Re: [PATCH 2/2] iommu/tegra: gart: Reserve iomem resource

Thierry Reding
2012-05-21T14:12:01Z

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* Hiroshi DOYU wrote:
> GART Register/Aperture range should be reserved.
>
> Signed-off-by: Hiroshi DOYU <hdoyu@nvidia.com>
> ---
> drivers/iommu/tegra-gart.c | 8 +++++++-
> 1 files changed, 7 insertions(+), 1 deletions(-)
>
> diff --git a/drivers/iommu/tegra-gart.c b/drivers/iommu/tegra-gart.c
> index 33a23b6..a431006 100644
> --- a/drivers/iommu/tegra-gart.c
> +++ b/drivers/iommu/tegra-gart.c
> @@ -366,12 +366,18 @@ static int tegra_gart_probe(struct platform_device *pdev)
> return -ENOMEM;
> }
>
> - gart_regs = devm_ioremap(dev, res->start, resource_size(res));
> + gart_regs = devm_request_and_ioremap(dev, res);
> if (!gart_regs) {
> dev_err(dev, "failed to remap GART registers\n");
> return -ENXIO;
> }
>
> + if (!devm_request_mem_region(dev, res_remap->start,
> + resource_size(res_remap), dev_name(dev))) {
> + dev_err(dev, "failed to reserve GART aperture\n");
> + return -EBUSY;
> + }
> +

I'm not so sure that this is a good idea. If the GART driver requests the
GART aperture, then users of the GART aperture (e.g. the DRM driver) will no
longer be able to use it.

Thierry

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