From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from devils.ext.ti.com ([198.47.26.153]) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1ZmN7c-0008M8-QA for linux-mtd@lists.infradead.org; Wed, 14 Oct 2015 14:33:41 +0000 From: "Franklin S Cooper Jr." To: Roger Quadros CC: , , , , , , , Subject: Re: [PATCH 1/5] mtd: nand: omap2: Support parsing dma channel information from DT References: <1444700338-27582-1-git-send-email-fcooper@ti.com> <1444700338-27582-2-git-send-email-fcooper@ti.com> <561E3E4F.9020302@ti.com> <561E41EB.3050005@ti.com> <561E5803.5090609@ti.com> <561E629F.5070202@ti.com> Message-ID: <561E6791.3030404@ti.com> Date: Wed, 14 Oct 2015 09:32:49 -0500 MIME-Version: 1.0 In-Reply-To: <561E629F.5070202@ti.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On 10/14/2015 09:11 AM, Roger Quadros wrote: > On 14/10/15 16:26, Franklin S Cooper Jr. wrote: >> >> On 10/14/2015 06:52 AM, Roger Quadros wrote: >>> Franklin, >>> >>> On 14/10/15 14:36, Roger Quadros wrote: >>>> On 13/10/15 04:38, Franklin S Cooper Jr wrote: >>>>> Switch from dma_request_channel to allow passing dma channel >>>>> information from DT rather than hardcoding a value. >>>>> >>>>> Signed-off-by: Franklin S Cooper Jr >>>> Acked-by: Roger Quadros >>>> >>>>> --- >>>>> drivers/mtd/nand/omap2.c | 4 +++- >>>>> 1 file changed, 3 insertions(+), 1 deletion(-) >>>>> >>>>> diff --git a/drivers/mtd/nand/omap2.c b/drivers/mtd/nand/omap2.c >>>>> index d0f2620..957c32f 100644 >>>>> --- a/drivers/mtd/nand/omap2.c >>>>> +++ b/drivers/mtd/nand/omap2.c >>>>> @@ -1866,7 +1866,9 @@ static int omap_nand_probe(struct platform_device *pdev) >>>>> dma_cap_zero(mask); >>>>> dma_cap_set(DMA_SLAVE, mask); >>>>> sig = OMAP24XX_DMA_GPMC; >>>>> - info->dma = dma_request_channel(mask, omap_dma_filter_fn, &sig); >>>>> + info->dma = dma_request_slave_channel_compat(mask, >>>>> + omap_dma_filter_fn, &sig, pdev->dev.parent, "rxtx"); >>>>> + >>> Just discovered that you are using the parent device node. >>> >>> How about moving the dma bindings to the nand node instead and using >>> pdev->dev here? >> Roger, >> >> From what I can tell the interrupt number and the dma channel will always be >> the same no matter what. Doesn't matter if you have multiple nands or a >> combination of nands and nors. Since that is the case I think it just makes >> sense to leave it in the gpmc parent node and define it once. > Is prefetch/writepost dma used for NOR or any other GPMC peripheral > or only for NAND? The dma seems tied to the prefetch. From what I can tell the prefetch is only used by nand. > > Let's also get Tony's inputs on this. Sure. > >>>>> if (!info->dma) { >>>>> dev_err(&pdev->dev, "DMA engine request failed\n"); >>>>> err = -ENXIO; >>>>> > -- > cheers, > -roger