diff options
Diffstat (limited to 'drivers/clocksource')
| -rw-r--r-- | drivers/clocksource/Kconfig | 5 | ||||
| -rw-r--r-- | drivers/clocksource/Makefile | 1 | ||||
| -rw-r--r-- | drivers/clocksource/fsl_ftm_timer.c | 367 |
3 files changed, 373 insertions, 0 deletions
diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig index 96918e1f26a3..04377675c3fa 100644 --- a/drivers/clocksource/Kconfig +++ b/drivers/clocksource/Kconfig @@ -136,6 +136,11 @@ config CLKSRC_SAMSUNG_PWM for all devicetree enabled platforms. This driver will be needed only on systems that do not have the Exynos MCT available. +config FSL_FTM_TIMER + bool + help + Support for Freescale FlexTimer Module (FTM) timer. + config VF_PIT_TIMER bool help diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile index 98cb6c51aa87..0770916a818e 100644 --- a/drivers/clocksource/Makefile +++ b/drivers/clocksource/Makefile @@ -31,6 +31,7 @@ obj-$(CONFIG_CADENCE_TTC_TIMER) += cadence_ttc_timer.o obj-$(CONFIG_CLKSRC_EFM32) += time-efm32.o obj-$(CONFIG_CLKSRC_EXYNOS_MCT) += exynos_mct.o obj-$(CONFIG_CLKSRC_SAMSUNG_PWM) += samsung_pwm_timer.o +obj-$(CONFIG_FSL_FTM_TIMER) += fsl_ftm_timer.o obj-$(CONFIG_VF_PIT_TIMER) += vf_pit_timer.o obj-$(CONFIG_CLKSRC_QCOM) += qcom-timer.o diff --git a/drivers/clocksource/fsl_ftm_timer.c b/drivers/clocksource/fsl_ftm_timer.c new file mode 100644 index 000000000000..454227d4f895 --- /dev/null +++ b/drivers/clocksource/fsl_ftm_timer.c @@ -0,0 +1,367 @@ +/* + * Freescale FlexTimer Module (FTM) timer driver. + * + * Copyright 2014 Freescale Semiconductor, Inc. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version 2 + * of the License, or (at your option) any later version. + */ + +#include <linux/clk.h> +#include <linux/clockchips.h> +#include <linux/clocksource.h> +#include <linux/err.h> +#include <linux/interrupt.h> +#include <linux/io.h> +#include <linux/of_address.h> +#include <linux/of_irq.h> +#include <linux/sched_clock.h> +#include <linux/slab.h> + +#define FTM_SC 0x00 +#define FTM_SC_CLK_SHIFT 3 +#define FTM_SC_CLK_MASK (0x3 << FTM_SC_CLK_SHIFT) +#define FTM_SC_CLK(c) ((c) << FTM_SC_CLK_SHIFT) +#define FTM_SC_PS_MASK 0x7 +#define FTM_SC_TOIE BIT(6) +#define FTM_SC_TOF BIT(7) + +#define FTM_CNT 0x04 +#define FTM_MOD 0x08 +#define FTM_CNTIN 0x4C + +#define FTM_PS_MAX 7 + +struct ftm_clock_device { + void __iomem *clksrc_base; + void __iomem *clkevt_base; + unsigned long periodic_cyc; + unsigned long ps; + bool big_endian; +}; + +static struct ftm_clock_device *priv; + +static inline u32 ftm_readl(void __iomem *addr) +{ + if (priv->big_endian) + return ioread32be(addr); + else + return ioread32(addr); +} + +static inline void ftm_writel(u32 val, void __iomem *addr) +{ + if (priv->big_endian) + iowrite32be(val, addr); + else + iowrite32(val, addr); +} + +static inline void ftm_counter_enable(void __iomem *base) +{ + u32 val; + + /* select and enable counter clock source */ + val = ftm_readl(base + FTM_SC); + val &= ~(FTM_SC_PS_MASK | FTM_SC_CLK_MASK); + val |= priv->ps | FTM_SC_CLK(1); + ftm_writel(val, base + FTM_SC); +} + +static inline void ftm_counter_disable(void __iomem *base) +{ + u32 val; + + /* disable counter clock source */ + val = ftm_readl(base + FTM_SC); + val &= ~(FTM_SC_PS_MASK | FTM_SC_CLK_MASK); + ftm_writel(val, base + FTM_SC); +} + +static inline void ftm_irq_acknowledge(void __iomem *base) +{ + u32 val; + + val = ftm_readl(base + FTM_SC); + val &= ~FTM_SC_TOF; + ftm_writel(val, base + FTM_SC); +} + +static inline void ftm_irq_enable(void __iomem *base) +{ + u32 val; + + val = ftm_readl(base + FTM_SC); + val |= FTM_SC_TOIE; + ftm_writel(val, base + FTM_SC); +} + +static inline void ftm_irq_disable(void __iomem *base) +{ + u32 val; + + val = ftm_readl(base + FTM_SC); + val &= ~FTM_SC_TOIE; + ftm_writel(val, base + FTM_SC); +} + +static inline void ftm_reset_counter(void __iomem *base) +{ + /* + * The CNT register contains the FTM counter value. + * Reset clears the CNT register. Writing any value to COUNT + * updates the counter with its initial value, CNTIN. + */ + ftm_writel(0x00, base + FTM_CNT); +} + +static u64 ftm_read_sched_clock(void) +{ + return ftm_readl(priv->clksrc_base + FTM_CNT); +} + +static int ftm_set_next_event(unsigned long delta, + struct clock_event_device *unused) +{ + /* + * The CNNIN and MOD are all double buffer registers, writing + * to the MOD register latches the value into a buffer. The MOD + * register is updated with the value of its write buffer with + * the following scenario: + * a, the counter source clock is diabled. + */ + ftm_counter_disable(priv->clkevt_base); + + /* Force the value of CNTIN to be loaded into the FTM counter */ + ftm_reset_counter(priv->clkevt_base); + + /* + * The counter increments until the value of MOD is reached, + * at which point the counter is reloaded with the value of CNTIN. + * The TOF (the overflow flag) bit is set when the FTM counter + * changes from MOD to CNTIN. So we should using the delta - 1. + */ + ftm_writel(delta - 1, priv->clkevt_base + FTM_MOD); + + ftm_counter_enable(priv->clkevt_base); + + ftm_irq_enable(priv->clkevt_base); + + return 0; +} + +static void ftm_set_mode(enum clock_event_mode mode, + struct clock_event_device *evt) +{ + switch (mode) { + case CLOCK_EVT_MODE_PERIODIC: + ftm_set_next_event(priv->periodic_cyc, evt); + break; + case CLOCK_EVT_MODE_ONESHOT: + ftm_counter_disable(priv->clkevt_base); + break; + default: + return; + } +} + +static irqreturn_t ftm_evt_interrupt(int irq, void *dev_id) +{ + struct clock_event_device *evt = dev_id; + + ftm_irq_acknowledge(priv->clkevt_base); + + if (likely(evt->mode == CLOCK_EVT_MODE_ONESHOT)) { + ftm_irq_disable(priv->clkevt_base); + ftm_counter_disable(priv->clkevt_base); + } + + evt->event_handler(evt); + + return IRQ_HANDLED; +} + +static struct clock_event_device ftm_clockevent = { + .name = "Freescale ftm timer", + .features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT, + .set_mode = ftm_set_mode, + .set_next_event = ftm_set_next_event, + .rating = 300, +}; + +static struct irqaction ftm_timer_irq = { + .name = "Freescale ftm timer", + .flags = IRQF_TIMER | IRQF_IRQPOLL, + .handler = ftm_evt_interrupt, + .dev_id = &ftm_clockevent, +}; + +static int __init ftm_clockevent_init(unsigned long freq, int irq) +{ + int err; + + ftm_writel(0x00, priv->clkevt_base + FTM_CNTIN); + ftm_writel(~0UL, priv->clkevt_base + FTM_MOD); + + ftm_reset_counter(priv->clkevt_base); + + err = setup_irq(irq, &ftm_timer_irq); + if (err) { + pr_err("ftm: setup irq failed: %d\n", err); + return err; + } + + ftm_clockevent.cpumask = cpumask_of(0); + ftm_clockevent.irq = irq; + + clockevents_config_and_register(&ftm_clockevent, + freq / (1 << priv->ps), + 1, 0xffff); + + ftm_counter_enable(priv->clkevt_base); + + return 0; +} + +static int __init ftm_clocksource_init(unsigned long freq) +{ + int err; + + ftm_writel(0x00, priv->clksrc_base + FTM_CNTIN); + ftm_writel(~0UL, priv->clksrc_base + FTM_MOD); + + ftm_reset_counter(priv->clksrc_base); + + sched_clock_register(ftm_read_sched_clock, 16, freq / (1 << priv->ps)); + err = clocksource_mmio_init(priv->clksrc_base + FTM_CNT, "fsl-ftm", + freq / (1 << priv->ps), 300, 16, + clocksource_mmio_readl_up); + if (err) { + pr_err("ftm: init clock source mmio failed: %d\n", err); + return err; + } + + ftm_counter_enable(priv->clksrc_base); + + return 0; +} + +static int __init __ftm_clk_init(struct device_node *np, char *cnt_name, + char *ftm_name) +{ + struct clk *clk; + int err; + + clk = of_clk_get_by_name(np, cnt_name); + if (IS_ERR(clk)) { + pr_err("ftm: Cannot get \"%s\": %ld\n", cnt_name, PTR_ERR(clk)); + return PTR_ERR(clk); + } + err = clk_prepare_enable(clk); + if (err) { + pr_err("ftm: clock failed to prepare+enable \"%s\": %d\n", + cnt_name, err); + return err; + } + + clk = of_clk_get_by_name(np, ftm_name); + if (IS_ERR(clk)) { + pr_err("ftm: Cannot get \"%s\": %ld\n", ftm_name, PTR_ERR(clk)); + return PTR_ERR(clk); + } + err = clk_prepare_enable(clk); + if (err) + pr_err("ftm: clock failed to prepare+enable \"%s\": %d\n", + ftm_name, err); + + return clk_get_rate(clk); +} + +static unsigned long __init ftm_clk_init(struct device_node *np) +{ + unsigned long freq; + + freq = __ftm_clk_init(np, "ftm-evt-counter-en", "ftm-evt"); + if (freq <= 0) + return 0; + + freq = __ftm_clk_init(np, "ftm-src-counter-en", "ftm-src"); + if (freq <= 0) + return 0; + + return freq; +} + +static int __init ftm_calc_closest_round_cyc(unsigned long freq) +{ + priv->ps = 0; + + /* The counter register is only using the lower 16 bits, and + * if the 'freq' value is to big here, then the periodic_cyc + * may exceed 0xFFFF. + */ + do { + priv->periodic_cyc = DIV_ROUND_CLOSEST(freq, + HZ * (1 << priv->ps++)); + } while (priv->periodic_cyc > 0xFFFF); + + if (priv->ps > FTM_PS_MAX) { + pr_err("ftm: the prescaler is %lu > %d\n", + priv->ps, FTM_PS_MAX); + return -EINVAL; + } + + return 0; +} + +static void __init ftm_timer_init(struct device_node *np) +{ + unsigned long freq; + int irq; + + priv = kzalloc(sizeof(*priv), GFP_KERNEL); + if (!priv) + return; + + priv->clkevt_base = of_iomap(np, 0); + if (!priv->clkevt_base) { + pr_err("ftm: unable to map event timer registers\n"); + goto err; + } + + priv->clksrc_base = of_iomap(np, 1); + if (!priv->clksrc_base) { + pr_err("ftm: unable to map source timer registers\n"); + goto err; + } + + irq = irq_of_parse_and_map(np, 0); + if (irq <= 0) { + pr_err("ftm: unable to get IRQ from DT, %d\n", irq); + goto err; + } + + priv->big_endian = of_property_read_bool(np, "big-endian"); + + freq = ftm_clk_init(np); + if (!freq) + goto err; + + if (ftm_calc_closest_round_cyc(freq)) + goto err; + + if (ftm_clocksource_init(freq)) + goto err; + + if (ftm_clockevent_init(freq, irq)) + goto err; + + return; + +err: + kfree(priv); +} +CLOCKSOURCE_OF_DECLARE(flextimer, "fsl,ftm-timer", ftm_timer_init); |