diff options
Diffstat (limited to 'drivers/clocksource/timer-ixp4xx.c')
| -rw-r--r-- | drivers/clocksource/timer-ixp4xx.c | 293 |
1 files changed, 293 insertions, 0 deletions
diff --git a/drivers/clocksource/timer-ixp4xx.c b/drivers/clocksource/timer-ixp4xx.c new file mode 100644 index 000000000..ad904bbba --- /dev/null +++ b/drivers/clocksource/timer-ixp4xx.c @@ -0,0 +1,293 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * IXP4 timer driver + * Copyright (C) 2019 Linus Walleij <linus.walleij@linaro.org> + * + * Based on arch/arm/mach-ixp4xx/common.c + * Copyright 2002 (C) Intel Corporation + * Copyright 2003-2004 (C) MontaVista, Software, Inc. + * Copyright (C) Deepak Saxena <dsaxena@plexity.net> + */ +#include <linux/interrupt.h> +#include <linux/io.h> +#include <linux/clockchips.h> +#include <linux/clocksource.h> +#include <linux/sched_clock.h> +#include <linux/slab.h> +#include <linux/bitops.h> +#include <linux/delay.h> +#include <linux/of_address.h> +#include <linux/of_irq.h> +/* Goes away with OF conversion */ +#include <linux/platform_data/timer-ixp4xx.h> + +/* + * Constants to make it easy to access Timer Control/Status registers + */ +#define IXP4XX_OSTS_OFFSET 0x00 /* Continuous Timestamp */ +#define IXP4XX_OST1_OFFSET 0x04 /* Timer 1 Timestamp */ +#define IXP4XX_OSRT1_OFFSET 0x08 /* Timer 1 Reload */ +#define IXP4XX_OST2_OFFSET 0x0C /* Timer 2 Timestamp */ +#define IXP4XX_OSRT2_OFFSET 0x10 /* Timer 2 Reload */ +#define IXP4XX_OSWT_OFFSET 0x14 /* Watchdog Timer */ +#define IXP4XX_OSWE_OFFSET 0x18 /* Watchdog Enable */ +#define IXP4XX_OSWK_OFFSET 0x1C /* Watchdog Key */ +#define IXP4XX_OSST_OFFSET 0x20 /* Timer Status */ + +/* + * Timer register values and bit definitions + */ +#define IXP4XX_OST_ENABLE 0x00000001 +#define IXP4XX_OST_ONE_SHOT 0x00000002 +/* Low order bits of reload value ignored */ +#define IXP4XX_OST_RELOAD_MASK 0x00000003 +#define IXP4XX_OST_DISABLED 0x00000000 +#define IXP4XX_OSST_TIMER_1_PEND 0x00000001 +#define IXP4XX_OSST_TIMER_2_PEND 0x00000002 +#define IXP4XX_OSST_TIMER_TS_PEND 0x00000004 +#define IXP4XX_OSST_TIMER_WDOG_PEND 0x00000008 +#define IXP4XX_OSST_TIMER_WARM_RESET 0x00000010 + +#define IXP4XX_WDT_KEY 0x0000482E +#define IXP4XX_WDT_RESET_ENABLE 0x00000001 +#define IXP4XX_WDT_IRQ_ENABLE 0x00000002 +#define IXP4XX_WDT_COUNT_ENABLE 0x00000004 + +struct ixp4xx_timer { + void __iomem *base; + unsigned int tick_rate; + u32 latch; + struct clock_event_device clkevt; +#ifdef CONFIG_ARM + struct delay_timer delay_timer; +#endif +}; + +/* + * A local singleton used by sched_clock and delay timer reads, which are + * fast and stateless + */ +static struct ixp4xx_timer *local_ixp4xx_timer; + +static inline struct ixp4xx_timer * +to_ixp4xx_timer(struct clock_event_device *evt) +{ + return container_of(evt, struct ixp4xx_timer, clkevt); +} + +static unsigned long ixp4xx_read_timer(void) +{ + return __raw_readl(local_ixp4xx_timer->base + IXP4XX_OSTS_OFFSET); +} + +static u64 notrace ixp4xx_read_sched_clock(void) +{ + return ixp4xx_read_timer(); +} + +static u64 ixp4xx_clocksource_read(struct clocksource *c) +{ + return ixp4xx_read_timer(); +} + +static irqreturn_t ixp4xx_timer_interrupt(int irq, void *dev_id) +{ + struct ixp4xx_timer *tmr = dev_id; + struct clock_event_device *evt = &tmr->clkevt; + + /* Clear Pending Interrupt */ + __raw_writel(IXP4XX_OSST_TIMER_1_PEND, + tmr->base + IXP4XX_OSST_OFFSET); + + evt->event_handler(evt); + + return IRQ_HANDLED; +} + +static int ixp4xx_set_next_event(unsigned long cycles, + struct clock_event_device *evt) +{ + struct ixp4xx_timer *tmr = to_ixp4xx_timer(evt); + u32 val; + + val = __raw_readl(tmr->base + IXP4XX_OSRT1_OFFSET); + /* Keep enable/oneshot bits */ + val &= IXP4XX_OST_RELOAD_MASK; + __raw_writel((cycles & ~IXP4XX_OST_RELOAD_MASK) | val, + tmr->base + IXP4XX_OSRT1_OFFSET); + + return 0; +} + +static int ixp4xx_shutdown(struct clock_event_device *evt) +{ + struct ixp4xx_timer *tmr = to_ixp4xx_timer(evt); + u32 val; + + val = __raw_readl(tmr->base + IXP4XX_OSRT1_OFFSET); + val &= ~IXP4XX_OST_ENABLE; + __raw_writel(val, tmr->base + IXP4XX_OSRT1_OFFSET); + + return 0; +} + +static int ixp4xx_set_oneshot(struct