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From: Miquel Raynal <miquel.raynal@bootlin.com>
To: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: linux-renesas-soc@vger.kernel.org,
	Magnus Damm <magnus.damm@gmail.com>,
	Gareth Williams <gareth.williams.jx@renesas.com>,
	Phil Edworthy <phil.edworthy@renesas.com>,
	Geert Uytterhoeven <geert@linux-m68k.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Jiri Slaby <jirislaby@kernel.org>,
	Milan Stevanovic <milan.stevanovic@se.com>,
	Jimmy Lalande <jimmy.lalande@se.com>,
	Pascal Eberhard <pascal.eberhard@se.com>,
	Thomas Petazzoni <thomas.petazzoni@bootlin.com>,
	Herve Codina <herve.codina@bootlin.com>,
	Clement Leger <clement.leger@bootlin.com>,
	linux-serial@vger.kernel.org
Subject: Re: [PATCH v2 05/10] serial: 8250: dw: Check when possible if DMA is effectively supported
Date: Fri, 18 Mar 2022 15:33:46 +0100	[thread overview]
Message-ID: <20220318153346.152b3ff6@xps13> (raw)
In-Reply-To: <YjSOFII3l+vz0q8L@smile.fi.intel.com>

Hi Andy,

andriy.shevchenko@linux.intel.com wrote on Fri, 18 Mar 2022 15:50:12
+0200:

> On Thu, Mar 17, 2022 at 06:46:22PM +0100, Miquel Raynal wrote:
> > The CPR register can give the information whether the IP is DMA capable
> > or not. Let's extract this information when the CPR register is valid
> > and use it to discriminate when the DMA cannot be hooked up.
> > 
> > We assume existing designs either provide a valid CPR register or do not
> > provide any.  
> 
> ...
> 
> > +	if (!(reg & DW_UART_CPR_DMA_EXTRA))
> > +		data->no_dma = 1;  
> 
> My question still remains: Does this bit is _guaranteed_ to be set when this IP
> is integrated on all possible DMAs?

I'll get rid of that entirely, let's just hope there is always DMA
support.

Thanks,
Miquèl

  reply	other threads:[~2022-03-18 14:33 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-03-17 17:46 [PATCH v2 00/10] serial: 8250: dw: RZN1 DMA support Miquel Raynal
2022-03-17 17:46 ` [PATCH v2 01/10] serial: 8250: dw: Move the per-device structure Miquel Raynal
2022-03-18 10:51   ` Andy Shevchenko
2022-03-29  8:10     ` Miquel Raynal
2022-03-29 11:11       ` Andy Shevchenko
2022-03-29 14:27         ` Miquel Raynal
2022-03-17 17:46 ` [PATCH v2 02/10] serial: 8250: dw: Use the device API Miquel Raynal
2022-03-18  8:05   ` Geert Uytterhoeven
2022-03-17 17:46 ` [PATCH v2 03/10] serial: 8250: dw: Create a more generic platform data structure Miquel Raynal
2022-03-18  8:07   ` Geert Uytterhoeven
2022-03-18 13:57   ` Andy Shevchenko
2022-03-17 17:46 ` [PATCH v2 04/10] serial: 8250: dw: Allow to use a fallback CPR value if not synthesized Miquel Raynal
2022-03-18 13:56   ` Andy Shevchenko
2022-03-17 17:46 ` [PATCH v2 05/10] serial: 8250: dw: Check when possible if DMA is effectively supported Miquel Raynal
2022-03-18 13:50   ` Andy Shevchenko
2022-03-18 14:33     ` Miquel Raynal [this message]
2022-03-17 17:46 ` [PATCH v2 06/10] serial: 8250: dma: Allow driver operations before starting DMA transfers Miquel Raynal
2022-03-17 17:46 ` [PATCH v2 07/10] serial: 8250: dw: Introduce an rx_timeout variable in the IRQ path Miquel Raynal
2022-03-17 17:46 ` [PATCH v2 08/10] serial: 8250: dw: Add support for DMA flow controlling devices Miquel Raynal
2022-03-18 14:24   ` Andy Shevchenko
2022-03-29  8:29     ` Miquel Raynal
2022-03-17 17:46 ` [PATCH v2 09/10] serial: 8250: dw: Improve RZN1 support Miquel Raynal
2022-03-17 17:46 ` [PATCH v2 10/10] ARM: dts: r9a06g032: Fill the UART DMA properties Miquel Raynal

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