Re: [PATCH 3/3 v17] iommu/fsl: Freescale PAMU driver and iommu implementation.

+#define REQ_ACS_FLAGS	(PCI_ACS_SV | PCI_ACS_RR | PCI_ACS_CR | PCI_ACS_UF)
+
+static struct iommu_group *get_device_iommu_group(struct device *dev)
+{
+	struct iommu_group *group;
+
+	group = iommu_group_get(dev);
+	if (!group)
+		group = iommu_group_alloc();
+
+	return group;
+}
+
+static  bool check_pci_ctl_endpt_part(struct pci_controller *pci_ctl)
+{
+	u32 version;
+
+	/* Check the PCI controller version number by readding BRR1 register */
+	version = in_be32(pci_ctl->cfg_addr + (PCI_FSL_BRR1 >> 2));
+	version &= PCI_FSL_BRR1_VER;
+	/* If PCI controller version is >= 0x204 we can partition endpoints*/
+	if (version >= 0x204)
+		return 1;
+
+	return 0;
+}
+
+/* Get iommu group information from peer devices or devices on the parent bus */
+static struct iommu_group *get_peer_pci_device_group(struct pci_dev *pdev)
+{
+	struct pci_dev *tmp;
+	struct iommu_group *group = NULL;
+
+	/* check if this is the first device on the bus*/
+	if (list_is_singular(&pdev->bus_list)) {
+		struct pci_bus *bus = pdev->bus->parent;
+		/* Traverese the parent bus list to get
+		 * the iommu group for devices on the
+		 * parent bus.
+		 */
+		while (bus && !group) {
+			list_for_each_entry(tmp, &bus->devices, bus_list) {
+				group = iommu_group_get(&tmp->dev);
+				if (group)
+					break;
+			}
+
+			bus = bus->parent;
+		}
+	} else {
+		/*
+		 * Get the iommu group for the sibling device
+		 */
+		list_for_each_entry(tmp, &pdev->bus_list, bus_list) {
+			if (tmp == pdev)
+				continue;
+			group = iommu_group_get(&tmp->dev);
+			if (group)
+				break;
+		}
+	}
+
+	return group;

+}
+
+static struct iommu_group *get_pci_device_group(struct pci_dev *pdev)
+{
+	struct pci_controller *pci_ctl;
+	bool pci_endpt_partioning;
+	struct iommu_group *group = NULL;
+	struct pci_dev *bridge, *dma_pdev = NULL;
+
+	pci_ctl = pci_bus_to_host(pdev->bus);
+	pci_endpt_partioning = check_pci_ctl_endpt_part(pci_ctl);
+	/* We can partition PCIe devices so assign device group to the device */
+	if (pci_endpt_partioning) {
+		bridge = pci_find_upstream_pcie_bridge(pdev);
+		if (bridge) {
+			if (pci_is_pcie(bridge))
+				dma_pdev = pci_get_domain_bus_and_slot(
+						pci_domain_nr(pdev->bus),
+						bridge->subordinate->number, 0);
+			if (!dma_pdev)
+				dma_pdev = pci_dev_get(bridge);
+		} else
+			dma_pdev = pci_dev_get(pdev);
+
+		/* Account for quirked devices */
+		swap_pci_ref(&dma_pdev, pci_get_dma_source(dma_pdev));
+
+		/*
+		 * If it's a multifunction device that does not support our
+		 * required ACS flags, add to the same group as lowest numbered
+		 * function that also does not suport the required ACS flags.
+		 */
+		if (dma_pdev->multifunction &&
+		    !pci_acs_enabled(dma_pdev, REQ_ACS_FLAGS)) {
+			u8 i, slot = PCI_SLOT(dma_pdev->devfn);
+
+			for (i = 0; i < 8; i++) {
+				struct pci_dev *tmp;
+
+				tmp = pci_get_slot(dma_pdev->bus, PCI_DEVFN(slot, i));
+				if (!tmp)
+					continue;
+
+				if (!pci_acs_enabled(tmp, REQ_ACS_FLAGS)) {
+					swap_pci_ref(&dma_pdev, tmp);
+					break;
+				}
+				pci_dev_put(tmp);
+			}
+		}
+
+		/*
+		 * Devices on the root bus go through the iommu.  If that's not us,
+	 	 * find the next upstream device and test ACS up to the root bus.
+		 * Finding the next device may require skipping virtual buses.
+		 */
+		while (!pci_is_root_bus(dma_pdev->bus)) {
+			struct pci_bus *bus = dma_pdev->bus;
+
+			while (!bus->self) {
+				if (!pci_is_root_bus(bus))
+					bus = bus->parent;
+				else
+					goto root_bus;
+			}
+
+			if (pci_acs_path_enabled(bus->self, NULL, REQ_ACS_FLAGS))
+				break;
+
+			swap_pci_ref(&dma_pdev, pci_dev_get(bus->self));
+		}
+
+root_bus:
+		group = get_device_iommu_group(&dma_pdev->dev);
+		pci_dev_put(dma_pdev);
+		/*
+		 * PCIe controller is not a paritionable entity
+		 * free the controller device iommu_group.
+		 */
+		if (pci_ctl->parent->iommu_group)
+			iommu_group_remove_device(pci_ctl->parent);
+	} else {
+		/*
+		 * All devices connected to the controller will share the
+		 * PCI controllers device group. If this is the first
+		 * device to be probed for the pci controller, copy the
+		 * device group information from the PCI controller device
+		 * node and remove the PCI controller iommu group.
+		 * For subsequent devices, the iommu group information can
+		 * be obtained from sibling devices (i.e. from the bus_devices
+		 * link list).
+		 */
+		if (pci_ctl->parent->iommu_group) {
+			group = get_device_iommu_group(pci_ctl->parent);
+			iommu_group_remove_device(pci_ctl->parent);
+		} else
+			group = get_peer_pci_device_group(pdev);
+	}
+
+	return group;
+}
+
+static int fsl_pamu_add_device(struct device *dev)
+{
+	struct iommu_group *group = NULL;
+	struct pci_dev *pdev;
+	const u32 *prop;
+	int ret, len;
+
+	/*
+	 * For platform devices we allocate a separate group for
+	 * each of the devices.
+	 */
+	if (dev->bus == &pci_bus_type) {
+		pdev = to_pci_dev(dev);
+		/* Don't create device groups for virtual PCI bridges */
+		if (pdev->subordinate)
+			return 0;
+
+		group = get_pci_device_group(pdev);
+
+	} else {
+		prop = of_get_property(dev->of_node, "fsl,liodn", &len);
+		if (prop)
+			group = get_device_iommu_group(dev);
+	}
+
+	if (!group || IS_ERR(group))
+		return PTR_ERR(group);
+
+	ret = iommu_group_add_device(group, dev);
+
+	iommu_group_put(group);
+	return ret;
+}
+
+static void fsl_pamu_remove_device(struct device *dev)
+{
+	iommu_group_remove_device(dev);
+}