linux/drivers/of
Saravana Kannan f7514a6630 of: property: fw_devlink: Add support for remote-endpoint
remote-endpoint property seems to always come in pairs where two devices
point to each other. So, we can't really tell from DT if there is a
functional probe order dependency between these two devices.

However, there can be other dependencies between two devices that point
to each other with remote-endpoint. This non-remote-endpoint dependency
combined with one of the remote-endpoint dependency can lead to a cyclic
dependency[1].

To avoid this cyclic dependency from incorrectly blocking probes,
fw_devlink needs to be made aware of remote-endpoint dependencies even
though remote-endpoint dependencies by themselves won't affect probe
ordering (because fw_devlink will see the cyclic dependency between
remote-endpoint devices and ignore the dependencies that cause the
cycle).

Also, if a device ever needs to know if a non-probe-blocking
remote-endpoint has finished probing, it can now use the sync_state() to
figure it out.

[1] - https://lore.kernel.org/lkml/CAGETcx9Snf23wrXqjDhJiTok9M3GcoVYDSyNYSMj9QnSRrA=cA@mail.gmail.com/#t

Fixes: ea718c6990 ("Revert "Revert "driver core: Set fw_devlink=on by default""")
Reported-by: Stephen Boyd <swboyd@chromium.org>
Tested-by: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20210330185056.1022008-1-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-04-02 17:06:58 +02:00
..
unittest-data of: unittest: Use bigger address cells to catch parser regressions 2020-08-03 16:24:49 -06:00
Kconfig net: phy: Move of_mdio from drivers/of to drivers/net/mdio 2020-10-10 10:55:05 -07:00
Makefile net: phy: Move of_mdio from drivers/of to drivers/net/mdio 2020-10-10 10:55:05 -07:00
address.c arm64 updates for 5.11: 2020-12-14 16:24:30 -08:00
base.c of: base: improve error msg in of_phandle_iterator_next() 2021-01-15 11:26:09 -06:00
device.c Devicetree updates for v5.12: 2021-02-22 10:05:12 -08:00
dynamic.c driver core: Add fwnode link support 2020-12-09 19:10:21 +01:00
fdt.c of/fdt: Make sure no-map does not remove already reserved regions 2021-01-15 11:30:14 -06:00
fdt_address.c of: Use SPDX license tag for DT files 2018-01-08 08:22:45 -06:00
irq.c of/irq: Make of_msi_map_rid() PCI bus agnostic 2020-07-28 15:51:32 +01:00
kobj.c of: Fix a refcounting bug in __of_attach_node_sysfs() 2020-05-27 19:30:25 -06:00
of_net.c net: of_get_phy_mode: Change API to solve int/unit warnings 2019-11-04 11:21:25 -08:00
of_numa.c of, numa: Validate some distance map rules 2018-11-08 12:44:34 -06:00
of_private.h dma-mapping: introduce DMA range map, supplanting dma_pfn_offset 2020-09-17 18:43:56 +02:00
of_reserved_mem.c of: Fix reserved-memory overlap detection 2020-10-25 20:37:55 -05:00
overlay.c of: overlay: kmemleak in dup_and_fixup_symbol_prop() 2020-04-17 08:31:34 -05:00
pdt.c of: Remove struct device_node.type pointer 2019-01-10 16:24:44 -06:00
platform.c Char/Misc driver patches for 5.12-rc1 2021-02-24 10:25:37 -08:00
property.c of: property: fw_devlink: Add support for remote-endpoint 2021-04-02 17:06:58 +02:00
resolver.c of: overlay: log the error cause on resolver failure 2020-03-02 11:32:44 -06:00
unittest.c of: Remove of_dev_{get,put}() 2021-02-12 19:23:39 -06:00