lkml.org 
[lkml]   [2020]   [Sep]   [30]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH v3 2/3] iommu/tegra-smmu: Rework .probe_device and .attach_dev
Date
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 <nicoleotsuka@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
\
 
 \ /
  Last update: 2020-09-30 10:49    [W:0.208 / U:11.208 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site