kernel/linux.git/drivers/of/base.c, branch v4.19.112

of: make PowerMac cache node search conditional on CONFIG_PPC_PMAC

2019-11-20T17:46:06+00:00

[ Upstream commit f6707fd6241e483f6fea2caae82d876e422bb11a ] Cache nodes under the cpu node(s) is PowerMac specific according to the comment above, so make the code enforce that. Signed-off-by: Rob Herring Signed-off-by: Sasha Levin

of: __of_detach_node() - remove node from phandle cache

2019-01-13T08:51:10+00:00

commit 5801169a2ed20003f771acecf3ac00574cf10a38 upstream. 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 Cc: stable@vger.kernel.org # v4.17+ Signed-off-by: Frank Rowand Signed-off-by: Rob Herring Signed-off-by: Greg Kroah-Hartman

of: of_node_get()/of_node_put() nodes held in phandle cache

2019-01-13T08:51:10+00:00

commit b8a9ac1a5b99a2fcbed19fd29d2d59270c281a31 upstream. The phandle cache contains struct device_node pointers. The refcount of the pointers was not incremented while in the cache, allowing use after free error after kfree() of the node. Add the proper increment and decrement of the use count. Fixes: 0b3ce78e90fc ("of: cache phandle nodes to reduce cost of of_find_node_by_phandle()") Cc: stable@vger.kernel.org # v4.17+ Signed-off-by: Frank Rowand Signed-off-by: Rob Herring Signed-off-by: Greg Kroah-Hartman

of: Add missing exports of node name compare functions

2018-11-13T19:08:32+00:00

[ Upstream commit 173ee3962959a1985a109f81539a403b5cd07ae7 ] Commit f42b0e18f2e5 ("of: add node name compare helper functions") failed to add the module exports to of_node_name_eq() and of_node_name_prefix(). Add them now. Fixes: f42b0e18f2e5 ("of: add node name compare helper functions") Signed-off-by: Rob Herring Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

of: fix phandle cache creation for DTs with no phandles

2018-09-11T16:28:40+00:00

With commit 0b3ce78e90fc ("of: cache phandle nodes to reduce cost of of_find_node_by_phandle()"), a G3 PowerMac fails to boot. The root cause is the DT for this system has no phandle properties when booted with BootX. of_populate_phandle_cache() does not handle the case of no phandles correctly. The problem is roundup_pow_of_two() for 0 is undefined. The implementation subtracts 1 underflowing and then things are in the weeds. Fixes: 0b3ce78e90fc ("of: cache phandle nodes to reduce cost of of_find_node_by_phandle()") Cc: stable@vger.kernel.org # 4.17+ Reported-by: Finn Thain Tested-by: Stan Johnson Reviewed-by: Frank Rowand Cc: Benjamin Herrenschmidt Signed-off-by: Rob Herring

of: add node name compare helper functions

2018-08-30T18:53:05+00:00

In preparation to remove device_node.name pointer, add helper functions for node name comparisons which are a common pattern throughout the kernel. Cc: Frank Rowand Signed-off-by: Rob Herring

of: add helper to lookup compatible child node

2018-08-29T13:06:46+00:00

Add of_get_compatible_child() helper that can be used to lookup compatible child nodes. Several drivers currently use of_find_compatible_node() to lookup child nodes while failing to notice that the of_find_ functions search the entire tree depth-first (from a given start node) and therefore can match unrelated nodes. The fact that these functions also drop a reference to the node they start searching from (e.g. the parent node) is typically also overlooked, something which can lead to use-after-free bugs. Signed-off-by: Johan Hovold Signed-off-by: Rob Herring

of: overlay: update phandle cache on overlay apply and remove

2018-07-16T14:41:32+00:00

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 Suggested-by: Alan Tull Signed-off-by: Frank Rowand Signed-off-by: Rob Herring

of: cache phandle nodes to reduce cost of of_find_node_by_phandle()

2018-03-07T20:50:09+00:00

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 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 Signed-off-by: Frank Rowand Signed-off-by: Rob Herring

of: Support parsing phandle argument lists through a nexus node

2018-02-12T14:37:58+00:00

Platforms like 96boards have a standardized connector/expansion slot that exposes signals like GPIOs to expansion boards in an SoC agnostic way. We'd like the DT overlays for the expansion boards to be written once without knowledge of the SoC on the other side of the connector. This avoids the unscalable combinatorial explosion of a different DT overlay for each expansion board and SoC pair. We need a way to describe the GPIOs routed through the connector in an SoC agnostic way. Let's introduce nexus property parsing into the OF core to do this. This is largely based on the interrupt nexus support we already have. This allows us to remap a phandle list in a consumer node (e.g. reset-gpios) through a connector in a generic way (e.g. via gpio-map). Do this in a generic routine so that we can remap any sort of variable length phandle list. Taking GPIOs as an example, the connector would be a GPIO nexus, supporting the remapping of a GPIO specifier space to multiple GPIO providers on the SoC. DT would look as shown below, where 'soc_gpio1' and 'soc_gpio2' are inside the SoC, 'connector' is an expansion port where boards can be plugged in, and 'expansion_device' is a device on the expansion board. soc { soc_gpio1: gpio-controller1 { #gpio-cells = <2>; }; soc_gpio2: gpio-controller2 { #gpio-cells = <2>; }; }; connector: connector { #gpio-cells = <2>; gpio-map = <0 0 &soc_gpio1 1 0>, <1 0 &soc_gpio2 4 0>, <2 0 &soc_gpio1 3 0>, <3 0 &soc_gpio2 2 0>; gpio-map-mask = <0xf 0x0>; gpio-map-pass-thru = <0x0 0x1> }; expansion_device { reset-gpios = <&connector 2 GPIO_ACTIVE_LOW>; }; The GPIO core would use of_parse_phandle_with_args_map() instead of of_parse_phandle_with_args() and arrive at the same type of result, a phandle and argument list. The difference is that the phandle and arguments will be remapped through the nexus node to the underlying SoC GPIO controller node. In the example above, we would remap 'reset-gpios' from <&connector 2 GPIO_ACTIVE_LOW> to <&soc_gpio1 3 GPIO_ACTIVE_LOW>. Cc: Pantelis Antoniou Cc: Linus Walleij Cc: Mark Brown Signed-off-by: Stephen Boyd Signed-off-by: Rob Herring