WSL2-Linux-Kernel/drivers/of/dynamic.c

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C
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// SPDX-License-Identifier: GPL-2.0
/*
* Support for dynamic device trees.
*
* On some platforms, the device tree can be manipulated at runtime.
* The routines in this section support adding, removing and changing
* device tree nodes.
*/
#define pr_fmt(fmt) "OF: " fmt
#include <linux/of.h>
#include <linux/spinlock.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/proc_fs.h>
#include "of_private.h"
static struct device_node *kobj_to_device_node(struct kobject *kobj)
{
return container_of(kobj, struct device_node, kobj);
}
/**
* of_node_get() - Increment refcount of a node
* @node: Node to inc refcount, NULL is supported to simplify writing of
* callers
*
* Return: The node with refcount incremented.
*/
struct device_node *of_node_get(struct device_node *node)
{
if (node)
kobject_get(&node->kobj);
return node;
}
EXPORT_SYMBOL(of_node_get);
/**
* of_node_put() - Decrement refcount of a node
* @node: Node to dec refcount, NULL is supported to simplify writing of
* callers
*/
void of_node_put(struct device_node *node)
{
if (node)
kobject_put(&node->kobj);
}
EXPORT_SYMBOL(of_node_put);
static BLOCKING_NOTIFIER_HEAD(of_reconfig_chain);
int of_reconfig_notifier_register(struct notifier_block *nb)
{
return blocking_notifier_chain_register(&of_reconfig_chain, nb);
}
EXPORT_SYMBOL_GPL(of_reconfig_notifier_register);
int of_reconfig_notifier_unregister(struct notifier_block *nb)
{
return blocking_notifier_chain_unregister(&of_reconfig_chain, nb);
}
EXPORT_SYMBOL_GPL(of_reconfig_notifier_unregister);
#ifdef DEBUG
const char *action_names[] = {
[OF_RECONFIG_ATTACH_NODE] = "ATTACH_NODE",
[OF_RECONFIG_DETACH_NODE] = "DETACH_NODE",
[OF_RECONFIG_ADD_PROPERTY] = "ADD_PROPERTY",
[OF_RECONFIG_REMOVE_PROPERTY] = "REMOVE_PROPERTY",
[OF_RECONFIG_UPDATE_PROPERTY] = "UPDATE_PROPERTY",
};
#endif
int of_reconfig_notify(unsigned long action, struct of_reconfig_data *p)
{
int rc;
#ifdef DEBUG
struct of_reconfig_data *pr = p;
switch (action) {
case OF_RECONFIG_ATTACH_NODE:
case OF_RECONFIG_DETACH_NODE:
pr_debug("notify %-15s %pOF\n", action_names[action],
pr->dn);
break;
case OF_RECONFIG_ADD_PROPERTY:
case OF_RECONFIG_REMOVE_PROPERTY:
case OF_RECONFIG_UPDATE_PROPERTY:
pr_debug("notify %-15s %pOF:%s\n", action_names[action],
pr->dn, pr->prop->name);
break;
}
#endif
rc = blocking_notifier_call_chain(&of_reconfig_chain, action, p);
return notifier_to_errno(rc);
}
/*
* of_reconfig_get_state_change() - Returns new state of device
* @action - action of the of notifier
* @arg - argument of the of notifier
*
* Returns the new state of a device based on the notifier used.
*
* Return: 0 on device going from enabled to disabled, 1 on device
* going from disabled to enabled and -1 on no change.
