<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-stable.git/drivers/of/base.c, branch v5.13.2</title>
<subtitle>Linux kernel stable tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/'/>
<entry>
<title>of: base: Fix spelling issue with function param 'prop'</title>
<updated>2021-03-29T18:51:26+00:00</updated>
<author>
<name>Lee Jones</name>
<email>lee.jones@linaro.org</email>
</author>
<published>2021-03-29T15:24:35+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=31e46db02ac1351c84e56a18606d17fc1b8390dd'/>
<id>31e46db02ac1351c84e56a18606d17fc1b8390dd</id>
<content type='text'>
Fixes the following W=1 kernel build warning(s):

 drivers/of/base.c:1781: warning: Function parameter or member 'prop' not described in '__of_add_property'
 drivers/of/base.c:1781: warning: Excess function parameter 'prob' description in '__of_add_property'
 drivers/of/base.c:1804: warning: Function parameter or member 'prop' not described in 'of_add_property'
 drivers/of/base.c:1804: warning: Excess function parameter 'prob' description in 'of_add_property'
 drivers/of/base.c:1855: warning: Function parameter or member 'prop' not described in 'of_remove_property'
 drivers/of/base.c:1855: warning: Excess function parameter 'prob' description in 'of_remove_property'

Cc: Rob Herring &lt;robh+dt@kernel.org&gt;
Cc: Frank Rowand &lt;frowand.list@gmail.com&gt;
Cc: "David S. Miller" &lt;davem@davemloft.net&gt;
Cc: devicetree@vger.kernel.org
Signed-off-by: Lee Jones &lt;lee.jones@linaro.org&gt;
Link: https://lore.kernel.org/r/20210329152435.900225-1-lee.jones@linaro.org
Signed-off-by: Rob Herring &lt;robh@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Fixes the following W=1 kernel build warning(s):

 drivers/of/base.c:1781: warning: Function parameter or member 'prop' not described in '__of_add_property'
 drivers/of/base.c:1781: warning: Excess function parameter 'prob' description in '__of_add_property'
 drivers/of/base.c:1804: warning: Function parameter or member 'prop' not described in 'of_add_property'
 drivers/of/base.c:1804: warning: Excess function parameter 'prob' description in 'of_add_property'
 drivers/of/base.c:1855: warning: Function parameter or member 'prop' not described in 'of_remove_property'
 drivers/of/base.c:1855: warning: Excess function parameter 'prob' description in 'of_remove_property'

Cc: Rob Herring &lt;robh+dt@kernel.org&gt;
Cc: Frank Rowand &lt;frowand.list@gmail.com&gt;
Cc: "David S. Miller" &lt;davem@davemloft.net&gt;
Cc: devicetree@vger.kernel.org
Signed-off-by: Lee Jones &lt;lee.jones@linaro.org&gt;
Link: https://lore.kernel.org/r/20210329152435.900225-1-lee.jones@linaro.org
Signed-off-by: Rob Herring &lt;robh@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>of: Add missing 'Return' section in kerneldoc comments</title>
<updated>2021-03-27T18:59:03+00:00</updated>
<author>
<name>Rob Herring</name>
<email>robh@kernel.org</email>
</author>
<published>2021-03-25T16:47:12+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=8c8239c2c1fb82f171cb22a707f3bb88a2f22109'/>
<id>8c8239c2c1fb82f171cb22a707f3bb88a2f22109</id>
<content type='text'>
Many of the DT kerneldoc comments are lacking a 'Return' section. Let's
add the section in cases we have a description of return values. There's
still some cases where the return values are not documented.

Cc: Frank Rowand &lt;frowand.list@gmail.com&gt;
Cc: Mauro Carvalho Chehab &lt;mchehab@kernel.org&gt;
Signed-off-by: Rob Herring &lt;robh@kernel.org&gt;
Reviewed-by: Mauro Carvalho Chehab &lt;mchehab+huawei@kernel.org&gt;
Link: https://lore.kernel.org/r/20210325164713.1296407-8-robh@kernel.org
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Many of the DT kerneldoc comments are lacking a 'Return' section. Let's
add the section in cases we have a description of return values. There's
still some cases where the return values are not documented.

