From patchwork Fri Dec 20 10:45:41 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Sebastian Andrzej Siewior X-Patchwork-Id: 3387791 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 1A16F9F37A for ; Fri, 20 Dec 2013 10:47:54 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id BE16C2060E for ; Fri, 20 Dec 2013 10:47:52 +0000 (UTC) Received: from casper.infradead.org (casper.infradead.org [85.118.1.10]) (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 398F82060C for ; Fri, 20 Dec 2013 10:47:51 +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 1Vtxbb-00085i-Be; Fri, 20 Dec 2013 10:46:55 +0000 Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1VtxbN-0007DI-7G; Fri, 20 Dec 2013 10:46:41 +0000 Received: from galois.linutronix.de ([2001:470:1f0b:db:abcd:42:0:1]) by merlin.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1Vtxb1-00078V-Fl for linux-arm-kernel@lists.infradead.org; Fri, 20 Dec 2013 10:46:21 +0000 Received: from localhost ([127.0.0.1] helo=bazinga.breakpoint.cc) by Galois.linutronix.de with esmtp (Exim 4.72) (envelope-from ) id 1Vtxaa-0002c3-Gr; Fri, 20 Dec 2013 11:45:52 +0100 From: Sebastian Andrzej Siewior To: linux-arm-kernel@lists.infradead.org Subject: [PATCH 2/2] clocksource: TCLIB: Allow higher clock rates for clock events Date: Fri, 20 Dec 2013 11:45:41 +0100 Message-Id: <1387536341-7452-3-git-send-email-bigeasy@linutronix.de> X-Mailer: git-send-email 1.8.5.1 In-Reply-To: <1387536341-7452-1-git-send-email-bigeasy@linutronix.de> References: <1387536341-7452-1-git-send-email-bigeasy@linutronix.de> MIME-Version: 1.0 X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1, SHORTCIRCUIT=-0.0001, URIBL_BLOCKED=0.001 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20131220_054619_878461_1D9D2D8A X-CRM114-Status: GOOD ( 18.39 ) X-Spam-Score: -2.4 (--) Cc: Benedikt Spranger , Sebastian Andrzej Siewior , Daniel Lezcano , Nicolas Ferre , linux-kernel@vger.kernel.org, tglx@linutronix.de, =?UTF-8?q?Sami=20Pietik=C3=A4inen?= , Jean-Christophe Plagniol-Villard , Andrew Victor 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: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Spam-Status: No, score=-4.7 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 From: Benedikt Spranger As default the TCLIB uses the 32KiHz base clock rate for clock events. Add a compile time selection to allow higher clock resulution. (fixed up by Sami Pietikäinen around v3.12) Signed-off-by: Benedikt Spranger Signed-off-by: Thomas Gleixner [bigeasy: update against v3.13-rc4] Signed-off-by: Sebastian Andrzej Siewior --- drivers/clocksource/tcb_clksrc.c | 37 ++++++++++++++++++++++--------------- drivers/misc/Kconfig | 12 ++++++++++-- 2 files changed, 32 insertions(+), 17 deletions(-) diff --git a/drivers/clocksource/tcb_clksrc.c b/drivers/clocksource/tcb_clksrc.c index 00fdd11..df62eaa 100644 --- a/drivers/clocksource/tcb_clksrc.c +++ b/drivers/clocksource/tcb_clksrc.c @@ -23,8 +23,7 @@ * this 32 bit free-running counter. the second channel is not used. * * - The third channel may be used to provide a 16-bit clockevent - * source, used in either periodic or oneshot mode. This runs - * at 32 KiHZ, and can handle delays of up to two seconds. + * source, used in either periodic or oneshot mode. * * A boot clocksource and clockevent source are also currently needed, * unless the relevant platforms (ARM/AT91, AVR32/AT32) are changed so @@ -74,6 +73,7 @@ static struct clocksource clksrc = { struct tc_clkevt_device { struct clock_event_device clkevt; struct clk *clk; + u32 freq; void __iomem *regs; }; @@ -82,13 +82,6 @@ static struct tc_clkevt_device *to_tc_clkevt(struct clock_event_device *clkevt) return container_of(clkevt, struct tc_clkevt_device, clkevt); } -/* For now, we always use the 32K clock ... this optimizes for NO_HZ, - * because using one of the divided clocks