drivers/of/device.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0
 #include <linux/kernel.h>
 #include <linux/of.h>
 #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>
 #include <linux/mod_devicetable.h>
 #include <linux/slab.h>
 #include <linux/platform_device.h>

 #include <asm/errno.h>
 #include "of_private.h"

 /**
  * of_match_device - Tell if a struct device matches an of_device_id list
  * @matches: array of of device match structures to search in
  * @dev: the of device structure to match against
  *
  * Used by a driver to check whether an platform_device present in the
  * system is in its list of supported devices.
  */
 const struct of_device_id *of_match_device(const struct of_device_id *matches,
 					   const struct device *dev)
 {
 	if (!matches || !dev->of_node || dev->of_node_reused)
 		return NULL;
 	return of_match_node(matches, dev->of_node);
 }
 EXPORT_SYMBOL(of_match_device);

 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)) {
 			of_node_put(node);
 			break;
 		}
 		of_node_put(node);
 	}

 	/*
 	 * Attempt to initialize a restricted-dma-pool region if one was found.
 	 * Note that count can hold a negative error code.
 	 */
 	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
  * @np:		Pointer to OF node having DMA configuration
  * @force_dma:  Whether device is to be set up by of_dma_configure() even if
  *		DMA capability is not explicitly described by firmware.
  * @id:		Optional const pointer value input id
  *
  * Try to get devices's DMA configuration from DT and update it
  * accordingly.
  *
  * If platform code needs to use its own special DMA configuration, it
  * can use a platform bus notifier and handle BUS_NOTIFY_ADD_DEVICE events
  * to fix up DMA configuration.
  */
 int of_dma_configure_id(struct device *dev, struct device_node *np,
 			bool force_dma, const u32 *id)
 {
 	const struct iommu_ops *iommu;
 	const struct bus_dma_region *map = NULL;
 	struct device_node *bus_np;
 	u64 dma_start = 0;
 	u64 mask, end, size = 0;
 	bool coherent;
 	int ret;

 	if (np == dev->of_node)
 		bus_np = __of_get_dma_parent(np);
 	else
 		bus_np = of_node_get(np);

 	ret = of_dma_get_range(bus_np, &map);
 	of_node_put(bus_np);
 	if (ret < 0) {
 		/*
 		 * For legacy reasons, we have to assume some devices need
 		 * DMA configuration regardless of whether "dma-ranges" is
 		 * correctly specified or not.
 		 */
 		if (!force_dma)
 			return ret == -ENODEV ? 0 : ret;
 	} else {
 		const struct bus_dma_region *r = map;
 		u64 dma_end = 0;

 		/* Determine the overall bounds of all DMA regions */
 		for (dma_start = ~0; r->size; r++) {
 			/* Take lower and upper limits */
 			if (r->dma_start < dma_start)
 				dma_start = r->dma_start;
 			if (r->dma_start + r->size > dma_end)
 				dma_end = r->dma_start + r->size;
 		}
 		size = dma_end - dma_start;

 		/*
 		 * Add a work around to treat the size as mask + 1 in case
 		 * it is defined in DT as a mask.
 		 */
 		if (size & 1) {
 			dev_warn(dev, "Invalid size 0x%llx for dma-range(s)\n",
 				 size);
 			size = size + 1;
 		}

 		if (!size) {
 			dev_err(dev, "Adjusted size 0x%llx invalid\n", size);
 			kfree(map);
 			return -EINVAL;
 		}
 	}

 	/*
 	 * If @dev is expected to be DMA-capable then the bus code that created
 	 * it should have initialised its dma_mask pointer by this point. For
 	 * now, we'll continue the legacy behaviour of coercing it to the
 	 * coherent mask if not, but we'll no longer do so quietly.
 	 */
 	if (!dev->dma_mask) {
 		dev_warn(dev, "DMA mask not set\n");
 		dev->dma_mask = &dev->coherent_dma_mask;
 	}

 	if (!size && dev->coherent_dma_mask)
 		size = max(dev->coherent_dma_mask, dev->coherent_dma_mask + 1);
 	else if (!size)
 		size = 1ULL << 32;

