linux/drivers/of/dynamic.c

1042 lines
26 KiB

treewide: Fix probing of devices in DT overlays When loading a DT overlay that creates a device, the device is not probed, unless the DT overlay is unloaded and reloaded again. After the recent refactoring to improve fw_devlink, it no longer depends on the "compatible" property to identify which device tree nodes will become struct devices. fw_devlink now picks up dangling consumers (consumers pointing to descendent device tree nodes of a device that aren't converted to child devices) when a device is successfully bound to a driver. See __fw_devlink_pickup_dangling_consumers(). However, during DT overlay, a device's device tree node can have sub-nodes added/removed without unbinding/rebinding the driver. This difference in behavior between the normal device instantiation and probing flow vs. the DT overlay flow has a bunch of implications that are pointed out elsewhere[1]. One of them is that the fw_devlink logic to pick up dangling consumers is never exercised. This patch solves the fw_devlink issue by marking all DT nodes added by DT overlays with FWNODE_FLAG_NOT_DEVICE (fwnode that won't become device), and by clearing the flag when a struct device is actually created for the DT node. This way, fw_devlink knows not to have consumers waiting on these newly added DT nodes, and to propagate the dependency to an ancestor DT node that has the corresponding struct device. Based on a patch by Saravana Kannan, which covered only platform and spi devices. [1] https://lore.kernel.org/r/CAGETcx_bkuFaLCiPrAWCPQz+w79ccDp6=9e881qmK=vx3hBMyg@mail.gmail.com Fixes: 4a032827daa89350 ("of: property: Simplify of_link_to_phandle()") Link: https://lore.kernel.org/r/CAGETcx_+rhHvaC_HJXGrr5_WAd2+k5f=rWYnkCZ6z5bGX-wj4w@mail.gmail.com Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Acked-by: Mark Brown <broonie@kernel.org> Acked-by: Wolfram Sang <wsa@kernel.org> # for I2C Acked-by: Shawn Guo <shawnguo@kernel.org> Acked-by: Saravana Kannan <saravanak@google.com> Tested-by: Ivan Bornyakov <i.bornyakov@metrotek.ru> Link: https://lore.kernel.org/r/e1fa546682ea4c8474ff997ab6244c5e11b6f8bc.1680182615.git.geert+renesas@glider.be Signed-off-by: Rob Herring <robh@kernel.org>
2023-03-30 15:26:13 +02:00
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>
2014-07-23 17:05:06 -06:00
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>
2014-07-23 17:05:06 -06:00
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>
2019-12-06 16:27:41 -06:00
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>
2014-07-23 17:05:06 -06:00
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>
2014-07-23 17:05:06 -06:00