Cc: Frank Rowand &lt;frowand.list@gmail.com&gt;
Cc: Mauro Carvalho Chehab &lt;mchehab@kernel.org&gt;
Signed-off-by: Rob Herring &lt;robh@kernel.org&gt;
Reviewed-by: Mauro Carvalho Chehab &lt;mchehab+huawei@kernel.org&gt;
Link: https://lore.kernel.org/r/20210325164713.1296407-8-robh@kernel.org
</pre>
</div>
</content>
</entry>
<entry>
<title>of: Fix kerneldoc output formatting</title>
<updated>2021-03-27T18:58:42+00:00</updated>
<author>
<name>Rob Herring</name>
<email>robh@kernel.org</email>
</author>
<published>2021-03-26T19:26:06+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=62f026f082e4d762a47b43ea693b38f025122332'/>
<id>62f026f082e4d762a47b43ea693b38f025122332</id>
<content type='text'>
The indentation of the kerneldoc comments affects the output formatting.
Leading tabs in particular don't work, sections need to be indented
under the section header, and several code blocks are reformatted.

Cc: Frank Rowand &lt;frowand.list@gmail.com&gt;
Cc: Mauro Carvalho Chehab &lt;mchehab@kernel.org&gt;
Signed-off-by: Rob Herring &lt;robh@kernel.org&gt;
Reviewed-by: Mauro Carvalho Chehab &lt;mchehab+huawei@kernel.org&gt;
Link: https://lore.kernel.org/r/20210326192606.3702739-1-robh@kernel.org
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The indentation of the kerneldoc comments affects the output formatting.
Leading tabs in particular don't work, sections need to be indented
under the section header, and several code blocks are reformatted.

Cc: Frank Rowand &lt;frowand.list@gmail.com&gt;
Cc: Mauro Carvalho Chehab &lt;mchehab@kernel.org&gt;
Signed-off-by: Rob Herring &lt;robh@kernel.org&gt;
Reviewed-by: Mauro Carvalho Chehab &lt;mchehab+huawei@kernel.org&gt;
Link: https://lore.kernel.org/r/20210326192606.3702739-1-robh@kernel.org
</pre>
</div>
</content>
</entry>
<entry>
<title>of: base: Fix some formatting issues and provide missing descriptions</title>
<updated>2021-03-23T21:27:52+00:00</updated>
<author>
<name>Lee Jones</name>
<email>lee.jones@linaro.org</email>
</author>
<published>2021-03-18T10:40:30+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=3637d49e11219512920aca8b8ccd0994be33fa8b'/>
<id>3637d49e11219512920aca8b8ccd0994be33fa8b</id>
<content type='text'>
Fixes the following W=1 kernel build warning(s):

 drivers/of/base.c:315: warning: Function parameter or member 'cpun' not described in '__of_find_n_match_cpu_property'
 drivers/of/base.c:315: warning: Function parameter or member 'prop_name' not described in '__of_find_n_match_cpu_property'
 drivers/of/base.c:315: warning: Function parameter or member 'cpu' not described in '__of_find_n_match_cpu_property'
 drivers/of/base.c:315: warning: Function parameter or member 'thread' not described in '__of_find_n_match_cpu_property'
 drivers/of/base.c:315: warning: expecting prototype for property holds the physical id of the(). Prototype was for __of_find_n_match_cpu_property() instead
 drivers/of/base.c:1139: warning: Function parameter or member 'match' not described in 'of_find_matching_node_and_match'
 drivers/of/base.c:1779: warning: Function parameter or member 'np' not described in '__of_add_property'
 drivers/of/base.c:1779: warning: Function parameter or member 'prop' not described in '__of_add_property'
 drivers/of/base.c:1800: warning: Function parameter or member 'np' not described in 'of_add_property'
 drivers/of/base.c:1800: warning: Function parameter or member 'prop' not described in 'of_add_property'
 drivers/of/base.c:1849: warning: Function parameter or member 'np' not described in 'of_remove_property'
 drivers/of/base.c:1849: warning: Function parameter or member 'prop' not described in 'of_remove_property'
 drivers/of/base.c:2137: warning: Function parameter or member 'dn' not described in 'of_console_check'
 drivers/of/base.c:2137: warning: Function parameter or member 'name' not described in 'of_console_check'
 drivers/of/base.c:2137: warning: Function parameter or member 'index' not described in 'of_console_check'

