On 10/15/2015 02:35 AM, Roger Quadros wrote: > On 14/10/15 23:03, Franklin S Cooper Jr. wrote: >> >> On 10/14/2015 01:13 PM, Tony Lindgren wrote: >>> * Franklin S Cooper Jr. <fcooper@xxxxxx> [151014 09:27]: >>>> 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. >>> OK up to you guys to figure out if it may be usable in a generic way then :) >> Ok I just got clarification from hw folks. DMA for GPMC can be used for any of the >> various modes. But the prefetch is specific to NAND. > In that case the dma information must be in the GPMC node. Ok I'll be sending a v2 patchset soon but I'll be leaving this as is. > > cheers, > -roger -- 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