 	/*
 	 * Limit coherent and dma mask based on size and default mask
 	 * set by the driver.
 	 */
 	end = dma_start + size - 1;
 	mask = DMA_BIT_MASK(ilog2(end) + 1);
 	dev->coherent_dma_mask &= mask;
 	*dev->dma_mask &= mask;
 	/* ...but only set bus limit and range map if we found valid dma-ranges earlier */
 	if (!ret) {
 		dev->bus_dma_limit = end;
 		dev->dma_range_map = map;
 	}

 	coherent = of_dma_is_coherent(np);
 	dev_dbg(dev, "device is%sdma coherent\n",
 		coherent ? " " : " not ");

 	iommu = of_iommu_configure(dev, np, id);
 	if (PTR_ERR(iommu) == -EPROBE_DEFER) {
 		/* Don't touch range map if it wasn't set from a valid dma-ranges */
 		if (!ret)
 			dev->dma_range_map = NULL;
 		kfree(map);
 		return -EPROBE_DEFER;
 	}

 	dev_dbg(dev, "device is%sbehind an iommu\n",
 		iommu ? " " : " not ");

 	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);

 const void *of_device_get_match_data(const struct device *dev)
 {
 	const struct of_device_id *match;

 	match = of_match_device(dev->driver->of_match_table, dev);
 	if (!match)
 		return NULL;

 	return match->data;
 }
 EXPORT_SYMBOL(of_device_get_match_data);

 /**
  * of_device_modalias - Fill buffer with newline terminated modalias string
  * @dev:	Calling device
  * @str:	Modalias string
  * @len:	Size of @str
  */
 ssize_t of_device_modalias(struct device *dev, char *str, ssize_t len)
 {
 	ssize_t sl;

 	if (!dev || !dev->of_node || dev->of_node_reused)
 		return -ENODEV;

 	sl = of_modalias(dev->of_node, str, len - 2);
 	if (sl < 0)
 		return sl;
 	if (sl > len - 2)
 		return -ENOMEM;

 	str[sl++] = '\n';
 	str[sl] = 0;
 	return sl;
 }
 EXPORT_SYMBOL_GPL(of_device_modalias);

 /**
  * of_device_uevent - Display OF related uevent information
  * @dev:	Device to display the uevent information for
  * @env:	Kernel object's userspace event reference to fill up
  */
 void of_device_uevent(const struct device *dev, struct kobj_uevent_env *env)
 {
 	const char *compat, *type;
 	struct alias_prop *app;
 	struct property *p;
 	int seen = 0;

 	if ((!dev) || (!dev->of_node))
 		return;

 	add_uevent_var(env, "OF_NAME=%pOFn", dev->of_node);
 	add_uevent_var(env, "OF_FULLNAME=%pOF", dev->of_node);
 	type = of_node_get_device_type(dev->of_node);
 	if (type)
 		add_uevent_var(env, "OF_TYPE=%s", type);

 	/* Since the compatible field can contain pretty much anything
 	 * it's not really legal to split it out with commas. We split it
 	 * up using a number of environment variables instead. */
 	of_property_for_each_string(dev->of_node, "compatible", p, compat) {
 		add_uevent_var(env, "OF_COMPATIBLE_%d=%s", seen, compat);
 		seen++;
 	}
 	add_uevent_var(env, "OF_COMPATIBLE_N=%d", seen);

 	seen = 0;
 	mutex_lock(&of_mutex);
 	list_for_each_entry(app, &aliases_lookup, link) {
 		if (dev->of_node == app->np) {
 			add_uevent_var(env, "OF_ALIAS_%d=%s", seen,
 				       app->alias);
 			seen++;
 		}
 	}
 	mutex_unlock(&of_mutex);
 }
 EXPORT_SYMBOL_GPL(of_device_uevent);

 int of_device_uevent_modalias(const struct device *dev, struct kobj_uevent_env *env)
 {
 	int sl;

 	if ((!dev) || (!dev->of_node) || dev->of_node_reused)
 		return -ENODEV;

