From patchwork Fri Jun 27 07:57:52 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tomeu Vizoso X-Patchwork-Id: 4433811 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork1.web.kernel.org (Postfix) with ESMTP id 731049F73E for ; Fri, 27 Jun 2014 08:01:28 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 678ED20351 for ; Fri, 27 Jun 2014 08:01:27 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.9]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 4D9E02038F for ; Fri, 27 Jun 2014 08:01:26 +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 1X0R4Q-00031K-Se; Fri, 27 Jun 2014 07:59:42 +0000 Received: from mail-wi0-x233.google.com ([2a00:1450:400c:c05::233]) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1X0R3b-00028x-Vl for linux-arm-kernel@lists.infradead.org; Fri, 27 Jun 2014 07:59:02 +0000 Received: by mail-wi0-f179.google.com with SMTP id cc10so2336991wib.6 for ; Fri, 27 Jun 2014 00:58:31 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=sender:from:to:cc:subject:date:message-id:in-reply-to:references; bh=4qEMpezCXlIskZgWAC/ZhNHYfBeXbdkyNRdxXymzRQQ=; b=ZL6ILkKEBqOQJTFjf6+ZfuY/ACitX+4XwE7lcoRxnpAAkGqBrNzjB5Wv0hLj+ilRD9 cSIEnz8cBmjUsIBmEwrLLyZyPUAp9WnUCTHkmqOY+/6hyUNqcPGBaSkJjtvqD54hNcEw uAGwCYk9AJ6LcwbqVCeqHWyTaWTwedD+jBKfwlD+uDrcC5MWN3oZc9rKnr/eq3WXAgQc N7gedmzSOmqInZMYbKWJvzcCPHup4UN4buniGwwnUO3jqnc9ehnVXHOTYlaJbz3dWch4 RFgPMJpdAJ+hGdn9Ck9U15Zj1qIchuEdFwq6/XahxA2aCT2xFq1jbfMA3En0QgthjekN e6vg== X-Received: by 10.194.63.196 with SMTP id i4mr24309179wjs.50.1403855911591; Fri, 27 Jun 2014 00:58:31 -0700 (PDT) Received: from localhost.localdomain (37-48-33-191.tmcz.cz. [37.48.33.191]) by mx.google.com with ESMTPSA id cj8sm19723648wjb.5.2014.06.27.00.58.29 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 27 Jun 2014 00:58:30 -0700 (PDT) From: Tomeu Vizoso To: Stephen Warren , Thierry Reding , Mike Turquette , Rabin Vincent , linux-tegra@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: [RFC 5/5] clk: Add floor and ceiling constraints to clock rates Date: Fri, 27 Jun 2014 09:57:52 +0200 Message-Id: <1403855872-14749-6-git-send-email-tomeu.vizoso@collabora.com> X-Mailer: git-send-email 1.9.3 In-Reply-To: <1403855872-14749-1-git-send-email-tomeu.vizoso@collabora.com> References: <1403855872-14749-1-git-send-email-tomeu.vizoso@collabora.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20140627_005852_395010_1AFC60E5 X-CRM114-Status: GOOD ( 20.06 ) X-Spam-Score: -0.7 (/) Cc: Tomeu Vizoso X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.18-1 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Spam-Status: No, score=-1.8 required=5.0 tests=BAYES_00,DKIM_SIGNED, T_DKIM_INVALID, T_RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=no version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Adds a way for clock consumers to set maximum and minimum rates. This can be used for thermal drivers to set ceiling rates, or by misc. drivers to set floor rates to assure a minimum performance level. Signed-off-by: Tomeu Vizoso --- drivers/clk/clk.c | 105 ++++++++++++++++++++++++++++++++++++++++++++ drivers/clk/clk.h | 1 + drivers/clk/clkdev.c | 7 +-- include/linux/clk-private.h | 1 + include/linux/clk.h | 18 ++++++++ 5 files changed, 126 insertions(+), 6 deletions(-) diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c index 7fc1937..4d93066 100644 --- a/drivers/clk/clk.c +++ b/drivers/clk/clk.c @@ -23,6 +23,19 @@ #include "clk.h" +enum constraint_type { + CONSTRAINT_FLOOR, + CONSTRAINT_CEILING, +}; + +struct rate_constraint { + struct hlist_node node; + const char *dev_id; + const char *con_id; + enum constraint_type type; + unsigned long rate; +}; + static DEFINE_SPINLOCK(enable_lock); static DEFINE_MUTEX(prepare_lock); @@ -1624,6 +1637,7 @@ static void clk_change_rate(struct clk_core *clk) int __clk_set_rate_internal(struct clk_core *clk, unsigned long rate) { struct clk_core *top, *fail_clk; + struct rate_constraint *constraint; int ret = 0; if (!clk) @@ -1632,6 +1646,17 @@ int __clk_set_rate_internal(struct clk_core *clk, unsigned long rate) /* prevent racing with updates to the clock topology */ clk_prepare_lock(); + hlist_for_each_entry(constraint, &clk->rate_constraints, node) { + switch(constraint->type) { + case CONSTRAINT_FLOOR: + rate = max(rate, constraint->rate); + break; + case CONSTRAINT_CEILING: + rate = min(rate, constraint->rate); + break; + } + } + /* bail early if nothing to do */ if (rate == __clk_get_rate_internal(clk)) goto out; @@ -1695,6 +1720,67 @@ int clk_set_rate(struct clk *clk_user, unsigned long rate) } EXPORT_SYMBOL_GPL(clk_set_rate); +static