From patchwork Thu Jul 16 19:31:14 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stephen Boyd X-Patchwork-Id: 6810721 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork2.web.kernel.org (Postfix) with ESMTP id C0D41C05AC for ; Thu, 16 Jul 2015 19:34:06 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id BC58B2066E for ; Thu, 16 Jul 2015 19:34:05 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.9]) (using TLSv1.2 with cipher AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id BEE4320668 for ; Thu, 16 Jul 2015 19:34:04 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1ZFose-0008MW-DT; Thu, 16 Jul 2015 19:31:40 +0000 Received: from smtp.codeaurora.org ([198.145.29.96]) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1ZFosb-0008Ir-3c for linux-arm-kernel@lists.infradead.org; Thu, 16 Jul 2015 19:31:37 +0000 Received: from smtp.codeaurora.org (localhost [127.0.0.1]) by smtp.codeaurora.org (Postfix) with ESMTP id B912E141D9E; Thu, 16 Jul 2015 19:31:15 +0000 (UTC) Received: by smtp.codeaurora.org (Postfix, from userid 486) id A746F141EFD; Thu, 16 Jul 2015 19:31:15 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Spam-Level: X-Spam-Status: No, score=-5.5 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_MED, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 Received: from localhost (i-global254.qualcomm.com [199.106.103.254]) (using TLSv1.2 with cipher DHE-RSA-AES128-SHA (128/128 bits)) (No client certificate requested) (Authenticated sender: sboyd@smtp.codeaurora.org) by smtp.codeaurora.org (Postfix) with ESMTPSA id 0F4EF141D9E; Thu, 16 Jul 2015 19:31:14 +0000 (UTC) Date: Thu, 16 Jul 2015 12:31:14 -0700 From: Stephen Boyd To: Sudeep Holla Subject: Re: [PATCH v4 3/8] clk: add support for clocks provided by SCP(System Control Processor) Message-ID: <20150716193114.GA17952@codeaurora.org> References: <1433760002-24120-1-git-send-email-sudeep.holla@arm.com> <1433760002-24120-4-git-send-email-sudeep.holla@arm.com> <20150702172310.GF4301@codeaurora.org> <5596A1B6.8020307@arm.com> <559ADC94.4080505@codeaurora.org> <559BF858.1020301@arm.com> <20150708014606.GH30412@codeaurora.org> <55A7D79B.3080305@arm.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <55A7D79B.3080305@arm.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-Virus-Scanned: ClamAV using ClamSMTP X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20150716_123137_195673_834BC48E X-CRM114-Status: GOOD ( 33.19 ) X-Spam-Score: -3.2 (---) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: "Jon Medhurst \(Tixy\)" , Lorenzo Pieralisi , Arnd Bergmann , "linux-pm@vger.kernel.org" , Mike Turquette , Kevin Hilman , Liviu Dudau , "linux-kernel@vger.kernel.org" , Olof Johansson , "linux-clk@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Virus-Scanned: ClamAV using ClamSMTP On 07/16, Sudeep Holla wrote: > On 08/07/15 02:46, Stephen Boyd wrote: > > > >Yes struct clk would have min/max, and struct clk_core would have > >min/max. Then some sort of provider API (or possibly even > >clk_init_data) would take the min/max fields and copy them over > >to struct clk_core. Then during set_rate operations we would > >aggregate the constraints from struct clk like we already do and > >add in the constrains in struct clk_core. > > > >One downside to adding new fields to clk_init_data is that there > >are drivers out there that aren't initializing that structure to > >0, and they're putting it on the stack, so stack junk can come > >through. Furthermore, min/max would mean that every driver needs > >to specify some large number for max or we have to special case > >min == max == 0 and ignore it. Somehow it needs to be opt-in. If > >we want to go down the clk_init_data route then perhaps we need > >some sort of rate_constraint struct pointer in there that drivers > >can optionally setup. > > > > struct clk_rate_constraint { > > unsigned long min; > > unsigned long max; > > }; > > > > struct clk_init_data { > > ... > > struct clk_rate_constraint *rate_constraint; > > }; > > > >I haven't thought it through completely, but I can probably write > >up some patch tomorrow after I sleep on it. > > > > I am hoping to get this series for v4.3. In order to avoid using > consumer API, I can revert back to the min,max check I had in the > round_rate earlier if that's fine with you ? Let me know so that I can > post the next version based on that. All the other comments are already > addressed. Ok. I'm fine with the consumer API being used, but it would be nice if we didn't have to do so. Try out the patch below, hopefully it's good enough for your purposes. It may need to be more robust, and we may still want to use the init_data structure to avoid races with providers and consumers, but we can leave that for later after sweeping all the structure users. > > Also since this series depends on SCPI, I was thinking to get it merged > via ARM-SoC, but that might conflict with the round_rate prototype > change. Do do plan to share a stable base with arm-soc guys or you > expect all the changes to be contained in clk tree ? > We can share a stable branch for the determine_rate change with arm-soc. We already have it on a separate branch but haven't published it so far because nobody has asked. Signed-off-by: Stephen Boyd -----8<------ diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c index a1d34a2ed9c6..8760b743bb70 100644 --- a/drivers/clk/clk.c +++ b/drivers/clk/clk.c @@ -58,6 +58,8 @@ struct clk_core { unsigned long flags; unsigned int enable_count; unsigned int prepare_count; + unsigned long min_rate; + unsigned long max_rate; unsigned long accuracy; int phase; struct hlist_head children; @@ -512,8 +514,8 @@ static void clk_core_get_boundaries(struct clk_core *core, { struct clk *clk_user; - *min_rate = 0; - *max_rate = ULONG_MAX; + *min_rate = core->min_rate; + *max_rate = core->max_rate; hlist_for_each_entry(clk_user, &core->clks, clks_node) *min_rate = max(*min_rate, clk_user->min_rate); @@ -522,6 +524,13 @@ static void clk_core_get_boundaries(struct clk_core *core, *max_rate = min(*max_rate, clk_user->max_rate); } +void clk_hw_set_rate_range(struct clk_hw *hw, unsigned long min_rate, + unsigned long max_rate) +{ + hw->core->min_rate = min_rate; + hw->core->max_rate = max_rate; +} + /* * Helper for finding best parent to provide a given frequency. This can be used * directly as a determine_rate callback (e.g. for a mux), or from a more @@ -2496,6 +2505,8 @@ struct clk *clk_register(struct device *dev, struct clk_hw *hw) core->hw = hw; core->flags = hw->init->flags; core->num_parents = hw->init->num_parents; + core->min_rate = 0; + core->max_rate = ULONG_MAX; hw->core = core; /* allocate local copy in case parent_names is __initdata */ diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h index 2116e2b8a5f2..d62e7eab1dbe 100644 --- a/include/linux/clk-provider.h +++ b/include/linux/clk-provider.h @@ -619,6 +619,8 @@ int __clk_determine_rate(struct clk_hw *core, struct clk_rate_request *req); int __clk_mux_determine_rate_closest(struct clk_hw *hw, struct clk_rate_request *req); void clk_hw_reparent(struct clk_hw *hw, struct clk_hw *new_parent); +void clk_hw_set_rate_range(struct clk_hw *hw, unsigned long min_rate, + unsigned long max_rate); static inline void __clk_hw_set_clk(struct clk_hw *dst, struct clk_hw *src) {