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-rw-r--r--drivers/clocksource/timer-imx-sysctr.c150
1 files changed, 150 insertions, 0 deletions
diff --git a/drivers/clocksource/timer-imx-sysctr.c b/drivers/clocksource/timer-imx-sysctr.c
new file mode 100644
index 0000000000..5a7a951c4e
--- /dev/null
+++ b/drivers/clocksource/timer-imx-sysctr.c
@@ -0,0 +1,150 @@
+// SPDX-License-Identifier: GPL-2.0+
+//
+// Copyright 2017-2019 NXP
+
+#include <linux/interrupt.h>
+#include <linux/clockchips.h>
+
+#include "timer-of.h"
+
+#define CMP_OFFSET 0x10000
+
+#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 SYS_CTR_EN 0x1
+#define SYS_CTR_IRQ_MASK 0x2
+
+#define SYS_CTR_CLK_DIV 0x3
+
+static void __iomem *sys_ctr_base __ro_after_init;
+static u32 cmpcr __ro_after_init;
+
+static void sysctr_timer_enable(bool enable)
+{
+ writel(enable ? cmpcr | SYS_CTR_EN : cmpcr, sys_ctr_base + CMPCR);
+}
+
+static void sysctr_irq_acknowledge(void)
+{
+ /*
+ * clear the enable bit(EN =0) will clear
+ * the status bit(ISTAT = 0), then the interrupt
+ * signal will be negated(acknowledged).
+ */
+ sysctr_timer_enable(false);
+}
+
+static inline u64 sysctr_read_counter(void)
+{
+ u32 cnt_hi, tmp_hi, cnt_lo;
+
+ do {
+ cnt_hi = readl_relaxed(sys_ctr_base + CNTCV_HI);
+ cnt_lo = readl_relaxed(sys_ctr_base + CNTCV_LO);
+ tmp_hi = readl_relaxed(sys_ctr_base + CNTCV_HI);
+ } 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)
+{
+ u32 cmp_hi, cmp_lo;
+ u64 next;
+
+ sysctr_timer_enable(false);
+
+ next = sysctr_read_counter();
+
+ next += delta;
+
+ cmp_hi = (next >> 32) & 0x00fffff;
+ cmp_lo = next & 0xffffffff;
+
+ writel_relaxed(cmp_hi, sys_ctr_base + CMPCV_HI);
+ writel_relaxed(cmp_lo, sys_ctr_base + CMPCV_LO);
+
+ sysctr_timer_enable(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(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->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 void __init sysctr_clockevent_init(void)
+{
+ to_sysctr.clkevt.cpumask = cpu_possible_mask;
+
+ clockevents_config_and_register(&to_sysctr.clkevt,
+ timer_of_rate(&to_sysctr),
+ 0xff, 0x7fffffff);
+}
+
+static int __init sysctr_timer_init(struct device_node *np)
+{
+ int ret = 0;
+
+ ret = timer_of_init(np, &to_sysctr);
+ if (ret)
+ 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;
+ }
+
+ sys_ctr_base = timer_of_base(&to_sysctr);
+ cmpcr = readl(sys_ctr_base + CMPCR);
+ cmpcr &= ~SYS_CTR_EN;
+
+ sysctr_clockevent_init();
+
+ return 0;
+}
+TIMER_OF_DECLARE(sysctr_timer, "nxp,sysctr-timer", sysctr_timer_init);