 	/* Devicetree modalias is tricky, we add it in 2 steps */
 	if (add_uevent_var(env, "MODALIAS="))
 		return -ENOMEM;

 	sl = of_modalias(dev->of_node, &env->buf[env->buflen-1],
 			 sizeof(env->buf) - env->buflen);
 	if (sl < 0)
 		return sl;
 	if (sl >= (sizeof(env->buf) - env->buflen))
 		return -ENOMEM;
 	env->buflen += sl;

 	return 0;
 }
 EXPORT_SYMBOL_GPL(of_device_uevent_modalias);
	// SPDX-License-Identifier: GPL-2.0
	#include <linux/kernel.h>
	#include <linux/of.h>
	#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>
	#include <linux/mod_devicetable.h>
	#include <linux/slab.h>
	#include <linux/platform_device.h>

	#include <asm/errno.h>
	#include "of_private.h"

	/**
	* of_match_device - Tell if a struct device matches an of_device_id list
	* @matches: array of of device match structures to search in
	* @dev: the of device structure to match against
	*
	* Used by a driver to check whether an platform_device present in the
	* system is in its list of supported devices.
	*/
	const struct of_device_id of_match_device(const struct of_device_id matches,
	const struct device *dev)
	{
	if (!matches \|\| !dev->of_node \|\| dev->of_node_reused)
	return NULL;
	return of_match_node(matches, dev->of_node);
	}
	EXPORT_SYMBOL(of_match_device);

	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)) {
	of_node_put(node);
	break;
	}
	of_node_put(node);
	}

	/*
	* Attempt to initialize a restricted-dma-pool region if one was found.
	* Note that count can hold a negative error code.
	*/
	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
	* @np: Pointer to OF node having DMA configuration
	* @force_dma: Whether device is to be set up by of_dma_configure() even if
	* DMA capability is not explicitly described by firmware.
	* @id: Optional const pointer value input id
	*
	* Try to get devices's DMA configuration from DT and update it
	* accordingly.
	*
	* If platform code needs to use its own special DMA configuration, it
	* can use a platform bus notifier and handle BUS_NOTIFY_ADD_DEVICE events
	* to fix up DMA configuration.
	*/
	int of_dma_configure_id(struct device dev, struct device_node np,
	bool force_dma, const u32 *id)
	{
	const struct iommu_ops *iommu;
	const struct bus_dma_region *map = NULL;
	struct device_node *bus_np;
	u64 dma_start = 0;
	u64 mask, end, size = 0;
	bool coherent;
	int ret;

	if (np == dev->of_node)
	bus_np = __of_get_dma_parent(np);
	else
	bus_np = of_node_get(np);

	ret = of_dma_get_range(bus_np, &map);
	of_node_put(bus_np);
	if (ret < 0) {
	/*
	* For legacy reasons, we have to assume some devices need
	* DMA configuration regardless of whether "dma-ranges" is
	* correctly specified or not.
	*/
	if (!force_dma)
	return ret == -ENODEV ? 0 : ret;
	} else {
	const struct bus_dma_region *r = map;
	u64 dma_end = 0;

	/* Determine the overall bounds of all DMA regions */
	for (dma_start = ~0; r->size; r++) {
	/* Take lower and upper limits */
	if (r->dma_start < dma_start)
	dma_start = r->dma_start;
	if (r->dma_start + r->size > dma_end)
	dma_end = r->dma_start + r->size;
	}
	size = dma_end - dma_start;

	/*
	* Add a work around to treat the size as mask + 1 in case
	* it is defined in DT as a mask.
	*/
	if (size & 1) {
	dev_warn(dev, "Invalid size 0x%llx for dma-range(s)\n",
	size);
	size = size + 1;
	}

	if (!size) {
	dev_err(dev, "Adjusted size 0x%llx invalid\n", size);
	kfree(map);
	return -EINVAL;
	}
	}

	/*
	* If @dev is expected to be DMA-capable then the bus code that created
	* it should have initialised its dma_mask pointer by this point. For
	* now, we'll continue the legacy behaviour of coercing it to the
	* coherent mask if not, but we'll no longer do so quietly.
	*/
	if (!dev->dma_mask) {
	dev_warn(dev, "DMA mask not set\n");
	dev->dma_mask = &dev->coherent_dma_mask;
	}

	if (!size && dev->coherent_dma_mask)
	size = max(dev->coherent_dma_mask, dev->coherent_dma_mask + 1);
	else if (!size)
	size = 1ULL << 32;

