[RFC v3 09/10] iommu/arm-smmu: Implement reserved region get/put callbacks

[Eric Auger <eric.auger@xxxxxxxxxx>]

The get() populates the list with the PCI host bridge windows
and the MSI IOVA range.

At the moment an arbitray MSI IOVA window is set at 0x8000000
of size 1MB. This will allow to report those info in iommu-group
sysfs?

Signed-off-by: Eric Auger <eric.auger@xxxxxxxxxx>

---

RFC v2 -> v3:
- use existing get/put_resv_regions

RFC v1 -> v2:
- use defines for MSI IOVA base and length
---
 drivers/iommu/arm-smmu.c | 52 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 52 insertions(+)

diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c
index 8f72814..81f1a83 100644
--- a/drivers/iommu/arm-smmu.c
+++ b/drivers/iommu/arm-smmu.c
@@ -278,6 +278,9 @@ enum arm_smmu_s2cr_privcfg {
 
 #define FSYNR0_WNR			(1 << 4)
 
+#define MSI_IOVA_BASE			0x8000000
+#define MSI_IOVA_LENGTH			0x100000
+
 static int force_stage;
 module_param(force_stage, int, S_IRUGO);
 MODULE_PARM_DESC(force_stage,
@@ -1545,6 +1548,53 @@ static int arm_smmu_of_xlate(struct device *dev, struct of_phandle_args *args)
 	return iommu_fwspec_add_ids(dev, &fwid, 1);
 }
 
+static void arm_smmu_get_resv_regions(struct device *dev,
+				      struct list_head *head)
+{
+	struct iommu_resv_region *region;
+	struct pci_host_bridge *bridge;
+	struct resource_entry *window;
+
+	/* MSI region */
+	region = iommu_alloc_resv_region(MSI_IOVA_BASE, MSI_IOVA_LENGTH,
+					 IOMMU_RESV_MSI);
+	if (!region)
+		return;
+
+	list_add_tail(&region->list, head);
+
+	if (!dev_is_pci(dev))
+		return;
+
+	bridge = pci_find_host_bridge(to_pci_dev(dev)->bus);
+
+	resource_list_for_each_entry(window, &bridge->windows) {
+		phys_addr_t start;
+		size_t length;
+
+		if (resource_type(window->res) != IORESOURCE_MEM &&
+		    resource_type(window->res) != IORESOURCE_IO)
+			continue;
+
+		start = window->res->start - window->offset;
+		length = window->res->end - window->res->start + 1;
+		region = iommu_alloc_resv_region(start, length,
+						 IOMMU_RESV_NOMAP);
+		if (!region)
+			return;
+		list_add_tail(&region->list, head);
+	}
+}
+
+static void arm_smmu_put_resv_regions(struct device *dev,
+				      struct list_head *head)
+{
+	struct iommu_resv_region *entry, *next;
+
+	list_for_each_entry_safe(entry, next, head, list)
+		kfree(entry);
+}
+
 static struct iommu_ops arm_smmu_ops = {
 	.capable		= arm_smmu_capable,
 	.domain_alloc		= arm_smmu_domain_alloc,
@@ -1560,6 +1610,8 @@ static int arm_smmu_of_xlate(struct device *dev, struct of_phandle_args *args)
 	.domain_get_attr	= arm_smmu_domain_get_attr,
 	.domain_set_attr	= arm_smmu_domain_set_attr,
 	.of_xlate		= arm_smmu_of_xlate,
+	.get_resv_regions	= arm_smmu_get_resv_regions,
+	.put_resv_regions	= arm_smmu_put_resv_regions,
 	.pgsize_bitmap		= -1UL, /* Restricted during device attach */
 };
 
-- 
1.9.1

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