Merge tag 'of-iommu-configure' of git://git.kernel.org/pub/scm/linux/…

…kernel/git/will/linux into next/iommu-config

Pull "Automatic DMA configuration for OF-based IOMMU masters" from Will Deacon:

This series adds automatic IOMMU and DMA-mapping configuration for
OF-based DMA masters described using the generic IOMMU devicetree
bindings. Although there is plenty of future work around splitting up
iommu_ops, adding default IOMMU domains and sorting out automatic IOMMU
group creation for the platform_bus, this is already useful enough for
people to port over their IOMMU drivers and start using the new probing
infrastructure (indeed, Marek has patches queued for the Exynos IOMMU).

* tag 'of-iommu-configure' of git://git.kernel.org/pub/scm/linux/kernel/git/will/linux:
  iommu: store DT-probed IOMMU data privately
  arm: dma-mapping: plumb our iommu mapping ops into arch_setup_dma_ops
  arm: call iommu_init before of_platform_populate
  dma-mapping: detect and configure IOMMU in of_dma_configure
  iommu: fix initialization without 'add_device' callback
  iommu: provide helper function to configure an IOMMU for an of master
  iommu: add new iommu_ops callback for adding an OF device
  dma-mapping: replace set_arch_dma_coherent_ops with arch_setup_dma_ops
  iommu: provide early initialisation hook for IOMMU drivers

Signed-off-by: Arnd Bergmann <[email protected]>

arch/arm/include/asm/dma-mapping.h

@@ -121,12 +121,12 @@ static inline unsigned long dma_max_pfn(struct device *dev)
 }
 #define dma_max_pfn(dev) dma_max_pfn(dev)
 
-static inline int set_arch_dma_coherent_ops(struct device *dev)
-{
-	set_dma_ops(dev, &arm_coherent_dma_ops);
-	return 0;
-}
-#define set_arch_dma_coherent_ops(dev)	set_arch_dma_coherent_ops(dev)
+#define arch_setup_dma_ops arch_setup_dma_ops
+extern void arch_setup_dma_ops(struct device *dev, u64 dma_base, u64 size,
+			       struct iommu_ops *iommu, bool coherent);
+
+#define arch_teardown_dma_ops arch_teardown_dma_ops
+extern void arch_teardown_dma_ops(struct device *dev);
 
 static inline dma_addr_t phys_to_dma(struct device *dev, phys_addr_t paddr)
 {

arch/arm/kernel/setup.c

@@ -18,6 +18,7 @@
 #include <linux/bootmem.h>
 #include <linux/seq_file.h>
 #include <linux/screen_info.h>
+#include <linux/of_iommu.h>
 #include <linux/of_platform.h>
 #include <linux/init.h>
 #include <linux/kexec.h>
@@ -806,6 +807,7 @@ static int __init customize_machine(void)
 	 * machine from the device tree, if no callback is provided,
 	 * otherwise we would always need an init_machine callback.
 	 */
+	of_iommu_init();
 	if (machine_desc->init_machine)
 		machine_desc->init_machine();
 #ifdef CONFIG_OF

arch/arm/mm/dma-mapping.c

@@ -1947,9 +1947,8 @@ EXPORT_SYMBOL_GPL(arm_iommu_release_mapping);
  *	arm_iommu_create_mapping)
  *
  * Attaches specified io address space mapping to the provided device,
- * this replaces the dma operations (dma_map_ops pointer) with the
- * IOMMU aware version. More than one client might be attached to
- * the same io address space mapping.
+ * More than one client might be attached to the same io address space
+ * mapping.
  */
 int arm_iommu_attach_device(struct device *dev,
 			    struct dma_iommu_mapping *mapping)
@@ -1962,7 +1961,6 @@ int arm_iommu_attach_device(struct device *dev,
 
 	kref_get(&mapping->kref);
 	dev->archdata.mapping = mapping;
-	set_dma_ops(dev, &iommu_ops);
 
 	pr_debug("Attached IOMMU controller to %s device.\n", dev_name(dev));
 	return 0;
@@ -1974,7 +1972,6 @@ EXPORT_SYMBOL_GPL(arm_iommu_attach_device);
  * @dev: valid struct device pointer
  *
  * Detaches the provided device from a previously attached map.
- * This voids the dma operations (dma_map_ops pointer)
  */
 void arm_iommu_detach_device(struct device *dev)
 {
@@ -1989,10 +1986,82 @@ void arm_iommu_detach_device(struct device *dev)
 	iommu_detach_device(mapping->domain, dev);
 	kref_put(&mapping->kref, release_iommu_mapping);
 	dev->archdata.mapping = NULL;
-	set_dma_ops(dev, NULL);
 
 	pr_debug("Detached IOMMU controller from %s device.\n", dev_name(dev));
 }
 EXPORT_SYMBOL_GPL(arm_iommu_detach_device);
 
-#endif
+static struct dma_map_ops *arm_get_iommu_dma_map_ops(bool coherent)
+{
+	return coherent ? &iommu_coherent_ops : &iommu_ops;
+}
+
+static bool arm_setup_iommu_dma_ops(struct device *dev, u64 dma_base, u64 size,
+				    struct iommu_ops *iommu)
+{
+	struct dma_iommu_mapping *mapping;
+
+	if (!iommu)
+		return false;
+
+	mapping = arm_iommu_create_mapping(dev->bus, dma_base, size);
+	if (IS_ERR(mapping)) {
+		pr_warn("Failed to create %llu-byte IOMMU mapping for device %s\n",
+				size, dev_name(dev));
+		return false;
+	}
+
+	if (arm_iommu_attach_device(dev, mapping)) {
+		pr_warn("Failed to attached device %s to IOMMU_mapping\n",
+				dev_name(dev));
+		arm_iommu_release_mapping(mapping);
+		return false;
+	}
+
+	return true;
+}
+
+static void arm_teardown_iommu_dma_ops(struct device *dev)
+{
+	struct dma_iommu_mapping *mapping = dev->archdata.mapping;
+
+	arm_iommu_detach_device(dev);
+	arm_iommu_release_mapping(mapping);
+}
+
+#else
+
+static bool arm_setup_iommu_dma_ops(struct device *dev, u64 dma_base, u64 size,
+				    struct iommu_ops *iommu)
+{
+	return false;
+}
+
+static void arm_teardown_iommu_dma_ops(struct device *dev) { }
+
+#define arm_get_iommu_dma_map_ops arm_get_dma_map_ops
+
+#endif	/* CONFIG_ARM_DMA_USE_IOMMU */
+
+static struct dma_map_ops *arm_get_dma_map_ops(bool coherent)
+{
+	return coherent ? &arm_coherent_dma_ops : &arm_dma_ops;
+}
+
+void arch_setup_dma_ops(struct device *dev, u64 dma_base, u64 size,
+			struct iommu_ops *iommu, bool coherent)
+{
+	struct dma_map_ops *dma_ops;
+
+	if (arm_setup_iommu_dma_ops(dev, dma_base, size, iommu))
+		dma_ops = arm_get_iommu_dma_map_ops(coherent);
+	else
+		dma_ops = arm_get_dma_map_ops(coherent);
+
+	set_dma_ops(dev, dma_ops);
+}
+
+void arch_teardown_dma_ops(struct device *dev)
+{
+	arm_teardown_iommu_dma_ops(dev);
+}

drivers/iommu/Kconfig

@@ -15,7 +15,7 @@ if IOMMU_SUPPORT
 
 config OF_IOMMU
        def_bool y
-       depends on OF
+       depends on OF && IOMMU_API
 
 config FSL_PAMU
 	bool "Freescale IOMMU support"

drivers/iommu/iommu.c

@@ -737,7 +737,7 @@ static int add_iommu_group(struct device *dev, void *data)
 	const struct iommu_ops *ops = cb->ops;
 
 	if (!ops->add_device)
-		return -ENODEV;
+		return 0;
 
 	WARN_ON(dev->iommu_group);
 

drivers/iommu/of_iommu.c

@@ -18,9 +18,14 @@
  */
 
 #include <linux/export.h>
+#include <linux/iommu.h>
 #include <linux/limits.h>
 #include <linux/of.h>
 #include <linux/of_iommu.h>
+#include <linux/slab.h>
+
+static const struct of_device_id __iommu_of_table_sentinel
+	__used __section(__iommu_of_table_end);
 