	/*
	* Limit coherent and dma mask based on size and default mask
	* set by the driver.
	*/
	end = dma_start + size - 1;
	mask = DMA_BIT_MASK(ilog2(end) + 1);
	dev->coherent_dma_mask &= mask;
	*dev->dma_mask &= mask;
	/* ...but only set bus limit and range map if we found valid dma-ranges earlier */
	if (!ret) {
	dev->bus_dma_limit = end;
	dev->dma_range_map = map;
	}

	coherent = of_dma_is_coherent(np);
	dev_dbg(dev, "device is%sdma coherent\n",
	coherent ? " " : " not ");

	iommu = of_iommu_configure(dev, np, id);
	if (PTR_ERR(iommu) == -EPROBE_DEFER) {
	/* Don't touch range map if it wasn't set from a valid dma-ranges */
	if (!ret)
	dev->dma_range_map = NULL;
	kfree(map);
	return -EPROBE_DEFER;
	}

	dev_dbg(dev, "device is%sbehind an iommu\n",
	iommu ? " " : " not ");

	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);

	const void of_device_get_match_data(const struct device dev)
	{
	const struct of_device_id *match;

	match = of_match_device(dev->driver->of_match_table, dev);
	if (!match)
	return NULL;

	return match->data;
	}
	EXPORT_SYMBOL(of_device_get_match_data);

	/**
	* of_device_modalias - Fill buffer with newline terminated modalias string
	* @dev: Calling device
	* @str: Modalias string
	* @len: Size of @str
	*/
	ssize_t of_device_modalias(struct device dev, char str, ssize_t len)
	{
	ssize_t sl;

	if (!dev \|\| !dev->of_node \|\| dev->of_node_reused)
	return -ENODEV;

	sl = of_modalias(dev->of_node, str, len - 2);
	if (sl < 0)
	return sl;
	if (sl > len - 2)
	return -ENOMEM;

	str[sl++] = '\n';
	str[sl] = 0;
	return sl;
	}
	EXPORT_SYMBOL_GPL(of_device_modalias);

	/**
	* of_device_uevent - Display OF related uevent information
	* @dev: Device to display the uevent information for
	* @env: Kernel object's userspace event reference to fill up
	*/
	void of_device_uevent(const struct device dev, struct kobj_uevent_env env)
	{
	const char compat, type;
	struct alias_prop *app;
	struct property *p;
	int seen = 0;

	if ((!dev) \|\| (!dev->of_node))
	return;

	add_uevent_var(env, "OF_NAME=%pOFn", dev->of_node);
	add_uevent_var(env, "OF_FULLNAME=%pOF", dev->of_node);
	type = of_node_get_device_type(dev->of_node);
	if (type)
	add_uevent_var(env, "OF_TYPE=%s", type);

	/* Since the compatible field can contain pretty much anything
	* it's not really legal to split it out with commas. We split it
	* up using a number of environment variables instead. */
	of_property_for_each_string(dev->of_node, "compatible", p, compat) {
	add_uevent_var(env, "OF_COMPATIBLE_%d=%s", seen, compat);
	seen++;
	}
	add_uevent_var(env, "OF_COMPATIBLE_N=%d", seen);

	seen = 0;
	mutex_lock(&of_mutex);
	list_for_each_entry(app, &aliases_lookup, link) {
	if (dev->of_node == app->np) {
	add_uevent_var(env, "OF_ALIAS_%d=%s", seen,
	app->alias);
	seen++;
	}
	}
	mutex_unlock(&of_mutex);
	}
	EXPORT_SYMBOL_GPL(of_device_uevent);

	int of_device_uevent_modalias(const struct device dev, struct kobj_uevent_env env)
	{
	int sl;

	if ((!dev) \|\| (!dev->of_node) \|\| dev->of_node_reused)
	return -ENODEV;

	/* Devicetree modalias is tricky, we add it in 2 steps */
	if (add_uevent_var(env, "MODALIAS="))
	return -ENOMEM;

	sl = of_modalias(dev->of_node, &env->buf[env->buflen-1],
	sizeof(env->buf) - env->buflen);
	if (sl < 0)
	return sl;
	if (sl >= (sizeof(env->buf) - env->buflen))
	return -ENOMEM;
	env->buflen += sl;

	return 0;
	}
	EXPORT_SYMBOL_GPL(of_device_uevent_modalias);