kernel/linux.git/drivers/opp/opp.h, branch linux-4.20.y

OPP: Prevent creating multiple OPP tables for devices sharing OPP nodes

2018-10-01T09:30:31+00:00

When two or more devices are sharing their clock and voltage rails, they share the same OPP table. But there are some corner cases where the OPP core incorrectly creates separate OPP tables for them. For example, CPU 0 and 1 share clock/voltage rails. The platform specific code calls dev_pm_opp_set_regulators() for CPU0 and the OPP core creates an OPP table for it (the individual OPPs aren't initialized as of now). The same is repeated for CPU1 then. Because _opp_get_opp_table() doesn't compare DT node pointers currently, it fails to find the link between CPU0 and CPU1 and so creates a new OPP table. Fix this by calling _managed_opp() from _opp_get_opp_table(). _managed_opp() gain an additional argument (index) to get the right node pointer. This resulted in simplifying code in _of_add_opp_table_v2() as well. Tested-by: Niklas Cassel Signed-off-by: Viresh Kumar

OPP: Use a single mechanism to free the OPP table

2018-09-19T21:56:46+00:00

Currently there are two separate ways to free the OPP table based on how it is created in the first place. We call _dev_pm_opp_remove_table() to free the static and/or dynamic OPP, OPP list devices, etc. This is done for the case where the OPP table is added while initializing the OPPs, like via the path dev_pm_opp_of_add_table(). We also call dev_pm_opp_put_opp_table() in some cases which eventually frees the OPP table structure once the reference count reaches 0. This is used by the first case as well as other cases like dev_pm_opp_set_regulators() where the OPPs aren't necessarily initialized at this point. This whole thing is a bit unclear and messy and obstruct any further cleanup/fixup of OPP core. This patch tries to streamline this by keeping a single path for OPP table destruction, i.e. dev_pm_opp_put_opp_table(). All the cleanup happens in _opp_table_kref_release() now after the reference count reaches 0. _dev_pm_opp_remove_table() is removed as it isn't required anymore. We don't drop the reference to the OPP table after creating it from _of_add_opp_table_v{1|2}() anymore and the same is dropped only when we try to remove them. Tested-by: Niklas Cassel Signed-off-by: Viresh Kumar

OPP: Don't remove dynamic OPPs from _dev_pm_opp_remove_table()

2018-09-19T21:56:45+00:00

Only one platform was depending on this feature and it is already updated now. Stop removing dynamic OPPs from _dev_pm_opp_remove_table(). This simplifies lot of paths and removes unnecessary parameters. Tested-by: Niklas Cassel Signed-off-by: Viresh Kumar

OPP: Create separate kref for static OPPs list

2018-09-19T21:56:43+00:00

The static OPPs don't always get freed with the OPP table, it can happen before that as well. For example, if the OPP table is first created using helpers like dev_pm_opp_set_supported_hw() and the OPPs are created at a later point. Now when the OPPs are removed, the OPP table stays until the time dev_pm_opp_put_supported_hw() is called. Later patches will streamline the freeing of OPP table and that requires the static OPPs to get freed with help of a separate kernel reference. This patch prepares for that by creating a separate kref for static OPPs list. Tested-by: Niklas Cassel Signed-off-by: Viresh Kumar

OPP: Parse OPP table's DT properties from _of_init_opp_table()

2018-09-19T21:56:42+00:00

Parse the DT properties present in the OPP table from _of_init_opp_table(), which is a dedicated routine for DT parsing. Minor relocation of helpers is required for this. It is possible now for _managed_opp() to return a partially initialized OPP table if the OPP table is created via the helpers like dev_pm_opp_set_supported_hw() and we need another flag to indicate if the static OPP are already parsed or not to make sure we don't incorrectly skip initializing the static OPPs. Tested-by: Niklas Cassel Signed-off-by: Viresh Kumar

OPP: Pass index to _of_init_opp_table()

2018-09-19T21:56:41+00:00

This is a preparatory patch required for the next commit which will start using OPP table's node pointer in _of_init_opp_table(), which requires the index in order to read the OPP table's phandle. This commit adds the index argument in the call chains in order to get it delivered to _of_init_opp_table(). Tested-by: Niklas Cassel Signed-off-by: Viresh Kumar

OPP: Protect dev_list with opp_table lock

2018-09-19T21:56:40+00:00

The dev_list needs to be protected with a lock, else we may have simultaneous access (addition/removal) to it and that would be racy. Extend scope of the opp_table lock to protect dev_list as well. Tested-by: Niklas Cassel Signed-off-by: Viresh Kumar

OPP: Don't try to remove all OPP tables on failure

2018-09-19T21:56:40+00:00

dev_pm_opp_of_cpumask_add_table() creates the OPP table for all CPUs present in the cpumask and on errors it should revert all changes it has done. It actually is doing a bit more than that. On errors, it tries to free all the OPP tables, even the one it hasn't created yet. This may also end up freeing the OPP tables which were created from separate path, like dev_pm_opp_set_supported_hw(). Reported-and-tested-by: Niklas Cassel Signed-off-by: Viresh Kumar

PM / OPP: Remove dev_pm_opp_{un}register_get_pstate_helper()

2018-05-09T04:45:21+00:00

These helpers aren't used anymore, remove them. Signed-off-by: Viresh Kumar Reviewed-by: Ulf Hansson

PM / OPP: Implement of_dev_pm_opp_find_required_opp()

2018-05-09T04:45:19+00:00

A device's DT node or its OPP nodes can contain a phandle to other device's OPP node, in the "required-opps" property. This patch implements a routine to find that required OPP from the node that contains the "required-opps" property. Signed-off-by: Viresh Kumar Reviewed-by: Ulf Hansson