Re: [PATCH 1/5] mtd: nand: omap2: Support parsing dma channel information from DT
From: Tony Lindgren <hidden>
Date: 2015-10-14 16:18:17
Also in:
linux-omap, lkml
* Franklin S Cooper Jr. [off-list ref] [151014 07:37]:
On 10/14/2015 09:11 AM, Roger Quadros wrote:quoted
On 14/10/15 16:26, Franklin S Cooper Jr. wrote:quoted
On 10/14/2015 06:52 AM, Roger Quadros wrote:quoted
Franklin, On 14/10/15 14:36, Roger Quadros wrote:quoted
On 13/10/15 04:38, Franklin S Cooper Jr wrote:quoted
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 <redacted>Acked-by: Roger Quadros <redacted>quoted
--- 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.quoted
Let's also get Tony's inputs on this.Sure.
Hmm so what would keep other devices from using the prefetch? Regards, Tony -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html