From patchwork Fri Jan 16 16:52:44 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: =?utf-8?q?Heiko_St=C3=BCbner?= X-Patchwork-Id: 5649491 Return-Path: X-Original-To: patchwork-linux-rockchip@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork1.web.kernel.org (Postfix) with ESMTP id 154769F3A0 for ; Fri, 16 Jan 2015 16:53:25 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 3B7622021A for ; Fri, 16 Jan 2015 16:53:24 +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 C92372020F for ; Fri, 16 Jan 2015 16:53:20 +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 1YCA99-0004KO-3y; Fri, 16 Jan 2015 16:53:19 +0000 Received: from gloria.sntech.de ([95.129.55.99]) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1YCA96-0004Br-CY; Fri, 16 Jan 2015 16:53:17 +0000 Received: from ip545477c2.speed.planet.nl ([84.84.119.194] helo=phil.localnet) by gloria.sntech.de with esmtpsa (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.80) (envelope-from ) id 1YCA8i-0001sT-7z; Fri, 16 Jan 2015 17:52:52 +0100 From: Heiko =?ISO-8859-1?Q?St=FCbner?= To: linux-rockchip@lists.infradead.org Subject: [PATCH] clk: rockchip: fix deadlock possibility in cpuclk Date: Fri, 16 Jan 2015 17:52:44 +0100 Message-ID: <355359386.nxMIlHNuqO@phil> User-Agent: KMail/4.14.2 (Linux/3.16.0-4-amd64; KDE/4.14.1; x86_64; ; ) MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20150116_085316_601100_1CD450CB X-CRM114-Status: GOOD ( 10.43 ) X-Spam-Score: -0.0 (/) Cc: Mike Turquette , dianders@chromium.org, linux-arm-kernel@lists.infradead.org X-BeenThere: linux-rockchip@lists.infradead.org X-Mailman-Version: 2.1.18-1 Precedence: list List-Id: Upstream kernel work for Rockchip platforms List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "Linux-rockchip" Errors-To: linux-rockchip-bounces+patchwork-linux-rockchip=patchwork.kernel.org@lists.infradead.org X-Spam-Status: No, score=-4.2 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_MED, T_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 Lockdep reported a possible deadlock between the cpuclk lock and for example the i2c driver. CPU0 CPU1 ---- ---- lock(clk_lock); local_irq_disable(); lock(&(&i2c->lock)->rlock); lock(clk_lock); lock(&(&i2c->lock)->rlock); *** DEADLOCK *** The generic clock-types of the core ccf already use spin_lock_irqsave when touching clock registers, so do the same for the cpuclk. Signed-off-by: Heiko Stuebner Reviewed-by: Doug Anderson --- drivers/clk/rockchip/clk-cpu.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/drivers/clk/rockchip/clk-cpu.c b/drivers/clk/rockchip/clk-cpu.c index 75c8c45..3ecdf7d 100644 --- a/drivers/clk/rockchip/clk-cpu.c +++ b/drivers/clk/rockchip/clk-cpu.c @@ -124,10 +124,11 @@ static int rockchip_cpuclk_pre_rate_change(struct rockchip_cpuclk *cpuclk, { const struct rockchip_cpuclk_reg_data *reg_data = cpuclk->reg_data; unsigned long alt_prate, alt_div; + unsigned long flags = 0; alt_prate = clk_get_rate(cpuclk->alt_parent); - spin_lock(cpuclk->lock); + spin_lock_irqsave(cpuclk->lock, flags); /* * If the old parent clock speed is less than the clock speed @@ -164,7 +165,7 @@ static int rockchip_cpuclk_pre_rate_change(struct rockchip_cpuclk *cpuclk, cpuclk->reg_base + reg_data->core_reg); } - spin_unlock(cpuclk->lock); + spin_unlock_irqrestore(cpuclk->lock, flags); return 0; } @@ -173,6 +174,7 @@ static int rockchip_cpuclk_post_rate_change(struct rockchip_cpuclk *cpuclk, { const struct rockchip_cpuclk_reg_data *reg_data = cpuclk->reg_data; const struct rockchip_cpuclk_rate_table *rate; + unsigned long flags = 0; rate = rockchip_get_cpuclk_settings(cpuclk, ndata->new_rate); if (!rate) { @@ -181,7 +183,7 @@ static int rockchip_cpuclk_post_rate_change(struct rockchip_cpuclk *cpuclk, return -EINVAL; } - spin_lock(cpuclk->lock); + spin_lock_irqsave(cpuclk->lock, flags); if (ndata->old_rate < ndata->new_rate) rockchip_cpuclk_set_dividers(cpuclk, rate); @@ -201,7 +203,7 @@ static int rockchip_cpuclk_post_rate_change(struct rockchip_cpuclk *cpuclk, if (ndata->old_rate > ndata->new_rate) rockchip_cpuclk_set_dividers(cpuclk, rate); - spin_unlock(cpuclk->lock); + spin_unlock_irqrestore(cpuclk->lock, flags); return 0; }