*/
int of_reconfig_get_state_change(unsigned long action, struct of_reconfig_data *pr)
{
struct property *prop, *old_prop = NULL;
int is_status, status_state, old_status_state, prev_state, new_state;
/* figure out if a device should be created or destroyed */
switch (action) {
case OF_RECONFIG_ATTACH_NODE:
case OF_RECONFIG_DETACH_NODE:
prop = of_find_property(pr->dn, "status", NULL);
break;
case OF_RECONFIG_ADD_PROPERTY:
case OF_RECONFIG_REMOVE_PROPERTY:
prop = pr->prop;
break;
case OF_RECONFIG_UPDATE_PROPERTY:
prop = pr->prop;
old_prop = pr->old_prop;
break;
default:
return OF_RECONFIG_NO_CHANGE;
}
is_status = 0;
status_state = -1;
old_status_state = -1;
prev_state = -1;
new_state = -1;
if (prop && !strcmp(prop->name, "status")) {
is_status = 1;
status_state = !strcmp(prop->value, "okay") ||
!strcmp(prop->value, "ok");
if (old_prop)
old_status_state = !strcmp(old_prop->value, "okay") ||
!strcmp(old_prop->value, "ok");
}
switch (action) {
case OF_RECONFIG_ATTACH_NODE:
prev_state = 0;
/* -1 & 0 status either missing or okay */
new_state = status_state != 0;
break;
case OF_RECONFIG_DETACH_NODE:
/* -1 & 0 status either missing or okay */
prev_state = status_state != 0;
new_state = 0;
break;
case OF_RECONFIG_ADD_PROPERTY:
if (is_status) {
/* no status property -> enabled (legacy) */
prev_state = 1;
new_state = status_state;
}
break;
case OF_RECONFIG_REMOVE_PROPERTY:
if (is_status) {
prev_state = status_state;
/* no status property -> enabled (legacy) */
new_state = 1;
}
break;
case OF_RECONFIG_UPDATE_PROPERTY:
if (is_status) {
prev_state = old_status_state != 0;
new_state = status_state != 0;
}
break;
}
if (prev_state == new_state)
return OF_RECONFIG_NO_CHANGE;
return new_state ? OF_RECONFIG_CHANGE_ADD : OF_RECONFIG_CHANGE_REMOVE;
}
EXPORT_SYMBOL_GPL(of_reconfig_get_state_change);
int of_property_notify(int action, struct device_node *np,
struct property *prop, struct property *oldprop)
{
struct of_reconfig_data pr;
/* only call notifiers if the node is attached */
if (!of_node_is_attached(np))
return 0;
pr.dn = np;
pr.prop = prop;
pr.old_prop = oldprop;
return of_reconfig_notify(action, &pr);
}
static void __of_attach_node(struct device_node *np)
{
const __be32 *phandle;
int sz;
if (!of_node_check_flag(np, OF_OVERLAY)) {
np->name = __of_get_property(np, "name", NULL);
if (!np->name)
np->name = "<NULL>";
phandle = __of_get_property(np, "phandle", &sz);
if (!phandle)
phandle = __of_get_property(np, "linux,phandle", &sz);
if (IS_ENABLED(CONFIG_PPC_PSERIES) && !phandle)
phandle = __of_get_property(np, "ibm,phandle", &sz);
if (phandle && (sz >= 4))
np->phandle = be32_to_cpup(phandle);
else
np->phandle = 0;
}
np->child = NULL;
np->sibling = np->parent->child;
np->parent->child = np;
of_node_clear_flag(np, OF_DETACHED);
}
/**
* of_attach_node() - Plug a device node into the tree and global list.
* @np: Pointer to the caller's Device Node
*/
int of_attach_node(struct device_node *np)
{
struct of_reconfig_data rd;
unsigned long flags;
memset(&rd, 0, sizeof(rd));
rd.dn = np;
of: Make devicetree sysfs update functions consistent. All of the DT modification functions are split into two parts, the first part manipulates the DT data structure, and the second part updates sysfs, but the code isn't very consistent about how the second half is called. They don't all enforce the same rules about when it is valid to update sysfs, and there isn't any clarity on locking. The transactional DT modification feature that is coming also needs access to these functions so that it can perform all the structure changes together, and then all the sysfs updates as a second stage instead of doing each one at a time. Fix up the second have by creating a separate __of_*_sysfs() function for each of the helpers. The new functions have consistent naming (ie. of_node_add() becomes __of_attach_node_sysfs()) and all of them now defer if of_init hasn't been called yet. Callers of the new functions must hold the of_mutex to ensure there are no race conditions with of_init(). The mutex ensures that there will only ever be one writer to the tree at any given time. There can still be any number of readers and the raw_spin_lock is still used to make sure access to the data structure is still consistent. Finally, put the function prototypes into of_private.h so they are accessible to the transaction code. Signed-off-by: Pantelis Antoniou <pantelis.antoniou@konsulko.com> [grant.likely: Changed suffix from _post to _sysfs to match existing code] [grant.likely: Reorganized to eliminate trivial wrappers] Signed-off-by: Grant Likely <grant.likely@linaro.org>
2014-07-24 03:05:06 +04:00
mutex_lock(&of_mutex);
raw_spin_lock_irqsave(&devtree_lock, flags);
__of_attach_node(np);
raw_spin_unlock_irqrestore(&devtree_lock, flags);
