Previously the driver relies on bus_set_iommu() in .probe() to call in .probe_device() function so each client can poll iommus property in DTB to configure fwspec via tegra_smmu_configure(). According to the comments in .probe(), this is a bit of a hack. And this doesn't work for a client that doesn't exist in DTB, PCI device for example.
Actually when a device/client gets probed, the of_iommu_configure() will call in .probe_device() function again, with a prepared fwspec from of_iommu_configure() that reads the SWGROUP id in DTB as we do in tegra-smmu driver. Additionally, as a new helper devm_tegra_get_memory_controller() is introduced, there's no need to poll the iommus property in order to get mc->smmu pointers or SWGROUP id. This patch reworks .probe_device() and .attach_dev() by doing: 1) Using fwspec to get swgroup id in .attach_dev/.dettach_dev() 2) Removing DT polling code, tegra_smmu_find/tegra_smmu_configure() 3) Calling devm_tegra_get_memory_controller() in .probe_device() 4) Also dropping the hack in .probe() that's no longer needed. Signed-off-by: Nicolin Chen <nicoleots...@gmail.com> --- Changelog v2->v3 * Used devm_tegra_get_memory_controller() to get mc pointer * Replaced IS_ERR_OR_NULL with IS_ERR in .probe_device() v1->v2 * Replaced in .probe_device() tegra_smmu_find/tegra_smmu_configure() with tegra_get_memory_controller call. * Dropped the hack in tegra_smmu_probe(). drivers/iommu/tegra-smmu.c | 144 ++++++++++--------------------------- 1 file changed, 36 insertions(+), 108 deletions(-) diff --git a/drivers/iommu/tegra-smmu.c b/drivers/iommu/tegra-smmu.c index 6a3ecc334481..636dc3b89545 100644 --- a/drivers/iommu/tegra-smmu.c +++ b/drivers/iommu/tegra-smmu.c @@ -61,6 +61,8 @@ struct tegra_smmu_as { u32 attr; }; +static const struct iommu_ops tegra_smmu_ops; + static struct tegra_smmu_as *to_smmu_as(struct iommu_domain *dom) { return container_of(dom, struct tegra_smmu_as, domain); @@ -484,60 +486,50 @@ static void tegra_smmu_as_unprepare(struct tegra_smmu *smmu, static int tegra_smmu_attach_dev(struct iommu_domain *domain, struct device *dev) { + struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev); struct tegra_smmu *smmu = dev_iommu_priv_get(dev); struct tegra_smmu_as *as = to_smmu_as(domain); - struct device_node *np = dev->of_node; - struct of_phandle_args args; unsigned int index = 0; int err = 0; - while (!of_parse_phandle_with_args(np, "iommus", "#iommu-cells", index, - &args)) { - unsigned int swgroup = args.args[0]; - - if (args.np != smmu->dev->of_node) { - of_node_put(args.np); - continue; - } - - of_node_put(args.np); + if (!fwspec || fwspec->ops != &tegra_smmu_ops) + return -ENOENT; + for (index = 0; index < fwspec->num_ids; index++) { err = tegra_smmu_as_prepare(smmu, as); - if (err < 0) - return err; + if (err) + goto disable; - tegra_smmu_enable(smmu, swgroup, as->id); - index++; + tegra_smmu_enable(smmu, fwspec->ids[index], as->id); } if (index == 0) return -ENODEV; return 0; + +disable: + while (index--) { + tegra_smmu_disable(smmu, fwspec->ids[index], as->id); + tegra_smmu_as_unprepare(smmu, as); + } + + return err; } static void tegra_smmu_detach_dev(struct iommu_domain *domain, struct device *dev) { + struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev); struct tegra_smmu_as *as = to_smmu_as(domain); - struct device_node *np = dev->of_node; struct tegra_smmu *smmu = as->smmu; - struct of_phandle_args args; unsigned int index = 0; - while (!of_parse_phandle_with_args(np, "iommus", "#iommu-cells", index, - &args)) { - unsigned int swgroup = args.args[0]; - - if (args.np != smmu->dev->of_node) { - of_node_put(args.np); - continue; - } - - of_node_put(args.np); + if (!fwspec || fwspec->ops != &tegra_smmu_ops) + return; - tegra_smmu_disable(smmu, swgroup, as->id); + for (index = 0; index < fwspec->num_ids; index++) { + tegra_smmu_disable(smmu, fwspec->ids[index], as->id); tegra_smmu_as_unprepare(smmu, as); - index++; } } @@ -807,80 +799,26 @@ static phys_addr_t tegra_smmu_iova_to_phys(struct iommu_domain *domain, return SMMU_PFN_PHYS(pfn) + SMMU_OFFSET_IN_PAGE(iova); } -static struct tegra_smmu *tegra_smmu_find(struct device_node *np) -{ - struct platform_device *pdev; - struct tegra_mc *mc; - - pdev = of_find_device_by_node(np); - if (!pdev) - return NULL; - - mc = platform_get_drvdata(pdev); - if (!mc) - return NULL; - - return mc->smmu; -} - -static int tegra_smmu_configure(struct tegra_smmu *smmu, struct device *dev, - struct of_phandle_args *args) -{ - const struct iommu_ops *ops = smmu->iommu.ops; - int err; - - err = iommu_fwspec_init(dev, &dev->of_node->fwnode, ops); - if (err < 0) { - dev_err(dev, "failed to initialize fwspec: %d\n", err); - return err; - } - - err = ops->of_xlate(dev, args); - if (err < 0) { - dev_err(dev, "failed to parse SW group ID: %d\n", err); - iommu_fwspec_free(dev); - return err; - } - - return 0; -} - static struct iommu_device *tegra_smmu_probe_device(struct device *dev) { - struct device_node *np = dev->of_node; - struct tegra_smmu *smmu = NULL; - struct of_phandle_args args; - unsigned int index = 0; - int err; - - while (of_parse_phandle_with_args(np, "iommus", "#iommu-cells", index, - &args) == 0) { - smmu = tegra_smmu_find(args.np); - if (smmu) { - err = tegra_smmu_configure(smmu, dev, &args); - of_node_put(args.np); - - if (err < 0) - return ERR_PTR(err); - - /* - * Only a single IOMMU master interface is currently - * supported by the Linux kernel, so abort after the - * first match. - */ - dev_iommu_priv_set(dev, smmu); - - break; - } + struct tegra_mc *mc = devm_tegra_get_memory_controller(dev); + struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev); - of_node_put(args.np); - index++; - } + /* An invalid mc pointer means mc and smmu drivers are not ready */ + if (IS_ERR(mc)) + return ERR_PTR(-EPROBE_DEFER); - if (!smmu) + /* + * IOMMU core allows -ENODEV return to carry on. So bypass any call + * from bus_set_iommu() during tegra_smmu_probe(), as a device will + * call in again via of_iommu_configure when fwspec is prepared. + */ + if (!mc->smmu || !fwspec || fwspec->ops != &tegra_smmu_ops) return ERR_PTR(-ENODEV); - return &smmu->iommu; + dev_iommu_priv_set(dev, mc->smmu); + + return &mc->smmu->iommu; } static void tegra_smmu_release_device(struct device *dev) @@ -1089,16 +1027,6 @@ struct tegra_smmu *tegra_smmu_probe(struct device *dev, if (!smmu) return ERR_PTR(-ENOMEM); - /* - * This is a bit of a hack. Ideally we'd want to simply return this - * value. However the IOMMU registration process will attempt to add - * all devices to the IOMMU when bus_set_iommu() is called. In order - * not to rely on global variables to track the IOMMU instance, we - * set it here so that it can be looked up from the .probe_device() - * callback via the IOMMU device's .drvdata field. - */ - mc->smmu = smmu; - size = BITS_TO_LONGS(soc->num_asids) * sizeof(long); smmu->asids = devm_kzalloc(dev, size, GFP_KERNEL); -- 2.17.1 _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu