diff options
Diffstat (limited to 'drivers/clocksource/time-armada-370-xp.c')
| -rw-r--r-- | drivers/clocksource/time-armada-370-xp.c | 314 |
1 files changed, 314 insertions, 0 deletions
diff --git a/drivers/clocksource/time-armada-370-xp.c b/drivers/clocksource/time-armada-370-xp.c new file mode 100644 index 00000000000..0451e62fac7 --- /dev/null +++ b/drivers/clocksource/time-armada-370-xp.c @@ -0,0 +1,314 @@ +/* + * Marvell Armada 370/XP SoC timer handling. + * + * Copyright (C) 2012 Marvell + * + * Lior Amsalem <alior@marvell.com> + * Gregory CLEMENT <gregory.clement@free-electrons.com> + * Thomas Petazzoni <thomas.petazzoni@free-electrons.com> + * + * This file is licensed under the terms of the GNU General Public + * License version 2. This program is licensed "as is" without any + * warranty of any kind, whether express or implied. + * + * Timer 0 is used as free-running clocksource, while timer 1 is + * used as clock_event_device. + * + * --- + * Clocksource driver for Armada 370 and Armada XP SoC. + * This driver implements one compatible string for each SoC, given + * each has its own characteristics: + * + * * Armada 370 has no 25 MHz fixed timer. + * + * * Armada XP cannot work properly without such 25 MHz fixed timer as + * doing otherwise leads to using a clocksource whose frequency varies + * when doing cpufreq frequency changes. + * + * See Documentation/devicetree/bindings/timer/marvell,armada-370-xp-timer.txt + */ + +#include <linux/init.h> +#include <linux/platform_device.h> +#include <linux/kernel.h> +#include <linux/clk.h> +#include <linux/cpu.h> +#include <linux/timer.h> +#include <linux/clockchips.h> +#include <linux/interrupt.h> +#include <linux/of.h> +#include <linux/of_irq.h> +#include <linux/of_address.h> +#include <linux/irq.h> +#include <linux/module.h> +#include <linux/sched_clock.h> +#include <linux/percpu.h> + +/* + * Timer block registers. + */ +#define TIMER_CTRL_OFF 0x0000 +#define TIMER0_EN BIT(0) +#define TIMER0_RELOAD_EN BIT(1) +#define TIMER0_25MHZ BIT(11) +#define TIMER0_DIV(div) ((div) << 19) +#define TIMER1_EN BIT(2) +#define TIMER1_RELOAD_EN BIT(3) +#define TIMER1_25MHZ BIT(12) +#define TIMER1_DIV(div) ((div) << 22) +#define TIMER_EVENTS_STATUS 0x0004 +#define TIMER0_CLR_MASK (~0x1) +#define TIMER1_CLR_MASK (~0x100) +#define TIMER0_RELOAD_OFF 0x0010 +#define TIMER0_VAL_OFF 0x0014 +#define TIMER1_RELOAD_OFF 0x0018 +#define TIMER1_VAL_OFF 0x001c + +#define LCL_TIMER_EVENTS_STATUS 0x0028 +/* Global timers are connected to the coherency fabric clock, and the + below divider reduces their incrementing frequency. */ +#define TIMER_DIVIDER_SHIFT 5 +#define TIMER_DIVIDER (1 << TIMER_DIVIDER_SHIFT) + +/* + * SoC-specific data. + */ +static void __iomem *timer_base, *local_base; +static unsigned int timer_clk; +static bool timer25Mhz = true; +static u32 enable_mask; + +/* + * Number of timer ticks per jiffy. + */ +static u32 ticks_per_jiffy; + +static struct clock_event_device __percpu *armada_370_xp_evt; + +static void local_timer_ctrl_clrset(u32 clr, u32 set) +{ + writel((readl(local_base + TIMER_CTRL_OFF) & ~clr) | set, + local_base + TIMER_CTRL_OFF); +} + +static u64 notrace armada_370_xp_read_sched_clock(void) +{ + return ~readl(timer_base + TIMER0_VAL_OFF); +} + +/* + * Clockevent handling. + */ +static int +armada_370_xp_clkevt_next_event(unsigned long delta, + struct clock_event_device *dev) +{ + /* + * Clear clockevent timer interrupt. + */ + writel(TIMER0_CLR_MASK, local_base + LCL_TIMER_EVENTS_STATUS); + + /* + * Setup new clockevent timer value. + */ + writel(delta, local_base + TIMER0_VAL_OFF); + + /* + * Enable the timer. + */ + local_timer_ctrl_clrset(TIMER0_RELOAD_EN, enable_mask); + return 0; +} + +static void +armada_370_xp_clkevt_mode(enum clock_event_mode mode, + struct clock_event_device *dev) +{ + if (mode == CLOCK_EVT_MODE_PERIODIC) { + + /* + * Setup timer to fire at 1/HZ intervals. + */ + writel(ticks_per_jiffy - 1, local_base + TIMER0_RELOAD_OFF); + writel(ticks_per_jiffy - 1, local_base + TIMER0_VAL_OFF); + + /* + * Enable timer. + */ + local_timer_ctrl_clrset(0, TIMER0_RELOAD_EN | enable_mask); + } else { + /* + * Disable timer. + */ + local_timer_ctrl_clrset(TIMER0_EN, 0); + + /* + * ACK pending timer interrupt. + */ + writel(TIMER0_CLR_MASK, local_base + LCL_TIMER_EVENTS_STATUS); + } +} + +static int armada_370_xp_clkevt_irq; + +static irqreturn_t armada_370_xp_timer_interrupt(int irq, void *dev_id) +{ + /* + * ACK timer interrupt and call event handler. + */ + struct clock_event_device *evt = dev_id; + + writel(TIMER0_CLR_MASK, local_base + LCL_TIMER_EVENTS_STATUS); + evt->event_handler(evt); + + return IRQ_HANDLED; +} + +/* + * Setup the local clock events for a CPU. + */ +static int armada_370_xp_timer_setup(struct clock_event_device *evt) +{ + u32 clr = 0, set = 0; + int cpu = smp_processor_id(); + + if (timer25Mhz) + set = TIMER0_25MHZ; + else + clr = TIMER0_25MHZ; + local_timer_ctrl_clrset(clr, set); + + evt->name = "armada_370_xp_per_cpu_tick", + evt->features = CLOCK_EVT_FEAT_ONESHOT | + CLOCK_EVT_FEAT_PERIODIC; + evt->shift = 32, + evt->rating = 300, + evt->set_next_event = armada_370_xp_clkevt_next_event, + evt->set_mode = armada_370_xp_clkevt_mode, + evt->irq = armada_370_xp_clkevt_irq; + evt->cpumask = cpumask_of(cpu); + + clockevents_config_and_register(evt, timer_clk, 1, 0xfffffffe); + enable_percpu_irq(evt->irq, 0); + + return 0; +} + +static void armada_370_xp_timer_stop(struct clock_event_device *evt) +{ + evt->set_mode(CLOCK_EVT_MODE_UNUSED, evt); + disable_percpu_irq(evt->irq); +} + +static int armada_370_xp_timer_cpu_notify(struct notifier_block *self, + unsigned long action, void *hcpu) +{ + /* + * Grab cpu pointer in each case to avoid spurious + * preemptible warnings + */ + switch (action & ~CPU_TASKS_FROZEN) { + case CPU_STARTING: + armada_370_xp_timer_setup(this_cpu_ptr(armada_370_xp_evt)); + break; + case CPU_DYING: + armada_370_xp_timer_stop(this_cpu_ptr(armada_370_xp_evt)); + break; + } + + return NOTIFY_OK; +} + +static struct notifier_block armada_370_xp_timer_cpu_nb = { + .notifier_call = armada_370_xp_timer_cpu_notify, +}; + +static void __init armada_370_xp_timer_common_init(struct device_node *np) +{ + u32 clr = 0, set = 0; + int res; + + timer_base = of_iomap(np, 0); + WARN_ON(!timer_base); + local_base = of_iomap(np, 1); + + if (timer25Mhz) { + set = TIMER0_25MHZ; + enable_mask = TIMER0_EN; + } else { + clr = TIMER0_25MHZ; + enable_mask = TIMER0_EN | TIMER0_DIV(TIMER_DIVIDER_SHIFT); + } + atomic_io_modify(timer_base + TIMER_CTRL_OFF, clr | set, set); + local_timer_ctrl_clrset(clr, set); + + /* + * We use timer 0 as clocksource, and private(local) timer 0 + * for clockevents + */ + armada_370_xp_clkevt_irq = irq_of_parse_and_map(np, 4); + + ticks_per_jiffy = (timer_clk + HZ / 2) / HZ; + + /* + * Setup free-running clocksource timer (interrupts + * disabled). + */ + writel(0xffffffff, timer_base + TIMER0_VAL_OFF); + writel(0xffffffff, timer_base + TIMER0_RELOAD_OFF); + + atomic_io_modify(timer_base + TIMER_CTRL_OFF, + TIMER0_RELOAD_EN | enable_mask, + TIMER0_RELOAD_EN | enable_mask); + + /* + * Set scale and timer for sched_clock. + */ + sched_clock_register(armada_370_xp_read_sched_clock, 32, timer_clk); + + clocksource_mmio_init(timer_base + TIMER0_VAL_OFF, + "armada_370_xp_clocksource", + timer_clk, 300, 32, clocksource_mmio_readl_down); + + register_cpu_notifier(&armada_370_xp_timer_cpu_nb); + + armada_370_xp_evt = alloc_percpu(struct clock_event_device); + + + /* + * Setup clockevent timer (interrupt-driven). + */ + res = request_percpu_irq(armada_370_xp_clkevt_irq, + armada_370_xp_timer_interrupt, + "armada_370_xp_per_cpu_tick", + armada_370_xp_evt); + /* Immediately configure the timer on the boot CPU */ + if (!res) + armada_370_xp_timer_setup(this_cpu_ptr(armada_370_xp_evt)); +} + +static void __init armada_xp_timer_init(struct device_node *np) +{ + struct clk *clk = of_clk_get_by_name(np, "fixed"); + + /* The 25Mhz fixed clock is mandatory, and must always be available */ + BUG_ON(IS_ERR(clk)); + timer_clk = clk_get_rate(clk); + + armada_370_xp_timer_common_init(np); +} +CLOCKSOURCE_OF_DECLARE(armada_xp, "marvell,armada-xp-timer", + armada_xp_timer_init); + +static void __init armada_370_timer_init(struct device_node *np) +{ + struct clk *clk = of_clk_get(np, 0); + + BUG_ON(IS_ERR(clk)); + timer_clk = clk_get_rate(clk) / TIMER_DIVIDER; + timer25Mhz = false; + + armada_370_xp_timer_common_init(np); +} +CLOCKSOURCE_OF_DECLARE(armada_370, "marvell,armada-370-timer", + armada_370_timer_init); |