From patchwork Fri Aug 9 16:34:05 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Sylwester Nawrocki/Kernel \\(PLT\\) /SRPOL/Staff Engineer/Samsung Electronics" X-Patchwork-Id: 2842019 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 EF06B9F271 for ; Fri, 9 Aug 2013 16:36:08 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 0899B203E9 for ; Fri, 9 Aug 2013 16:36:08 +0000 (UTC) Received: from casper.infradead.org (casper.infradead.org [85.118.1.10]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 9D0CB200DB for ; Fri, 9 Aug 2013 16:36:06 +0000 (UTC) Received: from merlin.infradead.org ([2001:4978:20e::2]) by casper.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1V7pew-0003F1-Mp; Fri, 09 Aug 2013 16:35:26 +0000 Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1V7pef-0002ln-EW; Fri, 09 Aug 2013 16:35:09 +0000 Received: from mailout2.samsung.com ([203.254.224.25]) by merlin.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1V7peO-0002j9-1U for linux-arm-kernel@lists.infradead.org; Fri, 09 Aug 2013 16:34:53 +0000 Received: from epcpsbgm1.samsung.com (epcpsbgm1 [203.254.230.26]) by mailout2.samsung.com (Oracle Communications Messaging Server 7u4-24.01(7.0.4.24.0) 64bit (built Nov 17 2011)) with ESMTP id <0MR9006VYVDC4M20@mailout2.samsung.com> for linux-arm-kernel@lists.infradead.org; Sat, 10 Aug 2013 01:34:27 +0900 (KST) X-AuditID: cbfee61a-b7f196d000007dfa-54-52051a137e41 Received: from epmmp2 ( [203.254.227.17]) by epcpsbgm1.samsung.com (EPCPMTA) with SMTP id 22.9C.32250.31A15025; Sat, 10 Aug 2013 01:34:27 +0900 (KST) Received: from amdc1344.digital.local ([106.116.147.32]) by mmp2.samsung.com (Oracle Communications Messaging Server 7u4-24.01 (7.0.4.24.0) 64bit (built Nov 17 2011)) with ESMTPA id <0MR900KZ8VCXG190@mmp2.samsung.com>; Sat, 10 Aug 2013 01:34:27 +0900 (KST) From: Sylwester Nawrocki To: linux@arm.linux.org.uk, mturquette@linaro.org Subject: [PATCH RFC 1/2] clk: Provide not locked variant of of_clk_get_from_provider() Date: Fri, 09 Aug 2013 18:34:05 +0200 Message-id: <1376066046-16037-2-git-send-email-s.nawrocki@samsung.com> X-Mailer: git-send-email 1.7.9.5 In-reply-to: <1376066046-16037-1-git-send-email-s.nawrocki@samsung.com> References: <1376066046-16037-1-git-send-email-s.nawrocki@samsung.com> X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFprBLMWRmVeSWpSXmKPExsVy+t9jQV1hKdYgg/Y+MYsDf3YwWpxtesNu senxNVaL25d5LZ5OuMhmcXjFASaLw2/aWS3Wz3jN4sDh0dLcw+ax4PMVdo871/aweWxeUu/R t2UVYwBrFJdNSmpOZllqkb5dAlfG3N8tjAX3pSoe3TzH0sC4XayLkZNDQsBE4tzsc0wQtpjE hXvr2boYuTiEBKYzSmybspcVwulgkjj98CBYFZuAoUTv0T5GEFsEyP568i0TSBGzwC5GiRnT 7rOAJIQFIiSaFq5nBrFZBFQlzqz6BxbnFXCTmHJxIdAKDqB1ChJzJtmAhDkF3CWWbb8ONl8I qOT93wcsExh5FzAyrGIUTS1ILihOSs811CtOzC0uzUvXS87P3cQIDq9nUjsYVzZYHGIU4GBU 4uGd8IslSIg1say4MvcQowQHs5II72su1iAh3pTEyqrUovz4otKc1OJDjNIcLErivAdarQOF BNITS1KzU1MLUotgskwcnFINjCt2rL32gXG3d4RQTNrk7Xcv8zF/uJ+QMs+qtGQj8xTeUsU/ WU1KS6fNrlrIpOgU5xbbfX26d0jDoyDWU/W6fN8WdMy+2GjF6P1ebipznNOfva9t9JsEcqMO nZgfy/LS/5HcjNpLc6ZobziuNctvVg+PtYhtmsQiHunUNU0sT3M01yrOnLA0WYmlOCPRUIu5 qDgRAET3uWorAgAA X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20130809_123452_346101_398FAADB X-CRM114-Status: GOOD ( 11.91 ) X-Spam-Score: -6.9 (------) Cc: t.figa@samsung.com, rob.herring@calxeda.com, kyungmin.park@samsung.com, Sylwester Nawrocki , grant.likely@linaro.org, linux-arm-kernel@lists.infradead.org X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.15 