device.c

  1// SPDX-License-Identifier: GPL-2.0
  2#include <linux/kernel.h>
  3#include <linux/of.h>
  4#include <linux/of_device.h>
  5#include <linux/of_address.h>
  6#include <linux/of_iommu.h>
  7#include <linux/of_reserved_mem.h>
  8#include <linux/dma-direct.h> /* for bus_dma_region */
  9#include <linux/dma-map-ops.h>
 10#include <linux/init.h>
 11#include <linux/mod_devicetable.h>
 12#include <linux/slab.h>
 13#include <linux/platform_device.h>
 14
 15#include <asm/errno.h>
 16#include "of_private.h"
 17
 18/**
 19 * of_match_device - Tell if a struct device matches an of_device_id list
 20 * @matches: array of of_device_id match structures to search in
 21 * @dev: the OF device structure to match against
 22 *
 23 * Used by a driver to check whether an platform_device present in the
 24 * system is in its list of supported devices.
 25 */
 26const struct of_device_id *of_match_device(const struct of_device_id *matches,
 27					   const struct device *dev)
 28{
 29	if (!matches || !dev->of_node || dev->of_node_reused)
 30		return NULL;
 31	return of_match_node(matches, dev->of_node);
 32}
 33EXPORT_SYMBOL(of_match_device);
 34
 35static void
 36of_dma_set_restricted_buffer(struct device *dev, struct device_node *np)
 37{
 38	struct device_node *of_node = dev->of_node;
 39	struct of_phandle_iterator it;
 40	int rc, i = 0;
 41
 42	if (!IS_ENABLED(CONFIG_DMA_RESTRICTED_POOL))
 43		return;
 44
 45	/*
 46	 * If dev->of_node doesn't exist or doesn't contain memory-region, try
 47	 * the OF node having DMA configuration.
 48	 */
 49	if (!of_property_present(of_node, "memory-region"))
 50		of_node = np;
 51
 52	of_for_each_phandle(&it, rc, of_node, "memory-region", NULL, 0) {
 53		/*
 54		 * There might be multiple memory regions, but only one
 55		 * restricted-dma-pool region is allowed.
 56		 */
 57		if (of_device_is_compatible(it.node, "restricted-dma-pool") &&
 58		    of_device_is_available(it.node)) {
 59			if (of_reserved_mem_device_init_by_idx(dev, of_node, i))
 60				dev_warn(dev, "failed to initialise \"restricted-dma-pool\" memory node\n");
 61			of_node_put(it.node);
 62			break;
 63		}
 64		i++;
 65	}
 66
 67}
 68
 69/**
 70 * of_dma_configure_id - Setup DMA configuration
 71 * @dev:	Device to apply DMA configuration
 72 * @np:		Pointer to OF node having DMA configuration
 73 * @force_dma:  Whether device is to be set up by of_dma_configure() even if
 74 *		DMA capability is not explicitly described by firmware.
 75 * @id:		Optional const pointer value input id
 76 *
 77 * Try to get devices's DMA configuration from DT and update it
 78 * accordingly.
 79 *
 80 * If platform code needs to use its own special DMA configuration, it
 81 * can use a platform bus notifier and handle BUS_NOTIFY_ADD_DEVICE events
 82 * to fix up DMA configuration.
 83 */
 84int of_dma_configure_id(struct device *dev, struct device_node *np,
 85			bool force_dma, const u32 *id)
 86{
 87	const struct bus_dma_region *map = NULL;
 88	struct device_node *bus_np;
 89	u64 mask, end = 0;
 90	bool coherent, set_map = false;
 91	int ret;
 92
 93	if (dev->dma_range_map) {
 94		dev_dbg(dev, "dma_range_map already set\n");
 95		goto skip_map;
 96	}
 97
 98	if (np == dev->of_node)
 99		bus_np = __of_get_dma_parent(np);
100	else
101		bus_np = of_node_get(np);
102
103	ret = of_dma_get_range(bus_np, &map);
104	of_node_put(bus_np);
105	if (ret < 0) {
106		/*
107		 * For legacy reasons, we have to assume some devices need
108		 * DMA configuration regardless of whether "dma-ranges" is
109		 * correctly specified or not.
