Re: [PATCH v3] iommu/rockchip: Add missing set_platform_dma_ops callback
From: Robin Murphy
Date: Thu Mar 30 2023 - 11:10:27 EST
On 2023-03-30 15:46, Steven Price wrote:
Similar to exynos, we need a set_platform_dma_ops() callback for proper
operation on ARM 32 bit after recent changes in the IOMMU framework
(detach ops removal). But also the use of a NULL domain is confusing.
Rework the code to have a singleton rk_identity_domain which is assigned
to domain when using an identity mapping rather than "detaching". This
makes the code easier to reason about.
Really this is adding complete support for IOMMU_DOMAIN_IDENTITY in
general, which will also be visible on arm64. The part then using it to
bodge a pseudo-default-domain for Arm seems more incidental ;)
Signed-off-by: Steven Price <steven.price@xxxxxxx>
Reviewed-by: Jason Gunthorpe <jgg@xxxxxxxxxx>
---
Changes since v2[1]:
* Fixed suspend/resume handlers to check against rk_identity_domain
rather than NULL (thanks John).
[1] https://lore.kernel.org/r/20230324111127.221640-1-steven.price%40arm.com
drivers/iommu/rockchip-iommu.c | 56 +++++++++++++++++++++++++---------
1 file changed, 42 insertions(+), 14 deletions(-)
diff --git a/drivers/iommu/rockchip-iommu.c b/drivers/iommu/rockchip-iommu.c
index f30db22ea5d7..4f97af471671 100644
--- a/drivers/iommu/rockchip-iommu.c
+++ b/drivers/iommu/rockchip-iommu.c
@@ -124,6 +124,7 @@ struct rk_iommudata {
static struct device *dma_dev;
static const struct rk_iommu_ops *rk_ops;
+static struct iommu_domain rk_identity_domain;
static inline void rk_table_flush(struct rk_iommu_domain *dom, dma_addr_t dma,
unsigned int count)
@@ -646,7 +647,7 @@ static irqreturn_t rk_iommu_irq(int irq, void *dev_id)
* Ignore the return code, though, since we always zap cache
* and clear the page fault anyway.
*/
- if (iommu->domain)
+ if (iommu->domain != &rk_identity_domain)
report_iommu_fault(iommu->domain, iommu->dev, iova,
flags);
else
@@ -980,26 +981,27 @@ static int rk_iommu_enable(struct rk_iommu *iommu)
return ret;
}
-static void rk_iommu_detach_device(struct iommu_domain *domain,
- struct device *dev)
+static int rk_iommu_identity_attach(struct iommu_domain *identity_domain,
+ struct device *dev)
{
struct rk_iommu *iommu;
- struct rk_iommu_domain *rk_domain = to_rk_domain(domain);
+ struct rk_iommu_domain *rk_domain;
unsigned long flags;
int ret;
/* Allow 'virtual devices' (eg drm) to detach from domain */
iommu = rk_iommu_from_dev(dev);
if (!iommu)
- return;
+ return -ENODEV;
+
+ rk_domain = to_rk_domain(iommu->domain);
dev_dbg(dev, "Detaching from iommu domain\n");
- /* iommu already detached */
- if (iommu->domain != domain)
- return;
+ if (iommu->domain == identity_domain)
+ return 0;
- iommu->domain = NULL;
+ iommu->domain = identity_domain;
spin_lock_irqsave(&rk_domain->iommus_lock, flags);
list_del_init(&iommu->node);
@@ -1011,7 +1013,25 @@ static void rk_iommu_detach_device(struct iommu_domain *domain,
rk_iommu_disable(iommu);
pm_runtime_put(iommu->dev);
}
+
+ return 0;
+}
+
+static struct iommu_domain_ops rk_identity_ops = {
+ .attach_dev = rk_iommu_identity_attach,
Since it's going to behave like a regular identity domain and be treated
as one, it needs to support .free as well.
Thanks,
Robin.
+};
+
+static struct iommu_domain rk_identity_domain = {
+ .type = IOMMU_DOMAIN_IDENTITY,
+ .ops = &rk_identity_ops,
+};
+
+#ifdef CONFIG_ARM
+static void rk_iommu_set_platform_dma(struct device *dev)
+{
+ WARN_ON(rk_iommu_identity_attach(&rk_identity_domain, dev));
}
+#endif
static int rk_iommu_attach_device(struct iommu_domain *domain,
struct device *dev)
@@ -1035,8 +1055,9 @@ static int rk_iommu_attach_device(struct iommu_domain *domain,
if (iommu->domain == domain)
return 0;
- if (iommu->domain)
- rk_iommu_detach_device(iommu->domain, dev);
+ ret = rk_iommu_identity_attach(&rk_identity_domain, dev);
+ if (ret)
+ return ret;
iommu->domain = domain;
@@ -1050,7 +1071,7 @@ static int rk_iommu_attach_device(struct iommu_domain *domain,
ret = rk_iommu_enable(iommu);
if (ret)
- rk_iommu_detach_device(iommu->domain, dev);
+ WARN_ON(rk_iommu_identity_attach(&rk_identity_domain, dev));
pm_runtime_put(iommu->dev);
@@ -1061,6 +1082,9 @@ static struct iommu_domain *rk_iommu_domain_alloc(unsigned type)
{
struct rk_iommu_domain *rk_domain;
+ if (type == IOMMU_DOMAIN_IDENTITY)
+ return &rk_identity_domain;
+
if (type != IOMMU_DOMAIN_UNMANAGED && type != IOMMU_DOMAIN_DMA)
return NULL;
@@ -1176,6 +1200,7 @@ static int rk_iommu_of_xlate(struct device *dev,
iommu_dev = of_find_device_by_node(args->np);
data->iommu = platform_get_drvdata(iommu_dev);
+ data->iommu->domain = &rk_identity_domain;
dev_iommu_priv_set(dev, data);
platform_device_put(iommu_dev);
@@ -1188,6 +1213,9 @@ static const struct iommu_ops rk_iommu_ops = {
.probe_device = rk_iommu_probe_device,
.release_device = rk_iommu_release_device,
.device_group = rk_iommu_device_group,
+#ifdef CONFIG_ARM
+ .set_platform_dma_ops = rk_iommu_set_platform_dma,
+#endif
.pgsize_bitmap = RK_IOMMU_PGSIZE_BITMAP,
.of_xlate = rk_iommu_of_xlate,
.default_domain_ops = &(const struct iommu_domain_ops) {
@@ -1343,7 +1371,7 @@ static int __maybe_unused rk_iommu_suspend(struct device *dev)
{
struct rk_iommu *iommu = dev_get_drvdata(dev);
- if (!iommu->domain)
+ if (iommu->domain == &rk_identity_domain)
return 0;
rk_iommu_disable(iommu);
@@ -1354,7 +1382,7 @@ static int __maybe_unused rk_iommu_resume(struct device *dev)
{
struct rk_iommu *iommu = dev_get_drvdata(dev);
- if (!iommu->domain)
+ if (iommu->domain == &rk_identity_domain)
return 0;
return rk_iommu_enable(iommu);