On Tue, Jul 5, 2011 at 12:35 PM, Kukjin Kim <kgene.kim@xxxxxxxxxxx> wrote: > Grant Likely wrote: >> >> On Mon, Jul 04, 2011 at 09:51:43PM +0200, Heiko Stübner wrote: >> > Am Montag 04 Juli 2011, 19:02:17 schrieb Grant Likely: >> > > On Mon, Jul 04, 2011 at 06:59:11PM +0200, Heiko Stübner wrote: >> > > > Am Montag 04 Juli 2011, 18:42:51 schrieb Grant Likely: >> > > > > >> > > > > Wow. A lot of #ifdefs here. It does not look multiplatform > friendly >> > > > > at all. Are the s3c2410_dma functions obsolete when DMADEV_PL330 > is >> > > > > selected? If so, can they be removed entirely, or are they > required >> > > > > to support certain hardware? >> > > > >> > > > The spi_s3c64xx driver can also support the SPI controller of the >> > > > S3C2416/S3C2443 line of SoCs. >> > > > As I'm currently working on a S3C2416 based project, my small wish > from >> > > > the sidelines would be to not break this support with whatever > solution >> > > > you will decide on :-) . >> > > >> > > I will not merge a patch that either breaks a platform, or requires >> > > a compile time either/or choice of device support (enabling support >> > > for one device should not break support for another). >> > >> > The patch above seems to contain the support for both SoCs (i.e. >> s3c2410_dma_* >> > for S3C2416 etc), so it wouldn't break the support. >> > But this form will definitly break future multiplatform kernels when the > 2416 >> > and some variant using the DMADEV_PL330 are selected at the same time. >> >> Yes, that's the breakage I'm talking about. >> >> > The 2416/2443 seem to be the first Samsung-SoCs to have a SPI-controller > of >> > this type. Implementing the DMA engine stuff for these SoCs would > obviously >> > solve the ifdef-problem but I don't know if this is possible to do. >> >> Of course it's possible, it's just software. :-D >> >> If a config option is either/or then it needs to be really well >> justified before I will accept it. Most either/or options I've seen >> aren't for any strong technical reason other than it was easier to >> code that way. > > Hi all, > > Yes I know your concerns on this. > > First of all, please see below which is block diagram of Samsung DMA usage > and 1st step will be finished with other patches for S5PC100 and S5PV210 > soon. Basically we need more time maybe 2 or 3 days to test on boards. > > +---------------------------------------------------------------------+ > | Each drivers which uses DMA | > +---------------------------------------------------------------------+ > | S3C DMA API (such as s3c2410_dma_xxxx) | > +-------------------------------+-------------------------------------+ > | PL080 DMA driver | S3C PL330 DMA API driver | > | for S3C24XX and S3C64XX | (arch/arm/plat-samsung/s3c-pl330.c) | > | +-------------------------------------+ > | (arch/arm/plat-s3c24xx/dma.c) | Common DMA core driver | > | (arch/arm/mach-s3c64xx/dma.c) | (arch/arm/common/pl330.c) | > +-------------------------------+-------------------------------------+ > || > (1st step. removing S3C DMA API for PL330) > || > \/ > +---------------------------------------------------------------------+ > | Each drivers which uses DMA | > +-------------------------------+-------------------------------------+ > | S3C DMA API(s3c2410_dma_xxx) | DMA generic API for PL330 | > +-------------------------------+-------------------------------------+ > | PL080 DMA driver | PL330 DMA API driver | > | for S3C24XX and S3C64XX | (drivers/dma/pl330.c) | > | +-------------------------------------+ > | (arch/arm/plat-s3c24xx/dma.c) | Common DMA core driver | > | (arch/arm/mach-s3c64xx/dma.c) | (arch/arm/common/pl330.c) | > +-------------------------------+-------------------------------------+ > > As you saw, the S3C_DMA_API is still used for PL080 DMA for compatibilities > with this patches in each driver, e.g., spi and audio. As a note, S3C24XX > and S3C64XX include PL080 DMAC not PL330. Not exactly. S3C24XX use 2-3 different versions of Samsung's DMA implementations. S3C6400/10 use PL080 S5P and later series use PL330 > > Of course, if we can remove every S3C_DMA_API, that can be the best solution > but it needs more time. I'd like to go to our goal step by step. > Ideally, like PL330 for S5Pxxxx, drivers/dma/pl080 should be enabled for s3c64xx And new generic dma api drivers written for S3C24xx in drivers/dma/ -j -- To unsubscribe from this list: send the line "unsubscribe linux-samsung-soc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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