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path: root/drivers/of/of_private.h
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2019-12-24of: Rework and simplify phandle cache to use a fixed sizeRob Herring
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>
2019-10-08of: Factor out #{addr,size}-cells parsingRobin Murphy
In some cases such as PCI host controllers, we may have a "parent bus" which is an OF leaf node, but still need to correctly parse ranges from the point of view of that bus. For that, factor out variants of the "#addr-cells" and "#size-cells" parsers which do not assume they have a device node and thus immediately traverse upwards before reading the relevant property. Signed-off-by: Robin Murphy <robin.murphy@arm.com> [robh: don't make of_bus_n_{addr,size}_cells() public] Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be> Tested-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de> Reviewed-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de> Signed-off-by: Rob Herring <robh@kernel.org>
2019-10-08of: Make of_dma_get_range() privateRob Herring
of_dma_get_range() is only used within the DT core code, so remove the export and move the header declaration to the private header. Cc: Robin Murphy <robin.murphy@arm.com> Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be> Tested-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de> Reviewed-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Rob Herring <robh@kernel.org>
2018-12-21of: __of_detach_node() - remove node from phandle cacheFrank Rowand
Non-overlay dynamic devicetree node removal may leave the node in the phandle cache. Subsequent calls to of_find_node_by_phandle() will incorrectly find the stale entry. Remove the node from the cache. Add paranoia checks in of_find_node_by_phandle() as a second level of defense (do not return cached node if detached, do not add node to cache if detached). Fixes: 0b3ce78e90fc ("of: cache phandle nodes to reduce cost of of_find_node_by_phandle()") Reported-by: Michael Bringmann <mwb@linux.vnet.ibm.com> Cc: stable@vger.kernel.org # v4.17+ Signed-off-by: Frank Rowand <frank.rowand@sony.com> Signed-off-by: Rob Herring <robh@kernel.org>
2018-09-07of: make default address and size cells sizes privateRob Herring
Only some old OpenFirmware implementations rely on default sizes. Any FDT and modern implementation should have explicit properties. Make the OF_ROOT_NODE_*_CELLS_DEFAULT defines private so we don't get any outside users. This also gets us one step closer to removing the asm/prom.h dependency on Sparc. Cc: "David S. Miller" <davem@davemloft.net> Cc: Frank Rowand <frowand.list@gmail.com> Cc: sparclinux@vger.kernel.org Signed-off-by: Rob Herring <robh@kernel.org>
2018-07-16of: overlay: update phandle cache on overlay apply and removeFrank Rowand
A comment in the review of the patch adding the phandle cache said that the cache would have to be updated when modules are applied and removed. This patch implements the cache updates. Fixes: 0b3ce78e90fc ("of: cache phandle nodes to reduce cost of of_find_node_by_phandle()") Reported-by: Alan Tull <atull@kernel.org> Suggested-by: Alan Tull <atull@kernel.org> Signed-off-by: Frank Rowand <frank.rowand@sony.com> Signed-off-by: Rob Herring <robh@kernel.org>
2018-03-07of: cache phandle nodes to reduce cost of of_find_node_by_phandle()Frank Rowand
Create a cache of the nodes that contain a phandle property. Use this cache to find the node for a given phandle value instead of scanning the devicetree to find the node. If the phandle value is not found in the cache, of_find_node_by_phandle() will fall back to the tree scan algorithm. The cache is initialized in of_core_init(). The cache is freed via a late_initcall_sync() if modules are not enabled. If the devicetree is created by the dtc compiler, with all phandle property values auto generated, then the size required by the cache could be 4 * (1 + number of phandles) bytes. This results in an O(1) node lookup cost for a given phandle value. Due to a concern that the phandle property values might not be consistent