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![Grant Likely](/assets/img/avatar_default.png)
When userspace needs to find a specific device, it currently isn't easy to resolve a /sys/devices/ path from a specific device tree node. Nor is it easy to obtain the compatible list for devices. This patch generalizes the code that inserts OF_* values into the uevent device attribute so that any device that is attached to an OF node will have that information exported to userspace. Without this patch only platform devices and some powerpc-specific busses have access to this data. The original function also creates a MODALIAS property for the compatible list, but that code has not been generalized into the common case because it has the potential to break module loading on a lot of bus types. Bus types are still responsible for their own MODALIAS properties. Boot tested on ARM and compile tested on PowerPC and SPARC. Signed-off-by: Grant Likely <grant.likely@secretlab.ca> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Tobias Klauser <tklauser@distanz.ch> Cc: Frederic Lambert <frdrc66@gmail.com> Cc: Rob Herring <rob.herring@calxeda.com> Cc: Mark Brown <broonie@sirena.org.uk> Cc: "David S. Miller" <davem@davemloft.net> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
176 lines
4.3 KiB
C
176 lines
4.3 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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/**
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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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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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}
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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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