linux-kernel - Re: [PATCH v2] drm/msm/mdp5: Find correct node for creating gem address space

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Message-ID: <20190708161026.GB27383@builder>
Date:   Mon, 8 Jul 2019 09:10:26 -0700
From:   Bjorn Andersson <bjorn.andersson@...aro.org>
To:     Jeffrey Hugo <jeffrey.l.hugo@...il.com>
Cc:     robdclark@...il.com, sean@...rly.run, airlied@...ux.ie,
        daniel@...ll.ch, linux-arm-msm@...r.kernel.org,
        dri-devel@...ts.freedesktop.org, freedreno@...ts.freedesktop.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] drm/msm/mdp5: Find correct node for creating gem
 address space

On Mon 08 Jul 08:12 PDT 2019, Jeffrey Hugo wrote:

> Creating the msm gem address space requires a reference to the dev where
> the iommu is located.  The driver currently assumes this is the same as
> the platform device, which breaks when the iommu is outside of the
> platform device (ie in the parent).  Default to using the platform device,
> but check to see if that has an iommu reference, and if not, use the parent
> device instead.  This should handle all the various iommu designs for
> mdp5 supported systems.
> 
> Signed-off-by: Jeffrey Hugo <jeffrey.l.hugo@...il.com>

Tested-by: Bjorn Andersson <bjorn.andersson@...aro.org>

> ---
> 
> v2: It turns out there isn't a universal way to get the iommu device, so 
> check to see if its in the current node or parent
> 
>  drivers/gpu/drm/msm/disp/mdp5/mdp5_kms.c | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/msm/disp/mdp5/mdp5_kms.c b/drivers/gpu/drm/msm/disp/mdp5/mdp5_kms.c
> index 4a60f5fca6b0..02dc7d426cb0 100644
> --- a/drivers/gpu/drm/msm/disp/mdp5/mdp5_kms.c
> +++ b/drivers/gpu/drm/msm/disp/mdp5/mdp5_kms.c
> @@ -663,6 +663,7 @@ struct msm_kms *mdp5_kms_init(struct drm_device *dev)
>  	struct msm_kms *kms;
>  	struct msm_gem_address_space *aspace;
>  	int irq, i, ret;
> +	struct device *iommu_dev;
>  
>  	/* priv->kms would have been populated by the MDP5 driver */
>  	kms = priv->kms;
> @@ -702,7 +703,11 @@ struct msm_kms *mdp5_kms_init(struct drm_device *dev)
>  	mdelay(16);
>  
>  	if (config->platform.iommu) {
> -		aspace = msm_gem_address_space_create(&pdev->dev,
> +		iommu_dev = &pdev->dev;
> +		if (!iommu_dev->iommu_fwspec)
> +			iommu_dev = iommu_dev->parent;
> +
> +		aspace = msm_gem_address_space_create(iommu_dev,
>  				config->platform.iommu, "mdp5");
>  		if (IS_ERR(aspace)) {
>  			ret = PTR_ERR(aspace);
> -- 
> 2.17.1
>