From 49e62e0d96baf7236615e4ec2878d8db229de9c2 Mon Sep 17 00:00:00 2001 From: Maxime Ripard Date: Wed, 26 Oct 2022 15:46:59 +0200 Subject: clk: Add trace events for rate requests It is currently fairly difficult to follow what clk_rate_request are issued, and how they have been modified once done. Indeed, there's multiple paths that can be taken, some functions are recursive and will just forward the request to its parent, etc. Adding a lot of debug prints is just not very convenient, so let's add trace events for the clock requests, one before they are submitted and one after they are returned. That way we can simply toggle the tracing on without modifying the kernel code and without affecting performances or the kernel logs too much. Reviewed-by: Steven Rostedt (Google) Signed-off-by: Maxime Ripard Link: https://lore.kernel.org/r/20221018-clk-rate-request-tracing-v2-2-5170b363c413@cerno.tech Signed-off-by: Stephen Boyd --- drivers/clk/clk.c | 31 +++++++++++++++++++++++++++++++ 1 file changed, 31 insertions(+) (limited to 'drivers/clk/clk.c') diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c index 042e32acce0b..f0288499866a 100644 --- a/drivers/clk/clk.c +++ b/drivers/clk/clk.c @@ -603,10 +603,15 @@ int clk_mux_determine_rate_flags(struct clk_hw *hw, } clk_core_forward_rate_req(core, req, parent, &parent_req, req->rate); + + trace_clk_rate_request_start(&parent_req); + ret = clk_core_round_rate_nolock(parent, &parent_req); if (ret) return ret; + trace_clk_rate_request_done(&parent_req); + best = parent_req.rate; } else if (parent) { best = clk_core_get_rate_nolock(parent); @@ -630,10 +635,15 @@ int clk_mux_determine_rate_flags(struct clk_hw *hw, struct clk_rate_request parent_req; clk_core_forward_rate_req(core, req, parent, &parent_req, req->rate); + + trace_clk_rate_request_start(&parent_req); + ret = clk_core_round_rate_nolock(parent, &parent_req); if (ret) continue; + trace_clk_rate_request_done(&parent_req); + parent_rate = parent_req.rate; } else { parent_rate = clk_core_get_rate_nolock(parent); @@ -1547,10 +1557,15 @@ static int clk_core_round_rate_nolock(struct clk_core *core, struct clk_rate_request parent_req; clk_core_forward_rate_req(core, req, core->parent, &parent_req, req->rate); + + trace_clk_rate_request_start(&parent_req); + ret = clk_core_round_rate_nolock(core->parent, &parent_req); if (ret) return ret; + trace_clk_rate_request_done(&parent_req); + req->best_parent_rate = parent_req.rate; req->rate = parent_req.rate; @@ -1601,10 +1616,14 @@ unsigned long clk_hw_round_rate(struct clk_hw *hw, unsigned long rate) clk_core_init_rate_req(hw->core, &req, rate); + trace_clk_rate_request_start(&req); + ret = clk_core_round_rate_nolock(hw->core, &req); if (ret) return 0; + trace_clk_rate_request_done(&req); + return req.rate; } EXPORT_SYMBOL_GPL(clk_hw_round_rate); @@ -1633,8 +1652,12 @@ long clk_round_rate(struct clk *clk, unsigned long rate) clk_core_init_rate_req(clk->core, &req, rate); + trace_clk_rate_request_start(&req); + ret = clk_core_round_rate_nolock(clk->core, &req); + trace_clk_rate_request_done(&req); + if (clk->exclusive_count) clk_core_rate_protect(clk->core); @@ -2126,10 +2149,14 @@ static struct clk_core *clk_calc_new_rates(struct clk_core *core, clk_core_init_rate_req(core, &req, rate); + trace_clk_rate_request_start(&req); + ret = clk_core_determine_round_nolock(core, &req); if (ret < 0) return NULL; + trace_clk_rate_request_done(&req); + best_parent_rate = req.best_parent_rate; new_rate = req.rate; parent = req.best_parent_hw ? req.best_parent_hw->core : NULL; @@ -2325,8 +2352,12 @@ static unsigned long clk_core_req_round_rate_nolock(struct clk_core *core, clk_core_init_rate_req(core, &req, req_rate); + trace_clk_rate_request_start(&req); + ret = clk_core_round_rate_nolock(core, &req); + trace_clk_rate_request_done(&req); + /* restore the protection */ clk_core_rate_restore_protect(core, cnt); -- cgit