linux-stable.git/drivers/opp/core.c, branch v6.14

PM / OPP: Add reference counting helpers for Rust implementation

2025-01-20T03:35:51+00:00

To ensure that resources such as OPP tables or OPP nodes are not freed
while in use by the Rust implementation, it is necessary to increment
their reference count from Rust code.

This commit introduces a new helper function,
dev_pm_opp_get_opp_table_ref(), to increment the reference count of an
OPP table and declares the existing helper dev_pm_opp_get() in pm_opp.h.

Signed-off-by: Viresh Kumar

OPP: fix dev_pm_opp_find_bw_*() when bandwidth table not initialized

2024-12-23T10:57:24+00:00

If a driver calls dev_pm_opp_find_bw_ceil/floor() the retrieve bandwidth
from the OPP table but the bandwidth table was not created because the
interconnect properties were missing in the OPP consumer node, the
kernel will crash with:

Unable to handle kernel NULL pointer dereference at virtual address 0000000000000004
...
pc : _read_bw+0x8/0x10
lr : _opp_table_find_key+0x9c/0x174
...
Call trace:
  _read_bw+0x8/0x10 (P)
  _opp_table_find_key+0x9c/0x174 (L)
  _find_key+0x98/0x168
  dev_pm_opp_find_bw_ceil+0x50/0x88
...

In order to fix the crash, create an assert function to check
if the bandwidth table was created before trying to get a
bandwidth with _read_bw().

Fixes: add1dc094a74 ("OPP: Use generic key finding helpers for bandwidth key")
Signed-off-by: Neil Armstrong 
Signed-off-by: Viresh Kumar

OPP: add index check to assert to avoid buffer overflow in _read_freq()

2024-12-23T10:57:23+00:00

Pass the freq index to the assert function to make sure
we do not read a freq out of the opp->rates[] table when called
from the indexed variants:
dev_pm_opp_find_freq_exact_indexed() or
dev_pm_opp_find_freq_ceil/floor_indexed().

Add a secondary parameter to the assert function, unused
for assert_single_clk() then add assert_clk_index() which
will check for the clock index when called from the _indexed()
find functions.

Fixes: 142e17c1c2b4 ("OPP: Introduce dev_pm_opp_find_freq_{ceil/floor}_indexed() APIs")
Fixes: a5893928bb17 ("OPP: Add dev_pm_opp_find_freq_exact_indexed()")
Signed-off-by: Neil Armstrong 
Signed-off-by: Viresh Kumar

opp: core: Fix off by one in dev_pm_opp_get_bw()

2024-12-23T10:57:23+00:00

The "opp->bandwidth" array has "opp->opp_table->path_count" number of
elements.  It's allocated in _opp_allocate().  So this > needs to be >=
to prevent an out of bounds access.

Fixes: d78653dcd8bf ("opp: core: implement dev_pm_opp_get_bw")
Signed-off-by: Dan Carpenter 
Signed-off-by: Viresh Kumar

opp: core: implement dev_pm_opp_get_bw

2024-12-23T10:57:22+00:00

Add and implement dev_pm_opp_get_bw() to retrieve the OPP's
bandwidth in the same way as the dev_pm_opp_get_voltage() helper.

Retrieving bandwidth is required in the case of the Adreno GPU
where the GPU Management Unit can handle the Bandwidth scaling.

The helper can get the peak or average bandwidth for any of
the interconnect path.

Signed-off-by: Neil Armstrong 
[ Viresh: Fixed commit log and a comment in code ]
Signed-off-by: Viresh Kumar

OPP: Drop redundant *_opp_attach|detach_genpd()

2024-10-10T12:24:30+00:00

All users of *_opp_attach|detach_genpd(), have been converted to use
dev|devm_pm_domain_attach|detach_list(), hence let's drop it along with its
corresponding exported functions.

Acked-by: Viresh Kumar 
Signed-off-by: Ulf Hansson 
Link: https://lore.kernel.org/r/20241002122232.194245-12-ulf.hansson@linaro.org

OPP: Rework _set_required_devs() to manage a single device per call

2024-10-10T12:11:41+00:00

At this point there are no consumer drivers that makes use of
_set_required_devs(), hence it should be straightforward to rework the code
to enable it to better integrate with the PM domain attach procedure.

During attach, one device at the time is being hooked up to its
corresponding PM domain. Therefore, let's update the _set_required_devs()
to align to this behaviour, allowing callers to fill out one required_dev
per call. Subsequent changes starts making use of this.

Signed-off-by: Ulf Hansson 
Acked-by: Viresh Kumar 
Link: https://lore.kernel.org/r/20241002122232.194245-4-ulf.hansson@linaro.org

OPP: fix error code in dev_pm_opp_set_config()

2024-10-01T23:27:50+00:00

This is an error path so set the error code.  Smatch complains about the
current code:

    drivers/opp/core.c:2660 dev_pm_opp_set_config()
    error: uninitialized symbol 'ret'.

Fixes: e37440e7e2c2 ("OPP: Call dev_pm_opp_set_opp() for required OPPs")
Signed-off-by: Dan Carpenter 
Acked-by: Viresh Kumar 
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/3f3660af-4ea0-4a89-b3b7-58de7b16d7a5@stanley.mountain
Signed-off-by: Ulf Hansson

OPP: Fix support for required OPPs for multiple PM domains

2024-08-23T09:57:44+00:00

It has turned out that having _set_required_opps() to recursively call
dev_pm_opp_set_opp() to set the required OPPs, doesn't really work as well
as we expected.

More precisely, at each recursive call to dev_pm_opp_set_opp() we are
changing an OPP for a required_dev that belongs to a required-OPP table.
The problem with this, is that we may have several devices sharing the same
required-OPP table, which leads to an incorrect behaviour in regards to
aggregating the per device votes.

To fix the problem for a required-OPP table belonging to a PM domain, which
is the only existing usecase for now, let's simply replace the call to
dev_pm_opp_set_opp() in _set_required_opps() by a call to _set_opp_level().

Moving forward we may potentially need to add support for other types of
required-OPP tables. In this case, the aggregation needs to be thought of.

Fixes: e37440e7e2c2 ("OPP: Call dev_pm_opp_set_opp() for required OPPs")
Cc: stable@vger.kernel.org
Signed-off-by: Ulf Hansson 
Acked-by: Viresh Kumar 
Link: https://lore.kernel.org/r/20240822224547.385095-2-ulf.hansson@linaro.org

OPP: Drop a redundant in-parameter to _set_opp_level()

2024-06-25T11:27:41+00:00

The in-parameter "opp_table" isn't needed by _set_opp_level(). Let's
therefore drop it.

Signed-off-by: Ulf Hansson 
Signed-off-by: Viresh Kumar