diff options
Diffstat (limited to 'drivers/clocksource/tegra20_timer.c')
| -rw-r--r-- | drivers/clocksource/tegra20_timer.c | 285 |
1 files changed, 285 insertions, 0 deletions
diff --git a/drivers/clocksource/tegra20_timer.c b/drivers/clocksource/tegra20_timer.c new file mode 100644 index 00000000000..3b2f94781df --- /dev/null +++ b/drivers/clocksource/tegra20_timer.c @@ -0,0 +1,285 @@ +/* + * Copyright (C) 2010 Google, Inc. + * + * Author: + * Colin Cross <ccross@google.com> + * + * This software is licensed under the terms of the GNU General Public + * License version 2, as published by the Free Software Foundation, and + * may be copied, distributed, and modified under those terms. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + */ + +#include <linux/init.h> +#include <linux/err.h> +#include <linux/time.h> +#include <linux/interrupt.h> +#include <linux/irq.h> +#include <linux/clockchips.h> +#include <linux/clocksource.h> +#include <linux/clk.h> +#include <linux/io.h> +#include <linux/of_address.h> +#include <linux/of_irq.h> + +#include <asm/mach/time.h> +#include <asm/smp_twd.h> +#include <asm/sched_clock.h> + +#define RTC_SECONDS 0x08 +#define RTC_SHADOW_SECONDS 0x0c +#define RTC_MILLISECONDS 0x10 + +#define TIMERUS_CNTR_1US 0x10 +#define TIMERUS_USEC_CFG 0x14 +#define TIMERUS_CNTR_FREEZE 0x4c + +#define TIMER1_BASE 0x0 +#define TIMER2_BASE 0x8 +#define TIMER3_BASE 0x50 +#define TIMER4_BASE 0x58 + +#define TIMER_PTV 0x0 +#define TIMER_PCR 0x4 + +static void __iomem *timer_reg_base; +static void __iomem *rtc_base; + +static struct timespec persistent_ts; +static u64 persistent_ms, last_persistent_ms; + +#define timer_writel(value, reg) \ + __raw_writel(value, timer_reg_base + (reg)) +#define timer_readl(reg) \ + __raw_readl(timer_reg_base + (reg)) + +static int tegra_timer_set_next_event(unsigned long cycles, + struct clock_event_device *evt) +{ + u32 reg; + + reg = 0x80000000 | ((cycles > 1) ? (cycles-1) : 0); + timer_writel(reg, TIMER3_BASE + TIMER_PTV); + + return 0; +} + +static void tegra_timer_set_mode(enum clock_event_mode mode, + struct clock_event_device *evt) +{ + u32 reg; + + timer_writel(0, TIMER3_BASE + TIMER_PTV); + + switch (mode) { + case CLOCK_EVT_MODE_PERIODIC: + reg = 0xC0000000 | ((1000000/HZ)-1); + timer_writel(reg, TIMER3_BASE + TIMER_PTV); + break; + case CLOCK_EVT_MODE_ONESHOT: + break; + case CLOCK_EVT_MODE_UNUSED: + case CLOCK_EVT_MODE_SHUTDOWN: + case CLOCK_EVT_MODE_RESUME: + break; + } +} + +static struct clock_event_device tegra_clockevent = { + .name = "timer0", + .rating = 300, + .features = CLOCK_EVT_FEAT_ONESHOT | CLOCK_EVT_FEAT_PERIODIC, + .set_next_event = tegra_timer_set_next_event, + .set_mode = tegra_timer_set_mode, +}; + +static u32 notrace tegra_read_sched_clock(void) +{ + return timer_readl(TIMERUS_CNTR_1US); +} + +/* + * tegra_rtc_read - Reads the Tegra RTC registers + * Care must be taken that this funciton is not called while the + * tegra_rtc driver could be executing to avoid race conditions + * on the RTC shadow register + */ +static u64 tegra_rtc_read_ms(void) +{ + u32 ms = readl(rtc_base + RTC_MILLISECONDS); + u32 s = readl(rtc_base + RTC_SHADOW_SECONDS); + return (u64)s * MSEC_PER_SEC + ms; +} + +/* + * tegra_read_persistent_clock - Return time from a persistent clock. + * + * Reads the time from a source which isn't disabled during PM, the + * 32k sync timer. Convert the cycles elapsed since last read into + * nsecs and adds to a monotonically increasing timespec. + * Care must be taken that this funciton is not called while the + * tegra_rtc driver could be executing to avoid race conditions + * on the RTC shadow register + */ +static void tegra_read_persistent_clock(struct