[RFC PATCH 3/4] ACPI/IORT: Add RMR memory regions reservation helper

Shameer Kolothum
2020-10-27T11:28:21Z

Add a helper function that retrieves RMR memory descriptors
associated with a given endpoint dev. These memory regions
should have a unity mapping in the SMMU. So reserve them as
IOMMU_RESV_DIRECT.

Signed-off-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
---
drivers/acpi/arm64/iort.c | 56 +++++++++++++++++++++++++++++++++++++++
include/linux/acpi_iort.h | 4 +++
2 files changed, 60 insertions(+)

diff --git a/drivers/acpi/arm64/iort.c b/drivers/acpi/arm64/iort.c
index b32cd53cca08..c0700149e60b 100644
--- a/drivers/acpi/arm64/iort.c
+++ b/drivers/acpi/arm64/iort.c
@@ -842,6 +842,60 @@ static inline int iort_add_device_replay(struct device *dev)
return err;
}

+static bool iort_dev_has_rmr(struct device *dev, struct iort_rmr_entry *e)
+{
+ struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
+ struct acpi_iort_node *iommu;
+ struct iort_rmr_id *rmr_ids = e->rmr_ids;
+ int i, j;
+
+ iommu = iort_get_iort_node(fwspec->iommu_fwnode);
+
+ for (i = 0; i < e->rmr_ids_num; i++, rmr_ids++) {
+ for (j = 0; j < fwspec->num_ids; j++) {
+ if (rmr_ids->sid == fwspec->ids[j] &&
+ rmr_ids->smmu == iommu)
+ return true;
+ }
+ }
+
+ return false;
+}
+
+/**
+ * iort_dev_rmr_get_resv_regions - RMR Reserved region driver helper
+ * @dev: Device from iommu_get_resv_regions()
+ * @head: Reserved region list from iommu_get_resv_regions()
+ *
+ * Returns: 0 on success, <0 failure
+ */
+int iort_dev_rmr_get_resv_regions(struct device *dev, struct list_head *head)
+{
+ struct iort_rmr_entry *e;
+
+ list_for_each_entry(e, &iort_rmr_list, list) {
+ struct iommu_resv_region *region;
+ struct acpi_iort_rmr_desc *rmr;
+ int prot = IOMMU_READ | IOMMU_WRITE |
+ IOMMU_NOEXEC | IOMMU_MMIO;
+
+ if (!iort_dev_has_rmr(dev, e))
+ continue;
+
+ rmr = e->rmr_desc;
+ region = iommu_alloc_resv_region(rmr->base_address,
+ rmr->length, prot,
+ IOMMU_RESV_DIRECT);
+ if (!region) {
+ dev_err(dev, "Out of memory allocating RMR regions\n");
+ return -ENOMEM;
+ }
+ list_add_tail(&region->list, head);
+ }
+
+ return 0;
+}
+
/**
* iort_iommu_msi_get_resv_regions - Reserved region driver helper
* @dev: Device from iommu_get_resv_regions()
@@ -1112,6 +1166,8 @@ int iort_iommu_msi_get_resv_regions(struct device *dev, struct list_head *head)
const struct iommu_ops *iort_iommu_configure_id(struct device *dev,
const u32 *input_id)
{ return NULL; }
+int iort_dev_rmr_get_resv_regions(struct device *dev, struct list_head *head)
+{ return 0; }
#endif

static int nc_dma_get_range(struct device *dev, u64 *size)
diff --git a/include/linux/acpi_iort.h b/include/linux/acpi_iort.h
index 20a32120bb88..6dd89faf340c 100644
--- a/include/linux/acpi_iort.h
+++ b/include/linux/acpi_iort.h
@@ -38,6 +38,7 @@ void iort_dma_setup(struct device *dev, u64 *dma_addr, u64 *size);
const struct iommu_ops *iort_iommu_configure_id(struct device *dev,
const u32 *id_in);
int iort_iommu_msi_get_resv_regions(struct device *dev, struct list_head *head);
+int iort_dev_rmr_get_resv_regions(struct device *dev, struct list_head *head);
#else
static inline void acpi_iort_init(void) { }
static inline u32 iort_msi_map_id(struct device *dev, u32 id)
@@ -55,6 +56,9 @@ static inline const struct iommu_ops *iort_iommu_configure_id(
static inline
int iort_iommu_msi_get_resv_regions(struct device *dev, struct list_head *head)
{ return 0; }
+static inline
+int iort_dev_rmr_get_resv_regions(struct device *dev, struct list_head *head)
+{ return 0; }
#endif

#endif /* __ACPI_IORT_H__ */
--
2.17.1