 ++ > 2 files changed, 102 insertions(+), 6 deletions(-) >=20 Marc-Andr=C3=A9, ping. Could you please review when you get a chance? Thank= s in advance :) > diff --git a/hw/char/pl011.c b/hw/char/pl011.c > index 13e784f9d9..dccb8c42b0 100644 > --- a/hw/char/pl011.c > +++ b/hw/char/pl011.c > @@ -169,6 +169,73 @@ static void pl011_set_read_trigger(PL011State *s) > s->read_trigger =3D 1; > } > =20 > +static gboolean pl011_xmit(GIOChannel *chan, GIOCondition cond, void *op= aque) > +{ > + PL011State *s =3D PL011(opaque); > + int ret; > + > + /* Drain FIFO if there is no backend */ > + if (!qemu_chr_fe_backend_connected(&s->chr)) { > + s->write_count =3D 0; > + s->flags &=3D ~PL011_FLAG_TXFF; > + s->flags |=3D PL011_FLAG_TXFE; > + return G_SOURCE_REMOVE; > + } > + > + /* Nothing to do */ > + if (!s->write_count) { > + return FALSE; > + } > + > + ret =3D qemu_chr_fe_write(&s->chr, s->write_fifo, s->write_count); > + if (ret > 0) { > + s->write_count -=3D ret; > + memmove(s->write_fifo, s->write_fifo + ret, s->write_count); > + s->flags &=3D ~PL011_FLAG_TXFF; > + if (!s->write_count) { > + s->flags |=3D PL011_FLAG_TXFE; > + } > + } > + > + if (s->write_count) { > + s->watch_tag =3D qemu_chr_fe_add_watch(&s->chr, G_IO_OUT | G_IO_= HUP, > + pl011_xmit, s); > + if (!s->watch_tag) { > + s->write_count =3D 0; > + s->flags &=3D ~PL011_FLAG_TXFF; > + s->flags |=3D PL011_FLAG_TXFE; > + return FALSE; > + } > + } > + > + s->int_level |=3D PL011_INT_TX; > + pl011_update(s); > + return FALSE; > +} > + > +static void pl011_write_fifo(void *opaque, const unsigned char *buf, int= size) > +{ > + PL011State *s =3D PL011(opaque); > + int depth =3D (s->lcr & 0x10) ? 16 : 1; > + > + if (size >=3D depth - s->write_count) { > + size =3D depth - s->write_count; > + } > + > + if (size > 0) { > + memcpy(s->write_fifo + s->write_count, buf, size); > + s->write_count +=3D size; > + if (s->write_count >=3D depth) { > + s->flags |=3D PL011_FLAG_TXFF; > + } > + s->flags &=3D ~PL011_FLAG_TXFE; > + } > + > + if (!s->watch_tag) { > + pl011_xmit(NULL, G_IO_OUT, s); > + } > +} > + > static void pl011_write(void *opaque, hwaddr offset, > uint64_t value, unsigned size) > { > @@ -179,13 +246,8 @@ static void pl011_write(void *opaque, hwaddr offset, > =20 > switch (offset >> 2) { > case 0: /* UARTDR */ > - /* ??? Check if transmitter is enabled. */ > ch =3D value; > - /* XXX this blocks entire thread. Rewrite to use > - * qemu_chr_fe_write and background I/O callbacks */ > - qemu_chr_fe_write_all(&s->chr, &ch, 1); > - s->int_level |=3D PL011_INT_TX; > - pl011_update(s); > + pl011_write_fifo(opaque, &ch, 1); > break; > case 1: /* UARTRSR/UARTECR */ > s->rsr =3D 0; > @@ -207,7 +269,16 @@ static void pl011_write(void *opaque, hwaddr offset, > if ((s->lcr ^ value) & 0x10) { > s->read_count =3D 0; > s->read_pos =3D 0; > + > + if (s->watch_tag) { > + g_source_remove(s->watch_tag); > + s->watch_tag =3D 0; > + } > + s->write_count =3D 0; > + s->flags &=3D ~PL011_FLAG_TXFF; > + s->flags |=3D PL011_FLAG_TXFE; > } > + > s->lcr =3D value; > pl011_set_read_trigger(s); > break; > @@ -292,6 +363,24 @@ static const MemoryRegionOps pl011_ops =3D { > .endianness =3D DEVICE_NATIVE_ENDIAN, > }; > =20 > +static bool pl011_write_fifo_needed(void *opaque) > +{ > + PL011State *s =3D PL011(opaque); > + return s->write_count > 0; > +} > + > +static const VMStateDescription vmstate_pl011_write_fifo =3D { > + .name =3D "pl011/write_fifo", > + .version_id =3D 1, > + .minimum_version_id =3D 1, > + .needed =3D pl011_write_fifo_needed, > + .fields =3D (VMStateField[]) { > + VMSTATE_INT32(write_count, PL011State), > + VMSTATE_UINT8_ARRAY(write_fifo, PL011State, 16), > + VMSTATE_END_OF_LIST() > + } > +}; > + > static const VMStateDescription vmstate_pl011 =3D { > .name =3D "pl011", > .version_id =3D 2, > @@ -314,6 +403,10 @@ static const VMStateDescription vmstate_pl011 =3D { > VMSTATE_INT32(read_count, PL011State), > VMSTATE_INT32(read_trigger, PL011State), > VMSTATE_END_OF_LIST() > + }, > + .subsections =3D (const VMStateDescription * []) { > + &vmstate_pl011_write_fifo, > + NULL > } > }; > =20 > diff --git a/include/hw/char/pl011.h b/include/hw/char/pl011.h > index 14187165c6..9d1c24db48 100644 > --- a/include/hw/char/pl011.h > +++ b/include/hw/char/pl011.h > @@ -38,6 +38,7 @@ typedef struct PL011State { > uint32_t int_enabled; > uint32_t int_level; > uint32_t read_fifo[16]; > + uint8_t write_fifo[16]; > uint32_t ilpr; > uint32_t ibrd; > uint32_t fbrd; > @@ -45,6 +46,8 @@ typedef struct PL011State { > int read_pos; > int read_count; > int read_trigger; > + int write_count; > + guint watch_tag; > CharBackend chr; > qemu_irq irq[6]; > const unsigned char *id; >=20