Re: [PATCH v2 02/12] iommu/mediatek: Add probe_defer for smi-larb

Matthias Brugger
2019-06-19T13:52:40Z

On 10/06/2019 14:55, Yong Wu wrote:
> The iommu consumer should use device_link to connect with the
> smi-larb(supplier). then the smi-larb should run before the iommu
> consumer. Here we delay the iommu driver until the smi driver is
> ready, then all the iommu consumer always is after the smi driver.
>
> When there is no this patch, if some consumer drivers run before
> smi-larb, the supplier link_status is DL_DEV_NO_DRIVER(0) in the
> device_link_add, then device_links_driver_bound will use WARN_ON
> to complain that the link_status of supplier is not right.
>
> This is a preparing patch for adding device_link.
>
> Signed-off-by: Yong Wu <yong.wu@mediatek.com>
> ---
> drivers/iommu/mtk_iommu.c | 2 +-
> drivers/iommu/mtk_iommu_v1.c | 2 +-
> 2 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
> index 6fe3369..f7599d8 100644
> --- a/drivers/iommu/mtk_iommu.c
> +++ b/drivers/iommu/mtk_iommu.c
> @@ -664,7 +664,7 @@ static int mtk_iommu_probe(struct platform_device *pdev)
> id = i;
>
> plarbdev = of_find_device_by_node(larbnode);
> - if (!plarbdev) {
> + if (!plarbdev || !plarbdev->dev.driver) {

can't we use:
device_lock()
device_is_bound(struct device *dev)
device_unlock()

> of_node_put(larbnode);
> return -EPROBE_DEFER;
> }
> diff --git a/drivers/iommu/mtk_iommu_v1.c b/drivers/iommu/mtk_iommu_v1.c
> index 0b0908c..c43c4a0 100644
> --- a/drivers/iommu/mtk_iommu_v1.c
> +++ b/drivers/iommu/mtk_iommu_v1.c
> @@ -604,7 +604,7 @@ static int mtk_iommu_probe(struct platform_device *pdev)
> plarbdev = of_platform_device_create(
> larb_spec.np, NULL,
> platform_bus_type.dev_root);
> - if (!plarbdev) {
> + if (!plarbdev || !plarbdev->dev.driver) {
> of_node_put(larb_spec.np);
> return -EPROBE_DEFER;
> }
>