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=-4.2 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_MED, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable 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 Add helper functions for the of_clk_providers list locking and an unlocked variant of of_clk_get_from_provider(). These functions are intended to be used in the clkdev to avoid race condition in the device tree based clock look up in clk_get(). Signed-off-by: Sylwester Nawrocki Signed-off-by: Kyungmin Park --- drivers/clk/clk.c | 36 ++++++++++++++++++++++++++++-------- include/linux/clk.h | 3 +++ 2 files changed, 31 insertions(+), 8 deletions(-) diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c index 0d4c982..8b8c152 100644 --- a/drivers/clk/clk.c +++ b/drivers/clk/clk.c @@ -2143,7 +2143,18 @@ static const struct of_device_id __clk_of_table_sentinel __used __section(__clk_of_table_end); static LIST_HEAD(of_clk_providers); -static DEFINE_MUTEX(of_clk_lock); +static DEFINE_MUTEX(of_clk_mutex); + +/* of_clk_provider list locking helpers */ +void of_clk_lock(void) +{ + mutex_lock(&of_clk_mutex); +} + +void of_clk_unlock(void) +{ + mutex_unlock(&of_clk_mutex); +} struct clk *of_clk_src_simple_get(struct of_phandle_args *clkspec, void *data) @@ -2187,9 +2198,9 @@ int of_clk_add_provider(struct device_node *np, cp->data = data; cp->get = clk_src_get; - mutex_lock(&of_clk_lock); + mutex_lock(&of_clk_mutex); list_add(&cp->link, &of_clk_providers); - mutex_unlock(&of_clk_lock); + mutex_unlock(&of_clk_mutex); pr_info("Added clock from %s\n", np->full_name); return 0; @@ -2204,7 +2215,7 @@ void of_clk_del_provider(struct device_node *np) { struct of_clk_provider *cp; - mutex_lock(&of_clk_lock); + mutex_lock(&of_clk_mutex); list_for_each_entry(cp, &of_clk_providers, link) { if (cp->node == np) { list_del(&cp->link); @@ -2213,24 +2224,33 @@ void of_clk_del_provider(struct device_node *np) break; } } - mutex_unlock(&of_clk_lock); + mutex_unlock(&of_clk_mutex); } EXPORT_SYMBOL_GPL(of_clk_del_provider); -struct clk *of_clk_get_from_provider(struct of_phandle_args *clkspec) +struct clk *__of_clk_get_from_provider(struct of_phandle_args *clkspec) { struct of_clk_provider *provider; struct clk *clk = ERR_PTR(-ENOENT); /* Check if we have such a provider in our array */ - mutex_lock(&of_clk_lock); list_for_each_entry(provider, &of_clk_providers, link) { if (provider->node == clkspec->np) clk = provider->get(clkspec, provider->data); if (!IS_ERR(clk)) break; } - mutex_unlock(&of_clk_lock); + + return clk; +} + +struct clk *of_clk_get_from_provider(struct of_phandle_args *clkspec) +{ + struct clk *clk; + + mutex_lock(&of_clk_mutex); + clk = __of_clk_get_from_provider(clkspec); + mutex_unlock(&of_clk_mutex); return clk; } diff --git a/include/linux/clk.h b/include/linux/clk.h index 9a6d045..ea6822e 100644 --- a/include/linux/clk.h +++ b/include/linux/clk.h @@ -368,6 +368,9 @@ struct of_phandle_args; struct clk *of_clk_get(struct device_node *np, int index); struct clk *of_clk_get_by_name(struct device_node *np, const char *name); struct clk *of_clk_get_from_provider(struct of_phandle_args *clkspec); +struct clk *__of_clk_get_from_provider(struct of_phandle_args *clkspec); +void of_clk_lock(void); +void of_clk_unlock(void); #else static inline struct clk *of_clk_get(struct device_node *np, int index) {