would usually mean the - * tick rate can never be less than several dozen Hz (vs 0.5 Hz). - * - * A divided clock could be good for high resolution timers, since - * 30.5 usec resolution can seem "low". - */ static u32 timer_clock; static void tc_mode(enum clock_event_mode m, struct clock_event_device *d) @@ -111,11 +104,12 @@ static void tc_mode(enum clock_event_mode m, struct clock_event_device *d) case CLOCK_EVT_MODE_PERIODIC: clk_prepare_enable(tcd->clk); - /* slow clock, count up to RC, then irq and restart */ + /* count up to RC, then irq and restart */ __raw_writel(timer_clock | ATMEL_TC_WAVE | ATMEL_TC_WAVESEL_UP_AUTO, regs + ATMEL_TC_REG(2, CMR)); - __raw_writel((32768 + HZ/2) / HZ, tcaddr + ATMEL_TC_REG(2, RC)); + __raw_writel((tcd->freq + HZ / 2) / HZ, + tcaddr + ATMEL_TC_REG(2, RC)); /* Enable clock and interrupts on RC compare */ __raw_writel(ATMEL_TC_CPCS, regs + ATMEL_TC_REG(2, IER)); @@ -128,7 +122,7 @@ static void tc_mode(enum clock_event_mode m, struct clock_event_device *d) case CLOCK_EVT_MODE_ONESHOT: clk_prepare_enable(tcd->clk); - /* slow clock, count up to RC, then irq and stop */ + /* count up to RC, then irq and stop */ __raw_writel(timer_clock | ATMEL_TC_CPCSTOP | ATMEL_TC_WAVE | ATMEL_TC_WAVESEL_UP_AUTO, regs + ATMEL_TC_REG(2, CMR)); @@ -157,8 +151,12 @@ static struct tc_clkevt_device clkevt = { .name = "tc_clkevt", .features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT, +#ifdef CONFIG_ATMEL_TCB_CLKSRC_USE_SLOW_CLOCK /* Should be lower than at91rm9200's system timer */ .rating = 125, +#else + .rating = 200, +#endif .set_next_event = tc_next_event, .set_mode = tc_mode, }, @@ -184,8 +182,9 @@ static struct irqaction tc_irqaction = { .handler = ch2_irq, }; -static int __init setup_clkevents(struct atmel_tc *tc, int clk32k_divisor_idx) +static int __init setup_clkevents(struct atmel_tc *tc, int divisor_idx) { + unsigned divisor = atmel_tc_divisors[divisor_idx]; int ret; struct clk *t2_clk = tc->clk[2]; int irq = tc->irq[2]; @@ -200,7 +199,11 @@ static int __init setup_clkevents(struct atmel_tc *tc, int clk32k_divisor_idx) clkevt.clk = t2_clk; tc_irqaction.dev_id = &clkevt; - timer_clock = clk32k_divisor_idx; + timer_clock = divisor_idx; + if (!divisor) + clkevt.freq = 32768; + else + clkevt.freq = clk_get_rate(t2_clk) / divisor; clkevt.clkevt.cpumask = cpumask_of(0); @@ -208,7 +211,7 @@ static int __init setup_clkevents(struct atmel_tc *tc, int clk32k_divisor_idx) if (ret) return ret; - clockevents_config_and_register(&clkevt.clkevt, 32768, 1, 0xffff); + clockevents_config_and_register(&clkevt.clkevt, clkevt.freq, 1, 0xffff); return ret; } @@ -345,7 +348,11 @@ static int __init tcb_clksrc_init(void) goto err_disable_t1; /* channel 2: periodic and oneshot timer support */ +#ifdef CONFIG_ATMEL_TCB_CLKSRC_USE_SLOW_CLOCK ret = setup_clkevents(tc, clk32k_divisor_idx); +#else + ret = setup_clkevents(tc, best_divisor_idx); +#endif if (ret) goto err_unregister_clksrc; diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig index a3e291d..4a7d7d6 100644 --- a/drivers/misc/Kconfig +++ b/drivers/misc/Kconfig @@ -78,8 +78,7 @@ config ATMEL_TCB_CLKSRC are combined to make a single 32-bit timer. When GENERIC_CLOCKEVENTS is defined, the third timer channel - may be used as a clock event device supporting oneshot mode - (delays of up to two seconds) based on the 32 KiHz clock. + may be used as a clock event device supporting oneshot mode. config ATMEL_TCB_CLKSRC_BLOCK int @@ -93,6 +92,15 @@ config ATMEL_TCB_CLKSRC_BLOCK TC can be used for other purposes, such as PWM generation and interval timing. +config ATMEL_TCB_CLKSRC_USE_SLOW_CLOCK + bool "TC Block use 32 KiHz clock" + depends on ATMEL_TCB_CLKSRC + default y + help + Select this to use 32 KiHz base clock rate as TC block clock + source for clock events. + + config DUMMY_IRQ tristate "Dummy IRQ handler" default n