From patchwork Wed Sep 10 19:30:08 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: 4880611 Return-Path: X-Original-To: patchwork-linux-arm@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 E8B2E9F32E for ; Wed, 10 Sep 2014 19:58:34 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 1AC22201BC for ; Wed, 10 Sep 2014 19:58:34 +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 405B420142 for ; Wed, 10 Sep 2014 19:58:33 +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 1XRo0O-0007Tb-4N; Wed, 10 Sep 2014 19:56:40 +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 1XRo0K-0007J2-P7 for linux-arm-kernel@lists.infradead.org; Wed, 10 Sep 2014 19:56:37 +0000 Received: from localhost ([127.0.0.1] helo=bazinga.breakpoint.cc) by Galois.linutronix.de with esmtp (Exim 4.80) (envelope-from ) id 1XRnau-0001bs-Vw; Wed, 10 Sep 2014 21:30:21 +0200 From: Sebastian Andrzej Siewior To: linux-serial@vger.kernel.org Subject: [PATCH 13/16] tty: serial: 8250_dma: add pm runtime Date: Wed, 10 Sep 2014 21:30:08 +0200 Message-Id: <1410377411-26656-14-git-send-email-bigeasy@linutronix.de> X-Mailer: git-send-email 2.1.0 In-Reply-To: <1410377411-26656-1-git-send-email-bigeasy@linutronix.de> References: <1410377411-26656-1-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-20140910_125636_969240_17656EBA X-CRM114-Status: GOOD ( 13.80 ) X-Spam-Score: -2.5 (--) Cc: tony@atomide.com, gregkh@linuxfoundation.org, Sebastian Andrzej Siewior , linux-kernel@vger.kernel.org, balbi@ti.com, 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=-4.4 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. Reviewed-by: Tony Lindgren Tested-by: Tony Lindgren 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 898a6781d0b3..e8850219b150 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);