Cc: Rob Herring &lt;robh+dt@kernel.org&gt;
Cc: Frank Rowand &lt;frowand.list@gmail.com&gt;
Cc: "David S. Miller" &lt;davem@davemloft.net&gt;
Cc: devicetree@vger.kernel.org
Signed-off-by: Lee Jones &lt;lee.jones@linaro.org&gt;
Signed-off-by: Rob Herring &lt;robh@kernel.org&gt;
Link: https://lore.kernel.org/r/20210318104036.3175910-5-lee.jones@linaro.org
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Fixes the following W=1 kernel build warning(s):

 drivers/of/base.c:315: warning: Function parameter or member 'cpun' not described in '__of_find_n_match_cpu_property'
 drivers/of/base.c:315: warning: Function parameter or member 'prop_name' not described in '__of_find_n_match_cpu_property'
 drivers/of/base.c:315: warning: Function parameter or member 'cpu' not described in '__of_find_n_match_cpu_property'
 drivers/of/base.c:315: warning: Function parameter or member 'thread' not described in '__of_find_n_match_cpu_property'
 drivers/of/base.c:315: warning: expecting prototype for property holds the physical id of the(). Prototype was for __of_find_n_match_cpu_property() instead
 drivers/of/base.c:1139: warning: Function parameter or member 'match' not described in 'of_find_matching_node_and_match'
 drivers/of/base.c:1779: warning: Function parameter or member 'np' not described in '__of_add_property'
 drivers/of/base.c:1779: warning: Function parameter or member 'prop' not described in '__of_add_property'
 drivers/of/base.c:1800: warning: Function parameter or member 'np' not described in 'of_add_property'
 drivers/of/base.c:1800: warning: Function parameter or member 'prop' not described in 'of_add_property'
 drivers/of/base.c:1849: warning: Function parameter or member 'np' not described in 'of_remove_property'
 drivers/of/base.c:1849: warning: Function parameter or member 'prop' not described in 'of_remove_property'
 drivers/of/base.c:2137: warning: Function parameter or member 'dn' not described in 'of_console_check'
 drivers/of/base.c:2137: warning: Function parameter or member 'name' not described in 'of_console_check'
 drivers/of/base.c:2137: warning: Function parameter or member 'index' not described in 'of_console_check'

Cc: Rob Herring &lt;robh+dt@kernel.org&gt;
Cc: Frank Rowand &lt;frowand.list@gmail.com&gt;
Cc: "David S. Miller" &lt;davem@davemloft.net&gt;
Cc: devicetree@vger.kernel.org
Signed-off-by: Lee Jones &lt;lee.jones@linaro.org&gt;
Signed-off-by: Rob Herring &lt;robh@kernel.org&gt;
Link: https://lore.kernel.org/r/20210318104036.3175910-5-lee.jones@linaro.org
</pre>
</div>
</content>
</entry>
<entry>
<title>of: base: improve error msg in of_phandle_iterator_next()</title>
<updated>2021-01-15T17:26:09+00:00</updated>
<author>
<name>Enrico Weigelt, metux IT consult</name>
<email>info@metux.net</email>
</author>
<published>2021-01-14T10:11:27+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=12e17243d8a1591bba5041da6e7df7a390da94a1'/>
<id>12e17243d8a1591bba5041da6e7df7a390da94a1</id>
<content type='text'>
Also print out the phandle ID on error message, as a debug aid.

Signed-off-by: Enrico Weigelt, metux IT consult &lt;info@metux.net&gt;
Link: https://lore.kernel.org/r/20210114101127.16580-1-info@metux.net
Signed-off-by: Rob Herring &lt;robh@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Also print out the phandle ID on error message, as a debug aid.

Signed-off-by: Enrico Weigelt, metux IT consult &lt;info@metux.net&gt;
Link: https://lore.kernel.org/r/20210114101127.16580-1-info@metux.net
Signed-off-by: Rob Herring &lt;robh@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>of: Export of_remove_property() to modules</title>
<updated>2020-09-05T20:09:03+00:00</updated>
<author>
<name>Florian Fainelli</name>
<email>f.fainelli@gmail.com</email>
</author>
<published>2020-09-04T21:37:29+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=0f7c5317b89058e432d3e97efa19467ff4c3b86b'/>
<id>0f7c5317b89058e432d3e97efa19467ff4c3b86b</id>
<content type='text'>
We will need to remove some OF properties in drivers/net/dsa/bcm_sf2.c
with a subsequent commit. Export of_remove_property() to modules so we
can keep bcm_sf2 modular and provide an empty stub for when CONFIG_OF is
disabled to maintain the ability to compile test.