clock_event_device *evt) +{ + struct ixp4xx_timer *tmr = to_ixp4xx_timer(evt); + + __raw_writel(IXP4XX_OST_ENABLE | IXP4XX_OST_ONE_SHOT, + tmr->base + IXP4XX_OSRT1_OFFSET); + + return 0; +} + +static int ixp4xx_set_periodic(struct clock_event_device *evt) +{ + struct ixp4xx_timer *tmr = to_ixp4xx_timer(evt); + u32 val; + + val = tmr->latch & ~IXP4XX_OST_RELOAD_MASK; + val |= IXP4XX_OST_ENABLE; + __raw_writel(val, tmr->base + IXP4XX_OSRT1_OFFSET); + + return 0; +} + +static int ixp4xx_resume(struct clock_event_device *evt) +{ + struct ixp4xx_timer *tmr = to_ixp4xx_timer(evt); + u32 val; + + val = __raw_readl(tmr->base + IXP4XX_OSRT1_OFFSET); + val |= IXP4XX_OST_ENABLE; + __raw_writel(val, tmr->base + IXP4XX_OSRT1_OFFSET); + + return 0; +} + +/* + * IXP4xx timer tick + * We use OS timer1 on the CPU for the timer tick and the timestamp + * counter as a source of real clock ticks to account for missed jiffies. + */ +static __init int ixp4xx_timer_register(void __iomem *base, + int timer_irq, + unsigned int timer_freq) +{ + struct ixp4xx_timer *tmr; + int ret; + + tmr = kzalloc(sizeof(*tmr), GFP_KERNEL); + if (!tmr) + return -ENOMEM; + tmr->base = base; + tmr->tick_rate = timer_freq; + + /* + * The timer register doesn't allow to specify the two least + * significant bits of the timeout value and assumes them being zero. + * So make sure the latch is the best value with the two least + * significant bits unset. + */ + tmr->latch = DIV_ROUND_CLOSEST(timer_freq, + (IXP4XX_OST_RELOAD_MASK + 1) * HZ) + * (IXP4XX_OST_RELOAD_MASK + 1); + + local_ixp4xx_timer = tmr; + + /* Reset/disable counter */ + __raw_writel(0, tmr->base + IXP4XX_OSRT1_OFFSET); + + /* Clear any pending interrupt on timer 1 */ + __raw_writel(IXP4XX_OSST_TIMER_1_PEND, + tmr->base + IXP4XX_OSST_OFFSET); + + /* Reset time-stamp counter */ + __raw_writel(0, tmr->base + IXP4XX_OSTS_OFFSET); + + clocksource_mmio_init(NULL, "OSTS", timer_freq, 200, 32, + ixp4xx_clocksource_read); + + tmr->clkevt.name = "ixp4xx timer1"; + tmr->clkevt.features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT; + tmr->clkevt.rating = 200; + tmr->clkevt.set_state_shutdown = ixp4xx_shutdown; + tmr->clkevt.set_state_periodic = ixp4xx_set_periodic; + tmr->clkevt.set_state_oneshot = ixp4xx_set_oneshot; + tmr->clkevt.tick_resume = ixp4xx_resume; + tmr->clkevt.set_next_event = ixp4xx_set_next_event; + tmr->clkevt.cpumask = cpumask_of(0); + tmr->clkevt.irq = timer_irq; + ret = request_irq(timer_irq, ixp4xx_timer_interrupt, + IRQF_TIMER, "IXP4XX-TIMER1", tmr); + if (ret) { + pr_crit("no timer IRQ\n"); + return -ENODEV; + } + clockevents_config_and_register(&tmr->clkevt, timer_freq, + 0xf, 0xfffffffe); + + sched_clock_register(ixp4xx_read_sched_clock, 32, timer_freq); + +#ifdef CONFIG_ARM + /* Also use this timer for delays */ + tmr->delay_timer.read_current_timer = ixp4xx_read_timer; + tmr->delay_timer.freq = timer_freq; + register_current_timer_delay(&tmr->delay_timer); +#endif + + return 0; +} + +/** + * ixp4xx_timer_setup() - Timer setup function to be called from boardfiles + * @timerbase: physical base of timer block + * @timer_irq: Linux IRQ number for the timer + * @timer_freq: Fixed frequency of the timer + */ +void __init ixp4xx_timer_setup(resource_size_t timerbase, + int timer_irq, + unsigned int timer_freq) +{ + void __iomem *base; + + base = ioremap(timerbase, 0x100); + if (!base) { + pr_crit("IXP4xx: can't remap timer\n"); + return; + } + ixp4xx_timer_register(base, timer_irq, timer_freq); +} + +#ifdef CONFIG_OF +static __init int ixp4xx_of_timer_init(struct device_node *np) +{ + void __iomem *base; + int irq; + int ret; + + base = of_iomap(np, 0); + if (!base) { + pr_crit("IXP4xx: can't remap timer\n"); + return -ENODEV; + } + + irq = irq_of_parse_and_map(np, 0); + if (irq <= 0) { + pr_err("Can't parse IRQ\n"); + ret = -EINVAL; + goto out_unmap; + } + + /* TODO: get some fixed clocks into the device tree */ + ret = ixp4xx_timer_register(base, irq, 66666000); + if (ret) + goto out_unmap; + return 0; + +out_unmap: + iounmap(base); + return ret; +} +TIMER_OF_DECLARE(ixp4xx, "intel,ixp4xx-timer", ixp4xx_of_timer_init); +#endif |