From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ivan Khoronzhuk Subject: Re: [PATCH v4 1/3] clocksource: timer-keystone: introduce clocksource driver for Keystone Date: Tue, 4 Feb 2014 13:41:06 +0200 Message-ID: <52F0D1D2.4030603@ti.com> References: <1391513453-21140-1-git-send-email-ivan.khoronzhuk@ti.com> <1391513453-21140-2-git-send-email-ivan.khoronzhuk@ti.com> Mime-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1"; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1391513453-21140-2-git-send-email-ivan.khoronzhuk@ti.com> Sender: linux-doc-owner@vger.kernel.org To: santosh.shilimkar@ti.com, rob@landley.net, linux@arm.linux.org.uk, galak@codeaurora.org Cc: robh+dt@kernel.org, pawel.moll@arm.com, mark.rutland@arm.com, ijc+devicetree@hellion.org.uk, daniel.lezcano@linaro.org, tglx@linutronix.de, devicetree@vger.kernel.org, linux-doc@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, grygorii.strashko@ti.com, Ivan Khoronzhuk List-Id: devicetree@vger.kernel.org Reviewed-by: Stephen Boyd Acked-by: Santosh shilimkar On 02/04/2014 01:30 PM, Ivan Khoronzhuk wrote: > Add broadcast clock-event device for the Keystone arch. > > The timer can be configured as a general-purpose 64-bit timer, > dual general-purpose 32-bit timers. When configured as dual 32-bit > timers, each half can operate in conjunction (chain mode) or > independently (unchained mode) of each other. > > Signed-off-by: Ivan Khoronzhuk > --- > drivers/clocksource/Makefile | 1 + > drivers/clocksource/timer-keystone.c | 233 +++++++++++++++++++++++++++++++++++ > 2 files changed, 234 insertions(+) > create mode 100644 drivers/clocksource/timer-keystone.c > > diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile > index c7ca50a..4abe5aa 100644 > --- a/drivers/clocksource/Makefile > +++ b/drivers/clocksource/Makefile > @@ -37,3 +37,4 @@ obj-$(CONFIG_ARM_ARCH_TIMER) += arm_arch_timer.o > obj-$(CONFIG_ARM_GLOBAL_TIMER) += arm_global_timer.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/timer-keystone.c b/drivers/clocksource/timer-keystone.c > new file mode 100644 > index 0000000..cbac8d0 > --- /dev/null > +++ b/drivers/clocksource/timer-keystone.c > @@ -0,0 +1,233 @@ > +/* > + * Keystone broadcast clock-event > + * > + * Copyright 2013 Texas Instruments, Inc. > + * > + * Author: Ivan Khoronzhuk > + * > + * 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. > + * > + */ > + > +#include > +#include > +#include > +#include > +#include > +#include > + > +#define TIMER_NAME "timer-keystone" > + > +/* Timer register offsets */ > +#define TIM12 0x10 > +#define TIM34 0x14 > +#define PRD12 0x18 > +#define PRD34 0x1c > +#define TCR 0x20 > +#define TGCR 0x24 > +#define INTCTLSTAT 0x44 > + > +/* Timer register bitfields */ > +#define TCR_ENAMODE_MASK 0xC0 > +#define TCR_ENAMODE_ONESHOT_MASK 0x40 > +#define TCR_ENAMODE_PERIODIC_MASK 0x80 > + > +#define TGCR_TIM_UNRESET_MASK 0x03 > +#define INTCTLSTAT_ENINT_MASK 0x01 > + > +/** > + * struct keystone_timer: holds timer's data > + * @base: timer memory base address > + * @hz_period: cycles per HZ period > + * @event_dev: event device based on timer > + */ > +static struct keystone_timer { > + void __iomem *base; > + unsigned long hz_period; > + struct clock_event_device event_dev; > +} timer; > + > +static inline u32 keystone_timer_readl(unsigned long rg) > +{ > + return readl_relaxed(timer.base + rg); > +} > + > +static inline void keystone_timer_writel(u32 val, unsigned long rg) > +{ > + writel_relaxed(val, timer.base + rg); > +} > + > +/** > + * keystone_timer_config: configures timer to work in oneshot/periodic modes. > + * @ mode: mode to configure > + * @ period: cycles number to configure for > + */ > +static int keystone_timer_config(u64 period, enum clock_event_mode mode) > +{ > + u32 tcr; > + u32 off; > + > + tcr = keystone_timer_readl(TCR); > + off = tcr & ~(TCR_ENAMODE_MASK); > + > + /* set enable mode */ > + switch (mode) { > + case CLOCK_EVT_MODE_ONESHOT: > + tcr |= TCR_ENAMODE_ONESHOT_MASK; > + break; > + case CLOCK_EVT_MODE_PERIODIC: > + tcr |= TCR_ENAMODE_PERIODIC_MASK; > + break; > + default: > + return -1; > + } > + > + /* disable timer */ > + keystone_timer_writel(off, TCR); > + /* here we have to be sure the timer has been disabled */ > + wmb(); > + > + /* reset counter to zero, set new period */ > + keystone_timer_writel(0, TIM12); > + keystone_timer_writel(0, TIM34); > + keystone_timer_writel(period & 0xffffffff, PRD12); > + keystone_timer_writel(period >> 32, PRD34); > + > + /* > + * enable timer > + * here we have to be sure that CNTLO, CNTHI, PRDLO, PRDHI registers > + * have been written. > + */ > + wmb(); > + keystone_timer_writel(tcr, TCR); > + return 0; > +} > + > +static void keystone_timer_disable(void) > +{ > + u32 tcr; > + > + tcr = keystone_timer_readl(TCR); > + > + /* disable timer */ > + tcr &= ~(TCR_ENAMODE_MASK); > + keystone_timer_writel(tcr, TCR); > +} > + > +static irqreturn_t keystone_timer_interrupt(int irq, void *dev_id) > +{ > + struct clock_event_device *evt = dev_id; > + > + evt->event_handler(evt); > + return IRQ_HANDLED; > +} > + > +static int keystone_set_next_event(unsigned long cycles, > + struct clock_event_device *evt) > +{ > + return keystone_timer_config(cycles, evt->mode); > +} > + > +static void keystone_set_mode(enum clock_event_mode mode, > + struct clock_event_device *evt) > +{ > + switch (mode) { > + case CLOCK_EVT_MODE_PERIODIC: > + keystone_timer_config(timer.hz_period, CLOCK_EVT_MODE_PERIODIC); > + break; > + case CLOCK_EVT_MODE_UNUSED: > + case CLOCK_EVT_MODE_SHUTDOWN: > + case CLOCK_EVT_MODE_ONESHOT: > + keystone_timer_disable(); > + break; > + default: > + break; > + } > +} > + > +static void __init keystone_timer_init(struct device_node *np) > +{ > + struct clock_event_device *event_dev = &timer.event_dev; > + unsigned long rate; > + struct clk *clk; > + int irq, error; > + u32 tgcr; > + > + irq = irq_of_parse_and_map(np, 0); > + if (irq == NO_IRQ) { > + pr_err("%s: failed to map interrupts\n", __func__); > + return; > + } > + > + timer.base = of_iomap(np, 0); > + if (!timer.base) { > + pr_err("%s: failed to map registers\n", __func__); > + return; > + } > + > + clk = of_clk_get(np, 0); > + if (!clk) { > + pr_err("%s: failed to get clock\n", __func__); > + iounmap(timer.base); > + return; > + } > + > + error = clk_prepare_enable(clk); > + if (error) { > + pr_err("%s: failed to enable clock\n", __func__); > + goto err; > + } > + > + rate = clk_get_rate(clk); > + > + /* disable, use internal clock source */ > + keystone_timer_writel(0, TCR); > + /* here we have to be sure the timer has been disabled */ > + wmb(); > + > + /* reset timer as 64-bit, no pre-scaler, plus features are disabled */ > + tgcr = 0; > + keystone_timer_writel(0, TGCR); > + > + /* unreset timer */ > + tgcr |= TGCR_TIM_UNRESET_MASK; > + keystone_timer_writel(tgcr, TGCR); > + > + /* init counter to zero */ > + keystone_timer_writel(0, TIM12); > + keystone_timer_writel(0, TIM34); > + > + timer.hz_period = DIV_ROUND_UP(rate, HZ); > + > + /* enable timer interrupts */ > + keystone_timer_writel(INTCTLSTAT_ENINT_MASK, INTCTLSTAT); > + > + error = request_irq(irq, keystone_timer_interrupt, IRQF_TIMER, > + TIMER_NAME, event_dev); > + if (error) { > + pr_err("%s: failed to setup irq\n", __func__); > + goto err; > + } > + > + /* setup clockevent */ > + event_dev->features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT; > + event_dev->set_next_event = keystone_set_next_event; > + event_dev->set_mode = keystone_set_mode; > + event_dev->cpumask = cpu_all_mask; > + event_dev->owner = THIS_MODULE; > + event_dev->name = TIMER_NAME; > + event_dev->irq = irq; > + > + clockevents_config_and_register(event_dev, rate, 1, ULONG_MAX); > + > + pr_info("keystone timer clock @%lu Hz\n", rate); > + return; > +err: > + clk_put(clk); > + iounmap(timer.base); > +} > + > +CLOCKSOURCE_OF_DECLARE(keystone_timer, "ti,keystone-timer", > + keystone_timer_init); -- Regards, Ivan Khoronzhuk