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

OPP: Fix parsing of multiple phandles in "operating-points-v2" property

2018-11-23T05:17:21+00:00

We currently return error if more than one phandle is present in the "operating-points-v2" property, which is incorrect. We only want to check the count of phandles here and set index to 0 if only one phandle is present. Fix it. Fixes: 5ed4cecd75e9 ("OPP: Pass OPP table to _of_add_opp_table_v{1|2}()") Signed-off-by: Viresh Kumar

PM / OPP: _of_add_opp_table_v2(): increment count only if OPP is added

2018-10-04T03:51:36+00:00

Currently the _of_add_opp_table_v2 call loops through the OPP nodes in the operating-points-v2 table in the device tree and calls _opp_add_static_v2 for each to add them to the table. It counts each iteration through this loop as an added OPP, however there are cases where _opp_add_static_v2() returns 0 but no new OPP is added to the list. This can happen while adding duplicate OPP or if the OPP isn't supported by hardware. Because of this the count variable will contain the number of OPP nodes in the table in device tree but not necessarily the ones that are actually added. As this count value is what is checked to determine if there are any valid OPPs, if a platform has an operating-points-v2 table with all OPP nodes containing opp-supported-hw values that are not currently supported, then _of_add_opp_table_v2 will fail to abort as it should due to an empty table. Additionally, since commit 3ba98324e81a ("PM / OPP: Get performance state using genpd helper"), the same count variable is compared against the number of OPPs containing performance states and requires that either all or none have pstates set, however in the case of any opp table that has any entries that do not get added by _opp_add_static_v2 due to incompatible opp-supported-hw fields, these numbers will not match and _of_add_opp_table_v2 will incorrectly fail. We need to clearly identify all the three cases (success, failure, unsupported/duplicate OPPs) and then increment count only on success case. Change return type of _opp_add_static_v2() to return the pointer to the newly added OPP instead of an integer. This routine now returns a valid pointer if the OPP is really added, NULL for unsupported or duplicate OPPs, and error value cased as a pointer on errors. Ideally the fixes tag in this commit should point back to the commit that introduced OPP v2 initially, as that's where we started incorrectly accounting for duplicate OPPs: commit 274659029c9d ("PM / OPP: Add support to parse "operating-points-v2" bindings") But it wasn't a real problem until recently as the count was only used to check if any OPPs are added or not. And so this commit points to a rather recent commit where we added more code that depends on the value of "count". Fixes: 3ba98324e81a ("PM / OPP: Get performance state using genpd helper") Reported-by: Dave Gerlach Reported-by: Niklas Cassel Tested-by: Niklas Cassel Signed-off-by: Dave Gerlach Signed-off-by: Viresh Kumar

OPP: Improve error handling in dev_pm_opp_of_cpumask_add_table()

2018-10-04T03:40:56+00:00

The error handling wasn't appropriate in dev_pm_opp_of_cpumask_add_table(). For example it returns 0 on success and also for the case where cpumask is empty or cpu_device wasn't found for any of the CPUs. It should really return error on such cases, so that the callers can be aware of the outcome. Fix it. Signed-off-by: Viresh Kumar

OPP: Pass OPP table to _of_add_opp_table_v{1|2}()

2018-10-01T09:30:34+00:00

Both _of_add_opp_table_v1() and _of_add_opp_table_v2() contain similar code to get the OPP table and their parent routine also parses the DT to find the OPP table's node pointer. This can be simplified by getting the OPP table in advance and then passing it as argument to these routines. Tested-by: Niklas Cassel Signed-off-by: Viresh Kumar

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