struct rate_constraint *__ensure_constraint(struct clk *clk_user, + enum constraint_type type) +{ + struct clk_core *clk = clk_to_clk_core(clk_user); + struct rate_constraint *constraint = NULL; + bool found = false; + + hlist_for_each_entry(constraint, &clk->rate_constraints, node) { + if (constraint->dev_id == clk_user->dev_id && + constraint->con_id == clk_user->con_id && + constraint->type == type) + found = true; + } + + if (!found) { + constraint = kzalloc(sizeof(*constraint), GFP_KERNEL); + if (!constraint) { + pr_err("%s: could not allocate constraint\n", __func__); + return NULL; + } + hlist_add_head(&constraint->node, &clk->rate_constraints); + } + + return constraint; +} + +static int __clk_set_constraint(struct clk *clk_user, unsigned long rate, + enum constraint_type type) +{ + struct clk_core *clk = clk_to_clk_core(clk_user); + struct rate_constraint *constraint; + int ret; + + clk_prepare_lock(); + + constraint = __ensure_constraint(clk_user, type); + if (!constraint) + return -ENOMEM; + + constraint->rate = rate; + + /* Update the rate so the new constraint is taken into account */ + ret = __clk_set_rate_internal(clk, __clk_get_rate_internal(clk)); + + clk_prepare_unlock(); + + return ret; +} + +int clk_set_floor_rate(struct clk *clk_user, unsigned long rate) +{ + return __clk_set_constraint(clk_user, rate, CONSTRAINT_FLOOR); +} +EXPORT_SYMBOL_GPL(clk_set_floor_rate); + +int clk_set_ceiling_rate(struct clk *clk_user, unsigned long rate) +{ + return __clk_set_constraint(clk_user, rate, CONSTRAINT_CEILING); +} +EXPORT_SYMBOL_GPL(clk_set_ceiling_rate); + struct clk_core *__clk_get_parent_internal(struct clk_core *clk) { struct clk_core *parent; @@ -2028,6 +2114,8 @@ int __clk_init(struct device *dev, struct clk_core *clk) } } + INIT_HLIST_HEAD(&clk->rate_constraints); + /* * optional platform-specific magic * @@ -2458,6 +2546,23 @@ int clk_notifier_unregister(struct clk *clk_user, struct notifier_block *nb) } EXPORT_SYMBOL_GPL(clk_notifier_unregister); +void __clk_free_clk(struct clk *clk_user) +{ + struct clk_core *clk = clk_to_clk_core(clk_user); + struct rate_constraint *constraint; + struct hlist_node *tmp; + + hlist_for_each_entry_safe(constraint, tmp, &clk->rate_constraints, node) { + if (constraint->dev_id == clk_user->dev_id && + constraint->con_id == clk_user->con_id) { + hlist_del(&constraint->node); + kfree(constraint); + } + } + + kfree(clk); +} + #ifdef CONFIG_OF /** * struct of_clk_provider - Clock provider registration structure diff --git a/drivers/clk/clk.h b/drivers/clk/clk.h index 2f682bf..ea84797 100644 --- a/drivers/clk/clk.h +++ b/drivers/clk/clk.h @@ -18,4 +18,5 @@ void of_clk_unlock(void); #if defined(CONFIG_COMMON_CLK) struct clk_core *clk_to_clk_core(struct clk *clk); +void __clk_free_clk(struct clk *clk_user); #endif diff --git a/drivers/clk/clkdev.c b/drivers/clk/clkdev.c index bf1a2d7..88448b7 100644 --- a/drivers/clk/clkdev.c +++ b/drivers/clk/clkdev.c @@ -230,16 +230,11 @@ struct clk *clk_get(struct device *dev, const char *con_id) } EXPORT_SYMBOL(clk_get); -static void clk_free_clk(struct clk *clk) -{ - kfree(clk); -} - void clk_put(struct clk *clk) { clk_core_t *core = clk_to_clk_core(clk); - clk_free_clk(clk); + __clk_free_clk(clk); __clk_put(core); } EXPORT_SYMBOL(clk_put); diff --git a/include/linux/clk-private.h b/include/linux/clk-private.h index 9657fc8..a8279e1 100644 --- a/include/linux/clk-private.h +++ b/include/linux/clk-private.h @@ -48,6 +48,7 @@ struct clk_core { unsigned long accuracy; struct hlist_head children; struct hlist_node child_node; + struct hlist_head rate_constraints; unsigned int notifier_count; #ifdef CONFIG_DEBUG_FS struct dentry *dentry; diff --git a/include/linux/clk.h b/include/linux/clk.h index b8938e4..d6234bd 100644 --- a/include/linux/clk.h +++ b/include/linux/clk.h @@ -274,6 +274,24 @@ long clk_round_rate(struct clk *clk, unsigned long rate); int clk_set_rate(struct clk *clk, unsigned long rate); /** + * clk_set_floor_rate - set a minimum clock rate for a clock source + * @clk: clock source + * @rate: desired minimum clock rate in Hz + * + * Returns success (0) or negative errno. + */ +int clk_set_floor_rate(struct clk *clk, unsigned long rate); + +/** + * clk_set_ceiling_rate - set a maximum clock rate for a clock source + * @clk: clock source + * @rate: desired maximum clock rate in Hz + * + * Returns success (0) or negative errno. + */ +int clk_set_ceiling_rate(struct clk *clk, unsigned long rate); + +/** * clk_set_parent - set the parent clock source for this clock * @clk: clock source * @parent: parent clock source