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author | Maxime Ripard <maxime@cerno.tech> | 2022-08-16 13:25:20 +0200 |
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committer | Stephen Boyd <sboyd@kernel.org> | 2022-09-15 09:31:31 -0700 |
commit | 8cd9c39dce5b54494f967235f7eeac7c30c08b97 (patch) | |
tree | 06c6e8a7bd3a42798b9735df8b5c58fb9599b99d /drivers | |
parent | 718af795d3fd786928506cd5251597fbe29c7fda (diff) | |
download | linux-stable-8cd9c39dce5b54494f967235f7eeac7c30c08b97.tar.gz linux-stable-8cd9c39dce5b54494f967235f7eeac7c30c08b97.tar.bz2 linux-stable-8cd9c39dce5b54494f967235f7eeac7c30c08b97.zip |
clk: Move clk_core_init_rate_req() from clk_core_round_rate_nolock() to its caller
The clk_rate_request structure is used internally as an argument for
the clk_core_determine_round_nolock() and clk_core_round_rate_nolock().
In both cases, the clk_core_init_rate_req() function is used to
initialize the clk_rate_request structure.
However, the expectation on who gets to call that function is
inconsistent between those two functions. Indeed,
clk_core_determine_round_nolock() will assume the structure is properly
initialized and will just use it.
On the other hand, clk_core_round_rate_nolock() will call
clk_core_init_rate_req() itself, expecting the caller to have filled
only a minimal set of parameters (rate, min_rate and max_rate).
If we ignore the calling convention inconsistency, this leads to a
second inconsistency for drivers:
* If they get called by the framework through
clk_core_round_rate_nolock(), the rate, min_rate and max_rate
fields will be filled by the caller, and the best_parent_rate and
best_parent_hw fields will get filled by clk_core_init_rate_req().
* If they get called by a driver through __clk_determine_rate (and
thus clk_core_round_rate_nolock), only best_parent_rate and
best_parent_hw are being explicitly set by the framework. Even
though we can reasonably expect rate to be set, only one of the 6
in-tree users explicitly set min_rate and max_rate.
* If they get called by the framework through
clk_core_determine_round_nolock(), then we have two callpaths.
Either it will be called by clk_core_round_rate_nolock() itself, or
it will be called by clk_calc_new_rates(), which will properly
initialize rate, min_rate, max_rate itself, and best_parent_rate
and best_parent_hw through clk_core_init_rate_req().
Even though the first and third case seems equivalent, they aren't when
the clock has CLK_SET_RATE_PARENT. Indeed, in such a case
clk_core_round_rate_nolock() will call itself on the current parent
clock with the same clk_rate_request structure.
The clk_core_init_rate_req() function will then be called on the parent
clock, with the child clk_rate_request pointer and will fill the
best_parent_rate and best_parent_hw fields with the parent context.
When the whole recursion stops and the call returns, the initial caller
will end up with a clk_rate_request structure with some information of
the child clock (rate, min_rate, max_rate) and some others of the last
clock up the tree whose child had CLK_SET_RATE_PARENT (best_parent_hw,
best_parent_rate).
In the most common case, best_parent_rate is going to be equal on all
the parent clocks so it's not a big deal. However, best_parent_hw is
going to point to a clock that never has been a valid parent for that
clock which is definitely confusing.
In order to fix the calling inconsistency, let's move the
clk_core_init_rate_req() calls to the callers, which will also help a
bit with the clk_core_round_rate_nolock() recursion.
Tested-by: Alexander Stein <alexander.stein@ew.tq-group.com> # imx8mp
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com> # exynos4210, meson g12b
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://lore.kernel.org/r/20220816112530.1837489-16-maxime@cerno.tech
Tested-by: Linux Kernel Functional Testing <lkft@linaro.org>
Tested-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
Diffstat (limited to 'drivers')
-rw-r--r-- | drivers/clk/clk.c | 8 |
1 files changed, 3 insertions, 5 deletions
diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c index 75cfde9f917f..553e1e9eb300 100644 --- a/drivers/clk/clk.c +++ b/drivers/clk/clk.c @@ -1415,8 +1415,6 @@ static int clk_core_round_rate_nolock(struct clk_core *core, return 0; } - clk_core_init_rate_req(core, req, req->rate); - if (clk_core_can_round(core)) return clk_core_determine_round_nolock(core, req); else if (core->flags & CLK_SET_RATE_PARENT) @@ -1464,8 +1462,8 @@ unsigned long clk_hw_round_rate(struct clk_hw *hw, unsigned long rate) int ret; struct clk_rate_request req; + clk_core_init_rate_req(hw->core, &req, rate); clk_core_get_boundaries(hw->core, &req.min_rate, &req.max_rate); - req.rate = rate; ret = clk_core_round_rate_nolock(hw->core, &req); if (ret) @@ -1497,8 +1495,8 @@ long clk_round_rate(struct clk *clk, unsigned long rate) if (clk->exclusive_count) clk_core_rate_unprotect(clk->core); + clk_core_init_rate_req(clk->core, &req, rate); clk_core_get_boundaries(clk->core, &req.min_rate, &req.max_rate); - req.rate = rate; ret = clk_core_round_rate_nolock(clk->core, &req); @@ -2209,8 +2207,8 @@ static unsigned long clk_core_req_round_rate_nolock(struct clk_core *core, if (cnt < 0) return cnt; + clk_core_init_rate_req(core, &req, req_rate); clk_core_get_boundaries(core, &req.min_rate, &req.max_rate); - req.rate = req_rate; ret = clk_core_round_rate_nolock(core, &req); |