From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tero Kristo Subject: Re: [PATCH v5] clk: change clk_ops' ->determine_rate() prototype Date: Mon, 13 Jul 2015 12:01:05 +0300 Message-ID: <55A37E51.7080803@ti.com> References: <1436294888-25752-1-git-send-email-boris.brezillon@free-electrons.com> <20150708005748.GG30412@codeaurora.org> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <20150708005748.GG30412@codeaurora.org> Sender: linux-mips-bounce@linux-mips.org Errors-to: linux-mips-bounce@linux-mips.org List-help: List-unsubscribe: List-software: Ecartis version 1.0.0 List-subscribe: List-owner: List-post: List-archive: To: Stephen Boyd , Boris Brezillon Cc: Mike Turquette , linux-clk@vger.kernel.org, Jonathan Corbet , Tony Lindgren , Ralf Baechle , =?windows-1252?Q?Emilio_L=F3pez?= , Maxime Ripard , Peter De Schrijver , Prashant Gaikwad , Stephen Warren , Thierry Reding , Alexandre Courbot , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-omap@vger.kernel.org, linux-mips@linux-mips.org, linux-tegra@vger.kernel.org List-Id: linux-omap@vger.kernel.org On 07/08/2015 03:57 AM, Stephen Boyd wrote: > On 07/07, Boris Brezillon wrote: >> Clock rates are stored in an unsigned long field, but ->determine_ra= te() >> (which returns a rounded rate from a requested one) returns a long >> value (errors are reported using negative error codes), which can le= ad >> to long overflow if the clock rate exceed 2Ghz. >> >> Change ->determine_rate() prototype to return 0 or an error code, an= d pass >> a pointer to a clk_rate_request structure containing the expected ta= rget >> rate and the rate constraints imposed by clk users. >> >> The clk_rate_request structure might be extended in the future to co= ntain >> other kind of constraints like the rounding policy, the maximum cloc= k >> inaccuracy or other things that are not yet supported by the CCF >> (power consumption constraints ?). >> >> Signed-off-by: Boris Brezillon >> >> CC: Jonathan Corbet >> CC: Tony Lindgren >> CC: Ralf Baechle >> CC: "Emilio L=F3pez" >> CC: Maxime Ripard >> CC: Tero Kristo >> CC: Peter De Schrijver >> CC: Prashant Gaikwad >> CC: Stephen Warren >> CC: Thierry Reding >> CC: Alexandre Courbot >> CC: linux-doc@vger.kernel.org >> CC: linux-kernel@vger.kernel.org >> CC: linux-arm-kernel@lists.infradead.org >> CC: linux-omap@vger.kernel.org >> CC: linux-mips@linux-mips.org >> CC: linux-tegra@vger.kernel.org >> >> --- > > I'll throw this patch into -next now to see if any other problems > shake out. I'm hoping we get some more acks though, so it'll be > on it's own branch and become immutable in a week or so. One > question below. Gave this patch a quick test on the boards I have access to, and didn't= =20 notice any obvious problems. So, for the TI parts: Acked-by: Tero Kristo > >> diff --git a/drivers/clk/clk-composite.c b/drivers/clk/clk-composite= =2Ec >> index 616f5ae..9e69f34 100644 >> --- a/drivers/clk/clk-composite.c >> +++ b/drivers/clk/clk-composite.c >> @@ -99,33 +99,33 @@ static long clk_composite_determine_rate(struct = clk_hw *hw, unsigned long rate, >> >> parent_rate =3D __clk_get_rate(parent); >> >> - tmp_rate =3D rate_ops->round_rate(rate_hw, rate, >> + tmp_rate =3D rate_ops->round_rate(rate_hw, req->rate, >> &parent_rate); >> if (tmp_rate < 0) >> continue; >> >> - rate_diff =3D abs(rate - tmp_rate); >> + rate_diff =3D abs(req->rate - tmp_rate); >> >> - if (!rate_diff || !*best_parent_p >> + if (!rate_diff || !req->best_parent_hw >> || best_rate_diff > rate_diff) { >> - *best_parent_p =3D __clk_get_hw(parent); >> - *best_parent_rate =3D parent_rate; >> + req->best_parent_hw =3D __clk_get_hw(parent); >> + req->best_parent_rate =3D parent_rate; >> best_rate_diff =3D rate_diff; >> best_rate =3D tmp_rate; >> } >> >> if (!rate_diff) >> - return rate; >> + return 0; >> } >> >> - return best_rate; >> + req->rate =3D best_rate; >> + return 0; >> } else if (mux_hw && mux_ops && mux_ops->determine_rate) { >> __clk_hw_set_clk(mux_hw, hw); >> - return mux_ops->determine_rate(mux_hw, rate, min_rate, >> - max_rate, best_parent_rate, >> - best_parent_p); >> + return mux_ops->determine_rate(mux_hw, req); >> } else { >> pr_err("clk: clk_composite_determine_rate function called, but n= o mux or rate callback set!\n"); >> + req->rate =3D 0; >> return 0; > > Shouldn't this return an error now? And then assigning req->rate > wouldn't be necessary. Sorry I must have missed this last round. >