with what is generated by the dtc compiler, a mask has been added to the cache lookup algorithm. To maintain the O(1) node lookup cost, the size of the cache has been increased by rounding the number of entries up to the next power of two. The overhead of finding the devicetree node containing a given phandle value has been noted by several people in the recent past, in some cases with a patch to add a hashed index of devicetree nodes, based on the phandle value of the node. One concern with this approach is the extra space added to each node. This patch takes advantage of the phandle property values auto generated by the dtc compiler, which begin with one and monotonically increase by one, resulting in a range of 1..n for n phandle values. This implementation should also provide a good reduction of overhead for any range of phandle values that are mostly in a monotonic range. Performance measurements by Chintan Pandya <cpandya@codeaurora.org> of several implementations of patches that are similar to this one suggest an expected reduction of boot time by ~400ms for his test system. If the cache size was decreased to 64 entries, the boot time was reduced by ~340 ms. The measurements were on a 4.9.73 kernel for arch/arm64/boot/dts/qcom/sda670-mtp.dts, contains 2371 nodes and 814 phandle values. Reported-by: Chintan Pandya <cpandya@codeaurora.org> Signed-off-by: Frank Rowand <frank.rowand@sony.com> Signed-off-by: Rob Herring <robh@kernel.org>
2018-03-05of: overlay: do not include path in full_name of added nodesFrank Rowand
Struct device_node full_name no longer includes the full path name when the devicetree is created from a flattened device tree (FDT). The overlay node creation code was not modified to reflect this change. Fix the node full_name generated by overlay code to contain only the basename. Unittests call an overlay internal function to create new nodes. Fix up these calls to provide basename only instead of the full path. Fixes: a7e4cfb0a7ca ("of/fdt: only store the device node basename in full_name") Signed-off-by: Frank Rowand <frank.rowand@sony.com> Signed-off-by: Rob Herring <robh@kernel.org>
2018-01-08of: Use SPDX license tag for DT filesRob Herring
Convert remaining DT files to use SPDX-License-Identifier tags. Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Guennadi Liakhovetski <g.liakhovetski@gmx.de> Cc: Paul Mackerras <paulus@samba.org> Cc: Pantelis Antoniou <pantelis.antoniou@konsulko.com> Reviewed-by: Frank Rowand <frank.rowand@sony.com> Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com> Signed-off-by: Rob Herring <robh@kernel.org>
2017-10-17of: overlay: remove a dependency on device node full_nameFrank Rowand
The "%pOF" printf format was recently added to print the full name of a device tree node, with the intent of changing the node full_name field to contain only the node name instead of the full path of the node. dup_and_fixup_symbol_prop() duplicates a property from the "/__symbols__" node of an overlay device tree. The value of each duplicated property must be fixed up to include the full path of a node in the live device tree. The current code uses the node's full_name for that purpose. Update the code to use the "%pOF" printf format to determine the node's full path. Signed-off-by: Frank Rowand <frank.rowand@sony.com> Signed-off-by: Rob Herring <robh@kernel.org>
2017-10-17of: overlay: avoid race condition between applying multiple overlaysFrank Rowand
The process of applying an overlay consists of: - unflatten an overlay FDT (flattened device tree) into an EDT (expanded device tree) - fixup the phandle values in the overlay EDT to fit in a range above the phandle values in the live device tree - create the overlay changeset to reflect the contents of the overlay EDT - apply the overlay changeset, to modify the live device tree, potentially changing the maximum phandle value in the live device tree There is currently no protection against two overlay applies concurrently determining what range of phandle values are in use in the live device tree, and subsequently changing that range. Add a mutex to prevent multiple overlay applies from occurring simultaneously. Move of_resolve_phandles() into of_overlay_apply() so that it does not have to be duplicated by each caller of of_overlay_apply(). The test in of_resolve_phandles() that the overlay tree is detached is temporarily disabled so that old style overlay unittests do not fail. Signed-off-by: Frank Rowand <frank.rowand@sony.com> Signed-off-by: Rob Herring <robh@kernel.org>
2017-10-17of: overlay: detect cases where device tree may become corruptFrank Rowand
When an attempt to apply an overlay changeset fails, an effort is made to revert any partial application of the changeset. When an attempt to remove an overlay changeset fails, an effort is made to re-apply any partial reversion of the changeset. The existing code does not check for failure to recover a failed overlay changeset application or overlay changeset revert. Add the missing checks and flag the devicetree as corrupt if the state of the devicetree can not be determined. Improve and expand the returned errors to more fully reflect the result of the effort to undo the partial effects of a failed attempt to apply or remove an overlay changeset. If the device tree might be corrupt, do not allow further attempts to apply or remove an overlay changeset. When creating an overlay changeset from an overlay device tree, add some additional warnings if the state of the overlay device tree is not as expected. Signed-off-by: Frank Rowand <frank.rowand@sony.com> Signed-off-by: Rob Herring <robh@kernel.org>
2017-10-16of: make kobject and bin_attribute support configurableRob Herring
Having device_nodes be kobjects is only needed if sysfs or OF_DYNAMIC is enabled. Otherwise, having a kobject in struct device_node is unnecessary bloat in minimal kernel configurations. Likewise, bin_attribute is only needed in struct property when sysfs is enabled, so we can make it configurable too. Tested-by: Nicolas Pitre <nico@linaro.org> Reviewed-by: Frank Rowand <frowand.list@gmail.com> Acked-by: Grant Likely <grant.likely@secretlab.ca> Signed-off-by: Rob Herring <robh@kernel.org>
2017-10-16of: move kobj_to_device_node() into dynamic.cRob Herring
The only user of kobj_to_device_node() is in dynamic.c, so move it there. This avoids having to make it conditional once kobject is configurable. Tested-by: Nicolas Pitre <nico@linaro.org> Reviewed-by: Frank Rowand <frowand.list@gmail.com> Acked-by: Grant Likely <grant.likely@secretlab.ca> Signed-off-by: Rob Herring <robh@kernel.org>
2017-06-22of: find_node_by_full_name rewrite to compare each levelRob Herring
find_node_by_full_name() does the same thing as of_find_node_by_path(), but takes no locks and doesn't work on aliases. Refactor of_find_node_opts_by_path() into __of_find_node_by_full_path() and replace find_node_by_full_name() with it. Signed-off-by: Rob Herring <robh@kernel.org>
2017-06-22of: make __of_attach_node() staticFrank Rowand
__of_attach_node() is not used outside of drivers/of/dynamic.c. Make it static and remove it from drivers/of/of_private.h. Signed-off-by: Frank Rowand <frank.rowand@sony.com> Signed-off-by: Rob Herring <robh@kernel.org>
2017-04-28of: fix unittest build without CONFIG_OF_OVERLAYArnd Bergmann
We get a link error when the new tests are used by overlays are not: drivers/of/built-in.o: In function `unflatten_device_tree': (.init.text+0x967): undefined reference to `unittest_unflatten_overlay_base' This makes the #ifdef check match the symbols that lead to building the unittest_unflatten_overlay_base function. Fixes: 81d0848fc8d2 ("of: Add unit tests for applying overlays") Signed-off-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Frank Rowand <frank.rowand@sony.com> Tested-by: Frank Rowand <frank.rowand@sony.com> Signed-off-by: Rob Herring <robh@kernel.org>
2017-04-27of: Add unit tests for applying overlaysFrank Rowand
Existing overlay unit tests examine individual pieces of the overlay code. The new tests target the entire process of applying an overlay. Signed-off-by: Frank Rowand <frank.rowand@sony.com> Signed-off-by: Rob Herring <robh@kernel.org>
