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 3BE96C433FE for ; Wed, 30 Mar 2022 14:08:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1346625AbiC3OK2 (ORCPT ); Wed, 30 Mar 2022 10:10:28 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36974 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1346606AbiC3OKU (ORCPT ); Wed, 30 Mar 2022 10:10:20 -0400 Received: from mga18.intel.com (mga18.intel.com [134.134.136.126]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CCA9A19953F; Wed, 30 Mar 2022 07:08:34 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1648649314; x=1680185314; h=date:from:to:cc:subject:message-id:references: mime-version:in-reply-to; bh=OyxRUGrwm3w4ZfG3q5TyQTuBcEpsbNY9cFD4uvra/FU=; b=eZQZQp2uCCAbYaGr+99DSLzxL5lDeA9gWCyzrqUcHym3Xftvq4FpNTeX zszo6Fuvj5NqRwgj4FD4XZ4tGktnVjy4rAxQFr6QRfeXDStwsTHCWSjs6 jB60dKx/oEAqd2/NA2ykdbqBA0MJyDtPc3gDC9rmlKNOwzakexekAqQw9 /0ekQfyA6lbSQ81ZSEaQmWob1AEw6VNCoBwV5KxBikPPixM7djfSUC66l /NFOIG6U+eqB+F+V/l+AvPXB3H3TfJQSRVk9IfcejdkF69S6bxCHIBw36 Qrsdu5ty+Hn60lzj1T542Vjeeg8VF39yJdwEr4sKDlajXe+OxiWAJaKQL A==; X-IronPort-AV: E=McAfee;i="6200,9189,10301"; a="241706119" X-IronPort-AV: E=Sophos;i="5.90,222,1643702400"; d="scan'208";a="241706119" Received: from orsmga005.jf.intel.com ([10.7.209.41]) by orsmga106.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 30 Mar 2022 07:08:34 -0700 X-IronPort-AV: E=Sophos;i="5.90,222,1643702400"; d="scan'208";a="719987909" Received: from smile.fi.intel.com ([10.237.72.59]) by orsmga005-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 30 Mar 2022 07:08:31 -0700 Received: from andy by smile.fi.intel.com with local (Exim 4.95) (envelope-from ) id 1nZYzN-009RTH-Us; Wed, 30 Mar 2022 17:07:57 +0300 Date: Wed, 30 Mar 2022 17:07:57 +0300 From: Andy Shevchenko To: Miquel Raynal Cc: Geert Uytterhoeven , Magnus Damm , Greg Kroah-Hartman , Jiri Slaby , linux-renesas-soc@vger.kernel.org, linux-serial@vger.kernel.org, Milan Stevanovic , Jimmy Lalande , Pascal Eberhard , Thomas Petazzoni , Herve Codina , Clement Leger Subject: Re: [PATCH v4 5/9] serial: 8250: dma: Allow driver operations before starting DMA transfers Message-ID: References: <20220330132038.808679-1-miquel.raynal@bootlin.com> <20220330132038.808679-6-miquel.raynal@bootlin.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220330132038.808679-6-miquel.raynal@bootlin.com> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo Precedence: bulk List-ID: X-Mailing-List: linux-renesas-soc@vger.kernel.org On Wed, Mar 30, 2022 at 03:20:34PM +0200, Miquel Raynal wrote: > 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. OK! Reviewed-by: Andy Shevchenko > 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); > -- > 2.27.0 > -- With Best Regards, Andy Shevchenko