From patchwork Mon Feb 18 21:48:15 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Anthony Liguori X-Patchwork-Id: 221514 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id 155982C0291 for ; Tue, 19 Feb 2013 08:59:54 +1100 (EST) Received: from localhost ([::1]:36219 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1U7Yka-0001H2-9M for incoming@patchwork.ozlabs.org; Mon, 18 Feb 2013 16:59:52 -0500 Received: from eggs.gnu.org ([208.118.235.92]:60213) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1U7YaO-00047x-Rm for qemu-devel@nongnu.org; Mon, 18 Feb 2013 16:49:23 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1U7YaM-0004Si-L8 for qemu-devel@nongnu.org; Mon, 18 Feb 2013 16:49:20 -0500 Received: from e28smtp04.in.ibm.com ([122.248.162.4]:49348) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1U7YaM-0004SM-56 for qemu-devel@nongnu.org; Mon, 18 Feb 2013 16:49:18 -0500 Received: from /spool/local by e28smtp04.in.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Tue, 19 Feb 2013 03:16:51 +0530 Received: from d28dlp03.in.ibm.com (9.184.220.128) by e28smtp04.in.ibm.com (192.168.1.134) with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted; Tue, 19 Feb 2013 03:16:50 +0530 Received: from d28relay05.in.ibm.com (d28relay05.in.ibm.com [9.184.220.62]) by d28dlp03.in.ibm.com (Postfix) with ESMTP id BAEFB1258052 for ; Tue, 19 Feb 2013 03:20:00 +0530 (IST) Received: from d28av04.in.ibm.com (d28av04.in.ibm.com [9.184.220.66]) by d28relay05.in.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id r1ILnDHa32112862 for ; Tue, 19 Feb 2013 03:19:13 +0530 Received: from d28av04.in.ibm.com (loopback [127.0.0.1]) by d28av04.in.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id r1ILnE6g027818 for ; Tue, 19 Feb 2013 08:49:14 +1100 Received: from titi.austin.rr.com (sig-9-76-14-15.mts.ibm.com [9.76.14.15]) by d28av04.in.ibm.com (8.14.4/8.13.1/NCO v10.0 AVin) with ESMTP id r1ILmKBn025719; Tue, 19 Feb 2013 08:49:12 +1100 From: Anthony Liguori To: qemu-devel@nongnu.org Date: Mon, 18 Feb 2013 15:48:15 -0600 Message-Id: <1361224096-21075-19-git-send-email-aliguori@us.ibm.com> X-Mailer: git-send-email 1.8.0 In-Reply-To: <1361224096-21075-1-git-send-email-aliguori@us.ibm.com> References: <1361224096-21075-1-git-send-email-aliguori@us.ibm.com> X-Content-Scanned: Fidelis XPS MAILER x-cbid: 13021821-5564-0000-0000-000006A7DA1E X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.4.x-2.6.x [generic] X-Received-From: 122.248.162.4 Cc: Amit Shah , Paolo Bonzini , Anthony Liguori Subject: [Qemu-devel] [PATCH 18/19] serial: add flow control to transmit X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Signed-off-by: Anthony Liguori --- hw/serial.c | 28 +++++++++++----------------- hw/serial.h | 2 -- 2 files changed, 11 insertions(+), 19 deletions(-) diff --git a/hw/serial.c b/hw/serial.c index f0ce9b0..eb38f22 100644 --- a/hw/serial.c +++ b/hw/serial.c @@ -256,16 +256,17 @@ static void serial_update_msl(SerialState *s) qemu_mod_timer(s->modem_status_poll, qemu_get_clock_ns(vm_clock) + get_ticks_per_sec() / 100); } -static void serial_xmit(void *opaque) +static gboolean serial_xmit(GIOChannel *chan, GIOCondition cond, void *opaque) { SerialState *s = opaque; - uint64_t new_xmit_ts = qemu_get_clock_ns(vm_clock); if (s->tsr_retry <= 0) { if (s->fcr & UART_FCR_FE) { s->tsr = fifo_get(s,XMIT_FIFO); if (!s->xmit_fifo.count) s->lsr |= UART_LSR_THRE; + } else if ((s->lsr & UART_LSR_THRE)) { + return FALSE; } else { s->tsr = s->thr; s->lsr |= UART_LSR_THRE; @@ -277,30 +278,25 @@ static void serial_xmit(void *opaque) /* in loopback mode, say that we just received a char */ serial_receive1(s, &s->tsr, 1); } else if (qemu_chr_fe_write(s->chr, &s->tsr, 1) != 1) { - if ((s->tsr_retry > 0) && (s->tsr_retry <= MAX_XMIT_RETRY)) { + if (s->tsr_retry >= 0 && s->tsr_retry < MAX_XMIT_RETRY && + qemu_chr_fe_add_watch(s->chr, G_IO_OUT, serial_xmit, s) > 0) { s->tsr_retry++; - qemu_mod_timer(s->transmit_timer, new_xmit_ts + s->char_transmit_time); - return; - } else if (s->poll_msl < 0) { - /* If we exceed MAX_XMIT_RETRY and the backend is not a real serial port, then - drop any further failed writes instantly, until we get one that goes through. - This is to prevent guests that log to unconnected pipes or pty's from stalling. */ - s->tsr_retry = -1; + return FALSE; } - } - else { + s->tsr_retry = 0; + } else { s->tsr_retry = 0; } s->last_xmit_ts = qemu_get_clock_ns(vm_clock); - if (!(s->lsr & UART_LSR_THRE)) - qemu_mod_timer(s->transmit_timer, s->last_xmit_ts + s->char_transmit_time); if (s->lsr & UART_LSR_THRE) { s->lsr |= UART_LSR_TEMT; s->thr_ipending = 1; serial_update_irq(s); } + + return FALSE; } @@ -330,7 +326,7 @@ static void serial_ioport_write(void *opaque, hwaddr addr, uint64_t val, s->lsr &= ~UART_LSR_THRE; serial_update_irq(s); } - serial_xmit(s); + serial_xmit(NULL, G_IO_OUT, s); } break; case 1: @@ -684,8 +680,6 @@ void serial_init_core(SerialState *s) s->modem_status_poll = qemu_new_timer_ns(vm_clock, (QEMUTimerCB *) serial_update_msl, s); s->fifo_timeout_timer = qemu_new_timer_ns(vm_clock, (QEMUTimerCB *) fifo_timeout_int, s); - s->transmit_timer = qemu_new_timer_ns(vm_clock, (QEMUTimerCB *) serial_xmit, s); - qemu_register_reset(serial_reset, s); qemu_chr_add_handlers(s->chr, serial_can_receive1, serial_receive1, diff --git a/hw/serial.h b/hw/serial.h index 98ee424..e57375d 100644 --- a/hw/serial.h +++ b/hw/serial.h @@ -72,8 +72,6 @@ struct SerialState { struct QEMUTimer *fifo_timeout_timer; int timeout_ipending; /* timeout interrupt pending state */ - struct QEMUTimer *transmit_timer; - uint64_t char_transmit_time; /* time to transmit a char in ticks */ int poll_msl;