From mboxrd@z Thu Jan 1 00:00:00 1970 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 30BF1C32763 for ; Mon, 15 Aug 2022 19:31:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344799AbiHOTbr (ORCPT ); Mon, 15 Aug 2022 15:31:47 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37304 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1344441AbiHOT0w (ORCPT ); Mon, 15 Aug 2022 15:26:52 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 958F13FA05; Mon, 15 Aug 2022 11:42:39 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 9DE2F60FEE; Mon, 15 Aug 2022 18:42:38 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8D611C433C1; Mon, 15 Aug 2022 18:42:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1660588958; bh=zZb3w4ZEQn3rVjMUEfbqtgtrFhNi4p7gFpwg8dCPZdY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=nb28TJvNIv8XJqe/Fyd/sLrk1cFbcRd/x6RdrEE8IygS1LGDD31EUuNbRmN+29NjM IBr//jFmXfmKUvoltVoB0t9+Hzwefecd60Q+9QA0boFma2ZBErOGMEODz48kqE34d3 dCDIVSyeBbF7UHPRkXzRIVRA5ye8EV5J3iLaHgXM= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Andy Shevchenko , Miquel Raynal , Sasha Levin Subject: [PATCH 5.15 569/779] serial: 8250: dma: Allow driver operations before starting DMA transfers Date: Mon, 15 Aug 2022 20:03:33 +0200 Message-Id: <20220815180401.657567808@linuxfoundation.org> X-Mailer: git-send-email 2.37.2 In-Reply-To: <20220815180337.130757997@linuxfoundation.org> References: <20220815180337.130757997@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Miquel Raynal [ Upstream commit e4fb03fe10c5e7a5d9aef7cefe815253274fb9ee ] 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 Reviewed-by: Andy Shevchenko Signed-off-by: Miquel Raynal Link: https://lore.kernel.org/r/20220422180615.9098-6-miquel.raynal@bootlin.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin --- 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 0efe4df24622..b3abc29aa927 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; @@ -331,6 +333,22 @@ 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 b3c3f7e5851a..1bdc8d6432fe 100644 --- a/drivers/tty/serial/8250/8250_dma.c +++ b/drivers/tty/serial/8250/8250_dma.c @@ -86,6 +86,8 @@ 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, @@ -123,6 +125,8 @@ 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); -- 2.35.1