of: Make devicetree sysfs update functions consistent. All of the DT modification functions are split into two parts, the first part manipulates the DT data structure, and the second part updates sysfs, but the code isn't very consistent about how the second half is called. They don't all enforce the same rules about when it is valid to update sysfs, and there isn't any clarity on locking. The transactional DT modification feature that is coming also needs access to these functions so that it can perform all the structure changes together, and then all the sysfs updates as a second stage instead of doing each one at a time. Fix up the second have by creating a separate __of_*_sysfs() function for each of the helpers. The new functions have consistent naming (ie. of_node_add() becomes __of_attach_node_sysfs()) and all of them now defer if of_init hasn't been called yet. Callers of the new functions must hold the of_mutex to ensure there are no race conditions with of_init(). The mutex ensures that there will only ever be one writer to the tree at any given time. There can still be any number of readers and the raw_spin_lock is still used to make sure access to the data structure is still consistent. Finally, put the function prototypes into of_private.h so they are accessible to the transaction code. Signed-off-by: Pantelis Antoniou <pantelis.antoniou@konsulko.com> [grant.likely: Changed suffix from _post to _sysfs to match existing code] [grant.likely: Reorganized to eliminate trivial wrappers] Signed-off-by: Grant Likely <grant.likely@linaro.org>
2014-07-24 03:05:06 +04:00
__of_attach_node_sysfs(np);
mutex_unlock(&of_mutex);
of_reconfig_notify(OF_RECONFIG_ATTACH_NODE, &rd);
return 0;
}
void __of_detach_node(struct device_node *np)
{
struct device_node *parent;
if (WARN_ON(of_node_check_flag(np, OF_DETACHED)))
return;
parent = np->parent;
if (WARN_ON(!parent))
return;
if (parent->child == np)
parent->child = np->sibling;
else {
struct device_node *prevsib;
for (prevsib = np->parent->child;
prevsib->sibling != np;
prevsib = prevsib->sibling)
;
prevsib->sibling = np->sibling;
}
of_node_set_flag(np, OF_DETACHED);
/* race with of_find_node_by_phandle() prevented by devtree_lock */
of: Rework and simplify phandle cache to use a fixed size The phandle cache was added to speed up of_find_node_by_phandle() by avoiding walking the whole DT to find a matching phandle. The implementation has several shortcomings: - The cache is designed to work on a linear set of phandle values. This is true for dtc generated DTs, but not for other cases such as Power. - The cache isn't enabled until of_core_init() and a typical system may see hundreds of calls to of_find_node_by_phandle() before that point. - The cache is freed and re-allocated when the number of phandles changes. - It takes a raw spinlock around a memory allocation which breaks on RT. Change the implementation to a fixed size and use hash_32() as the cache index. This greatly simplifies the implementation. It avoids the need for any re-alloc of the cache and taking a reference on nodes in the cache. We only have a single source of removing cache entries which is of_detach_node(). Using hash_32() removes any assumption on phandle values improving the hit rate for non-linear phandle values. The effect on linear values using hash_32() is about a 10% collision. The chances of thrashing on colliding values seems to be low. To compare performance, I used a RK3399 board which is a pretty typical system. I found that just measuring boot time as done previously is noisy and may be impacted by other things. Also bringing up secondary cores causes some issues with measuring, so I booted with 'nr_cpus=1'. With no caching, calls to of_find_node_by_phandle() take about 20124 us for 1248 calls. There's an additional 288 calls before time keeping is up. Using the average time per hit/miss with the cache, we can calculate these calls to take 690 us (277 hit / 11 miss) with a 128 entry cache and 13319 us with no cache or an uninitialized cache. Comparing the 3 implementations the time spent in of_find_node_by_phandle() is: no cache: 20124 us (+ 13319 us) 128 entry cache: 5134 us (+ 690 us) current cache: 819 us (+ 13319 us) We could move the allocation of the cache earlier to improve the current cache, but that just further complicates the situation as it needs to be after slab is up, so we can't do it when unflattening (which uses memblock). Reported-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Segher Boessenkool <segher@kernel.crashing.org> Cc: Frank Rowand <frowand.list@gmail.com> Acked-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Reviewed-by: Frank Rowand <frowand.list@gmail.com> Tested-by: Frank Rowand <frowand.list@gmail.com> Signed-off-by: Rob Herring <robh@kernel.org>
2019-12-07 01:27:41 +03:00
__of_phandle_cache_inv_entry(np->phandle);
}
/**
* of_detach_node() - "Unplug" a node from the device tree.