 /**
  * of_get_dma_window - Parse *dma-window property and returns 0 if found.
@@ -89,3 +94,87 @@ int of_get_dma_window(struct device_node *dn, const char *prefix, int index,
 	return 0;
 }
 EXPORT_SYMBOL_GPL(of_get_dma_window);
+
+struct of_iommu_node {
+	struct list_head list;
+	struct device_node *np;
+	struct iommu_ops *ops;
+};
+static LIST_HEAD(of_iommu_list);
+static DEFINE_SPINLOCK(of_iommu_lock);
+
+void of_iommu_set_ops(struct device_node *np, struct iommu_ops *ops)
+{
+	struct of_iommu_node *iommu = kzalloc(sizeof(*iommu), GFP_KERNEL);
+
+	if (WARN_ON(!iommu))
+		return;
+
+	INIT_LIST_HEAD(&iommu->list);
+	iommu->np = np;
+	iommu->ops = ops;
+	spin_lock(&of_iommu_lock);
+	list_add_tail(&iommu->list, &of_iommu_list);
+	spin_unlock(&of_iommu_lock);
+}
+
+struct iommu_ops *of_iommu_get_ops(struct device_node *np)
+{
+	struct of_iommu_node *node;
+	struct iommu_ops *ops = NULL;
+
+	spin_lock(&of_iommu_lock);
+	list_for_each_entry(node, &of_iommu_list, list)
+		if (node->np == np) {
+			ops = node->ops;
+			break;
+		}
+	spin_unlock(&of_iommu_lock);
+	return ops;
+}
+
+struct iommu_ops *of_iommu_configure(struct device *dev)
+{
+	struct of_phandle_args iommu_spec;
+	struct device_node *np;
+	struct iommu_ops *ops = NULL;
+	int idx = 0;
+
+	/*
+	 * We don't currently walk up the tree looking for a parent IOMMU.
+	 * See the `Notes:' section of
+	 * Documentation/devicetree/bindings/iommu/iommu.txt
+	 */
+	while (!of_parse_phandle_with_args(dev->of_node, "iommus",
+					   "#iommu-cells", idx,
+					   &iommu_spec)) {
+		np = iommu_spec.np;
+		ops = of_iommu_get_ops(np);
+
+		if (!ops || !ops->of_xlate || ops->of_xlate(dev, &iommu_spec))
+			goto err_put_node;
+
+		of_node_put(np);
+		idx++;
+	}
+
+	return ops;
+
+err_put_node:
+	of_node_put(np);
+	return NULL;
+}
+
+void __init of_iommu_init(void)
+{
+	struct device_node *np;
+	const struct of_device_id *match, *matches = &__iommu_of_table;
+
+	for_each_matching_node_and_match(np, matches, &match) {
+		const of_iommu_init_fn init_fn = match->data;
+
+		if (init_fn(np))
+			pr_err("Failed to initialise IOMMU %s\n",
+				of_node_full_name(np));
+	}
+}

drivers/of/platform.c

@@ -19,6 +19,7 @@
 #include <linux/slab.h>
 #include <linux/of_address.h>
 #include <linux/of_device.h>
+#include <linux/of_iommu.h>
 #include <linux/of_irq.h>
 #include <linux/of_platform.h>
 #include <linux/platform_device.h>
@@ -164,6 +165,9 @@ static void of_dma_configure(struct device *dev)
 {
 	u64 dma_addr, paddr, size;
 	int ret;
+	bool coherent;
+	unsigned long offset;
+	struct iommu_ops *iommu;
 
 	/*
 	 * Set default dma-mask to 32 bit. Drivers are expected to setup
@@ -178,28 +182,30 @@ static void of_dma_configure(struct device *dev)
 	if (!dev->dma_mask)
 		dev->dma_mask = &dev->coherent_dma_mask;
 
