Re: [PATCH v8 11/14] iommu/rockchip: Use OF_IOMMU to attach devices automatically

Daniel Kurtz
2018-03-26T06:31:12Z

On Fri, Mar 23, 2018 at 1:40 AM Jeffy Chen <jeffy.chen-TNX95d0MmH7DzftRWevZcw@public.gmane.org>
wrote:

> Converts the rockchip-iommu driver to use the OF_IOMMU infrastructure,
> which allows attaching master devices to their IOMMUs automatically
> according to DT properties.

> Signed-off-by: Jeffy Chen <jeffy.chen-TNX95d0MmH7DzftRWevZcw@public.gmane.org>
> Reviewed-by: Robin Murphy <robin.murphy-5wv7dgnIgG8@public.gmane.org>
> ---

> Changes in v8: None
> Changes in v7: None
> Changes in v6: None
> Changes in v5: None
> Changes in v4: None
> Changes in v3:
> Add struct rk_iommudata.
> Squash iommu/rockchip: Use iommu_group_get_for_dev() for add_device

> Changes in v2: None

> drivers/iommu/rockchip-iommu.c | 135
++++++++++++-----------------------------
> 1 file changed, 40 insertions(+), 95 deletions(-)

> diff --git a/drivers/iommu/rockchip-iommu.c
b/drivers/iommu/rockchip-iommu.c
> index 7970d21b9858..bd8580b897e9 100644
> --- a/drivers/iommu/rockchip-iommu.c
> +++ b/drivers/iommu/rockchip-iommu.c
> @@ -19,6 +19,7 @@
> #include <linux/mm.h>
> #include <linux/module.h>
> #include <linux/of.h>
> +#include <linux/of_iommu.h>
> #include <linux/of_platform.h>
> #include <linux/platform_device.h>
> #include <linux/slab.h>
> @@ -104,6 +105,10 @@ struct rk_iommu {
> struct iommu_domain *domain; /* domain to which iommu is attached
*/
> };

> +struct rk_iommudata {
> + struct rk_iommu *iommu;
> +};

Why do we need this struct? Can't we just assign a pointer to struct
rk_iommu directly to dev->archdata.iommu?

> +
> static struct device *dma_dev;

> static inline void rk_table_flush(struct rk_iommu_domain *dom,
dma_addr_t dma,
> @@ -807,18 +812,9 @@ static size_t rk_iommu_unmap(struct iommu_domain
*domain, unsigned long _iova,

> static struct rk_iommu *rk_iommu_from_dev(struct device *dev)
> {
> - struct iommu_group *group;
> - struct device *iommu_dev;
> - struct rk_iommu *rk_iommu;
> + struct rk_iommudata *data = dev->archdata.iommu;

> - group = iommu_group_get(dev);
> - if (!group)
> - return NULL;
> - iommu_dev = iommu_group_get_iommudata(group);
> - rk_iommu = dev_get_drvdata(iommu_dev);
> - iommu_group_put(group);
> -
> - return rk_iommu;
> + return data ? data->iommu : NULL;
> }

> static int rk_iommu_attach_device(struct iommu_domain *domain,
> @@ -989,110 +985,53 @@ static void rk_iommu_domain_free(struct
iommu_domain *domain)
> iommu_put_dma_cookie(&rk_domain->domain);
> }

> -static bool rk_iommu_is_dev_iommu_master(struct device *dev)
> -{
> - struct device_node *np = dev->of_node;
> - int ret;
> -
> - /*
> - * An iommu master has an iommus property containing a list of
phandles
> - * to iommu nodes, each with an #iommu-cells property with value
0.
> - */
> - ret = of_count_phandle_with_args(np, "iommus", "#iommu-cells");
> - return (ret > 0);
> -}
> -
> -static int rk_iommu_group_set_iommudata(struct iommu_group *group,
> - struct device *dev)
> +static int rk_iommu_add_device(struct device *dev)
> {
> - struct device_node *np = dev->of_node;
> - struct platform_device *pd;
> - int ret;
> - struct of_phandle_args args;
> + struct iommu_group *group;
> + struct rk_iommu *iommu;

> - /*
> - * An iommu master has an iommus property containing a list of
phandles
> - * to iommu nodes, each with an #iommu-cells property with value
0.
> - */
> - ret = of_parse_phandle_with_args(np, "iommus", "#iommu-cells", 0,
> - &args);
> - if (ret) {
> - dev_err(dev, "of_parse_phandle_with_args(%pOF) => %d\n",
> - np, ret);
> - return ret;
> - }
> - if (args.args_count != 0) {
> - dev_err(dev, "incorrect number of iommu params found for
%pOF (found %d, expected 0)\n",
> - args.np, args.args_count);
> - return -EINVAL;
> - }
> + iommu = rk_iommu_from_dev(dev);
> + if (!iommu)
> + return -ENODEV;

