diff options
Diffstat (limited to 'drivers/clocksource/timer-imx-sysctr.c')
| -rw-r--r-- | drivers/clocksource/timer-imx-sysctr.c | 207 |
1 files changed, 207 insertions, 0 deletions
diff --git a/drivers/clocksource/timer-imx-sysctr.c b/drivers/clocksource/timer-imx-sysctr.c new file mode 100644 index 000000000000..44525813be1e --- /dev/null +++ b/drivers/clocksource/timer-imx-sysctr.c @@ -0,0 +1,207 @@ +// SPDX-License-Identifier: GPL-2.0+ +// +// Copyright 2017-2019 NXP + +#include <linux/interrupt.h> +#include <linux/clockchips.h> +#include <linux/slab.h> + +#include "timer-of.h" + +#define CMP_OFFSET 0x10000 +#define RD_OFFSET 0x20000 + +#define CNTCV_LO 0x8 +#define CNTCV_HI 0xc +#define CMPCV_LO (CMP_OFFSET + 0x20) +#define CMPCV_HI (CMP_OFFSET + 0x24) +#define CMPCR (CMP_OFFSET + 0x2c) +#define CNTCV_LO_IMX95 (RD_OFFSET + 0x8) +#define CNTCV_HI_IMX95 (RD_OFFSET + 0xc) + +#define SYS_CTR_EN 0x1 +#define SYS_CTR_IRQ_MASK 0x2 + +#define SYS_CTR_CLK_DIV 0x3 + +struct sysctr_private { + u32 cmpcr; + u32 lo_off; + u32 hi_off; +}; + +static void sysctr_timer_enable(struct clock_event_device *evt, bool enable) +{ + struct timer_of *to = to_timer_of(evt); + struct sysctr_private *priv = to->private_data; + void __iomem *base = timer_of_base(to); + + writel(enable ? priv->cmpcr | SYS_CTR_EN : priv->cmpcr, base + CMPCR); +} + +static void sysctr_irq_acknowledge(struct clock_event_device *evt) +{ + /* + * clear the enable bit(EN =0) will clear + * the status bit(ISTAT = 0), then the interrupt + * signal will be negated(acknowledged). + */ + sysctr_timer_enable(evt, false); +} + +static inline u64 sysctr_read_counter(struct clock_event_device *evt) +{ + struct timer_of *to = to_timer_of(evt); + struct sysctr_private *priv = to->private_data; + void __iomem *base = timer_of_base(to); + u32 cnt_hi, tmp_hi, cnt_lo; + + do { + cnt_hi = readl_relaxed(base + priv->hi_off); + cnt_lo = readl_relaxed(base + priv->lo_off); + tmp_hi = readl_relaxed(base + priv->hi_off); + } while (tmp_hi != cnt_hi); + + return ((u64) cnt_hi << 32) | cnt_lo; +} + +static int sysctr_set_next_event(unsigned long delta, + struct clock_event_device *evt) +{ + struct timer_of *to = to_timer_of(evt); + void __iomem *base = timer_of_base(to); + u32 cmp_hi, cmp_lo; + u64 next; + + sysctr_timer_enable(evt, false); + + next = sysctr_read_counter(evt); + + next += delta; + + cmp_hi = (next >> 32) & 0x00fffff; + cmp_lo = next & 0xffffffff; + + writel_relaxed(cmp_hi, base + CMPCV_HI); + writel_relaxed(cmp_lo, base + CMPCV_LO); + + sysctr_timer_enable(evt, true); + + return 0; +} + +static int sysctr_set_state_oneshot(struct clock_event_device *evt) +{ + return 0; +} + +static int sysctr_set_state_shutdown(struct clock_event_device *evt) +{ + sysctr_timer_enable(evt, false); + + return 0; +} + +static irqreturn_t sysctr_timer_interrupt(int irq, void *dev_id) +{ + struct clock_event_device *evt = dev_id; + + sysctr_irq_acknowledge(evt); + + evt->event_handler(evt); + + return IRQ_HANDLED; +} + +static struct timer_of to_sysctr = { + .flags = TIMER_OF_IRQ | TIMER_OF_CLOCK | TIMER_OF_BASE, + .clkevt = { + .name = "i.MX system counter timer", + .features = CLOCK_EVT_FEAT_ONESHOT | + CLOCK_EVT_FEAT_DYNIRQ, + .set_state_oneshot = sysctr_set_state_oneshot, + .set_next_event = sysctr_set_next_event, + .set_state_shutdown = sysctr_set_state_shutdown, + .rating = 200, + }, + .of_irq = { + .handler = sysctr_timer_interrupt, + .flags = IRQF_TIMER, + }, + .of_clk = { + .name = "per", + }, +}; + +static int __init __sysctr_timer_init(struct device_node *np) +{ + struct sysctr_private *priv; + void __iomem *base; + int ret; + + priv = kzalloc(sizeof(struct sysctr_private), GFP_KERNEL); + if (!priv) + return -ENOMEM; + + ret = timer_of_init(np, &to_sysctr); + if (ret) { + kfree(priv); + return ret; + } + + if (!of_property_read_bool(np, "nxp,no-divider")) { + /* system counter clock is divided by 3 internally */ + to_sysctr.of_clk.rate /= SYS_CTR_CLK_DIV; + } + + to_sysctr.clkevt.cpumask = cpu_possible_mask; + to_sysctr.private_data = priv; + + base = timer_of_base(&to_sysctr); + priv->cmpcr = readl(base + CMPCR) & ~SYS_CTR_EN; + + return 0; +} + +static int __init sysctr_timer_init(struct device_node *np) +{ + struct sysctr_private *priv; + int ret; + + ret = __sysctr_timer_init(np); + if (ret) + return ret; + + priv = to_sysctr.private_data; + priv->lo_off = CNTCV_LO; + priv->hi_off = CNTCV_HI; + + clockevents_config_and_register(&to_sysctr.clkevt, + timer_of_rate(&to_sysctr), + 0xff, 0x7fffffff); + + return 0; +} + +static int __init sysctr_timer_imx95_init(struct device_node *np) +{ + struct sysctr_private *priv; + int ret; + + ret = __sysctr_timer_init(np); + if (ret) + return ret; + + priv = to_sysctr.private_data; + priv->lo_off = CNTCV_LO_IMX95; + priv->hi_off = CNTCV_HI_IMX95; + + clockevents_config_and_register(&to_sysctr.clkevt, + timer_of_rate(&to_sysctr), + 0xff, 0x7fffffff); + + return 0; +} + +TIMER_OF_DECLARE(sysctr_timer, "nxp,sysctr-timer", sysctr_timer_init); +TIMER_OF_DECLARE(sysctr_timer_imx95, "nxp,imx95-sysctr-timer", sysctr_timer_imx95_init); |