From 8cd9c39dce5b54494f967235f7eeac7c30c08b97 Mon Sep 17 00:00:00 2001 From: Maxime Ripard Date: Tue, 16 Aug 2022 13:25:20 +0200 Subject: 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 # imx8mp Tested-by: Marek Szyprowski # exynos4210, meson g12b Signed-off-by: Maxime Ripard Link: https://lore.kernel.org/r/20220816112530.1837489-16-maxime@cerno.tech Tested-by: Linux Kernel Functional Testing Tested-by: Naresh Kamboju Signed-off-by: Stephen Boyd --- drivers/clk/clk.c | 8 +++----- 1 file changed, 3 insertions(+), 5 deletions(-) (limited to 'drivers/clk/clk.c') 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); -- cgit