* @np: Pointer to the caller's Device Node
*/
int of_detach_node(struct device_node *np)
{
struct of_reconfig_data rd;
unsigned long flags;
memset(&rd, 0, sizeof(rd));
rd.dn = np;
of: Make devicetree sysfs update functions consistent. All of the DT modification functions are split into two parts, the first part manipulates the DT data structure, and the second part updates sysfs, but the code isn't very consistent about how the second half is called. They don't all enforce the same rules about when it is valid to update sysfs, and there isn't any clarity on locking. The transactional DT modification feature that is coming also needs access to these functions so that it can perform all the structure changes together, and then all the sysfs updates as a second stage instead of doing each one at a time. Fix up the second have by creating a separate __of_*_sysfs() function for each of the helpers. The new functions have consistent naming (ie. of_node_add() becomes __of_attach_node_sysfs()) and all of them now defer if of_init hasn't been called yet. Callers of the new functions must hold the of_mutex to ensure there are no race conditions with of_init(). The mutex ensures that there will only ever be one writer to the tree at any given time. There can still be any number of readers and the raw_spin_lock is still used to make sure access to the data structure is still consistent. Finally, put the function prototypes into of_private.h so they are accessible to the transaction code. Signed-off-by: Pantelis Antoniou <pantelis.antoniou@konsulko.com> [grant.likely: Changed suffix from _post to _sysfs to match existing code] [grant.likely: Reorganized to eliminate trivial wrappers] Signed-off-by: Grant Likely <grant.likely@linaro.org>
2014-07-24 03:05:06 +04:00
mutex_lock(&of_mutex);
raw_spin_lock_irqsave(&devtree_lock, flags);
__of_detach_node(np);
raw_spin_unlock_irqrestore(&devtree_lock, flags);
of: Make devicetree sysfs update functions consistent. All of the DT modification functions are split into two parts, the first part manipulates the DT data structure, and the second part updates sysfs, but the code isn't very consistent about how the second half is called. They don't all enforce the same rules about when it is valid to update sysfs, and there isn't any clarity on locking. The transactional DT modification feature that is coming also needs access to these functions so that it can perform all the structure changes together, and then all the sysfs updates as a second stage instead of doing each one at a time. Fix up the second have by creating a separate __of_*_sysfs() function for each of the helpers. The new functions have consistent naming (ie. of_node_add() becomes __of_attach_node_sysfs()) and all of them now defer if of_init hasn't been called yet. Callers of the new functions must hold the of_mutex to ensure there are no race conditions with of_init(). The mutex ensures that there will only ever be one writer to the tree at any given time. There can still be any number of readers and the raw_spin_lock is still used to make sure access to the data structure is still consistent. Finally, put the function prototypes into of_private.h so they are accessible to the transaction code. Signed-off-by: Pantelis Antoniou <pantelis.antoniou@konsulko.com> [grant.likely: Changed suffix from _post to _sysfs to match existing code] [grant.likely: Reorganized to eliminate trivial wrappers] Signed-off-by: Grant Likely <grant.likely@linaro.org>
2014-07-24 03:05:06 +04:00
__of_detach_node_sysfs(np);
mutex_unlock(&of_mutex);
of_reconfig_notify(OF_RECONFIG_DETACH_NODE, &rd);
return 0;
}
EXPORT_SYMBOL_GPL(of_detach_node);
static void property_list_free(struct property *prop_list)
{
struct property *prop, *next;
for (prop = prop_list; prop != NULL; prop = next) {
next = prop->next;
kfree(prop->name);
kfree(prop->value);
kfree(prop);
}
}
/**
* of_node_release() - release a dynamically allocated node
* @kobj: kernel object of the node to be released
*
* In of_node_put() this function is passed to kref_put() as the destructor.
*/
void of_node_release(struct kobject *kobj)
{
struct device_node *node = kobj_to_device_node(kobj);
/* We should never be releasing nodes that haven't been detached. */
if (!of_node_check_flag(node, OF_DETACHED)) {
pr_err("ERROR: Bad of_node_put() on %pOF\n", node);
dump_stack();
return;
}
if (!of_node_check_flag(node, OF_DYNAMIC))
return;
if (of_node_check_flag(node, OF_OVERLAY)) {
if (!of_node_check_flag(node, OF_OVERLAY_FREE_CSET)) {
/* premature refcount of zero, do not free memory */
pr_err("ERROR: memory leak before free overlay changeset, %pOF\n",
node);
return;
}
/*
* If node->properties non-empty then properties were added
* to this node either by different overlay that has not
* yet been removed, or by a non-overlay mechanism.
*/
if (node->properties)
pr_err("ERROR: %s(), unexpected properties in %pOF\n",
__func__, node);
}
property_list_free(node->properties);
property_list_free(node->deadprops);
fwnode_links_purge(of_fwnode_handle(node));
kfree(node->full_name);
kfree(node->data);
kfree(node);
}
/**
* __of_prop_dup - Copy a property dynamically.
* @prop: Property to copy
* @allocflags: Allocation flags (typically pass GFP_KERNEL)
*
* Copy a property by dynamically allocating the memory of both the
* property structure and the property name & contents. The property's
* flags have the OF_DYNAMIC bit set so that we can differentiate between
* dynamically allocated properties and not.
*
* Return: The newly allocated property or NULL on out of memory error.
*/
struct property *__of_prop_dup(const struct property *prop, gfp_t allocflags)
{
struct property *new;
new = kzalloc(sizeof(*new), allocflags);
if (!new)
return NULL;
/*
* NOTE: There is no check for zero length value.
* In case of a boolean property, this will allocate a value
* of zero bytes. We do this to work around the use
* of of_get_property() calls on boolean values.
*/
new->name = kstrdup(prop->name, allocflags);
new->value = kmemdup(prop->value, prop->length, allocflags);
new->length = prop->length;
if (!new->name || !new->value)
goto err_free;
/* mark the property as dynamic */
of_property_set_flag(new, OF_DYNAMIC);
return new;
err_free:
kfree(new->name);
kfree(new->value);
kfree(new);
return NULL;
}
/**
* __of_node_dup() - Duplicate or create an empty device node dynamically.
* @np: if not NULL, contains properties to be duplicated in new node
* @full_name: string value to be duplicated into new node's full_name field
*
* Create a device tree node, optionally duplicating the properties of
* another node. The node data are dynamically allocated and all the node
* flags have the OF_DYNAMIC & OF_DETACHED bits set.
*
* Return: The newly allocated node or NULL on out of memory error.
*/
struct device_node *__of_node_dup(const struct device_node *np,
const char *full_name)
{
struct device_node *node;
node = kzalloc(sizeof(*node), GFP_KERNEL);
if (!node)
return NULL;
node->full_name = kstrdup(full_name, GFP_KERNEL);
if (!node->full_name) {
kfree(node);
return NULL;
}
of_node_set_flag(node, OF_DYNAMIC);
of_node_set_flag(node, OF_DETACHED);
of_node_init(node);
/* Iterate over and duplicate all properties */
if (np) {
struct property *pp, *new_pp;
for_each_property_of_node(np, pp) {
new_pp = __of_prop_dup(pp, GFP_KERNEL);
if (!new_pp)
goto err_prop;
if (__of_add_property(node, new_pp)) {
kfree(new_pp->name);
kfree(new_pp->value);
kfree(new_pp);
goto err_prop;
}
}
}
return node;
err_prop:
of_node_put(node); /* Frees the node and properties */
return NULL;
}
static void __of_changeset_entry_destroy(struct of_changeset_entry *ce)
{
if (ce->action == OF_RECONFIG_ATTACH_NODE &&
of_node_check_flag(ce->np, OF_OVERLAY)) {
if (kref_read(&ce->np->kobj.kref) > 1) {
pr_err("ERROR: memory leak, expected refcount 1 instead of %d, of_node_get()/of_node_put() unbalanced - destroy cset entry: attach overlay node %pOF\n",
kref_read(&ce->np->kobj.kref), ce->np);
} else {
of_node_set_flag(ce->np, OF_OVERLAY_FREE_CSET);
}
}
of_node_put(ce->np);
list_del(&ce->node);
kfree(ce);
}
#ifdef DEBUG
static void __of_changeset_entry_dump(struct of_changeset_entry *ce)
{
switch (ce->action) {
case OF_RECONFIG_ADD_PROPERTY:
case OF_RECONFIG_REMOVE_PROPERTY:
case OF_RECONFIG_UPDATE_PROPERTY:
pr_debug("cset<%p> %-15s %pOF/%s\n", ce, action_names[ce->action],
ce->np, ce->prop->name);
break;
case OF_RECONFIG_ATTACH_NODE:
case OF_RECONFIG_DETACH_NODE:
pr_debug("cset<%p> %-15s %pOF\n", ce, action_names[ce->action],
ce->np);
break;
}
}
#else
static inline void __of_changeset_entry_dump(struct of_changeset_entry *ce)
{
/* empty */
}
#endif
static void __of_changeset_entry_invert(struct of_changeset_entry *ce,
struct of_changeset_entry *rce)
{
memcpy(rce, ce, sizeof(*rce));
switch (ce->action) {
case OF_RECONFIG_ATTACH_NODE:
rce->action = OF_RECONFIG_DETACH_NODE;
break;
case OF_RECONFIG_DETACH_NODE:
rce->action = OF_RECONFIG_ATTACH_NODE;
break;
case OF_RECONFIG_ADD_PROPERTY:
rce->action = OF_RECONFIG_REMOVE_PROPERTY;
break;
case OF_RECONFIG_REMOVE_PROPERTY:
rce->action = OF_RECONFIG_ADD_PROPERTY;
break;
case OF_RECONFIG_UPDATE_PROPERTY:
rce->old_prop = ce->prop;
rce->prop = ce->old_prop;
/* update was used but original property did not exist */
if (!rce->prop) {
rce->action = OF_RECONFIG_REMOVE_PROPERTY;
rce->prop = ce->prop;
}
break;
}
}
static int __of_changeset_entry_notify(struct of_changeset_entry *ce,
bool revert)
{
struct of_reconfig_data rd;
struct of_changeset_entry ce_inverted;
int ret = 0;
if (revert) {
__of_changeset_entry_invert(ce, &ce_inverted);
ce = &ce_inverted;
}
switch (ce->action) {
case OF_RECONFIG_ATTACH_NODE:
case OF_RECONFIG_DETACH_NODE:
memset(&rd, 0, sizeof(rd));
rd.dn = ce->np;
ret = of_reconfig_notify(ce->action, &rd);
break;
case OF_RECONFIG_ADD_PROPERTY:
case OF_RECONFIG_REMOVE_PROPERTY:
case OF_RECONFIG_UPDATE_PROPERTY:
ret = of_property_notify(ce->action, ce->np, ce->prop, ce->old_prop);
break;
default:
pr_err("invalid devicetree changeset action: %i\n",
(int)ce->action);
ret = -EINVAL;
}
if (ret)
pr_err("changeset notifier error @%pOF\n", ce->np);
return ret;
}
static int __of_changeset_entry_apply(struct of_changeset_entry *ce)
{
struct property *old_prop, **propp;
unsigned long flags;
int ret = 0;
__of_changeset_entry_dump(ce);
raw_spin_lock_irqsave(&devtree_lock, flags);
switch (ce->action) {
case OF_RECONFIG_ATTACH_NODE:
__of_attach_node(ce->np);
break;
case OF_RECONFIG_DETACH_NODE:
__of_detach_node(ce->np);
break;
case OF_RECONFIG_ADD_PROPERTY:
/* If the property is in deadprops then it must be removed */
for (propp = &ce->np->deadprops; *propp; propp = &(*propp)->next) {
if (*propp == ce->prop) {
*propp = ce->prop->next;
ce->prop->next = NULL;
break;
}
}
ret = __of_add_property(ce->np, ce->prop);
if (ret) {
pr_err("changeset: add_property failed @%pOF/%s\n",
ce->np,
ce->prop->name);
break;
}
break;
case OF_RECONFIG_REMOVE_PROPERTY:
ret = __of_remove_property(ce->np, ce->prop);
if (ret) {
pr_err("changeset: remove_property failed @%pOF/%s\n",
ce->np,
ce->prop->name);
break;
}
break;
case OF_RECONFIG_UPDATE_PROPERTY:
/* If the property is in deadprops then it must be removed */
for (propp = &ce->np->deadprops; *propp; propp = &(*propp)->next) {
if (*propp == ce->prop) {
*propp = ce->prop->next;
ce->prop->next = NULL;
break;
}
}
ret = __of_update_property(ce->np, ce->prop, &old_prop);
if (ret) {
pr_err("changeset: update_property failed @%pOF/%s\n",
ce->np,
ce->prop->name);
break;
}
break;
default:
ret = -EINVAL;
}
raw_spin_unlock_irqrestore(&devtree_lock, flags);
if (ret)
return ret;
switch (ce->action) {
case OF_RECONFIG_ATTACH_NODE:
__of_attach_node_sysfs(ce->np);
break;
case OF_RECONFIG_DETACH_NODE:
__of_detach_node_sysfs(ce->np);
break;
case OF_RECONFIG_ADD_PROPERTY:
/* ignore duplicate names */
__of_add_property_sysfs(ce->np, ce->prop);
break;
case OF_RECONFIG_REMOVE_PROPERTY:
__of_remove_property_sysfs(ce->np, ce->prop);
break;
case OF_RECONFIG_UPDATE_PROPERTY:
__of_update_property_sysfs(ce->np, ce->prop, ce->old_prop);
break;
}
return 0;
}
static inline int __of_changeset_entry_revert(struct of_changeset_entry *ce)
{
struct of_changeset_entry ce_inverted;
__of_changeset_entry_invert(ce, &ce_inverted);
return __of_changeset_entry_apply(&ce_inverted);
}
/**
* of_changeset_init - Initialize a changeset for use
*
* @ocs: changeset pointer
*
* Initialize a changeset structure
*/
void of_changeset_init(struct of_changeset *ocs)
{
memset(ocs, 0, sizeof(*ocs));
INIT_LIST_HEAD(&ocs->entries);
}
EXPORT_SYMBOL_GPL(of_changeset_init);
/**
* of_changeset_destroy - Destroy a changeset
*
* @ocs: changeset pointer
*
* Destroys a changeset. Note that if a changeset is applied,
* its changes to the tree cannot be reverted.
*/
void of_changeset_destroy(struct of_changeset *ocs)
{
struct of_changeset_entry *ce, *cen;
list_for_each_entry_safe_reverse(ce, cen, &ocs->entries, node)
__of_changeset_entry_destroy(ce);
}
EXPORT_SYMBOL_GPL(of_changeset_destroy);
/*
* Apply the changeset entries in @ocs.
* If apply fails, an attempt is made to revert the entries that were
* successfully applied.
*
* If multiple revert errors occur then only the final revert error is reported.
*
* Returns 0 on success, a negative error value in case of an error.
* If a revert error occurs, it is returned in *ret_revert.
*/
int __of_changeset_apply_entries(struct of_changeset *ocs, int *ret_revert)
{
struct of_changeset_entry *ce;
int ret, ret_tmp;
pr_debug("changeset: applying...\n");
list_for_each_entry(ce, &ocs->entries, node) {
ret = __of_changeset_entry_apply(ce);
if (ret) {
pr_err("Error applying changeset (%d)\n", ret);
list_for_each_entry_continue_reverse(ce, &ocs->entries,
node) {
ret_tmp = __of_changeset_entry_revert(ce);
if (ret_tmp)
*ret_revert = ret_tmp;
}
return ret;
}
}
return 0;
}
/*
* Returns 0 on success, a negative error value in case of an error.
*
* If multiple changeset entry notification errors occur then only the
* final notification error is reported.
*/
int __of_changeset_apply_notify(struct of_changeset *ocs)
{
struct of_changeset_entry *ce;
int ret = 0, ret_tmp;
pr_debug("changeset: emitting notifiers.\n");
/* drop the global lock while emitting notifiers */
mutex_unlock(&of_mutex);
list_for_each_entry(ce, &ocs->entries, node) {
ret_tmp = __of_changeset_entry_notify(ce, 0);
if (ret_tmp)
ret = ret_tmp;
}
mutex_lock(&of_mutex);
pr_debug("changeset: notifiers sent.\n");
return ret;
}
/*
* Returns 0 on success, a negative error value in case of an error.
*
* If a changeset entry apply fails, an attempt is made to revert any
* previous entries in the changeset. If any of the reverts fails,
* that failure is not reported. Thus the state of the device tree
* is unknown if an apply error occurs.
*/
static int __of_changeset_apply(struct of_changeset *ocs)
{
int ret, ret_revert = 0;
ret = __of_changeset_apply_entries(ocs, &ret_revert);
if (!ret)
ret = __of_changeset_apply_notify(ocs);
return ret;
}
/**
* of_changeset_apply - Applies a changeset
*
* @ocs: changeset pointer
*
* Applies a changeset to the live tree.