2016-06-24of: fix memory leak related to safe_name()Frank Rowand
Fix a memory leak resulting from memory allocation in safe_name(). This patch fixes all call sites of safe_name(). Mathieu Malaterre reported the memory leak on boot: On my PowerMac device-tree would generate a duplicate name: [ 0.023043] device-tree: Duplicate name in PowerPC,G4@0, renamed to "l2-cache#1" in this case a newly allocated name is generated by `safe_name`. However in this case it is never deallocated. The bug was found using kmemleak reported as: unreferenced object 0xdf532e60 (size 32): comm "swapper", pid 1, jiffies 4294892300 (age 1993.532s) hex dump (first 32 bytes): 6c 32 2d 63 61 63 68 65 23 31 00 dd e4 dd 1e c2 l2-cache#1...... ec d4 ba ce 04 ec cc de 8e 85 e9 ca c4 ec cc 9e ................ backtrace: [<c02d3350>] kvasprintf+0x64/0xc8 [<c02d3400>] kasprintf+0x4c/0x5c [<c0453814>] safe_name.isra.1+0x80/0xc4 [<c04545d8>] __of_attach_node_sysfs+0x6c/0x11c [<c075f21c>] of_core_init+0x8c/0xf8 [<c0729594>] kernel_init_freeable+0xd4/0x208 [<c00047e8>] kernel_init+0x24/0x11c [<c00158ec>] ret_from_kernel_thread+0x5c/0x64 Link: https://bugzilla.kernel.org/show_bug.cgi?id=120331 Signed-off-by: Frank Rowand <frank.rowand@am.sony.com> Reported-by: mathieu.malaterre@gmail.com Tested-by: Mathieu Malaterre <mathieu.malaterre@gmail.com> Cc: stable@vger.kernel.org Signed-off-by: Rob Herring <robh@kernel.org>
2016-01-13drivers/of: Export OF changeset functionsGavin Shan
The PowerNV PCI hotplug driver is going to use the OF changeset to manage the changed device sub-tree. This exports those OF changeset functions for that. Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com> Acked-by: Wolfram Sang <wsa+renesas@sang-engineering.com> Tested-by: Wolfram Sang <wsa+renesas@sang-engineering.com> Signed-off-by: Rob Herring <robh@kernel.org>
2014-11-24of: Refactor __of_node_alloc() into __of_node_dup()Grant Likely
Add a node argument to __of_node_alloc() and rename it to __of_node_dup() so that it can also be used to duplicate a node with its properties. This is important for the overlay code so that it can create new nodes without using separate changeset items for every single property. At the same time rework the overlay code to use the new function and drop the extra changeset items. Signed-off-by: Grant Likely <grant.likely@linaro.org>
2014-11-24of: Use vargs in __of_node_allocGrant Likely
The overlay code needs to construct a new full_name from the parent name and the node name, but the current method has to allocate and then free an temporary string which is wasteful. Fix this problem by using vargs to pass in a format and arguments into __of_node_alloc(). At the same time remove the allocflags argument to __of_node_alloc(). The only users all use GFP_KERNEL, so there is no need to provide it as an option. If there is ever a need later it can be added back. Signed-off-by: Grant Likely <grant.likely@linaro.org>
2014-07-23of: Transactional DT support.Pantelis Antoniou
Introducing DT transactional support. A DT transaction is a method which allows one to apply changes in the live tree, in such a way that either the full set of changes take effect, or the state of the tree can be rolled-back to the state it was before it was attempted. An applied transaction can be rolled-back at any time. Documentation is in Documentation/devicetree/changesets.txt Signed-off-by: Pantelis Antoniou <pantelis.antoniou@konsulko.com> [glikely: Removed device notifiers and reworked to be more consistent] Signed-off-by: Grant Likely <grant.likely@linaro.org>
2014-07-23of: Reorder device tree changes and notifiersGrant Likely