> - pd = of_find_device_by_node(args.np);
> - of_node_put(args.np);
> - if (!pd) {
> - dev_err(dev, "iommu %pOF not found\n", args.np);
> - return -EPROBE_DEFER;
> - }
> + group = iommu_group_get_for_dev(dev);
> + if (IS_ERR(group))
> + return PTR_ERR(group);
> + iommu_group_put(group);

> - /* TODO(djkurtz): handle multiple slave iommus for a single
master */
> - iommu_group_set_iommudata(group, &pd->dev, NULL);
> + iommu_device_link(&iommu->iommu, dev);

> return 0;
> }

> -static int rk_iommu_add_device(struct device *dev)
> +static void rk_iommu_remove_device(struct device *dev)
> {
> - struct iommu_group *group;
> struct rk_iommu *iommu;
> - int ret;
> -
> - if (!rk_iommu_is_dev_iommu_master(dev))
> - return -ENODEV;
> -
> - group = iommu_group_get(dev);
> - if (!group) {
> - group = iommu_group_alloc();
> - if (IS_ERR(group)) {
> - dev_err(dev, "Failed to allocate IOMMU group\n");
> - return PTR_ERR(group);
> - }
> - }
> -
> - ret = iommu_group_add_device(group, dev);
> - if (ret)
> - goto err_put_group;
> -
> - ret = rk_iommu_group_set_iommudata(group, dev);
> - if (ret)
> - goto err_remove_device;

> iommu = rk_iommu_from_dev(dev);
> - if (iommu)
> - iommu_device_link(&iommu->iommu, dev);

> - iommu_group_put(group);
> -
> - return 0;
> -
> -err_remove_device:
> + iommu_device_unlink(&iommu->iommu, dev);
> iommu_group_remove_device(dev);
> -err_put_group:
> - iommu_group_put(group);
> - return ret;
> }

> -static void rk_iommu_remove_device(struct device *dev)
> +static int rk_iommu_of_xlate(struct device *dev,
> + struct of_phandle_args *args)
> {
> - struct rk_iommu *iommu;
> + struct platform_device *iommu_dev;
> + struct rk_iommudata *data;

> - if (!rk_iommu_is_dev_iommu_master(dev))
> - return;
> + data = devm_kzalloc(dma_dev, sizeof(*data), GFP_KERNEL);
> + if (!data)
> + return -ENOMEM;

> - iommu = rk_iommu_from_dev(dev);
> - if (iommu)
> - iommu_device_unlink(&iommu->iommu, dev);
> + iommu_dev = of_find_device_by_node(args->np);

> - iommu_group_remove_device(dev);
> + data->iommu = platform_get_drvdata(iommu_dev);
> + dev->archdata.iommu = data;
> +
> + of_dev_put(iommu_dev);
> +
> + return 0;
> }

> static const struct iommu_ops rk_iommu_ops = {
> @@ -1106,7 +1045,9 @@ static const struct iommu_ops rk_iommu_ops = {
> .add_device = rk_iommu_add_device,
> .remove_device = rk_iommu_remove_device,
> .iova_to_phys = rk_iommu_iova_to_phys,
> + .device_group = generic_device_group,
> .pgsize_bitmap = RK_IOMMU_PGSIZE_BITMAP,
> + .of_xlate = rk_iommu_of_xlate,
> };

> static int rk_iommu_probe(struct platform_device *pdev)
> @@ -1178,6 +1119,8 @@ static int rk_iommu_probe(struct platform_device
*pdev)
> goto err_unprepare_clocks;

> iommu_device_set_ops(&iommu->iommu, &rk_iommu_ops);
> + iommu_device_set_fwnode(&iommu->iommu, &dev->of_node->fwnode);
> +
> err = iommu_device_register(&iommu->iommu);
> if (err)
> goto err_remove_sysfs;
> @@ -1250,6 +1193,8 @@ static int __init rk_iommu_init(void)
> }
> subsys_initcall(rk_iommu_init);

> +IOMMU_OF_DECLARE(rk_iommu_of, "rockchip,iommu");
> +
> MODULE_DESCRIPTION("IOMMU API for Rockchip");
> MODULE_AUTHOR("Simon Xue <xxm-TNX95d0MmH7DzftRWevZcw@public.gmane.org> and Daniel Kurtz <
djkurtz-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>");
> MODULE_ALIAS("platform:rockchip-iommu");
> --
> 2.11.0