[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-Id: <201306242228.23297.arnd@arndb.de>
Date: Mon, 24 Jun 2013 22:28:23 +0200
From: Arnd Bergmann <arnd@...db.de>
To: Joel A Fernandes <agnel.joel@...il.com>
Cc: Sekhar Nori <nsekhar@...com>, Joel A Fernandes <joelagnel@...com>,
Tony Lindgren <tony@...mide.com>,
Matt Porter <matt@...orter.com>,
Grant Likely <grant.likely@...retlab.ca>,
Rob Herring <rob.herring@...xeda.com>,
Vinod Koul <vinod.koul@...el.com>,
Mark Brown <broonie@...nsource.wolfsonmicro.com>,
Benoit Cousson <b-cousson@...com>,
Russell King <linux@....linux.org.uk>,
Rob Landley <rob@...dley.net>,
Andrew Morton <akpm@...ux-foundation.org>,
Jason Kridner <jkridner@...gleboard.org>,
Koen Kooi <koen@...gleboard.org>,
Devicetree Discuss <devicetree-discuss@...ts.ozlabs.org>,
Linux OMAP List <linux-omap@...r.kernel.org>,
Linux ARM Kernel List <linux-arm-kernel@...ts.infradead.org>,
Linux DaVinci Kernel List
<davinci-linux-open-source@...ux.davincidsp.com>,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
Linux Documentation List <linux-doc@...r.kernel.org>,
Linux MMC List <linux-mmc@...r.kernel.org>,
Linux SPI Devel List
<spi-devel-general@...ts.sourceforge.net>
Subject: Re: [PATCH v12 05/11] edma: config: Enable config options for EDMA
On Saturday 22 June 2013, Joel A Fernandes wrote:
>
> >> > config TI_EDMA
> >> > tristate "TI EDMA support"
> >> > default m if 'ARCH_DAVINCI || ARCH_OMAP1 || ARCH_OMAP2
> >> > select DMA_ENGINE
> >> > select DMA_VIRTUAL_CHANNELS
> >>
> >>
> >> MMC depends on EDMA specially on AM33xx there's no PIO mode AFAIK. The
> >> 'm' option will require some initramfs to load the module when needing
> >> to MMC boot, I suggest lets leave it as y.
> >>
> >
> > Ah, right: you still export a filter function from the edma driver
> > and use it in slave drivers:
> >
> > drivers/mmc/host/davinci_mmc.c: dma_request_slave_channel_compat(mask, edma_filter_fn,
> > drivers/mmc/host/davinci_mmc.c: dma_request_slave_channel_compat(mask, edma_filter_fn,
> > drivers/spi/spi-davinci.c: dspi->dma_rx = dma_request_channel(mask, edma_filter_fn,
> > drivers/spi/spi-davinci.c: dspi->dma_tx = dma_request_channel(mask, edma_filter_fn,
> >
> > As long as this is the case, you have to be careful with the dependencies
> > to make sure that davinci_mmc and spi-davinci either depend on TI_EDMA, or
> > edma_filter_fn gets defined to NULL when you are building for a DT-only platform.
>
> Yes sure, right now they are defined as follows in include/linux/edma.h:
>
> #if defined(CONFIG_TI_EDMA) || defined(CONFIG_TI_EDMA_MODULE)
> bool edma_filter_fn(struct dma_chan *, void *);
> #else
> static inline bool edma_filter_fn(struct dma_chan *chan, void *param)
> {
> return false;
> }
> #endif
It's best to just define the filter function in the platform
code and pass a pointer to it through platform data. The way you do
it above makes the slave drivers inherently nonportable.
Arnd
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists