clocksource/drivers/imx-sysctr: Drop use global variables

Clean up code to not use global variables and introduce sysctr_private
structure to prepare the support for i.MX95.

Signed-off-by: Peng Fan <peng.fan@nxp.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20240205-imx-sysctr-v4-2-ca5a6e1552e7@nxp.com

Author: MrVan

drivers/clocksource/timer-imx-sysctr.c

@@ -4,6 +4,7 @@
 
 #include <linux/interrupt.h>
 #include <linux/clockchips.h>
+#include <linux/slab.h>
 
 #include "timer-of.h"
 
@@ -20,32 +21,39 @@
 
 #define SYS_CTR_CLK_DIV		0x3
 
-static void __iomem *sys_ctr_base __ro_after_init;
-static u32 cmpcr __ro_after_init;
+struct sysctr_private {
+	u32 cmpcr;
+};
 
-static void sysctr_timer_enable(bool enable)
+static void sysctr_timer_enable(struct clock_event_device *evt, bool enable)
 {
-	writel(enable ? cmpcr | SYS_CTR_EN : cmpcr, sys_ctr_base + CMPCR);
+	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(void)
+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(false);
+	sysctr_timer_enable(evt, false);
 }
 
-static inline u64 sysctr_read_counter(void)
+static inline u64 sysctr_read_counter(struct clock_event_device *evt)
 {
+	struct timer_of *to = to_timer_of(evt);
+	void __iomem *base = timer_of_base(to);
 	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);
+		cnt_hi = readl_relaxed(base + CNTCV_HI);
+		cnt_lo = readl_relaxed(base + CNTCV_LO);
+		tmp_hi = readl_relaxed(base + CNTCV_HI);
 	} while (tmp_hi != cnt_hi);
 
 	return  ((u64) cnt_hi << 32) | cnt_lo;
@@ -54,22 +62,24 @@ static inline u64 sysctr_read_counter(void)
 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(false);
+	sysctr_timer_enable(evt, false);
 
-	next = sysctr_read_counter();
+	next = sysctr_read_counter(evt);
 
 	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);
+	writel_relaxed(cmp_hi, base + CMPCV_HI);
+	writel_relaxed(cmp_lo, base + CMPCV_LO);
 
-	sysctr_timer_enable(true);
+	sysctr_timer_enable(evt, true);
 
 	return 0;
 }
@@ -81,7 +91,7 @@ static int sysctr_set_state_oneshot(struct clock_event_device *evt)
 
 static int sysctr_set_state_shutdown(struct clock_event_device *evt)
 {
-	sysctr_timer_enable(false);
+	sysctr_timer_enable(evt, false);
 
 	return 0;
 }
@@ -90,7 +100,7 @@ static irqreturn_t sysctr_timer_interrupt(int irq, void *dev_id)
 {
 	struct clock_event_device *evt = dev_id;
 
-	sysctr_irq_acknowledge();
+	sysctr_irq_acknowledge(evt);
 
 	evt->event_handler(evt);
 
@@ -117,34 +127,36 @@ static struct timer_of to_sysctr = {
 	},
 };
 
-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;
+	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)
+	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;
 	}
 
-	sys_ctr_base = timer_of_base(&to_sysctr);
-	cmpcr = readl(sys_ctr_base + CMPCR);
-	cmpcr &= ~SYS_CTR_EN;
+	to_sysctr.clkevt.cpumask = cpu_possible_mask;
+	to_sysctr.private_data = priv;
 
-	sysctr_clockevent_init();
+	base = timer_of_base(&to_sysctr);
+	priv->cmpcr = readl(base + CMPCR) & ~SYS_CTR_EN;
 
+	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);