From mboxrd@z Thu Jan 1 00:00:00 1970 From: Matthias Brugger Subject: Re: [PATCH v9 2/4] soc: mediatek: Init MT8173 scpsys driver earlier Date: Mon, 31 Oct 2016 01:08:08 +0100 Message-ID: <14a1ebb2-fda2-278b-b2f0-8f9c6ff6a83d@gmail.com> References: <1476953798-23263-1-git-send-email-jamesjj.liao@mediatek.com> <1476953798-23263-3-git-send-email-jamesjj.liao@mediatek.com> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1476953798-23263-3-git-send-email-jamesjj.liao-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org> Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: James Liao , Sascha Hauer Cc: Rob Herring , Kevin Hilman , Daniel Kurtz , srv_heupstream-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org, devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, linux-mediatek-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org List-Id: linux-mediatek@lists.infradead.org Hi James, On 10/20/2016 10:56 AM, James Liao wrote: > Some power domain comsumers may init before module_init. > So the power domain provider (scpsys) need to be initialized > earlier too. > > Take an example for our IOMMU (M4U) and SMI. SMI is a bridge > between IOMMU and multimedia HW. SMI is responsible to > enable/disable iommu and help transfer data for each multimedia > HW. Both of them have to wait until the power and clocks are > enabled. > > So scpsys driver should be initialized before SMI, and SMI should > be initialized before IOMMU, and then init IOMMU consumers > (display/vdec/venc/camera etc.). > > IOMMU is subsys_init by default. So we need to init scpsys driver > before subsys_init. > > Signed-off-by: James Liao > Reviewed-by: Kevin Hilman > --- I didn't applied this patch for now. I answered you in v7 of this series [1]. I would prefer to see if we can fix that otherwise. Would be great if you or Yong could provide some feedback. Thanks, Matthias [1] https://patchwork.kernel.org/patch/9397405/ > drivers/soc/mediatek/mtk-scpsys.c | 19 ++++++++++++++++++- > 1 file changed, 18 insertions(+), 1 deletion(-) > > diff --git a/drivers/soc/mediatek/mtk-scpsys.c b/drivers/soc/mediatek/mtk-scpsys.c > index fa9ee69..dd7a07d 100644 > --- a/drivers/soc/mediatek/mtk-scpsys.c > +++ b/drivers/soc/mediatek/mtk-scpsys.c > @@ -613,4 +613,21 @@ static int scpsys_probe(struct platform_device *pdev) > .of_match_table = of_match_ptr(of_scpsys_match_tbl), > }, > }; > -builtin_platform_driver(scpsys_drv); > + > +static int __init scpsys_drv_init(void) > +{ > + return platform_driver_register(&scpsys_drv); > +} > + > +/* > + * There are some Mediatek drivers which depend on the power domain driver need > + * to probe in earlier initcall levels. So scpsys driver also need to probe > + * earlier. > + * > + * IOMMU(M4U) and SMI drivers for example. SMI is a bridge between IOMMU and > + * multimedia HW. IOMMU depends on SMI, and SMI is a power domain consumer, > + * so the proper probe sequence should be scpsys -> SMI -> IOMMU driver. > + * IOMMU drivers are initialized during subsys_init by default, so we need to > + * move SMI and scpsys drivers to subsys_init or earlier init levels. > + */ > +subsys_initcall(scpsys_drv_init); > -- 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