timespec *ts) +{ + u64 delta; + struct timespec *tsp = &persistent_ts; + + last_persistent_ms = persistent_ms; + persistent_ms = tegra_rtc_read_ms(); + delta = persistent_ms - last_persistent_ms; + + timespec_add_ns(tsp, delta * NSEC_PER_MSEC); + *ts = *tsp; +} + +static irqreturn_t tegra_timer_interrupt(int irq, void *dev_id) +{ + struct clock_event_device *evt = (struct clock_event_device *)dev_id; + timer_writel(1<<30, TIMER3_BASE + TIMER_PCR); + evt->event_handler(evt); + return IRQ_HANDLED; +} + +static struct irqaction tegra_timer_irq = { + .name = "timer0", + .flags = IRQF_DISABLED | IRQF_TIMER | IRQF_TRIGGER_HIGH, + .handler = tegra_timer_interrupt, + .dev_id = &tegra_clockevent, +}; + +static const struct of_device_id timer_match[] __initconst = { + { .compatible = "nvidia,tegra20-timer" }, + {} +}; + +static const struct of_device_id rtc_match[] __initconst = { + { .compatible = "nvidia,tegra20-rtc" }, + {} +}; + +static void __init tegra20_init_timer(void) +{ + struct device_node *np; + struct clk *clk; + unsigned long rate; + int ret; + + np = of_find_matching_node(NULL, timer_match); + if (!np) { + pr_err("Failed to find timer DT node\n"); + BUG(); + } + + timer_reg_base = of_iomap(np, 0); + if (!timer_reg_base) { + pr_err("Can't map timer registers"); + BUG(); + } + + tegra_timer_irq.irq = irq_of_parse_and_map(np, 2); + if (tegra_timer_irq.irq <= 0) { + pr_err("Failed to map timer IRQ\n"); + BUG(); + } + + clk = clk_get_sys("timer", NULL); + if (IS_ERR(clk)) { + pr_warn("Unable to get timer clock. Assuming 12Mhz input clock.\n"); + rate = 12000000; + } else { + clk_prepare_enable(clk); + rate = clk_get_rate(clk); + } + + of_node_put(np); + + np = of_find_matching_node(NULL, rtc_match); + if (!np) { + pr_err("Failed to find RTC DT node\n"); + BUG(); + } + + rtc_base = of_iomap(np, 0); + if (!rtc_base) { + pr_err("Can't map RTC registers"); + BUG(); + } + + /* + * rtc registers are used by read_persistent_clock, keep the rtc clock + * enabled + */ + clk = clk_get_sys("rtc-tegra", NULL); + if (IS_ERR(clk)) + pr_warn("Unable to get rtc-tegra clock\n"); + else + clk_prepare_enable(clk); + + of_node_put(np); + + switch (rate) { + case 12000000: + timer_writel(0x000b, TIMERUS_USEC_CFG); + break; + case 13000000: + timer_writel(0x000c, TIMERUS_USEC_CFG); + break; + case 19200000: + timer_writel(0x045f, TIMERUS_USEC_CFG); + break; + case 26000000: + timer_writel(0x0019, TIMERUS_USEC_CFG); + break; + default: + WARN(1, "Unknown clock rate"); + } + + setup_sched_clock(tegra_read_sched_clock, 32, 1000000); + + if (clocksource_mmio_init(timer_reg_base + TIMERUS_CNTR_1US, + "timer_us", 1000000, 300, 32, clocksource_mmio_readl_up)) { + pr_err("Failed to register clocksource\n"); + BUG(); + } + + ret = setup_irq(tegra_timer_irq.irq, &tegra_timer_irq); + if (ret) { + pr_err("Failed to register timer IRQ: %d\n", ret); + BUG(); + } + + clockevents_calc_mult_shift(&tegra_clockevent, 1000000, 5); + tegra_clockevent.max_delta_ns = + clockevent_delta2ns(0x1fffffff, &tegra_clockevent); + tegra_clockevent.min_delta_ns = + clockevent_delta2ns(0x1, &tegra_clockevent); + tegra_clockevent.cpumask = cpu_all_mask; + tegra_clockevent.irq = tegra_timer_irq.irq; + clockevents_register_device(&tegra_clockevent); +#ifdef CONFIG_HAVE_ARM_TWD + twd_local_timer_of_register(); +#endif + register_persistent_clock(NULL, tegra_read_persistent_clock); +} +CLOCKSOURCE_OF_DECLARE(tegra20, "nvidia,tegra20-timer", tegra20_init_timer); + +#ifdef CONFIG_PM +static u32 usec_config; + +void tegra_timer_suspend(void) +{ + usec_config = timer_readl(TIMERUS_USEC_CFG); +} + +void tegra_timer_resume(void) +{ + timer_writel(usec_config, TIMERUS_USEC_CFG); +} +#endif |