diff options
Diffstat (limited to 'drivers/clocksource/time-armada-370-xp.c')
| -rw-r--r-- | drivers/clocksource/time-armada-370-xp.c | 226 |
1 files changed, 226 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 000000000000..4674f94957cd --- /dev/null +++ b/drivers/clocksource/time-armada-370-xp.c @@ -0,0 +1,226 @@ +/* + * 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. + */ + +#include <linux/init.h> +#include <linux/platform_device.h> +#include <linux/kernel.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 <asm/sched_clock.h> + +/* + * Timer block registers. + */ +#define TIMER_CTRL_OFF 0x0000 +#define TIMER0_EN 0x0001 +#define TIMER0_RELOAD_EN 0x0002 +#define TIMER0_25MHZ 0x0800 +#define TIMER0_DIV(div) ((div) << 19) +#define TIMER1_EN 0x0004 +#define TIMER1_RELOAD_EN 0x0008 +#define TIMER1_25MHZ 0x1000 +#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 + +/* 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; +static int timer_irq; + +/* + * Number of timer ticks per jiffy. + */ +static u32 ticks_per_jiffy; + +static u32 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) +{ + u32 u; + + /* + * Clear clockevent timer interrupt. + */ + writel(TIMER1_CLR_MASK, timer_base + TIMER_EVENTS_STATUS); + + /* + * Setup new clockevent timer value. + */ + writel(delta, timer_base + TIMER1_VAL_OFF); + + /* + * Enable the timer. + */ + u = readl(timer_base + TIMER_CTRL_OFF); + u = ((u & ~TIMER1_RELOAD_EN) | TIMER1_EN | + TIMER1_DIV(TIMER_DIVIDER_SHIFT)); + writel(u, timer_base + TIMER_CTRL_OFF); + + return 0; +} + +static void +armada_370_xp_clkevt_mode(enum clock_event_mode mode, + struct clock_event_device *dev) +{ + u32 u; + + if (mode == CLOCK_EVT_MODE_PERIODIC) { + /* + * Setup timer to fire at 1/HZ intervals. + */ + writel(ticks_per_jiffy - 1, timer_base + TIMER1_RELOAD_OFF); + writel(ticks_per_jiffy - 1, timer_base + TIMER1_VAL_OFF); + + /* + * Enable timer. + */ + u = readl(timer_base + TIMER_CTRL_OFF); + + writel((u | TIMER1_EN | TIMER1_RELOAD_EN | + TIMER1_DIV(TIMER_DIVIDER_SHIFT)), + timer_base + TIMER_CTRL_OFF); + } else { + /* + * Disable timer. + */ + u = readl(timer_base + TIMER_CTRL_OFF); + writel(u & ~TIMER1_EN, timer_base + TIMER_CTRL_OFF); + + /* + * ACK pending timer interrupt. + */ + writel(TIMER1_CLR_MASK, timer_base + TIMER_EVENTS_STATUS); + + } +} + +static struct clock_event_device armada_370_xp_clkevt = { + .name = "armada_370_xp_tick", + .features = CLOCK_EVT_FEAT_ONESHOT | CLOCK_EVT_FEAT_PERIODIC, + .shift = 32, + .rating = 300, + .set_next_event = armada_370_xp_clkevt_next_event, + .set_mode = armada_370_xp_clkevt_mode, +}; + +static irqreturn_t armada_370_xp_timer_interrupt(int irq, void *dev_id) +{ + /* + * ACK timer interrupt and call event handler. + */ + + writel(TIMER1_CLR_MASK, timer_base + TIMER_EVENTS_STATUS); + armada_370_xp_clkevt.event_handler(&armada_370_xp_clkevt); + + return IRQ_HANDLED; +} + +static struct irqaction armada_370_xp_timer_irq = { + .name = "armada_370_xp_tick", + .flags = IRQF_DISABLED | IRQF_TIMER, + .handler = armada_370_xp_timer_interrupt +}; + +void __init armada_370_xp_timer_init(void) +{ + u32 u; + struct device_node *np; + unsigned int timer_clk; + int ret; + np = of_find_compatible_node(NULL, NULL, "marvell,armada-370-xp-timer"); + timer_base = of_iomap(np, 0); + WARN_ON(!timer_base); + + if (of_find_property(np, "marvell,timer-25Mhz", NULL)) { + /* The fixed 25MHz timer is available so let's use it */ + u = readl(timer_base + TIMER_CTRL_OFF); + writel(u | TIMER0_25MHZ | TIMER1_25MHZ, + timer_base + TIMER_CTRL_OFF); + timer_clk = 25000000; + } else { + u32 clk = 0; + ret = of_property_read_u32(np, "clock-frequency", &clk); + WARN_ON(!clk || ret < 0); + u = readl(timer_base + TIMER_CTRL_OFF); + writel(u & ~(TIMER0_25MHZ | TIMER1_25MHZ), + timer_base + TIMER_CTRL_OFF); + timer_clk = clk / TIMER_DIVIDER; + } + + /* We use timer 0 as clocksource, and timer 1 for + clockevents */ + timer_irq = irq_of_parse_and_map(np, 1); + + ticks_per_jiffy = (timer_clk + HZ / 2) / HZ; + + /* + * Set scale and timer for sched_clock. + */ + setup_sched_clock(armada_370_xp_read_sched_clock, 32, timer_clk); + + /* + * Setup free-running clocksource timer (interrupts + * disabled). + */ + writel(0xffffffff, timer_base + TIMER0_VAL_OFF); + writel(0xffffffff, timer_base + TIMER0_RELOAD_OFF); + + u = readl(timer_base + TIMER_CTRL_OFF); + + writel((u | TIMER0_EN | TIMER0_RELOAD_EN | + TIMER0_DIV(TIMER_DIVIDER_SHIFT)), timer_base + TIMER_CTRL_OFF); + + clocksource_mmio_init(timer_base + TIMER0_VAL_OFF, + "armada_370_xp_clocksource", + timer_clk, 300, 32, clocksource_mmio_readl_down); + + /* + * Setup clockevent timer (interrupt-driven). + */ + setup_irq(timer_irq, &armada_370_xp_timer_irq); + armada_370_xp_clkevt.cpumask = cpumask_of(0); + clockevents_config_and_register(&armada_370_xp_clkevt, + timer_clk, 1, 0xfffffffe); +} + |