From mboxrd@z Thu Jan 1 00:00:00 1970 From: Boris BREZILLON Subject: Re: [PATCH v4 1/5] drm/rockchip: Add basic drm driver Date: Mon, 22 Sep 2014 17:15:06 +0200 Message-ID: <20140922171506.31d59a76@bbrezillon> References: <1411382820-1615-1-git-send-email-mark.yao@rock-chips.com> <1411382934-1763-1-git-send-email-mark.yao@rock-chips.com> <3036415.u40f3Xnhod@wuerfel> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <3036415.u40f3Xnhod@wuerfel> Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Arnd Bergmann Cc: Mark yao , heiko-4mtYJXux2i+zQB+pC5nmwQ@public.gmane.org, David Airlie , Rob Clark , Rob Herring , Pawel Moll , Mark Rutland , Ian Campbell , Kumar Gala , Randy Dunlap , Grant Likely , Greg Kroah-Hartman , John Stultz , Rom Lemarchand , devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-doc-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, dri-devel-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public.gmane.org, linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-rockchip-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, dianders-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org, marcheu-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org, dbehr-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org, olof-nZhT3qVonbNeoWH0uzbU5w@public.gmane.org, djkurtz-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org, xjq-TNX95d0MmH7DzftRWevZcw@public.gmane.org, kfx-TNX95d0MmH7DzftRWevZcw@public.gmane.org, cym-TNX95d0MmH7DzftRWevZcw@public.gmane.org, cf-TNX95d0MmH7DzftRWevZcw@public.gmane.org, zyw@rock- List-Id: linux-api@vger.kernel.org On Mon, 22 Sep 2014 16:43:31 +0200 Arnd Bergmann wrote: > On Monday 22 September 2014 18:48:54 Mark yao wrote: > > diff --git a/drivers/gpu/drm/rockchip/Kconfig b/drivers/gpu/drm/rockchip/Kconfig > > new file mode 100644 > > index 0000000..7146c80 > > --- /dev/null > > +++ b/drivers/gpu/drm/rockchip/Kconfig > > @@ -0,0 +1,19 @@ > > +config DRM_ROCKCHIP > > + tristate "DRM Support for Rockchip" > > + depends on DRM && ROCKCHIP_IOMMU > > + select ARM_DMA_USE_IOMMU > > + select IOMMU_API > > + select DRM_KMS_HELPER > > + select DRM_KMS_FB_HELPER > > + select DRM_PANEL > > + select FB_CFB_FILLRECT > > + select FB_CFB_COPYAREA > > + select FB_CFB_IMAGEBLIT > > + select VT_HW_CONSOLE_BINDING if FRAMEBUFFER_CONSOLE > > + select VIDEOMODE_HELPERS > > Be careful with 'select', at least some of these should be 'depends on'. > In particular IOMMU_API and ARM_DMA_USE_IOMMU, but possibly others > as well. Just check how the symbols are used normally, if you get this > wrong, we can end up with incorrect dependencies or loops. > > > diff --git a/drivers/gpu/drm/rockchip/Makefile b/drivers/gpu/drm/rockchip/Makefile > > new file mode 100644 > > index 0000000..6e6d468 > > --- /dev/null > > +++ b/drivers/gpu/drm/rockchip/Makefile > > @@ -0,0 +1,10 @@ > > +# > > +# Makefile for the drm device driver. This driver provides support for the > > +# Direct Rendering Infrastructure (DRI) in XFree86 4.1.0 and higher. > > + > > +ccflags-y := -Iinclude/drm -Idrivers/gpu/drm/rockchip > > The second one should not be required. > > > +static int rockchip_drm_load(struct drm_device *drm_dev, unsigned long flags) > > +{ > > + struct rockchip_drm_private *private; > > + struct dma_iommu_mapping *mapping; > > + struct device *dev = drm_dev->dev; > > + int ret; > > + > > + private = devm_kzalloc(drm_dev->dev, sizeof(*private), GFP_KERNEL); > > + if (!private) > > + return -ENOMEM; > > + > > + dev_set_drvdata(drm_dev->dev, dev); > > + drm_dev->dev_private = private; > > + > > + drm_mode_config_init(drm_dev); > > + > > + rockchip_drm_mode_config_init(drm_dev); > > + > > + dev->dma_parms = devm_kzalloc(dev, sizeof(*dev->dma_parms), > > + GFP_KERNEL); > > + if (!dev->dma_parms) { > > + ret = -ENOMEM; > > + goto err_config_cleanup; > > + } > > + > > + /* TODO(djkurtz): fetch the mapping start/size from somewhere */ > > + mapping = arm_iommu_create_mapping(&platform_bus_type, 0x10000000, > > + SZ_1G); > > + if (IS_ERR(mapping)) { > > + ret = PTR_ERR(mapping); > > + goto err_config_cleanup; > > + } > > + > > + dma_set_coherent_mask(dev, DMA_BIT_MASK(32)); > > This is the default coherent mask. If you call this function, you > should normally check the return value, or call dma_set_mask first, > which you apparently don't do here, and in another place in this > patch. By "This is the default mask" do you mean it shouldn't be called at all ? Cause I ran into some trouble when not calling this in my atmel-hlcdc driver. Actually, in my case the platform device is created by the MFD core which seems to let the coherent_dma_mask uninitialized. Best Regards, Boris -- Boris Brezillon, Free Electrons Embedded Linux and Kernel engineering http://free-electrons.com -- 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