110		 */
111		if (!force_dma)
112			return ret == -ENODEV ? 0 : ret;
113	} else {
114		/* Determine the overall bounds of all DMA regions */
115		end = dma_range_map_max(map);
116		set_map = true;
117	}
118skip_map:
119	/*
120	 * If @dev is expected to be DMA-capable then the bus code that created
121	 * it should have initialised its dma_mask pointer by this point. For
122	 * now, we'll continue the legacy behaviour of coercing it to the
123	 * coherent mask if not, but we'll no longer do so quietly.
124	 */
125	if (!dev->dma_mask) {
126		dev_warn(dev, "DMA mask not set\n");
127		dev->dma_mask = &dev->coherent_dma_mask;
128	}
129
130	if (!end && dev->coherent_dma_mask)
131		end = dev->coherent_dma_mask;
132	else if (!end)
133		end = (1ULL << 32) - 1;
134
135	/*
136	 * Limit coherent and dma mask based on size and default mask
137	 * set by the driver.
138	 */
139	mask = DMA_BIT_MASK(ilog2(end) + 1);
140	dev->coherent_dma_mask &= mask;
141	*dev->dma_mask &= mask;
142	/* ...but only set bus limit and range map if we found valid dma-ranges earlier */
143	if (set_map) {
144		dev->bus_dma_limit = end;
145		dev->dma_range_map = map;
146	}
147
148	coherent = of_dma_is_coherent(np);
149	dev_dbg(dev, "device is%sdma coherent\n",
150		coherent ? " " : " not ");
151
152	ret = of_iommu_configure(dev, np, id);
153	if (ret == -EPROBE_DEFER) {
154		/* Don't touch range map if it wasn't set from a valid dma-ranges */
155		if (set_map)
156			dev->dma_range_map = NULL;
157		kfree(map);
158		return -EPROBE_DEFER;
159	}
160	/* Take all other IOMMU errors to mean we'll just carry on without it */
161	dev_dbg(dev, "device is%sbehind an iommu\n",
162		!ret ? " " : " not ");
163
164	arch_setup_dma_ops(dev, coherent);
165
166	if (ret)
167		of_dma_set_restricted_buffer(dev, np);
168
169	return 0;
170}
171EXPORT_SYMBOL_GPL(of_dma_configure_id);
172
173const void *of_device_get_match_data(const struct device *dev)
174{
175	const struct of_device_id *match;
176
177	match = of_match_device(dev->driver->of_match_table, dev);
178	if (!match)
179		return NULL;
180
181	return match->data;
182}
183EXPORT_SYMBOL(of_device_get_match_data);
184
185/**
186 * of_device_modalias - Fill buffer with newline terminated modalias string
187 * @dev:	Calling device
188 * @str:	Modalias string
189 * @len:	Size of @str
190 */
191ssize_t of_device_modalias(struct device *dev, char *str, ssize_t len)
192{
193	ssize_t sl;
194
195	if (!dev || !dev->of_node || dev->of_node_reused)
196		return -ENODEV;
197
198	sl = of_modalias(dev->of_node, str, len - 2);
199	if (sl < 0)
200		return sl;
201	if (sl > len - 2)
202		return -ENOMEM;
203
204	str[sl++] = '\n';
205	str[sl] = 0;
206	return sl;
207}
208EXPORT_SYMBOL_GPL(of_device_modalias);
209
210/**
211 * of_device_uevent - Display OF related uevent information
212 * @dev:	Device to display the uevent information for
213 * @env:	Kernel object's userspace event reference to fill up
214 */
215void of_device_uevent(const struct device *dev, struct kobj_uevent_env *env)
216{
217	const char *compat, *type;
218	struct alias_prop *app;
219	struct property *p;
220	int seen = 0;
221
