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![Stepan Moskovchenko](/assets/img/avatar_default.png)
In some situations, userspace may want to resolve a device by function and logical number (ie, "serial0") rather than by the base address or full device path. Being able to resolve a device by alias frees userspace from the burden of otherwise having to maintain a mapping between device addresses and their logical assignments on each platform when multiple instances of the same hardware block are present in the system. Although the uevent device attribute contains devicetree compatible information and the full device path, the uevent does not list the alises that may have been defined for the device. Signed-off-by: Stepan Moskovchenko <stepanm@codeaurora.org> [grant.likely: Removed OF_ALIAS_N field; I don't think it's needed] [grant.likely: Added #ifndef _LINUX_OF_PRIVATE_H wrapper] Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
189 lines
4.6 KiB
C
189 lines
4.6 KiB
C
#include <linux/string.h>
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#include <linux/kernel.h>
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#include <linux/of.h>
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#include <linux/of_device.h>
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/mod_devicetable.h>
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#include <linux/slab.h>
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#include <asm/errno.h>
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#include "of_private.h"
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/**
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* of_match_device - Tell if a struct device matches an of_device_id list
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* @ids: array of of device match structures to search in
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* @dev: the of device structure to match against
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*
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* Used by a driver to check whether an platform_device present in the
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* system is in its list of supported devices.
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*/
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const struct of_device_id *of_match_device(const struct of_device_id *matches,
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const struct device *dev)
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{
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if ((!matches) || (!dev->of_node))
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return NULL;
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return of_match_node(matches, dev->of_node);
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}
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EXPORT_SYMBOL(of_match_device);
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struct platform_device *of_dev_get(struct platform_device *dev)
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{
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struct device *tmp;
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if (!dev)
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return NULL;
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tmp = get_device(&dev->dev);
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if (tmp)
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return to_platform_device(tmp);
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else
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return NULL;
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}
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EXPORT_SYMBOL(of_dev_get);
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void of_dev_put(struct platform_device *dev)
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{
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if (dev)
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put_device(&dev->dev);
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}
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EXPORT_SYMBOL(of_dev_put);
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int of_device_add(struct platform_device *ofdev)
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{
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BUG_ON(ofdev->dev.of_node == NULL);
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/* name and id have to be set so that the platform bus doesn't get
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* confused on matching */
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ofdev->name = dev_name(&ofdev->dev);
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ofdev->id = -1;
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/* device_add will assume that this device is on the same node as
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* the parent. If there is no parent defined, set the node
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* explicitly */
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if (!ofdev->dev.parent)
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set_dev_node(&ofdev->dev, of_node_to_nid(ofdev->dev.of_node));
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return device_add(&ofdev->dev);
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}
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int of_device_register(struct platform_device *pdev)
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{
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device_initialize(&pdev->dev);
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return of_device_add(pdev);
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}
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EXPORT_SYMBOL(of_device_register);
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void of_device_unregister(struct platform_device *ofdev)
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{
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device_unregister(&ofdev->dev);
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}
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EXPORT_SYMBOL(of_device_unregister);
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ssize_t of_device_get_modalias(struct device *dev, char *str, ssize_t len)
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{
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const char *compat;
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int cplen, i;
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ssize_t tsize, csize, repend;
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/* Name & Type */
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csize = snprintf(str, len, "of:N%sT%s", dev->of_node->name,
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dev->of_node->type);
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/* Get compatible property if any */
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compat = of_get_property(dev->of_node, "compatible", &cplen);
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if (!compat)
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return csize;
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/* Find true end (we tolerate multiple \0 at the end */
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for (i = (cplen - 1); i >= 0 && !compat[i]; i--)
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cplen--;
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if (!cplen)
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return csize;
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cplen++;
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/* Check space (need cplen+1 chars including final \0) */
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tsize = csize + cplen;
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repend = tsize;
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if (csize >= len) /* @ the limit, all is already filled */
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return tsize;
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if (tsize >= len) { /* limit compat list */
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cplen = len - csize - 1;
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repend = len;
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}
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/* Copy and do char replacement */
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memcpy(&str[csize + 1], compat, cplen);
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for (i = csize; i < repend; i++) {
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char c = str[i];
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if (c == '\0')
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str[i] = 'C';
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else if (c == ' ')
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str[i] = '_';
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}
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return tsize;
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}
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/**
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* of_device_uevent - Display OF related uevent information
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*/
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void of_device_uevent(struct device *dev, struct kobj_uevent_env *env)
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{
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const char *compat;
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struct alias_prop *app;
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int seen = 0, cplen, sl;
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if ((!dev) || (!dev->of_node))
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return;
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add_uevent_var(env, "OF_NAME=%s", dev->of_node->name);
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add_uevent_var(env, "OF_FULLNAME=%s", dev->of_node->full_name);
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if (dev->of_node->type && strcmp("<NULL>", dev->of_node->type) != 0)
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add_uevent_var(env, "OF_TYPE=%s", dev->of_node->type);
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/* Since the compatible field can contain pretty much anything
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* it's not really legal to split it out with commas. We split it
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* up using a number of environment variables instead. */
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compat = of_get_property(dev->of_node, "compatible", &cplen);
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while (compat && *compat && cplen > 0) {
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add_uevent_var(env, "OF_COMPATIBLE_%d=%s", seen, compat);
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sl = strlen(compat) + 1;
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compat += sl;
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cplen -= sl;
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seen++;
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}
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add_uevent_var(env, "OF_COMPATIBLE_N=%d", seen);
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seen = 0;
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mutex_lock(&of_aliases_mutex);
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list_for_each_entry(app, &aliases_lookup, link) {
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if (dev->of_node == app->np) {
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add_uevent_var(env, "OF_ALIAS_%d=%s", seen,
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app->alias);
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seen++;
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}
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}
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mutex_unlock(&of_aliases_mutex);
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}
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int of_device_uevent_modalias(struct device *dev, struct kobj_uevent_env *env)
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{
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int sl;
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if ((!dev) || (!dev->of_node))
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return -ENODEV;
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/* Devicetree modalias is tricky, we add it in 2 steps */
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if (add_uevent_var(env, "MODALIAS="))
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return -ENOMEM;
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sl = of_device_get_modalias(dev, &env->buf[env->buflen-1],
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sizeof(env->buf) - env->buflen);
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if (sl >= (sizeof(env->buf) - env->buflen))
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return -ENOMEM;
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env->buflen += sl;
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return 0;
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}
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