diff options
author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:49:45 +0000 |
---|---|---|
committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:49:45 +0000 |
commit | 2c3c1048746a4622d8c89a29670120dc8fab93c4 (patch) | |
tree | 848558de17fb3008cdf4d861b01ac7781903ce39 /drivers/clocksource/timer-fsl-ftm.c | |
parent | Initial commit. (diff) | |
download | linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.tar.xz linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.zip |
Adding upstream version 6.1.76.upstream/6.1.76upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
-rw-r--r-- | drivers/clocksource/timer-fsl-ftm.c | 355 |
1 files changed, 355 insertions, 0 deletions
diff --git a/drivers/clocksource/timer-fsl-ftm.c b/drivers/clocksource/timer-fsl-ftm.c new file mode 100644 index 000000000..93f336ec8 --- /dev/null +++ b/drivers/clocksource/timer-fsl-ftm.c @@ -0,0 +1,355 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Freescale FlexTimer Module (FTM) timer driver. + * + * Copyright 2014 Freescale Semiconductor, Inc. + */ + +#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> +#include <linux/fsl/ftm.h> + +#define FTM_SC_CLK(c) ((c) << FTM_SC_CLK_MASK_SHIFT) + +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 notrace 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 disabled. + */ + 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 int ftm_set_oneshot(struct clock_event_device *evt) +{ + ftm_counter_disable(priv->clkevt_base); + return 0; +} + +static int ftm_set_periodic(struct clock_event_device *evt) +{ + ftm_set_next_event(priv->periodic_cyc, evt); + return 0; +} + +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(clockevent_state_oneshot(evt))) { + 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_state_periodic = ftm_set_periodic, + .set_state_oneshot = ftm_set_oneshot, + .set_next_event = ftm_set_next_event, + .rating = 300, +}; + +static int __init ftm_clockevent_init(unsigned long freq, int irq) +{ + int err; + + ftm_writel(0x00, priv->clkevt_base + FTM_CNTIN); + ftm_writel(~0u, priv->clkevt_base + FTM_MOD); + + ftm_reset_counter(priv->clkevt_base); + + err = request_irq(irq, ftm_evt_interrupt, IRQF_TIMER | IRQF_IRQPOLL, + "Freescale ftm timer", &ftm_clockevent); + 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(~0u, 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) +{ + 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 int __init ftm_timer_init(struct device_node *np) +{ + unsigned long freq; + int ret, irq; + + priv = kzalloc(sizeof(*priv), GFP_KERNEL); + if (!priv) + return -ENOMEM; + + ret = -ENXIO; + priv->clkevt_base = of_iomap(np, 0); + if (!priv->clkevt_base) { + pr_err("ftm: unable to map event timer registers\n"); + goto err_clkevt; + } + + priv->clksrc_base = of_iomap(np, 1); + if (!priv->clksrc_base) { + pr_err("ftm: unable to map source timer registers\n"); + goto err_clksrc; + } + + ret = -EINVAL; + 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; + + ret = ftm_calc_closest_round_cyc(freq); + if (ret) + goto err; + + ret = ftm_clocksource_init(freq); + if (ret) + goto err; + + ret = ftm_clockevent_init(freq, irq); + if (ret) + goto err; + + return 0; + +err: + iounmap(priv->clksrc_base); +err_clksrc: + iounmap(priv->clkevt_base); +err_clkevt: + kfree(priv); + return ret; +} +TIMER_OF_DECLARE(flextimer, "fsl,ftm-timer", ftm_timer_init); |