From patchwork Wed Mar 30 13:20:34 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Miquel Raynal X-Patchwork-Id: 555244 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id E7D22C433FE for ; Wed, 30 Mar 2022 13:20:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1345870AbiC3NWj (ORCPT ); Wed, 30 Mar 2022 09:22:39 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36050 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1345864AbiC3NWi (ORCPT ); Wed, 30 Mar 2022 09:22:38 -0400 Received: from relay1-d.mail.gandi.net (relay1-d.mail.gandi.net [IPv6:2001:4b98:dc4:8::221]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3AFD4488AB; Wed, 30 Mar 2022 06:20:52 -0700 (PDT) Received: (Authenticated sender: miquel.raynal@bootlin.com) by mail.gandi.net (Postfix) with ESMTPSA id 47AF7240011; Wed, 30 Mar 2022 13:20:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bootlin.com; s=gm1; t=1648646450; 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=Y2lJyEILsp8NDkKtykYkfjKRpqQEf+GhkYUQftZF+0c=; b=dnAzsA4ZsYQcxNGUI9CMvGqLfLKaPyquhYof+qd/Kc6tqumAWw+gB+cAqEZWV9wSPxNsxB tTDBJLSQvvX4ofkC3qm8Cpjl/Zdps7y8ytLPksA0CbihhTp05XRAEGpDDZtbg8LRPY6GX9 cHfTynIqnkRRzzgcJ5AjcinFJ8Nm4zyj6dUqZSKmCqPypo/G+YlkZdgSBl9YiafBrPyTPJ CYde9x13pUAwf+MMX45J2phmqQec7kLlWxHoPBV2WrsBvCVwN7etWEhwhNT/ev8kZFpTV0 soPPF1/ADlPK4GeuY+ArfsWG+/gF/YINiKdmTxqLiJ4o/xcR4DQ7bj0XgNJM4A== From: Miquel Raynal To: Geert Uytterhoeven , Magnus Damm , Greg Kroah-Hartman , Jiri Slaby Cc: Miquel Raynal , Andy Shevchenko , linux-renesas-soc@vger.kernel.org, linux-serial@vger.kernel.org, Milan Stevanovic , Jimmy Lalande , Pascal Eberhard , Thomas Petazzoni , Herve Codina , Clement Leger Subject: [PATCH v4 5/9] serial: 8250: dma: Allow driver operations before starting DMA transfers Date: Wed, 30 Mar 2022 15:20:34 +0200 Message-Id: <20220330132038.808679-6-miquel.raynal@bootlin.com> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20220330132038.808679-1-miquel.raynal@bootlin.com> References: <20220330132038.808679-1-miquel.raynal@bootlin.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-serial@vger.kernel.org One situation where this could be used is when configuring the UART controller to be the DMA flow controller. This is a typical case where the driver might need to program a few more registers before starting a DMA transfer. Provide the necessary infrastructure to support this case. Suggested-by: Andy Shevchenko Signed-off-by: Miquel Raynal --- drivers/tty/serial/8250/8250.h | 18 ++++++++++++++++++ drivers/tty/serial/8250/8250_dma.c | 4 ++++ 2 files changed, 22 insertions(+) diff --git a/drivers/tty/serial/8250/8250.h b/drivers/tty/serial/8250/8250.h index db784ace25d8..d19f24e4d13e 100644 --- a/drivers/tty/serial/8250/8250.h +++ b/drivers/tty/serial/8250/8250.h @@ -17,6 +17,8 @@ struct uart_8250_dma { int (*tx_dma)(struct uart_8250_port *p); int (*rx_dma)(struct uart_8250_port *p); + void (*prepare_tx_dma)(struct uart_8250_port *p); + void (*prepare_rx_dma)(struct uart_8250_port *p); /* Filter function */ dma_filter_fn fn; @@ -301,6 +303,22 @@ extern int serial8250_rx_dma(struct uart_8250_port *); extern void serial8250_rx_dma_flush(struct uart_8250_port *); extern int serial8250_request_dma(struct uart_8250_port *); extern void serial8250_release_dma(struct uart_8250_port *); + +static inline void serial8250_do_prepare_tx_dma(struct uart_8250_port *p) +{ + struct uart_8250_dma *dma = p->dma; + + if (dma->prepare_tx_dma) + dma->prepare_tx_dma(p); +} + +static inline void serial8250_do_prepare_rx_dma(struct uart_8250_port *p) +{ + struct uart_8250_dma *dma = p->dma; + + if (dma->prepare_rx_dma) + dma->prepare_rx_dma(p); +} #else static inline int serial8250_tx_dma(struct uart_8250_port *p) { diff --git a/drivers/tty/serial/8250/8250_dma.c b/drivers/tty/serial/8250/8250_dma.c index 890fa7ddaa7f..558d3a2ac65b 100644 --- a/drivers/tty/serial/8250/8250_dma.c +++ b/drivers/tty/serial/8250/8250_dma.c @@ -77,6 +77,8 @@ int serial8250_tx_dma(struct uart_8250_port *p) dma->tx_size = CIRC_CNT_TO_END(xmit->head, xmit->tail, UART_XMIT_SIZE); + serial8250_do_prepare_tx_dma(p); + desc = dmaengine_prep_slave_single(dma->txchan, dma->tx_addr + xmit->tail, dma->tx_size, DMA_MEM_TO_DEV, @@ -114,6 +116,8 @@ int serial8250_rx_dma(struct uart_8250_port *p) if (dma->rx_running) return 0; + serial8250_do_prepare_rx_dma(p); + desc = dmaengine_prep_slave_single(dma->rxchan, dma->rx_addr, dma->rx_size, DMA_DEV_TO_MEM, DMA_PREP_INTERRUPT | DMA_CTRL_ACK);