From: Tony Lindgren <tony@atomide.com>
To: Matt Porter <mporter@ti.com>
Cc: Sekhar Nori <nsekhar@ti.com>,
Grant Likely <grant.likely@secretlab.ca>,
Mark Brown <broonie@opensource.wolfsonmicro.com>,
Benoit Cousson <b-cousson@ti.com>,
Russell King <linux@arm.linux.org.uk>,
Vinod Koul <vinod.koul@intel.com>, Rob Landley <rob@landley.net>,
Chris Ball <cjb@laptop.org>,
Devicetree Discuss <devicetree-discuss@lists.ozlabs.org>,
Linux OMAP List <linux-omap@vger.kernel.org>,
Linux ARM Kernel List <linux-arm-kernel@lists.infradead.org>,
Linux DaVinci Kernel List
<davinci-linux-open-source@linux.davincidsp.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Linux Documentation List <linux-doc@vger.kernel.org>,
Linux MMC List <linux-mmc@vger.kernel.org>,
Linux SPI Devel List <spi-devel-general@lists.sourceforge.net>,
Arnd Bergmann <arnd@arndb.de>, Dan Williams <djbw@fb.com>,
Rob Herring <rob.herring@calxeda.com>
Subject: Re: [PATCH v4 09/14] mmc: omap_hsmmc: set max_segs based on dma engine limitations
Date: Fri, 11 Jan 2013 09:53:30 -0800 [thread overview]
Message-ID: <20130111175330.GH14149@atomide.com> (raw)
In-Reply-To: <1357883330-5364-10-git-send-email-mporter@ti.com>
* Matt Porter <mporter@ti.com> [130110 21:47]:
> The EDMA DMAC has a hardware limitation that prevents supporting
> scatter gather lists with any number of segments. The DMA Engine
> API reports the maximum number of segments a channel can support
> via the optional dma_get_channel_caps() API. If the nr_segs
> capability is present, the value is used to configure mmc->max_segs
> appropriately.
Acked-by: Tony Lindgren <tony@atomide.com>
> Signed-off-by: Matt Porter <mporter@ti.com>
> ---
> drivers/mmc/host/omap_hsmmc.c | 6 ++++++
> 1 file changed, 6 insertions(+)
>
> diff --git a/drivers/mmc/host/omap_hsmmc.c b/drivers/mmc/host/omap_hsmmc.c
> index e79b12d..f74bd69 100644
> --- a/drivers/mmc/host/omap_hsmmc.c
> +++ b/drivers/mmc/host/omap_hsmmc.c
> @@ -1769,6 +1769,7 @@ static int omap_hsmmc_probe(struct platform_device *pdev)
> const struct of_device_id *match;
> dma_cap_mask_t mask;
> unsigned tx_req, rx_req;
> + struct dmaengine_chan_caps *dma_chan_caps;
> struct pinctrl *pinctrl;
>
> match = of_match_device(of_match_ptr(omap_mmc_of_match), &pdev->dev);
> @@ -1935,6 +1936,11 @@ static int omap_hsmmc_probe(struct platform_device *pdev)
> goto err_irq;
> }
>
> + /* Some DMA Engines only handle a limited number of SG segments */
> + dma_chan_caps = dma_get_channel_caps(host->rx_chan, DMA_DEV_TO_MEM);
> + if (dma_chan_caps && dma_chan_caps->seg_nr)
> + mmc->max_segs = dma_chan_caps->seg_nr;
> +
> /* Request IRQ for MMC operations */
> ret = request_irq(host->irq, omap_hsmmc_irq, 0,
> mmc_hostname(mmc), host);
> --
> 1.7.9.5
>
next prev parent reply other threads:[~2013-01-11 17:53 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-01-11 5:48 [PATCH v4 00/14] DMA Engine support for AM33XX Matt Porter
[not found] ` <1357883330-5364-1-git-send-email-mporter-l0cyMroinI0@public.gmane.org>
2013-01-11 5:48 ` [PATCH v4 01/14] ARM: davinci: move private EDMA API to arm/common Matt Porter
[not found] ` <1357883330-5364-2-git-send-email-mporter-l0cyMroinI0@public.gmane.org>
2013-01-11 6:15 ` Hebbar, Gururaja
2013-01-11 14:27 ` Matt Porter
2013-01-11 5:48 ` [PATCH v4 02/14] ARM: edma: remove unused transfer controller handlers Matt Porter
2013-01-11 5:48 ` [PATCH v4 03/14] ARM: edma: add AM33XX support to the private EDMA API Matt Porter
2013-01-11 18:14 ` [PATCH v4,03/14] " Lars Poeschel
[not found] ` <9fda86bbbec3444393fd5a2dc5135a5e@DFLE73.ent.ti.com>
[not found] ` <9fda86bbbec3444393fd5a2dc5135a5e-jplQ/0hSbXKIQmiDNMet8wC/G2K4zDHf@public.gmane.org>
2013-01-11 18:21 ` Matt Porter
2013-01-11 5:48 ` [PATCH v4 04/14] dmaengine: edma: enable build for AM33XX Matt Porter
2013-01-11 5:48 ` [PATCH v4 05/14] dmaengine: edma: Add TI EDMA device tree binding Matt Porter
[not found] ` <1357883330-5364-6-git-send-email-mporter-l0cyMroinI0@public.gmane.org>
2013-01-11 7:54 ` Hebbar, Gururaja
[not found] ` <06e6ba0bd8984e1797c84d2926584909@DFLE72.ent.ti.com>
2013-01-11 14:30 ` Matt Porter
2013-01-11 5:48 ` [PATCH v4 06/14] ARM: dts: add AM33XX EDMA support Matt Porter
2013-01-11 5:48 ` [PATCH v4 07/14] dmaengine: add dma_request_slave_channel_compat() Matt Porter
2013-01-11 17:52 ` Tony Lindgren
2013-01-11 5:48 ` [PATCH v4 08/14] mmc: omap_hsmmc: convert to dma_request_slave_channel_compat() Matt Porter
2013-01-11 17:52 ` Tony Lindgren
2013-01-11 5:48 ` [PATCH v4 09/14] mmc: omap_hsmmc: set max_segs based on dma engine limitations Matt Porter
2013-01-11 17:53 ` Tony Lindgren [this message]
2013-01-11 5:48 ` [PATCH v4 10/14] mmc: omap_hsmmc: add generic DMA request support to the DT binding Matt Porter
2013-01-11 17:54 ` Tony Lindgren
2013-01-11 5:48 ` [PATCH v4 11/14] ARM: dts: add AM33XX MMC support Matt Porter
2013-01-11 17:55 ` Tony Lindgren
2013-01-11 5:48 ` [PATCH v4 12/14] spi: omap2-mcspi: convert to dma_request_slave_channel_compat() Matt Porter
2013-01-11 5:48 ` [PATCH v4 13/14] spi: omap2-mcspi: add generic DMA request support to the DT binding Matt Porter
2013-01-11 11:40 ` [PATCH v4 00/14] DMA Engine support for AM33XX Arnd Bergmann
2013-01-11 18:33 ` Matt Porter
2013-01-11 20:12 ` Arnd Bergmann
2013-01-11 5:48 ` [PATCH v4 14/14] ARM: dts: add AM33XX SPI DMA support Matt Porter
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