From patchwork Tue Apr 7 16:30:23 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Maxime Coquelin X-Patchwork-Id: 458728 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id A9F5B14021A for ; Wed, 8 Apr 2015 02:36:59 +1000 (AEST) Authentication-Results: ozlabs.org; dkim=fail reason="verification failed; unprotected key" header.d=gmail.com header.i=@gmail.com header.b=PoSEbxXN; dkim-adsp=none (unprotected policy); dkim-atps=neutral Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754011AbbDGQg3 (ORCPT ); Tue, 7 Apr 2015 12:36:29 -0400 Received: from mail-wi0-f182.google.com ([209.85.212.182]:36399 "EHLO mail-wi0-f182.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753149AbbDGQba (ORCPT ); Tue, 7 Apr 2015 12:31:30 -0400 Received: by wizk4 with SMTP id k4so24215174wiz.1; Tue, 07 Apr 2015 09:31:27 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=4NeUQua8aHcQVfr+gjuJU5gbfjePQVPCAgiZMpCrH9U=; b=PoSEbxXNgRzlKPB8co/Xuc3iip78uRjqW3k5ic4vUuQ6WRVc4A8tg+KmrZWDD/a3WZ WaJz2+EehNjIi172Tf/9jN03R5x3qajN9s0n4AZVt584C792eHraiv9vQcvqT1CsD332 ANmovkzrS651pGQkXhBjWeSPjPxfJLuiss+4J2xN201OWBHQuSIGhYy0Tk6tHLtLrtPf Ba/5ff+lkdR6m1z2DeRW4gaV2ezyqr8sXk8ztn/3r0qYiwArypNFaqefWxBSek+RpF+q lE/YCUkjP+dTux9jPLaVb0t7YyDw12GJGMJHYDWa8BeyAujH/0C/j2ev6sz3Uyhhs8pC pyaQ== X-Received: by 10.180.198.37 with SMTP id iz5mr5925730wic.95.1428424287810; Tue, 07 Apr 2015 09:31:27 -0700 (PDT) Received: from lmecul0520.st.com. (58.26.90.92.rev.sfr.net. [92.90.26.58]) by mx.google.com with ESMTPSA id gt4sm11681251wib.21.2015.04.07.09.31.24 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Tue, 07 Apr 2015 09:31:26 -0700 (PDT) From: Maxime Coquelin To: u.kleine-koenig@pengutronix.de, afaerber@suse.de, geert@linux-m68k.org, Rob Herring , Philipp Zabel , Linus Walleij , Arnd Bergmann , stefan@agner.ch, pmeerw@pmeerw.net, pebolle@tiscali.nl, peter@hurleysoftware.com, andy.shevchenko@gmail.com, cw00.choi@samsung.com, Russell King , Daniel Lezcano , joe@perches.com Cc: Jonathan Corbet , Pawel Moll , Mark Rutland , Ian Campbell , Kumar Gala , Thomas Gleixner , Greg Kroah-Hartman , Jiri Slaby , Andrew Morton , "David S. Miller" , Mauro Carvalho Chehab , Antti Palosaari , Tejun Heo , Will Deacon , Nikolay Borisov , Rusty Russell , Kees Cook , Michal Marek , linux-doc@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, linux-gpio@vger.kernel.org, linux-serial@vger.kernel.org, linux-arch@vger.kernel.org, linux-api@vger.kernel.org, mcoquelin.stm32@gmail.com Subject: [PATCH v6 04/15] clocksource/drivers: Add ARM System timer driver Date: Tue, 7 Apr 2015 18:30:23 +0200 Message-Id: <1428424234-28572-5-git-send-email-mcoquelin.stm32@gmail.