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Date:   Thu, 11 Apr 2019 09:23:13 +0100
From:   Ben Dooks <ben.dooks@codethink.co.uk>
To:     Stefan Agner <stefan@agner.ch>
Cc:     thierry.reding@gmail.com, digetx@gmail.com,
        dri-devel@lists.freedesktop.org, linux-tegra@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-tegra-owner@vger.kernel.org
Subject: Re: [PATCH] gpu: host1x: fix compile error when IOMMU API is not
 available
In-Reply-To: <4c3d021c73c001f633803e364cfbc6ace3381205.1554936354.git.stefan@agner.ch>
References: <4c3d021c73c001f633803e364cfbc6ace3381205.1554936354.git.stefan@agner.ch>
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On 2019-04-10 23:47, Stefan Agner wrote:
> In case the IOMMU API is not available compiling host1x fails with
> the following error:
>   In file included from drivers/gpu/host1x/hw/host1x06.c:27:
>   drivers/gpu/host1x/hw/channel_hw.c: In function 
> ‘host1x_channel_set_streamid’:
>   drivers/gpu/host1x/hw/channel_hw.c:118:30: error: implicit
> declaration of function
>     ‘dev_iommu_fwspec_get’; did you mean ‘iommu_fwspec_free’?
> [-Werror=implicit-function-declaration]
>   struct iommu_fwspec *spec = 
> dev_iommu_fwspec_get(channel->dev->parent);
>                               ^~~~~~~~~~~~~~~~~~~~
>                               iommu_fwspec_free
> 
> Fixes: de5469c21ff9 ("gpu: host1x: Program the channel stream ID")
> Signed-off-by: Stefan Agner <stefan@agner.ch>

would it be better to provide something like this i nthe header that
defines dev_iommu_fwspec_get() to be:

static inline struct iommu_fwspec *dev_iommu_fwspec_get(struct device 
*dev) { return NULL; }

although returning an PTR_ERR would have been better.

> ---
>  drivers/gpu/host1x/hw/channel_hw.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/host1x/hw/channel_hw.c
> b/drivers/gpu/host1x/hw/channel_hw.c
> index 27101c04a827..4030d64916f0 100644
> --- a/drivers/gpu/host1x/hw/channel_hw.c
> +++ b/drivers/gpu/host1x/hw/channel_hw.c
> @@ -114,7 +114,7 @@ static inline void synchronize_syncpt_base(struct
> host1x_job *job)
> 
>  static void host1x_channel_set_streamid(struct host1x_channel 
> *channel)
>  {
> -#if HOST1X_HW >= 6
> +#if IS_ENABLED(CONFIG_IOMMU_API) &&  HOST1X_HW >= 6
>  	struct iommu_fwspec *spec = 
> dev_iommu_fwspec_get(channel->dev->parent);
>  	u32 sid = spec ? spec->ids[0] & 0xffff : 0x7f;