Hi Magnus, On Thursday 31 October 2013 17:26:30 Magnus Damm wrote: > On Wed, Oct 30, 2013 at 8:23 PM, Laurent Pinchart wrote: > > Renesas ARM platforms are transitioning from single-platform to > > multi-platform kernels using the new ARCH_SHMOBILE_MULTI. Make the > > driver available on all ARM platforms to enable it on both ARCH_SHMOBILE > > and ARCH_SHMOBILE_MULTI and increase build testing coverage. > > > > Don't enable COMPILE_TEST support as the driver doesn't compile on x86 > > due (possibly among others) to missing readsw/writesw I/O accessors. > > > > Whether the CTL_DMA_ENABLE register is part of the standard TMIO > > controller or is Renesas-specific is unknown and impossible to test as > > we have no current or planned TMIO DMA users other than SUPERH and > > ARCH_SHMOBILE. Writing to the register is thus conditionally compiled > > for SUPERH and ARCH_SHMOBILE only. Adding ARCH_SHMOBILE_MULTI to the > > list would extend this to multiarch kernels, but would break the driver > > for non-shmobile platforms if the register is Renesas-specific. We can > > thus get rid of the conditional compilation completely without > > introducing any further issue, and let future non-Renesas users deal > > with the situation if it turns out to be a the problem. > > > > Cc: Chris Ball <cjb@xxxxxxxxxx> > > Cc: Guennadi Liakhovetski <g.liakhovetski@xxxxxx> > > Cc: Ian Molton <ian@xxxxxxxxxxxxxx> > > Cc: linux-mmc@xxxxxxxxxxxxxxx > > Signed-off-by: Laurent Pinchart > > <laurent.pinchart+renesas@xxxxxxxxxxxxxxxx> > > --- > > > > drivers/mmc/host/Kconfig | 2 +- > > drivers/mmc/host/tmio_mmc_dma.c | 4 +--- > > 2 files changed, 2 insertions(+), 4 deletions(-) > > > > diff --git a/drivers/mmc/host/Kconfig b/drivers/mmc/host/Kconfig > > index 7fc5099..51957d4 100644 > > --- a/drivers/mmc/host/Kconfig > > +++ b/drivers/mmc/host/Kconfig > > @@ -479,7 +479,7 @@ config MMC_TMIO > > > > config MMC_SDHI > > tristate "SH-Mobile SDHI SD/SDIO controller support" > > - depends on SUPERH || ARCH_SHMOBILE > > + depends on SUPERH || ARM > > select MMC_TMIO_CORE > > help > > This provides support for the SDHI SD/SDIO controller found in > > diff --git a/drivers/mmc/host/tmio_mmc_dma.c > > b/drivers/mmc/host/tmio_mmc_dma.c index 65edb4a..8a4fd2d 100644 > > --- a/drivers/mmc/host/tmio_mmc_dma.c > > +++ b/drivers/mmc/host/tmio_mmc_dma.c > > @@ -28,10 +28,8 @@ void tmio_mmc_enable_dma(struct tmio_mmc_host *host, > > bool enable)> > > if (!host->chan_tx || !host->chan_rx) > > return; > > > > -#if defined(CONFIG_SUPERH) || defined(CONFIG_ARCH_SHMOBILE) > > - /* Switch DMA mode on or off - SuperH specific? */ > > + /* Switch DMA mode on or off. This might be Renesas-specific. */ > > sd_ctrl_write16(host, CTL_DMA_ENABLE, enable ? 2 : 0); > > -#endif > > Hi Laurent, > > Thanks for your efforts. Hate to slow things down, but this last hunk looks > wrong to me. I believe the reason for the #ifdef is that non-Renesas IP may > be using the tmio_mmc driver, at least they used to. Not sure if anyone is > using DMA Engine though. If I were you I would play it safe and simply > update the #ifdef with same kind of dependencies that the Kconfig bits have. There are several points to consider here. - drivers/mmc/host/tmio_mmc_dma.c is only compiled in when CONFIG_MMC_SDHI is selected. The symbol currently depends on SUPERH || ARCH_SHMOBILE. We thus have no non-Renesas users for TMIO DMA at the moment. - I don't know whether the CTL_DMA_ENABLE register is specific to Renesas or not. I haven't been able to find a publicly available copy of the TMIO documentation. The Renesas datasheets I have access to don't document the SDHI module. Can you comment on that ? - Merely adding CONFIG_ARCH_SHMOBILE_MULTI to the CTL_DMA_ENABLE write #if guard will break on multiplatform kernels anyway. If a non-Renesas platform uses TMIO DMA, a kernel that supports both a Renesas SoC and that non-Renesas platform will have the CTL_DMA_ENABLE code compiled in. For those reasons I have decided to remove the #if and defer the fix (if needed, if CTL_DMA_ENGINE is indeed Renesas-specific) to the first non-Renesas TMIO DMA user. > Also, it would of course be nice to clean up the driver, perhaps with a > feature flag for this special register or why not simply move the code to > the sdhi file. But that's not really related to your multiplatform kconfig > change, is it? =) No, it isn't :-) I could try to find time to fix that later, but I don't like adding support for features that are not used. I would first want to be sure that the CTL_DMA_ENABLE register is indeed Renesas-specific, which might be a bit hard to ascertain of no non-Renesas chip implements TMIO DMA :-) -- Regards, Laurent Pinchart -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