* Any side-effects of live tree state changes are applied here on
* success, like creation/destruction of devices and side-effects
* like creation of sysfs properties and directories.
*
* Return: 0 on success, a negative error value in case of an error.
* On error the partially applied effects are reverted.
*/
int of_changeset_apply(struct of_changeset *ocs)
{
int ret;
mutex_lock(&of_mutex);
ret = __of_changeset_apply(ocs);
mutex_unlock(&of_mutex);
return ret;
}
EXPORT_SYMBOL_GPL(of_changeset_apply);
/*
* Revert the changeset entries in @ocs.
* If revert fails, an attempt is made to re-apply the entries that were
* successfully removed.
*
* If multiple re-apply errors occur then only the final apply error is
* reported.
*
* Returns 0 on success, a negative error value in case of an error.
* If an apply error occurs, it is returned in *ret_apply.
*/
int __of_changeset_revert_entries(struct of_changeset *ocs, int *ret_apply)
{
struct of_changeset_entry *ce;
int ret, ret_tmp;
pr_debug("changeset: reverting...\n");
list_for_each_entry_reverse(ce, &ocs->entries, node) {
ret = __of_changeset_entry_revert(ce);
if (ret) {
pr_err("Error reverting changeset (%d)\n", ret);
list_for_each_entry_continue(ce, &ocs->entries, node) {
ret_tmp = __of_changeset_entry_apply(ce);
if (ret_tmp)
*ret_apply = ret_tmp;
}
return ret;
}
}
return 0;
}
/*
* If multiple changeset entry notification errors occur then only the
* final notification error is reported.
*/
int __of_changeset_revert_notify(struct of_changeset *ocs)
{
struct of_changeset_entry *ce;
int ret = 0, ret_tmp;
pr_debug("changeset: emitting notifiers.\n");
/* drop the global lock while emitting notifiers */
mutex_unlock(&of_mutex);
list_for_each_entry_reverse(ce, &ocs->entries, node) {
ret_tmp = __of_changeset_entry_notify(ce, 1);
if (ret_tmp)
ret = ret_tmp;
}
mutex_lock(&of_mutex);
pr_debug("changeset: notifiers sent.\n");
return ret;
}
static int __of_changeset_revert(struct of_changeset *ocs)
{
int ret, ret_reply;
ret_reply = 0;
ret = __of_changeset_revert_entries(ocs, &ret_reply);
if (!ret)
ret = __of_changeset_revert_notify(ocs);
return ret;
}
/**
* of_changeset_revert - Reverts an applied changeset
*
* @ocs: changeset pointer
*
* Reverts a changeset returning the state of the tree to what it
* was before the application.
* Any side-effects like creation/destruction of devices and
* removal of sysfs properties and directories are applied.
*
* Return: 0 on success, a negative error value in case of an error.
*/
int of_changeset_revert(struct of_changeset *ocs)
{
int ret;
mutex_lock(&of_mutex);
ret = __of_changeset_revert(ocs);
mutex_unlock(&of_mutex);
return ret;
}
EXPORT_SYMBOL_GPL(of_changeset_revert);
/**
* of_changeset_action - Add an action to the tail of the changeset list
*
* @ocs: changeset pointer
* @action: action to perform
* @np: Pointer to device node
* @prop: Pointer to property
*
* On action being one of:
* + OF_RECONFIG_ATTACH_NODE
* + OF_RECONFIG_DETACH_NODE,
* + OF_RECONFIG_ADD_PROPERTY
* + OF_RECONFIG_REMOVE_PROPERTY,
* + OF_RECONFIG_UPDATE_PROPERTY
*
* Return: 0 on success, a negative error value in case of an error.
*/
int of_changeset_action(struct of_changeset *ocs, unsigned long action,
struct device_node *np, struct property *prop)
{
struct of_changeset_entry *ce;
ce = kzalloc(sizeof(*ce), GFP_KERNEL);
if (!ce)
return -ENOMEM;
/* get a reference to the node */
ce->action = action;
ce->np = of_node_get(np);
ce->prop = prop;
if (action == OF_RECONFIG_UPDATE_PROPERTY && prop)
ce->old_prop = of_find_property(np, prop->name, NULL);
/* add it to the list */
list_add_tail(&ce->node, &ocs->entries);
return 0;
}
EXPORT_SYMBOL_GPL(of_changeset_action);