On 10/14/2015 11:18 AM, Tony Lindgren wrote: > * Franklin S Cooper Jr. <fcooper@xxxxxx> [151014 07:37]: >> >> 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 <fcooper@xxxxxx> >>>>>> Acked-by: Roger Quadros <rogerq@xxxxxx> >>>>>> >>>>>>> --- >>>>>>> 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. > Hmm so what would keep other devices from using the prefetch Looking at the TRM any references to the prefetch are always with respect to NAND. I also see the below mentioned in the TRM. Pre-fetch and write posting engine associated with system DMA to get full performance from NAND device with minimum impact on NOR/SRAM concurrent access. > > Regards, > > Tony -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