Signed-off-by: Florian Fainelli &lt;f.fainelli@gmail.com&gt;
Acked-by: Rob Herring &lt;robh@kernel.org&gt;
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
We will need to remove some OF properties in drivers/net/dsa/bcm_sf2.c
with a subsequent commit. Export of_remove_property() to modules so we
can keep bcm_sf2 modular and provide an empty stub for when CONFIG_OF is
disabled to maintain the ability to compile test.

Signed-off-by: Florian Fainelli &lt;f.fainelli@gmail.com&gt;
Acked-by: Rob Herring &lt;robh@kernel.org&gt;
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>of/iommu: Make of_map_rid() PCI agnostic</title>
<updated>2020-07-28T14:51:31+00:00</updated>
<author>
<name>Lorenzo Pieralisi</name>
<email>lorenzo.pieralisi@arm.com</email>
</author>
<published>2020-06-19T08:20:07+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=746a71d02b5d15817fcb13c956ba999a87773952'/>
<id>746a71d02b5d15817fcb13c956ba999a87773952</id>
<content type='text'>
There is nothing PCI specific (other than the RID - requester ID)
in the of_map_rid() implementation, so the same function can be
reused for input/output IDs mapping for other busses just as well.

Rename the RID instances/names to a generic "id" tag.

No functionality change intended.

Signed-off-by: Lorenzo Pieralisi &lt;lorenzo.pieralisi@arm.com&gt;
Reviewed-by: Rob Herring &lt;robh@kernel.org&gt;
Acked-by: Joerg Roedel &lt;jroedel@suse.de&gt;
Cc: Rob Herring &lt;robh+dt@kernel.org&gt;
Cc: Joerg Roedel &lt;joro@8bytes.org&gt;
Cc: Robin Murphy &lt;robin.murphy@arm.com&gt;
Cc: Marc Zyngier &lt;maz@kernel.org&gt;
Link: https://lore.kernel.org/r/20200619082013.13661-7-lorenzo.pieralisi@arm.com
Signed-off-by: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
There is nothing PCI specific (other than the RID - requester ID)
in the of_map_rid() implementation, so the same function can be
reused for input/output IDs mapping for other busses just as well.

Rename the RID instances/names to a generic "id" tag.

No functionality change intended.

Signed-off-by: Lorenzo Pieralisi &lt;lorenzo.pieralisi@arm.com&gt;
Reviewed-by: Rob Herring &lt;robh@kernel.org&gt;
Acked-by: Joerg Roedel &lt;jroedel@suse.de&gt;
Cc: Rob Herring &lt;robh+dt@kernel.org&gt;
Cc: Joerg Roedel &lt;joro@8bytes.org&gt;
Cc: Robin Murphy &lt;robin.murphy@arm.com&gt;
Cc: Marc Zyngier &lt;maz@kernel.org&gt;
Link: https://lore.kernel.org/r/20200619082013.13661-7-lorenzo.pieralisi@arm.com
Signed-off-by: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'armsoc-drivers' of git://git.kernel.org/pub/scm/linux/kernel/git/soc/soc</title>
<updated>2020-02-08T22:04:19+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2020-02-08T22:04:19+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=eab3540562fb44f830e09492374fcc69a283ce47'/>
<id>eab3540562fb44f830e09492374fcc69a283ce47</id>
<content type='text'>
Pull ARM SoC-related driver updates from Olof Johansson:
 "Various driver updates for platforms:

   - Nvidia: Fuse support for Tegra194, continued memory controller
     pieces for Tegra30

   - NXP/FSL: Refactorings of QuickEngine drivers to support
     ARM/ARM64/PPC

   - NXP/FSL: i.MX8MP SoC driver pieces

   - TI Keystone: ring accelerator driver

   - Qualcomm: SCM driver cleanup/refactoring + support for new SoCs.

