On Tue, Jun 28, 2016 at 04:48:21PM +0100, Robin Murphy wrote:
> So far, all the users of the generic of_xlate configuration mechanism
> are resorting to explicit platform device creation to ensure the IOMMU
> device is ready before anything tries to refer to it. As I'm about to
> convert two more drivers that will need exactly the same thing, let's
> nip that proliferation in the bud and move it to a single place.
>
> A neat solution is to make of_get_iommu_ops() ensure an IOMMU device is
> instantiated before giving out its associated ops, since it's a fairly
> safe assumption that the ops aren't going to be much use if the IOMMU
> can't or won't exist to back them up.
>
> CC: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>
> CC: Yong Wu <yong.wu@xxxxxxxxxxxx>
> Signed-off-by: Robin Murphy <robin.murphy@xxxxxxx>
> ---
Marek, Yong, can I have your acks on this please? It's a fairly
straightforward change, but the subsequent arm-smmu patches rely on it.
Thanks,
Will
> drivers/iommu/exynos-iommu.c | 20 +++++++-------------
> drivers/iommu/mtk_iommu.c | 8 +-------
> drivers/iommu/of_iommu.c | 6 +++++-
> 3 files changed, 13 insertions(+), 21 deletions(-)
>
> diff --git a/drivers/iommu/exynos-iommu.c b/drivers/iommu/exynos-iommu.c
> index 5ecc86cb74c8..97380ee56d71 100644
> --- a/drivers/iommu/exynos-iommu.c
> +++ b/drivers/iommu/exynos-iommu.c
> @@ -665,6 +665,13 @@ static int __init exynos_sysmmu_probe(struct platform_device *pdev)
>
> pm_runtime_enable(dev);
>
> + /*
> + * use the first registered sysmmu device for performing
> + * dma mapping operations on iommu page tables (cpu cache flush)
> + */
> + if (!dma_dev)
> + dma_dev = dev;
> +
> return 0;
> }
>
> @@ -1341,22 +1348,9 @@ err_reg_driver:
>
> static int __init exynos_iommu_of_setup(struct device_node *np)
> {
> - struct platform_device *pdev;
> -
> if (!init_done)
> exynos_iommu_init();
>
> - pdev = of_platform_device_create(np, NULL, platform_bus_type.dev_root);
> - if (IS_ERR(pdev))
> - return PTR_ERR(pdev);
> -
> - /*
> - * use the first registered sysmmu device for performing
> - * dma mapping operations on iommu page tables (cpu cache flush)
> - */
> - if (!dma_dev)
> - dma_dev = &pdev->dev;
> -
> of_iommu_set_ops(np, &exynos_iommu_ops);
> return 0;
> }
> diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
> index c3043d8754e3..f7ae87abea99 100644
> --- a/drivers/iommu/mtk_iommu.c
> +++ b/drivers/iommu/mtk_iommu.c
> @@ -724,14 +724,8 @@ static struct platform_driver mtk_iommu_driver = {
>
> static int mtk_iommu_init_fn(struct device_node *np)
> {
> - int ret;
> - struct platform_device *pdev;
> + int ret = platform_driver_register(&mtk_iommu_driver);
>
> - pdev = of_platform_device_create(np, NULL, platform_bus_type.dev_root);
> - if (!pdev)
> - return -ENOMEM;
> -
> - ret = platform_driver_register(&mtk_iommu_driver);
> if (ret) {
> pr_err("%s: Failed to register driver\n", __func__);
> return ret;
> diff --git a/drivers/iommu/of_iommu.c b/drivers/iommu/of_iommu.c
> index af499aea0a1a..7e6369cffc95 100644
> --- a/drivers/iommu/of_iommu.c
> +++ b/drivers/iommu/of_iommu.c
> @@ -22,6 +22,7 @@
> #include <linux/limits.h>
> #include <linux/of.h>
> #include <linux/of_iommu.h>
> +#include <linux/of_platform.h>
> #include <linux/slab.h>
>
> static const struct of_device_id __iommu_of_table_sentinel
> @@ -127,7 +128,10 @@ const struct iommu_ops *of_iommu_get_ops(struct device_node *np)
> spin_lock(&of_iommu_lock);
> list_for_each_entry(node, &of_iommu_list, list)
> if (node->np == np) {
> - ops = node->ops;
> + if (of_node_check_flag(np, OF_POPULATED) ||
> + of_platform_device_create(np, NULL,
> + platform_bus_type.dev_root))
> + ops = node->ops;
> break;
> }
> spin_unlock(&of_iommu_lock);
> --
> 2.8.1.dirty
>
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