From mboxrd@z Thu Jan 1 00:00:00 1970 From: daniel.lezcano@linaro.org (Daniel Lezcano) Date: Thu, 12 Dec 2013 16:51:20 +0100 Subject: [PATCH 1/3] clocksource: timer-keystone: introduce clocksource driver for Keystone In-Reply-To: <1386784830-15863-2-git-send-email-ivan.khoronzhuk@ti.com> References: <1386784830-15863-1-git-send-email-ivan.khoronzhuk@ti.com> <1386784830-15863-2-git-send-email-ivan.khoronzhuk@ti.com> Message-ID: <52A9DB78.1040805@linaro.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 12/11/2013 07:00 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 | 223 ++++++++++++++++++++++++++++++++++ > 2 files changed, 224 insertions(+) > create mode 100644 drivers/clocksource/timer-keystone.c > > diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile > index 33621ef..2acf3fc 100644 > --- a/drivers/clocksource/Makefile > +++ b/drivers/clocksource/Makefile > @@ -36,3 +36,4 @@ 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..4a8083a > --- /dev/null > +++ b/drivers/clocksource/timer-keystone.c > @@ -0,0 +1,223 @@ > +/* > + * 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 "timer64-event" > + > +/* 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 > + * @clk_rate: source clock rate > + * @irqacrion: interrupt action descriptor > + * @event_dev: event device based on timer > + */ > +static struct keystone_timer { > + void __iomem *base; > + unsigned long clk_rate; > + struct irqaction irqaction; > + struct clock_event_device event_dev; > +} timer; > + > +static inline u32 keystone_timer_readl(unsigned long rg) > +{ > + return readl(timer.base + rg); > +} > + > +static inline void keystone_timer_writel(u32 val, unsigned long rg) > +{ > + writel(val, timer.base + rg); > +} > + > +/** > + * keystone_timer_config: configures timer to work in oneshot/periodic modes, in > + * other cases disables timer. > + * @ mode: mode to configure > + * @ period: cycles number to configure for > + */ > +static int keystone_timer_config(u64 period, enum clock_event_mode mode) > +{ > + u32 tcr; > + > + tcr = keystone_timer_readl(TCR); > + > + /* disable timer */ > + tcr &= ~(TCR_ENAMODE_MASK); > + keystone_timer_writel(tcr, TCR); Please move this write after the switch (cf. linked comment below) > + /* set enable mode or leave disabled timer */ > + 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 0; Shouldn't you return an error ? > + } > + > + /* 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 */ > + keystone_timer_writel(tcr, TCR); > + return 0; > +} > + > +static irqreturn_t keystone_timer_interrupt(int irq, void *dev_id) > +{ > + struct clock_event_device *evt = &timer.event_dev; > + > + 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) > +{ > + u64 period; > + > + switch (mode) { > + case CLOCK_EVT_MODE_PERIODIC: > + period = timer.clk_rate / (HZ); > + keystone_timer_config(period, CLOCK_EVT_MODE_PERIODIC); > + break; > + case CLOCK_EVT_MODE_UNUSED: > + case CLOCK_EVT_MODE_SHUTDOWN: > + case CLOCK_EVT_MODE_ONESHOT: > + keystone_timer_config(0, CLOCK_EVT_MODE_SHUTDOWN); I don't really this code assuming the side effect of specifying a unsupported mode will disable the timer. > + default: > + break; > + } > +} > + > +static void __init keystone_timer_init(struct device_node *np) > +{ > + struct clock_event_device *event_dev = &timer.event_dev; > + struct irqaction *irqaction = &timer.irqaction; > + 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); > + > + /* 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.clk_rate = rate; > + > + /* enable timer interrupts */ > + keystone_timer_writel(INTCTLSTAT_ENINT_MASK, INTCTLSTAT); > + > + keystone_timer_config(0, CLOCK_EVT_MODE_UNUSED); Same comment here. > + /* init irqaction */ > + irqaction->flags = IRQF_TIMER; > + irqaction->handler = keystone_timer_interrupt; > + irqaction->name = TIMER_NAME; > + irqaction->dev_id = (void *)&timer; > + error = setup_irq(irq, irqaction); > + 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; > + > + 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); > -- Linaro.org ? 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