   - Xilinx ZynqMP: feature checking interface for firmware. Mailbox
     communication for power management

   - Overall support patch set for cpuidle on more complex hierarchies
     (PSCI-based)

  and misc cleanups, refactorings of Marvell, TI, other platforms"

* tag 'armsoc-drivers' of git://git.kernel.org/pub/scm/linux/kernel/git/soc/soc: (166 commits)
  drivers: soc: xilinx: Use mailbox IPI callback
  dt-bindings: power: reset: xilinx: Add bindings for ipi mailbox
  drivers: soc: ti: knav_qmss_queue: Pass lockdep expression to RCU lists
  MAINTAINERS: Add brcmstb PCIe controller entry
  soc/tegra: fuse: Unmap registers once they are not needed anymore
  soc/tegra: fuse: Correct straps' address for older Tegra124 device trees
  soc/tegra: fuse: Warn if straps are not ready
  soc/tegra: fuse: Cache values of straps and Chip ID registers
  memory: tegra30-emc: Correct error message for timed out auto calibration
  memory: tegra30-emc: Firm up hardware programming sequence
  memory: tegra30-emc: Firm up suspend/resume sequence
  soc/tegra: regulators: Do nothing if voltage is unchanged
  memory: tegra: Correct reset value of xusb_hostr
  soc/tegra: fuse: Add APB DMA dependency for Tegra20
  bus: tegra-aconnect: Remove PM_CLK dependency
  dt-bindings: mediatek: add MT6765 power dt-bindings
  soc: mediatek: cmdq: delete not used define
  memory: tegra: Add support for the Tegra194 memory controller
  memory: tegra: Only include support for enabled SoCs
  memory: tegra: Support DVFS on Tegra186 and later
  ...
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull ARM SoC-related driver updates from Olof Johansson:
 "Various driver updates for platforms:

   - Nvidia: Fuse support for Tegra194, continued memory controller
     pieces for Tegra30

   - NXP/FSL: Refactorings of QuickEngine drivers to support
     ARM/ARM64/PPC

   - NXP/FSL: i.MX8MP SoC driver pieces

   - TI Keystone: ring accelerator driver

   - Qualcomm: SCM driver cleanup/refactoring + support for new SoCs.

   - Xilinx ZynqMP: feature checking interface for firmware. Mailbox
     communication for power management

   - Overall support patch set for cpuidle on more complex hierarchies
     (PSCI-based)

  and misc cleanups, refactorings of Marvell, TI, other platforms"

* tag 'armsoc-drivers' of git://git.kernel.org/pub/scm/linux/kernel/git/soc/soc: (166 commits)
  drivers: soc: xilinx: Use mailbox IPI callback
  dt-bindings: power: reset: xilinx: Add bindings for ipi mailbox
  drivers: soc: ti: knav_qmss_queue: Pass lockdep expression to RCU lists
  MAINTAINERS: Add brcmstb PCIe controller entry
  soc/tegra: fuse: Unmap registers once they are not needed anymore
  soc/tegra: fuse: Correct straps' address for older Tegra124 device trees
  soc/tegra: fuse: Warn if straps are not ready
  soc/tegra: fuse: Cache values of straps and Chip ID registers
  memory: tegra30-emc: Correct error message for timed out auto calibration
  memory: tegra30-emc: Firm up hardware programming sequence
  memory: tegra30-emc: Firm up suspend/resume sequence
  soc/tegra: regulators: Do nothing if voltage is unchanged
  memory: tegra: Correct reset value of xusb_hostr
  soc/tegra: fuse: Add APB DMA dependency for Tegra20
  bus: tegra-aconnect: Remove PM_CLK dependency
  dt-bindings: mediatek: add MT6765 power dt-bindings
  soc: mediatek: cmdq: delete not used define
  memory: tegra: Add support for the Tegra194 memory controller
  memory: tegra: Only include support for enabled SoCs
  memory: tegra: Support DVFS on Tegra186 and later
  ...
</pre>
</div>
</content>
</entry>
<entry>
<title>of: base: Add of_get_cpu_state_node() to get idle states for a CPU node</title>
<updated>2020-01-02T15:50:04+00:00</updated>
<author>
<name>Ulf Hansson</name>
<email>ulf.hansson@linaro.org</email>
</author>
<published>2019-10-10T10:01:48+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=b9f8c26afc405a4a616e765e949bdd551151e41d'/>
<id>b9f8c26afc405a4a616e765e949bdd551151e41d</id>
<content type='text'>
The CPU's idle state nodes are currently parsed at the common cpuidle DT
library, but also when initializing data for specific CPU idle operations,
as in the PSCI cpuidle driver case and qcom-spm cpuidle case.

