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Wed, 21 Aug 2013 02:35:59 +0900 (KST) From: Sylwester Nawrocki To: linux-arm-kernel@lists.infradead.org Subject: [PATCH v2 3/4] clk: Provide not locked variant of of_clk_get_from_provider() Date: Tue, 20 Aug 2013 19:34:22 +0200 Message-id: <1377020063-30213-4-git-send-email-s.nawrocki@samsung.com> X-Mailer: git-send-email 1.7.9.5 In-reply-to: <1377020063-30213-1-git-send-email-s.nawrocki@samsung.com> References: <1377020063-30213-1-git-send-email-s.nawrocki@samsung.com> X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFvrPLMWRmVeSWpSXmKPExsVy+t9jQV2GlcJBBkvusVtMffiEzeL9xnlM Fgf+7GC06PlTaXG26Q27RefEJewWmx5fY7W4vGsOm8WEqZPYLeb8mcJscfsyr8WBJ8vZLJ5O uMhmcWmPisX3b9/YLA6/aWe1eP/T0eLpuiXMFutnvGaxWNjwhd3i5oQfzA6iHi3NPWweK6d7 e1z+/obZY+esu+weHz7GeczumMnqMX/6I2aPTas62TzuXNvD5nF05Vomj81L6j12f21i9Ojb sorR4/MmuQC+KC6blNSczLLUIn27BK6MYzvTC17IVnx5fImlgfGZRBcjJ4eEgInEo6+72SFs MYkL99azdTFycQgJTGeUOLntOpTTwSTxcsJZNpAqNgFDid6jfYwgtoiAhsSUrsfsIEXMAotZ JLZtXsQMkhAWCJd4e/sVWBGLgKrE3H2HwOK8Am4Sm/qvA9kcQOsUJOZMsgEJcwq4S0w4uYMV xBYCKnk0YR7rBEbeBYwMqxhFUwuSC4qT0nON9IoTc4tL89L1kvNzNzGCo+WZ9A7GVQ0WhxgF OBiVeHg3FAoHCbEmlhVX5h5ilOBgVhLh3ZYBFOJNSaysSi3Kjy8qzUktPsQozcGiJM57sNU6 UEggPbEkNTs1tSC1CCbLxMEp1cCocUG9Le5c+1n+6577pnxYekVepGxzkduppWYsikXiv5M1 F77PbiwVvawy+f3EPWaRzwwv/cg58efjdV1zHZUDy9IusQj0Mu3b8e15wNFzAdem3Clw2Rsa uvCqRRnrE+uF/CuWa3Zd4ktOvZO65s+Eb6cZPWeUTlRmtLKO6/wUs4q54PC9JE5nJZbijERD Leai4kQAx6GEkZICAAA= X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20130820_133624_961865_37FFCCAF X-CRM114-Status: GOOD ( 15.38 ) X-Spam-Score: -9.7 (---------) Cc: vapier@gentoo.org, linux-mips@linux-mips.org, mturquette@linaro.org, linux-sh@vger.kernel.org, jiada_wang@mentor.com, t.figa@samsung.com, linux-kernel@vger.kernel.org, ralf@linux-mips.org, kyungmin.park@samsung.com, broonie@kernel.org, laurent.pinchart@ideasonboard.com, Sylwester Nawrocki , uclinux-dist-devel@blackfin.uclinux.org, grant.likely@linaro.org, linux@arm.linux.org.uk, shawn.guo@linaro.org, LW@KARO-electronics.de, g.liakhovetski@gmx.de, sebastian.hesselbarth@gmail.com 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=-7.0 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 Acked-by: Russell King --- Changes since v1: - moved the function declaractions to a local header. --- drivers/clk/clk.c | 38 ++++++++++++++++++++++++++++++-------- drivers/clk/clk.h | 16 ++++++++++++++++ 2 files changed, 46 insertions(+), 8 deletions(-) create mode 100644 drivers/clk/clk.h diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c index 549fcb7..0a90582 100644 --- a/drivers/clk/clk.c +++ b/drivers/clk/clk.c @@ -21,6 +21,8 @@ #include #include +#include "clk.h" + static DEFINE_SPINLOCK(enable_lock); static DEFINE_MUTEX(prepare_lock); @@ -2132,7 +2134,18 @@ 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) @@ -2176,9 +2189,9 @@ 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_debug("Added clock from %s\n", np->full_name); return 0; @@ -2193,7 +2206,7 @@ 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); @@ -2202,24 +2215,33 @@ 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/drivers/clk/clk.h b/drivers/clk/clk.h new file mode 100644 index 0000000..4f7d09c --- /dev/null +++ b/drivers/clk/clk.h @@ -0,0 +1,16 @@ +/* + * linux/drivers/clk/clk.h + * + * Copyright (C) 2013 Samsung Electroncs Co., Ltd. + * Sylwester Nawrocki + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#if defined(CONFIG_OF) && defined(CONFIG_COMMON_CLK) +struct clk *__of_clk_get_from_provider(struct of_phandle_args *clkspec); +void of_clk_lock(void); +void of_clk_unlock(void); +#endif