-	/*
-	 * if dma-coherent property exist, call arch hook to setup
-	 * dma coherent operations.
-	 */
-	if (of_dma_is_coherent(dev->of_node)) {
-		set_arch_dma_coherent_ops(dev);
-		dev_dbg(dev, "device is dma coherent\n");
-	}
-
-	/*
-	 * if dma-ranges property doesn't exist - just return else
-	 * setup the dma offset
-	 */
 	ret = of_dma_get_range(dev->of_node, &dma_addr, &paddr, &size);
 	if (ret < 0) {
-		dev_dbg(dev, "no dma range information to setup\n");
-		return;
+		dma_addr = offset = 0;
+		size = dev->coherent_dma_mask;
+	} else {
+		offset = PFN_DOWN(paddr - dma_addr);
+		dev_dbg(dev, "dma_pfn_offset(%#08lx)\n", dev->dma_pfn_offset);
 	}
+	dev->dma_pfn_offset = offset;
+
+	coherent = of_dma_is_coherent(dev->of_node);
+	dev_dbg(dev, "device is%sdma coherent\n",
+		coherent ? " " : " not ");
+
+	iommu = of_iommu_configure(dev);
+	dev_dbg(dev, "device is%sbehind an iommu\n",
+		iommu ? " " : " not ");
 
-	/* DMA ranges found. Calculate and set dma_pfn_offset */
-	dev->dma_pfn_offset = PFN_DOWN(paddr - dma_addr);
-	dev_dbg(dev, "dma_pfn_offset(%#08lx)\n", dev->dma_pfn_offset);
+	arch_setup_dma_ops(dev, dma_addr, size, iommu, coherent);
+}
+
+static void of_dma_deconfigure(struct device *dev)
+{
+	arch_teardown_dma_ops(dev);
 }
 
 /**
@@ -228,16 +234,12 @@ static struct platform_device *of_platform_device_create_pdata(
 	if (!dev)
 		goto err_clear_flag;
 
-	of_dma_configure(&dev->dev);
 	dev->dev.bus = &platform_bus_type;
 	dev->dev.platform_data = platform_data;
-
-	/* We do not fill the DMA ops for platform devices by default.
-	 * This is currently the responsibility of the platform code
-	 * to do such, possibly using a device notifier
-	 */
+	of_dma_configure(&dev->dev);
 
 	if (of_device_add(dev) != 0) {
+		of_dma_deconfigure(&dev->dev);
 		platform_device_put(dev);
 		goto err_clear_flag;
 	}

include/asm-generic/vmlinux.lds.h

@@ -164,6 +164,7 @@
 #define CLKSRC_OF_TABLES()	OF_TABLE(CONFIG_CLKSRC_OF, clksrc)
 #define IRQCHIP_OF_MATCH_TABLE() OF_TABLE(CONFIG_IRQCHIP, irqchip)
 #define CLK_OF_TABLES()		OF_TABLE(CONFIG_COMMON_CLK, clk)
+#define IOMMU_OF_TABLES()	OF_TABLE(CONFIG_OF_IOMMU, iommu)
 #define RESERVEDMEM_OF_TABLES()	OF_TABLE(CONFIG_OF_RESERVED_MEM, reservedmem)
 #define CPU_METHOD_OF_TABLES()	OF_TABLE(CONFIG_SMP, cpu_method)
 #define EARLYCON_OF_TABLES()	OF_TABLE(CONFIG_SERIAL_EARLYCON, earlycon)
@@ -497,6 +498,7 @@
 	CLK_OF_TABLES()							\
 	RESERVEDMEM_OF_TABLES()						\
 	CLKSRC_OF_TABLES()						\
+	IOMMU_OF_TABLES()						\
 	CPU_METHOD_OF_TABLES()						\
 	KERNEL_DTB()							\
 	IRQCHIP_OF_MATCH_TABLE()					\

include/linux/dma-mapping.h

@@ -129,11 +129,14 @@ static inline int dma_coerce_mask_and_coherent(struct device *dev, u64 mask)
 
 extern u64 dma_get_required_mask(struct device *dev);
 
-#ifndef set_arch_dma_coherent_ops
-static inline int set_arch_dma_coherent_ops(struct device *dev)
-{
-	return 0;
-}
+#ifndef arch_setup_dma_ops
+static inline void arch_setup_dma_ops(struct device *dev, u64 dma_base,
+				      u64 size, struct iommu_ops *iommu,
+				      bool coherent) { }
+#endif
+
+#ifndef arch_teardown_dma_ops
+static inline void arch_teardown_dma_ops(struct device *dev) { }
 #endif
 
 static inline unsigned int dma_get_max_seg_size(struct device *dev)