To avoid open-coding, let's introduce of_get_cpu_state_node(), which takes
the device node for the CPU and the index to the requested idle state node,
as in-parameters. In case a corresponding idle state node is found, it
returns the node with the refcount incremented for it, else it returns
NULL.

Moreover, for PSCI there are two options to describe the CPU's idle states
[1], either via a flattened description or a hierarchical layout. Hence,
let's take both options into account.

[1] Documentation/devicetree/bindings/arm/psci.yaml

Suggested-by: Sudeep Holla &lt;sudeep.holla@arm.com&gt;
Co-developed-by: Lina Iyer &lt;lina.iyer@linaro.org&gt;
Signed-off-by: Lina Iyer &lt;lina.iyer@linaro.org&gt;
Reviewed-by: Rob Herring &lt;robh@kernel.org&gt;
Reviewed-by: Daniel Lezcano &lt;daniel.lezcano@linaro.org&gt;
Signed-off-by: Ulf Hansson &lt;ulf.hansson@linaro.org&gt;
Reviewed-by: Sudeep Holla &lt;sudeep.holla@arm.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The CPU's idle state nodes are currently parsed at the common cpuidle DT
library, but also when initializing data for specific CPU idle operations,
as in the PSCI cpuidle driver case and qcom-spm cpuidle case.

To avoid open-coding, let's introduce of_get_cpu_state_node(), which takes
the device node for the CPU and the index to the requested idle state node,
as in-parameters. In case a corresponding idle state node is found, it
returns the node with the refcount incremented for it, else it returns
NULL.

Moreover, for PSCI there are two options to describe the CPU's idle states
[1], either via a flattened description or a hierarchical layout. Hence,
let's take both options into account.

[1] Documentation/devicetree/bindings/arm/psci.yaml

Suggested-by: Sudeep Holla &lt;sudeep.holla@arm.com&gt;
Co-developed-by: Lina Iyer &lt;lina.iyer@linaro.org&gt;
Signed-off-by: Lina Iyer &lt;lina.iyer@linaro.org&gt;
Reviewed-by: Rob Herring &lt;robh@kernel.org&gt;
Reviewed-by: Daniel Lezcano &lt;daniel.lezcano@linaro.org&gt;
Signed-off-by: Ulf Hansson &lt;ulf.hansson@linaro.org&gt;
Reviewed-by: Sudeep Holla &lt;sudeep.holla@arm.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>of: Rework and simplify phandle cache to use a fixed size</title>
<updated>2019-12-24T21:17:52+00:00</updated>
<author>
<name>Rob Herring</name>
<email>robh@kernel.org</email>
</author>
<published>2019-12-06T22:27:41+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=90dc0d1ce890419f977e460b8258d25187dde64f'/>
<id>90dc0d1ce890419f977e460b8258d25187dde64f</id>
<content type='text'>
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 &lt;bigeasy@linutronix.de&gt;
Cc: Michael Ellerman &lt;mpe@ellerman.id.au&gt;
Cc: Segher Boessenkool &lt;segher@kernel.crashing.org&gt;
Cc: Frank Rowand &lt;frowand.list@gmail.com&gt;
Acked-by: Sebastian Andrzej Siewior &lt;bigeasy@linutronix.de&gt;
Reviewed-by: Frank Rowand &lt;frowand.list@gmail.com&gt;
Tested-by: Frank Rowand &lt;frowand.list@gmail.com&gt;
Signed-off-by: Rob Herring &lt;robh@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
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 &lt;bigeasy@linutronix.de&gt;
Cc: Michael Ellerman &lt;mpe@ellerman.id.au&gt;
Cc: Segher Boessenkool &lt;segher@kernel.crashing.org&gt;
Cc: Frank Rowand &lt;frowand.list@gmail.com&gt;
Acked-by: Sebastian Andrzej Siewior &lt;bigeasy@linutronix.de&gt;
Reviewed-by: Frank Rowand &lt;frowand.list@gmail.com&gt;
Tested-by: Frank Rowand &lt;frowand.list@gmail.com&gt;
Signed-off-by: Rob Herring &lt;robh@kernel.org&gt;
</pre>
</div>
</content>
</entry>
</feed>
