From patchwork Fri Aug 15 17:42:40 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: 4728871 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 47DEAC0338 for ; Fri, 15 Aug 2014 18:08:47 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 75B7A2015A for ; Fri, 15 Aug 2014 18:08:46 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.9]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id A20CE2013D for ; Fri, 15 Aug 2014 18:08:45 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1XILsh-0006Hn-Ms; Fri, 15 Aug 2014 18:05:39 +0000 Received: from galois.linutronix.de ([2001:470:1f0b:db:abcd:42:0:1]) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1XILsf-0006By-BG for linux-arm-kernel@lists.infradead.org; Fri, 15 Aug 2014 18:05:37 +0000 Received: from localhost ([127.0.0.1] helo=bazinga.breakpoint.cc) by Galois.linutronix.de with esmtp (Exim 4.80) (envelope-from ) id 1XILWk-0006sE-Ah; Fri, 15 Aug 2014 19:42:58 +0200 From: Sebastian Andrzej Siewior To: linux-serial@vger.kernel.org Subject: [PATCH 12/15] tty: serial: 8250_dma: add pm runtime Date: Fri, 15 Aug 2014 19:42:40 +0200 Message-Id: <1408124563-31541-13-git-send-email-bigeasy@linutronix.de> X-Mailer: git-send-email 2.0.1 In-Reply-To: <1408124563-31541-1-git-send-email-bigeasy@linutronix.de> References: <1408124563-31541-1-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 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20140815_110537_543938_5D83A443 X-CRM114-Status: GOOD ( 13.60 ) X-Spam-Score: -0.7 (/) Cc: tony@atomide.com, Greg Kroah-Hartman , Sebastian Andrzej Siewior , linux-kernel@vger.kernel.org, balbi@ti.com, Vinod Koul , linux-omap@vger.kernel.org, linux-arm-kernel@lists.infradead.org X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.18-1 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Spam-Status: No, score=-2.6 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_NONE, 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 cfc83d4..8a26024 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) { - p->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) { + p->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);