diff options
Diffstat (limited to 'drivers/clocksource/tegra20_timer.c')
| -rw-r--r-- | drivers/clocksource/tegra20_timer.c | 264 |
1 files changed, 264 insertions, 0 deletions
diff --git a/drivers/clocksource/tegra20_timer.c b/drivers/clocksource/tegra20_timer.c new file mode 100644 index 000000000..aa624885e --- /dev/null +++ b/drivers/clocksource/tegra20_timer.c @@ -0,0 +1,264 @@ +/* + * 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 <linux/sched_clock.h> +#include <linux/delay.h> + +#include <asm/mach/time.h> +#include <asm/smp_twd.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 timespec64 persistent_ts; +static u64 persistent_ms, last_persistent_ms; + +static struct delay_timer tegra_delay_timer; + +#define timer_writel(value, reg) \ + writel_relaxed(value, timer_reg_base + (reg)) +#define timer_readl(reg) \ + readl_relaxed(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 inline void timer_shutdown(struct clock_event_device *evt) +{ + timer_writel(0, TIMER3_BASE + TIMER_PTV); +} + +static int tegra_timer_shutdown(struct clock_event_device *evt) +{ + timer_shutdown(evt); + return 0; +} + +static int tegra_timer_set_periodic(struct clock_event_device *evt) +{ + u32 reg = 0xC0000000 | ((1000000 / HZ) - 1); + + timer_shutdown(evt); + timer_writel(reg, TIMER3_BASE + TIMER_PTV); + return 0; +} + +static struct clock_event_device tegra_clockevent = { + .name = "timer0", + .rating = 300, + .features = CLOCK_EVT_FEAT_ONESHOT | + CLOCK_EVT_FEAT_PERIODIC | + CLOCK_EVT_FEAT_DYNIRQ, + .set_next_event = tegra_timer_set_next_event, + .set_state_shutdown = tegra_timer_shutdown, + .set_state_periodic = tegra_timer_set_periodic, + .set_state_oneshot = tegra_timer_shutdown, + .tick_resume = tegra_timer_shutdown, +}; + +static u64 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_clock64 - 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 timespec64. + * 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_clock64(struct timespec64 *ts) +{ + u64 delta; + + last_persistent_ms = persistent_ms; + persistent_ms = tegra_rtc_read_ms(); + delta = persistent_ms - last_persistent_ms; + + timespec64_add_ns(&persistent_ts, delta * NSEC_PER_MSEC); + *ts = persistent_ts; +} + +static unsigned long tegra_delay_timer_read_counter_long(void) +{ + return readl(timer_reg_base + TIMERUS_CNTR_1US); +} + +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_TIMER | IRQF_TRIGGER_HIGH, + .handler = tegra_timer_interrupt, + .dev_id = &tegra_clockevent, +}; + +static int __init tegra20_init_timer(struct device_node *np) +{ + struct clk *clk; + unsigned long rate; + int ret; + + timer_reg_base = of_iomap(np, 0); + if (!timer_reg_base) { + pr_err("Can't map timer registers\n"); + return -ENXIO; + } + + 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"); + return -EINVAL; + } + + clk = of_clk_get(np, 0); + 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); + } + + 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"); + } + + sched_clock_register(tegra_read_sched_clock, 32, 1000000); + + ret = clocksource_mmio_init(timer_reg_base + TIMERUS_CNTR_1US, + "timer_us", 1000000, 300, 32, + clocksource_mmio_readl_up); + if (ret) { + pr_err("Failed to register clocksource\n"); + return ret; + } + + tegra_delay_timer.read_current_timer = + tegra_delay_timer_read_counter_long; + tegra_delay_timer.freq = 1000000; + register_current_timer_delay(&tegra_delay_timer); + + ret = setup_irq(tegra_timer_irq.irq, &tegra_timer_irq); + if (ret) { + pr_err("Failed to register timer IRQ: %d\n", ret); + return ret; + } + + tegra_clockevent.cpumask = cpu_possible_mask; + tegra_clockevent.irq = tegra_timer_irq.irq; + clockevents_config_and_register(&tegra_clockevent, 1000000, + 0x1, 0x1fffffff); + + return 0; +} +TIMER_OF_DECLARE(tegra20_timer, "nvidia,tegra20-timer", tegra20_init_timer); + +static int __init tegra20_init_rtc(struct device_node *np) +{ + struct clk *clk; + + rtc_base = of_iomap(np, 0); + if (!rtc_base) { + pr_err("Can't map RTC registers\n"); + return -ENXIO; + } + + /* + * rtc registers are used by read_persistent_clock, keep the rtc clock + * enabled + */ + clk = of_clk_get(np, 0); + if (IS_ERR(clk)) + pr_warn("Unable to get rtc-tegra clock\n"); + else + clk_prepare_enable(clk); + + return register_persistent_clock(tegra_read_persistent_clock64); +} +TIMER_OF_DECLARE(tegra20_rtc, "nvidia,tegra20-rtc", tegra20_init_rtc); |