222	if ((!dev) || (!dev->of_node))
223		return;
224
225	add_uevent_var(env, "OF_NAME=%pOFn", dev->of_node);
226	add_uevent_var(env, "OF_FULLNAME=%pOF", dev->of_node);
227	type = of_node_get_device_type(dev->of_node);
228	if (type)
229		add_uevent_var(env, "OF_TYPE=%s", type);
230
231	/* Since the compatible field can contain pretty much anything
232	 * it's not really legal to split it out with commas. We split it
233	 * up using a number of environment variables instead. */
234	of_property_for_each_string(dev->of_node, "compatible", p, compat) {
235		add_uevent_var(env, "OF_COMPATIBLE_%d=%s", seen, compat);
236		seen++;
237	}
238	add_uevent_var(env, "OF_COMPATIBLE_N=%d", seen);
239
240	seen = 0;
241	mutex_lock(&of_mutex);
242	list_for_each_entry(app, &aliases_lookup, link) {
243		if (dev->of_node == app->np) {
244			add_uevent_var(env, "OF_ALIAS_%d=%s", seen,
245				       app->alias);
246			seen++;
247		}
248	}
249	mutex_unlock(&of_mutex);
250}
251EXPORT_SYMBOL_GPL(of_device_uevent);
252
253int of_device_uevent_modalias(const struct device *dev, struct kobj_uevent_env *env)
254{
255	int sl;
256
257	if ((!dev) || (!dev->of_node) || dev->of_node_reused)
258		return -ENODEV;
259
260	/* Devicetree modalias is tricky, we add it in 2 steps */
261	if (add_uevent_var(env, "MODALIAS="))
262		return -ENOMEM;
263
264	sl = of_modalias(dev->of_node, &env->buf[env->buflen-1],
265			 sizeof(env->buf) - env->buflen);
266	if (sl < 0)
267		return sl;
268	if (sl >= (sizeof(env->buf) - env->buflen))
269		return -ENOMEM;
270	env->buflen += sl;
271
272	return 0;
273}
274EXPORT_SYMBOL_GPL(of_device_uevent_modalias);
275
276/**
277 * of_device_make_bus_id - Use the device node data to assign a unique name
278 * @dev: pointer to device structure that is linked to a device tree node
279 *
280 * This routine will first try using the translated bus address to
281 * derive a unique name. If it cannot, then it will prepend names from
282 * parent nodes until a unique name can be derived.
283 */
284void of_device_make_bus_id(struct device *dev)
285{
286	struct device_node *node = dev->of_node;
287	const __be32 *reg;
288	u64 addr;
289	u32 mask;
290
291	/* Construct the name, using parent nodes if necessary to ensure uniqueness */
292	while (node->parent) {
293		/*
294		 * If the address can be translated, then that is as much
295		 * uniqueness as we need. Make it the first component and return
296		 */
297		reg = of_get_property(node, "reg", NULL);
298		if (reg && (addr = of_translate_address(node, reg)) != OF_BAD_ADDR) {
299			if (!of_property_read_u32(node, "mask", &mask))
300				dev_set_name(dev, dev_name(dev) ? "%llx.%x.%pOFn:%s" : "%llx.%x.%pOFn",
301					     addr, ffs(mask) - 1, node, dev_name(dev));
302
303			else
304				dev_set_name(dev, dev_name(dev) ? "%llx.%pOFn:%s" : "%llx.%pOFn",
305					     addr, node, dev_name(dev));
306			return;
307		}
308
309		/* format arguments only used if dev_name() resolves to NULL */
310		dev_set_name(dev, dev_name(dev) ? "%s:%s" : "%s",
311			     kbasename(node->full_name), dev_name(dev));
312		node = node->parent;
313	}
314}
315EXPORT_SYMBOL_GPL(of_device_make_bus_id);