Merge branch 'stable/for-linus-5.15' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/swiotlb

Pull swiotlb updates from Konrad Rzeszutek Wilk:
 "A new feature called restricted DMA pools. It allows SWIOTLB to
  utilize per-device (or per-platform) allocated memory pools instead of
  using the global one.

  The first big user of this is ARM Confidential Computing where the
  memory for DMA operations can be set per platform"

* 'stable/for-linus-5.15' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/swiotlb: (23 commits)
  swiotlb: use depends on for DMA_RESTRICTED_POOL
  of: restricted dma: Don't fail device probe on rmem init failure
  of: Move of_dma_set_restricted_buffer() into device.c
  powerpc/svm: Don't issue ultracalls if !mem_encrypt_active()
  s390/pv: fix the forcing of the swiotlb
  swiotlb: Free tbl memory in swiotlb_exit()
  swiotlb: Emit diagnostic in swiotlb_exit()
  swiotlb: Convert io_default_tlb_mem to static allocation
  of: Return success from of_dma_set_restricted_buffer() when !OF_ADDRESS
  swiotlb: add overflow checks to swiotlb_bounce
  swiotlb: fix implicit debugfs declarations
  of: Add plumbing for restricted DMA pool
  dt-bindings: of: Add restricted DMA pool
  swiotlb: Add restricted DMA pool initialization
  swiotlb: Add restricted DMA alloc/free support
  swiotlb: Refactor swiotlb_tbl_unmap_single
  swiotlb: Move alloc_size to swiotlb_find_slots
  swiotlb: Use is_swiotlb_force_bounce for swiotlb data bouncing
  swiotlb: Update is_swiotlb_active to add a struct device argument
  swiotlb: Update is_swiotlb_buffer to add a struct device argument
  ...

1 files changed, 40 insertions, 0 deletions

diff --git a/drivers/of/device.c b/drivers/of/device.c
index c5a9473a5fb1..5b043ee30824 100644
--- a/drivers/of/device.c
+++ b/drivers/of/device.c
@@ -5,6 +5,7 @@
 #include <linux/of_device.h>
 #include <linux/of_address.h>
 #include <linux/of_iommu.h>
+#include <linux/of_reserved_mem.h>
 #include <linux/dma-direct.h> /* for bus_dma_region */
 #include <linux/dma-map-ops.h>
 #include <linux/init.h>
@@ -52,6 +53,42 @@ int of_device_add(struct platform_device *ofdev)
 	return device_add(&ofdev->dev);
 }
 
+static void
+of_dma_set_restricted_buffer(struct device *dev, struct device_node *np)
+{
+	struct device_node *node, *of_node = dev->of_node;
+	int count, i;
+
+	if (!IS_ENABLED(CONFIG_DMA_RESTRICTED_POOL))
+		return;
+
+	count = of_property_count_elems_of_size(of_node, "memory-region",
+						sizeof(u32));
+	/*
+	 * If dev->of_node doesn't exist or doesn't contain memory-region, try
+	 * the OF node having DMA configuration.
+	 */
+	if (count <= 0) {
+		of_node = np;
+		count = of_property_count_elems_of_size(
+			of_node, "memory-region", sizeof(u32));
+	}
+
+	for (i = 0; i < count; i++) {
+		node = of_parse_phandle(of_node, "memory-region", i);
+		/*
+		 * There might be multiple memory regions, but only one
+		 * restricted-dma-pool region is allowed.
+		 */
+		if (of_device_is_compatible(node, "restricted-dma-pool") &&
+		    of_device_is_available(node))
+			break;
+	}
+
+	if (i != count && of_reserved_mem_device_init_by_idx(dev, of_node, i))
+		dev_warn(dev, "failed to initialise \"restricted-dma-pool\" memory node\n");
+}
+
 /**
  * of_dma_configure_id - Setup DMA configuration
  * @dev:	Device to apply DMA configuration
@@ -165,6 +202,9 @@ int of_dma_configure_id(struct device *dev, struct device_node *np,
 
 	arch_setup_dma_ops(dev, dma_start, size, iommu, coherent);
 
+	if (!iommu)
+		of_dma_set_restricted_buffer(dev, np);
+
 	return 0;
 }
 EXPORT_SYMBOL_GPL(of_dma_configure_id);