From patchwork Fri Sep 5 19:02:50 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sebastian Andrzej Siewior X-Patchwork-Id: 4854251 Return-Path: X-Original-To: patchwork-linux-omap@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork1.web.kernel.org (Postfix) with ESMTP id C83269F32F for ; Fri, 5 Sep 2014 19:26:37 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 04975201FA for ; Fri, 5 Sep 2014 19:26:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E57E32012D for ; Fri, 5 Sep 2014 19:26:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752208AbaIET0R (ORCPT ); Fri, 5 Sep 2014 15:26:17 -0400 Received: from www.linutronix.de ([62.245.132.108]:33903 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751552AbaIET0P (ORCPT ); Fri, 5 Sep 2014 15:26:15 -0400 Received: from localhost ([127.0.0.1] helo=bazinga.breakpoint.cc) by Galois.linutronix.de with esmtp (Exim 4.80) (envelope-from ) id 1XPymx-0002uU-9g; Fri, 05 Sep 2014 21:03:15 +0200 From: Sebastian Andrzej Siewior To: linux-serial@vger.kernel.org Cc: linux-kernel@vger.kernel.org, linux-omap@vger.kernel.org, linux-arm-kernel@lists.infradead.org, tony@atomide.com, balbi@ti.com, Greg Kroah-Hartman , Sebastian Andrzej Siewior Subject: [PATCH 15/18] tty: serial: 8250_dma: add pm runtime Date: Fri, 5 Sep 2014 21:02:50 +0200 Message-Id: <1409943773-7874-16-git-send-email-bigeasy@linutronix.de> X-Mailer: git-send-email 2.1.0 In-Reply-To: <1409943773-7874-1-git-send-email-bigeasy@linutronix.de> References: <1409943773-7874-1-git-send-email-bigeasy@linutronix.de> X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1, SHORTCIRCUIT=-0.0001 Sender: linux-omap-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-omap@vger.kernel.org X-Spam-Status: No, score=-8.6 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP There is nothing to do for RPM in the RX path. If the HW goes off then it won't assert the DMA line and the transfer won't happen. So we hope that the HW does not go off for RX to work (DMA or PIO makes no difference here). For TX the situation is slightly different. RPM is enabled on start_tx(). We can't disable RPM on DMA complete callback because there is still data in the FIFO which is being sent. We have to wait until the FIFO is empty before we disable it. For this to happen we fake a TX sent error and enable THRI. Once the FIFO is empty we receive an interrupt and since the TTY-buffer is still empty we "put RPM" via __stop_tx(). Should it been filed then in the start_tx() path we should program the DMA transfer and remove the error flag and the THRI bit. Signed-off-by: Sebastian Andrzej Siewior --- drivers/tty/serial/8250/8250_dma.c | 16 +++++++++++----- 1 file changed, 11 insertions(+), 5 deletions(-) diff --git a/drivers/tty/serial/8250/8250_dma.c b/drivers/tty/serial/8250/8250_dma.c index f0fce8236279..1b4a8e02e844 100644 --- a/drivers/tty/serial/8250/8250_dma.c +++ b/drivers/tty/serial/8250/8250_dma.c @@ -21,6 +21,7 @@ static void __dma_tx_complete(void *param) struct uart_8250_dma *dma = p->dma; struct circ_buf *xmit = &p->port.state->xmit; unsigned long flags; + bool en_thri = false; dma_sync_single_for_cpu(dma->txchan->device->dev, dma->tx_addr, UART_XMIT_SIZE, DMA_TO_DEVICE); @@ -40,11 +41,16 @@ static void __dma_tx_complete(void *param) int ret; ret = serial8250_tx_dma(p); - if (ret) { - dma->tx_err = 1; - p->ier |= UART_IER_THRI; - serial_port_out(&p->port, UART_IER, p->ier); - } + if (ret) + en_thri = true; + + } else if (p->capabilities & UART_CAP_RPM) + en_thri = true; + + if (en_thri) { + dma->tx_err = 1; + p->ier |= UART_IER_THRI; + serial_port_out(&p->port, UART_IER, p->ier); } spin_unlock_irqrestore(&p->port.lock, flags);