Currently, devicetree reconfig notifiers get emitted before the change is applied to the tree, but that behaviour is problematic if the receiver wants the determine the new state of the tree. The current users don't care, but the changeset code to follow will be making multiple changes at once. Reorder notifiers to get emitted after the change has been applied to the tree so that callbacks see the new tree state. At the same time, fixup the existing callbacks to expect the new order. There are a few callbacks that compare the old and new values of a changed property. Put both property pointers into the of_prop_reconfig structure. The current notifiers also allow the notifier callback to fail and cancel the change to the tree, but that feature isn't actually used. It really isn't valid to ignore a tree modification provided by firmware anyway, so remove the ability to cancel a change to the tree. Signed-off-by: Grant Likely <grant.likely@linaro.org> Cc: Nathan Fontenot <nfont@austin.ibm.com>
2014-07-23of: Move dynamic node fixups out of powerpc and into common codeGrant Likely
PowerPC does an odd thing with dynamic nodes. It uses a notifier to catch new node additions and set some of the values like name and type. This makes no sense since that same code can be put directly into of_attach_node(). Besides, all dynamic node users need this, not just powerpc. Fix this problem by moving the logic out of arch/powerpc and into drivers/of/dynamic.c. It is also important to remove this notifier because we want to move the firing of notifiers from before the tree is modified to after so that the receiver gets a consistent view of the tree, but that is incompatible with notifiers that modify the node. Signed-off-by: Grant Likely <grant.likely@linaro.org> Cc: Nathan Fontenot <nfont@austin.ibm.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2014-07-23of: Make devicetree sysfs update functions consistent.Grant Likely
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>
2014-07-16of: Create unlocked versions of node and property add/remove functionsPantelis Antoniou
The DT overlay code will need to manipulate nodes and properties while already holding the devicetree lock, or on nodes that are not yet attached to the tree, but the current helper functions don't allow that. Extract the core behaviour from the accessors and create the following unlocked variants. The unlocked variants require either the lock to already be held or for the nodes to be detached from the tree. Changes to live nodes will not get updated in sysfs, so the caller must arrange for housekeeping to take place after dropping the lock. The new functions are: __of_add_property(), __of_remove_property(), __of_update_property(), __of_attach_node() and __of_detach_node(). Signed-off-by: Pantelis Antoniou <pantelis.antoniou@konsulko.com> [Remove unnecessary diff hunks and rewrite commit text] Signed-off-by: Grant Likely <grant.likely@linaro.org>
2014-07-16OF: Utility helper functions for dynamic nodesPantelis Antoniou
Introduce helper functions for working with the live DT tree, all of them related to dynamically adding/removing nodes and properties. __of_prop_dup() copies a property dynamically __of_node_alloc() creates an empty node Bug fix about prop->len == 0 by Ionut Nicu <ioan.nicu.ext@nsn.com> Signed-off-by: Pantelis Antoniou <pantelis.antoniou@konsulko.com> [glikely: Added unittest for of_copy_property and dropped fine-grained allocations] [glikely: removed name, type and phandle arguments from __of_node_alloc] Signed-off-by: Grant Likely <grant.likely@linaro.org>
2014-07-07of: Move CONFIG_OF_DYNAMIC code into a separate fileGrant Likely
Split the dynamic device tree code into a separate file to make it really clear what features CONFIF_OF_DYNAMIC add to the kernel. Without CONFIG_OF_DYNAMIC only properties can be changed, and notifiers do not get sent. Enabling it turns on reference counting, notifiers and the ability to add and remove nodes. v2: Moved of_node_release() into dynamic.c Signed-off-by: Grant Likely <grant.likely@linaro.org> Signed-off-by: Pantelis Antoniou <pantelis.antoniou@konsulko.com> Cc: Rob Herring <robh+dt@kernel.org>
2014-07-07of: rename of_aliases_mutex to just of_mutexPantelis Antoniou
We're overloading usage of of_aliases_mutex for sysfs changes, so rename to something that is more generic. Signed-off-by: Pantelis Antoniou <pantelis.antoniou@konsulko.com> Signed-off-by: Grant Likely <grant.likely@linaro.org>
2013-02-06of: Output devicetree alias names in ueventStepan Moskovchenko
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>