[PATCH 04/04] iommu/ipmmu-vmsa: Add new IOMMU_DOMAIN_DMA ops

[Magnus Damm <magnus.damm@gmail.com>]

From: Magnus Damm <damm+renesas@opensource.se>

Introduce a new set of iommu_ops suitable for 64-bit ARM
as well as 32-bit ARM when CONFIG_IOMMU_DMA=y. The ->of_xlate()
callback is needed by the code exported by of_iommu.h and
it is wrapped in #ifdefs to also compile of x86_64.

Signed-off-by: Magnus Damm <damm+renesas@opensource.se>
---

 drivers/iommu/ipmmu-vmsa.c |   94 +++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 92 insertions(+), 2 deletions(-)

--- 0011/drivers/iommu/ipmmu-vmsa.c
+++ work/drivers/iommu/ipmmu-vmsa.c	2016-03-16 01:35:06.990513000 +0900
@@ -10,6 +10,7 @@
 
 #include <linux/bitmap.h>
 #include <linux/delay.h>
+#include <linux/dma-iommu.h>
 #include <linux/dma-mapping.h>
 #include <linux/err.h>
 #include <linux/export.h>
@@ -804,7 +805,7 @@ static void ipmmu_remove_device(struct d
 	dev->archdata.iommu = NULL;
 }
 
-static const struct iommu_ops ipmmu_ops = {
+static const struct iommu_ops __maybe_unused ipmmu_ops = {
 	.domain_alloc = ipmmu_domain_alloc,
 	.domain_free = ipmmu_domain_free,
 	.attach_dev = ipmmu_attach_device,
@@ -818,6 +819,92 @@ static const struct iommu_ops ipmmu_ops
 	.pgsize_bitmap = SZ_1G | SZ_2M | SZ_4K,
 };
 
+static struct iommu_domain *ipmmu_domain_alloc_dma(unsigned type)
+{
+	struct iommu_domain *io_domain;
+
+	if (type != IOMMU_DOMAIN_DMA)
+		return NULL;
+
+	io_domain = __ipmmu_domain_alloc(type);
+	if (io_domain)
+		iommu_get_dma_cookie(io_domain);
+
+	return io_domain;
+}
+
+static void ipmmu_domain_free_dma(struct iommu_domain *io_domain)
+{
+	iommu_put_dma_cookie(io_domain);
+	ipmmu_domain_free(io_domain);
+}
+
+static int ipmmu_add_device_dma(struct device *dev)
+{
+	struct iommu_group *group;
+
+	/* only accept devices with iommus property */
+	if (of_count_phandle_with_args(dev->of_node, "iommus",
+				       "#iommu-cells") < 0)
+		return -ENODEV;
+
+	group = iommu_group_get_for_dev(dev);
+	if (IS_ERR(group))
+		return PTR_ERR(group);
+
+	return 0;
+}
+
+static void ipmmu_remove_device_dma(struct device *dev)
+{
+	iommu_group_remove_device(dev);
+}
+
+static struct iommu_group *ipmmu_device_group_dma(struct device *dev)
+{
+	struct iommu_group *group;
+	int ret;
+
+	group = generic_device_group(dev);
+	if (IS_ERR(group))
+		return group;
+
+	ret = ipmmu_init_platform_device(dev, group);
+	if (ret) {
+		iommu_group_put(group);
+		group = ERR_PTR(ret);
+	}
+
+	return group;
+}
+
+#ifdef CONFIG_OF_IOMMU
+static int ipmmu_of_xlate_dma(struct device *dev,
+			      struct of_phandle_args *spec)
+{
+	/* dummy callback to satisfy of_iommu_configure() */
+	return 0;
+}
+#endif
+
+static const struct iommu_ops __maybe_unused ipmmu_ops_dma = {
+	.domain_alloc = ipmmu_domain_alloc_dma,
+	.domain_free = ipmmu_domain_free_dma,
+	.attach_dev = ipmmu_attach_device,
+	.detach_dev = ipmmu_detach_device,
+	.map = ipmmu_map,
+	.unmap = ipmmu_unmap,
+	.map_sg = default_iommu_map_sg,
+	.iova_to_phys = ipmmu_iova_to_phys,
+	.add_device = ipmmu_add_device_dma,
+	.remove_device = ipmmu_remove_device_dma,
+	.device_group = ipmmu_device_group_dma,
+	.pgsize_bitmap = SZ_1G | SZ_2M | SZ_4K,
+#ifdef CONFIG_OF_IOMMU
+	.of_xlate = ipmmu_of_xlate_dma,
+#endif
+};
+
 /* -----------------------------------------------------------------------------
  * Probe/remove and init
  */
@@ -929,14 +1016,17 @@ static struct platform_driver ipmmu_driv
 
 static int __init ipmmu_init(void)
 {
+	const struct iommu_ops *ops;
 	int ret;
 
 	ret = platform_driver_register(&ipmmu_driver);
 	if (ret < 0)
 		return ret;
 
+	ops = IS_ENABLED(CONFIG_IOMMU_DMA) ? &ipmmu_ops_dma : &ipmmu_ops;
+
 	if (!iommu_present(&platform_bus_type))
-		bus_set_iommu(&platform_bus_type, &ipmmu_ops);
+		bus_set_iommu(&platform_bus_type, ops);
 
 	return 0;
 }