2020-10-03 07:08:51

by Nicolin Chen

Subject: [PATCH v5 1/3] iommu/tegra-smmu: Use fwspec in tegra_smmu_(de)attach_dev

In tegra_smmu_(de)attach_dev() functions, we poll DTB for each
client's iommus property to get swgroup ID in order to prepare
"as" and enable smmu. Actually tegra_smmu_configure() prepared
an fwspec for each client, and added to the fwspec all swgroup
IDs of client DT node in DTB.

So this patch uses fwspec in tegra_smmu_(de)attach_dev() so as
to replace the redundant DT polling code.

Signed-off-by: Nicolin Chen <[email protected]>
---

Changelog
v4->v5:
* Removed "index" and "err" assigning to 0
v3->v4:
* Seperated the change, as a cleanup, from the rework patch
v1->v3:
* N/A

drivers/iommu/tegra-smmu.c | 56 ++++++++++++++++----------------------
1 file changed, 23 insertions(+), 33 deletions(-)

diff --git a/drivers/iommu/tegra-smmu.c b/drivers/iommu/tegra-smmu.c
index 6a3ecc334481..297d49f3f80e 100644
--- a/drivers/iommu/tegra-smmu.c
+++ b/drivers/iommu/tegra-smmu.c
@@ -484,60 +484,50 @@ 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;
- }
+ unsigned int index;
+ int err;

- of_node_put(args.np);
+ if (!fwspec)
+ 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];
+ unsigned int index;

- if (args.np != smmu->dev->of_node) {
- of_node_put(args.np);
- continue;
- }
-
- of_node_put(args.np);
+ if (!fwspec)
+ 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++;
}
}

--
2.17.1

2020-10-03 14:16:07

by Dmitry Osipenko

Subject: Re: [PATCH v5 1/3] iommu/tegra-smmu: Use fwspec in tegra_smmu_(de)attach_dev

03.10.2020 09:59, Nicolin Chen пишет:
> In tegra_smmu_(de)attach_dev() functions, we poll DTB for each
> client's iommus property to get swgroup ID in order to prepare
> "as" and enable smmu. Actually tegra_smmu_configure() prepared
> an fwspec for each client, and added to the fwspec all swgroup
> IDs of client DT node in DTB.
>
> So this patch uses fwspec in tegra_smmu_(de)attach_dev() so as
> to replace the redundant DT polling code.
>
> Signed-off-by: Nicolin Chen <[email protected]>
> ---

I'm still not highly impressed by seeing the !fwspec check in this
patch. But I'm not a maintainer of the SMMU driver, hence will leave it
up to Thierry and Joerg to decide whether this is good or needs to be
improved.

Otherwise this patch is good to me, thanks. I tested it on Nexus 7,
which is Tegra30.

Reviewed-by: Dmitry Osipenko <[email protected]>
Tested-by: Dmitry Osipenko <[email protected]>