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1428424234-28572-1-git-send-email-mcoquelin.stm32@gmail.com> References: <1428424234-28572-1-git-send-email-mcoquelin.stm32@gmail.com> Sender: linux-gpio-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-gpio@vger.kernel.org This patch adds clocksource support for ARMv7-M's System timer, also known as SysTick. Tested-by: Chanwoo Choi Signed-off-by: Maxime Coquelin Acked-by: Daniel Lezcano --- drivers/clocksource/Kconfig | 7 ++++ drivers/clocksource/Makefile | 1 + drivers/clocksource/armv7m_systick.c | 79 ++++++++++++++++++++++++++++++++++++ 3 files changed, 87 insertions(+) create mode 100644 drivers/clocksource/armv7m_systick.c diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig index 1c2506f..b82e58b 100644 --- a/drivers/clocksource/Kconfig +++ b/drivers/clocksource/Kconfig @@ -134,6 +134,13 @@ config CLKSRC_ARM_GLOBAL_TIMER_SCHED_CLOCK help Use ARM global timer clock source as sched_clock +config ARMV7M_SYSTICK + bool + select CLKSRC_OF if OF + select CLKSRC_MMIO + help + This options enables support for the ARMv7M system timer unit + config ATMEL_PIT select CLKSRC_OF if OF def_bool SOC_AT91SAM9 || SOC_SAMA5 diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile index 752d5c7..1c9a643 100644 --- a/drivers/clocksource/Makefile +++ b/drivers/clocksource/Makefile @@ -44,6 +44,7 @@ obj-$(CONFIG_MTK_TIMER) += mtk_timer.o obj-$(CONFIG_ARM_ARCH_TIMER) += arm_arch_timer.o obj-$(CONFIG_ARM_GLOBAL_TIMER) += arm_global_timer.o +obj-$(CONFIG_ARMV7M_SYSTICK) += armv7m_systick.o obj-$(CONFIG_CLKSRC_METAG_GENERIC) += metag_generic.o obj-$(CONFIG_ARCH_HAS_TICK_BROADCAST) += dummy_timer.o obj-$(CONFIG_ARCH_KEYSTONE) += timer-keystone.o diff --git a/drivers/clocksource/armv7m_systick.c b/drivers/clocksource/armv7m_systick.c new file mode 100644 index 0000000..addfd2c --- /dev/null +++ b/drivers/clocksource/armv7m_systick.c @@ -0,0 +1,79 @@ +/* + * Copyright (C) Maxime Coquelin 2015 + * Author: Maxime Coquelin + * License terms: GNU General Public License (GPL), version 2 + */ + +#include +#include +#include +#include +#include +#include +#include + +#define SYST_CSR 0x00 +#define SYST_RVR 0x04 +#define SYST_CVR 0x08 +#define SYST_CALIB 0x0c + +#define SYST_CSR_ENABLE BIT(0) + +#define SYSTICK_LOAD_RELOAD_MASK 0x00FFFFFF + +static void __init system_timer_of_register(struct device_node *np) +{ + struct clk *clk = NULL; + void __iomem *base; + u32 rate; + int ret; + + base = of_iomap(np, 0); + if (!base) { + pr_warn("system-timer: invalid base address\n"); + return; + } + + ret = of_property_read_u32(np, "clock-frequency", &rate); + if (ret) { + clk = of_clk_get(np, 0); + if (IS_ERR(clk)) + goto out_unmap; + + ret = clk_prepare_enable(clk); + if (ret) + goto out_clk_put; + + rate = clk_get_rate(clk); + if (!rate) + goto out_clk_disable; + } + + writel_relaxed(SYSTICK_LOAD_RELOAD_MASK, base + SYST_RVR); + writel_relaxed(SYST_CSR_ENABLE, base + SYST_CSR); + + ret = clocksource_mmio_init(base + SYST_CVR, "arm_system_timer", rate, + 200, 24, clocksource_mmio_readl_down); + if (ret) { + pr_err("failed to init clocksource (%d)\n", ret); + if (clk) + goto out_clk_disable; + else + goto out_unmap; + } + + pr_info("ARM System timer initialized as clocksource\n"); + + return; + +out_clk_disable: + clk_disable_unprepare(clk); +out_clk_put: + clk_put(clk); +out_unmap: + iounmap(base); + pr_warn("ARM System timer register failed (%d)\n", ret); +} + +CLOCKSOURCE_OF_DECLARE(arm_systick, "arm,armv7m-systick", + system_timer_of_register);