[PATCH v2 13/13] iommu/rockchip: Support sharing IOMMU between masters

Jeffy Chen
2018-01-16T13:25:40Z

There would be some masters sharing the same IOMMU device. Put them in
the same iommu group and share the same iommu domain.

Signed-off-by: Jeffy Chen <jeffy.chen-TNX95d0MmH7DzftRWevZcw@public.gmane.org>
---

Changes in v2: None

drivers/iommu/rockchip-iommu.c | 39 +++++++++++++++++++++++++++++++--------
1 file changed, 31 insertions(+), 8 deletions(-)

diff --git a/drivers/iommu/rockchip-iommu.c b/drivers/iommu/rockchip-iommu.c
index c8de1456a016..6c316dd0dd2d 100644
--- a/drivers/iommu/rockchip-iommu.c
+++ b/drivers/iommu/rockchip-iommu.c
@@ -100,11 +100,13 @@ struct rk_iommu {
struct iommu_device iommu;
struct list_head node; /* entry in rk_iommu_domain.iommus */
struct iommu_domain *domain; /* domain to which iommu is attached */
+ struct iommu_group *group;
struct mutex pm_mutex; /* serializes power transitions */
};

struct rk_iommudata {
struct device_link *link; /* runtime PM link from IOMMU to master */
+ struct iommu_domain *domain; /* domain to which device is attached */
struct rk_iommu *iommu;
};

@@ -964,6 +966,7 @@ static void rk_iommu_detach_device(struct iommu_domain *domain,
{
struct rk_iommu *iommu;
struct rk_iommu_domain *rk_domain = to_rk_domain(domain);
+ struct rk_iommudata *data = dev->archdata.iommu;
unsigned long flags;

/* Allow 'virtual devices' (eg drm) to detach from domain */
@@ -971,6 +974,12 @@ static void rk_iommu_detach_device(struct iommu_domain *domain,
if (!iommu)
return;

+ /* device already detached */
+ if (data->domain != domain)
+ return;
+
+ data->domain = NULL;
+
dev_dbg(dev, "Detaching from iommu domain\n");

/* iommu already detached */
@@ -994,6 +1003,7 @@ static int rk_iommu_attach_device(struct iommu_domain *domain,
{
struct rk_iommu *iommu;
struct rk_iommu_domain *rk_domain = to_rk_domain(domain);
+ struct rk_iommudata *data = dev->archdata.iommu;
unsigned long flags;
int ret;

@@ -1005,15 +1015,21 @@ static int rk_iommu_attach_device(struct iommu_domain *domain,
if (!iommu)
return 0;

+ /* device already attached */
+ if (data->domain == domain)
+ return 0;
+
+ if (data->domain)
+ rk_iommu_detach_device(data->domain, dev);
+
+ data->domain = domain;
+
dev_dbg(dev, "Attaching to iommu domain\n");

/* iommu already attached */
if (iommu->domain == domain)
return 0;

- if (iommu->domain)
- rk_iommu_detach_device(iommu->domain, dev);
-
iommu->domain = domain;

spin_lock_irqsave(&rk_domain->iommus_lock, flags);
@@ -1150,13 +1166,11 @@ static void rk_iommu_remove_device(struct device *dev)

static struct iommu_group *rk_iommu_device_group(struct device *dev)
{
- struct iommu_group *group;
+ struct rk_iommu *iommu;

- group = iommu_group_get(dev);
- if (!group)
- group = iommu_group_alloc();
+ iommu = rk_iommu_from_dev(dev);

- return group;
+ return iommu ? iommu->group : NULL;
}

static int rk_iommu_of_xlate(struct device *dev,
@@ -1263,6 +1277,12 @@ static int rk_iommu_probe(struct platform_device *pdev)
if (err)
goto err_remove_sysfs;

+ iommu->group = iommu_group_alloc();
+ if (IS_ERR(iommu->group)) {
+ err = PTR_ERR(iommu->group);
+ goto err_unreg_iommu;
+ }
+
/*
* Use the first registered IOMMU device for domain to use with DMA
* API, since a domain might not physically correspond to a single
@@ -1276,6 +1296,8 @@ static int rk_iommu_probe(struct platform_device *pdev)
pm_runtime_enable(dev);

return 0;
+err_unreg_iommu:
+ iommu_device_unregister(&iommu->iommu);
err_remove_sysfs:
iommu_device_sysfs_remove(&iommu->iommu);
err_put_clocks:
@@ -1289,6 +1311,7 @@ static int rk_iommu_remove(struct platform_device *pdev)

pm_runtime_disable(&pdev->dev);

+ iommu_group_put(iommu->group);
iommu_device_unregister(&iommu->iommu);
iommu_device_sysfs_remove(&iommu->iommu);
rk_iommu_put_clocks(iommu);
--
2.11.0