[PATCH v7 3/9] iommu/dma: Introduce generic helper to retrieve RMR info

Shameer Kolothum
2021-08-05T08:09:08Z

Reserved Memory Regions(RMR) associated with an IOMMU can be
described through ACPI IORT tables in systems with devices
that require a unity mapping or bypass for those
regions.

Introduce a generic interface so that IOMMU drivers can retrieve
and set up necessary mappings.

Signed-off-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
---
drivers/iommu/dma-iommu.c | 29 +++++++++++++++++++++++++++++
include/linux/dma-iommu.h | 13 +++++++++++++
2 files changed, 42 insertions(+)

diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
index 98ba927aee1a..2fa2445e9070 100644
--- a/drivers/iommu/dma-iommu.c
+++ b/drivers/iommu/dma-iommu.c
@@ -174,6 +174,35 @@ void iommu_put_dma_cookie(struct iommu_domain *domain)
}
EXPORT_SYMBOL(iommu_put_dma_cookie);

+/**
+ *
+ * iommu_dma_get_rmrs - Retrieve Reserved Memory Regions(RMRs) associated
+ * with a given IOMMU
+ * @iommu_fwnode: fwnode associated with IOMMU
+ * @list: RMR list to be populated
+ *
+ */
+int iommu_dma_get_rmrs(struct fwnode_handle *iommu_fwnode,
+ struct list_head *list)
+{
+ return -EINVAL;
+}
+EXPORT_SYMBOL(iommu_dma_get_rmrs);
+
+/**
+ *
+ * iommu_dma_put_rmrs - Release Reserved Memory Regions(RMRs) associated
+ * with a given IOMMU
+ * @iommu_fwnode: fwnode associated with IOMMU
+ * @list: RMR list
+ *
+ */
+void iommu_dma_put_rmrs(struct fwnode_handle *iommu_fwnode,
+ struct list_head *list)
+{
+}
+EXPORT_SYMBOL(iommu_dma_put_rmrs);
+
/**
* iommu_dma_get_resv_regions - Reserved region driver helper
* @dev: Device from iommu_get_resv_regions()
diff --git a/include/linux/dma-iommu.h b/include/linux/dma-iommu.h
index 758ca4694257..3b7b2d096c6e 100644
--- a/include/linux/dma-iommu.h
+++ b/include/linux/dma-iommu.h
@@ -42,12 +42,16 @@ void iommu_dma_free_cpu_cached_iovas(unsigned int cpu,

extern bool iommu_dma_forcedac;

+int iommu_dma_get_rmrs(struct fwnode_handle *iommu, struct list_head *list);
+void iommu_dma_put_rmrs(struct fwnode_handle *iommu, struct list_head *list);
+
#else /* CONFIG_IOMMU_DMA */

struct iommu_domain;
struct msi_desc;
struct msi_msg;
struct device;
+struct fwnode_handle;

static inline void iommu_setup_dma_ops(struct device *dev, u64 dma_base,
u64 dma_limit)
@@ -83,5 +87,14 @@ static inline void iommu_dma_get_resv_regions(struct device *dev, struct list_he
{
}

+static int iommu_dma_get_rmrs(struct fwnode_handle *iommu, struct list_head *list)
+{
+ return -ENODEV;
+}
+
+static void iommu_dma_put_rmrs(struct fwnode_handle *iommu, struct list_head *list)
+{
+}
+
#endif /* CONFIG_IOMMU_DMA */
#endif /* __DMA_IOMMU_H */
--
2.17.1