1 files changed, 149 insertions, 0 deletions
diff --git a/arch/m68k/coldfire/sltimers.c b/arch/m68k/coldfire/sltimers.c
new file mode 100644
index 000000000..f9d572ee6
--- /dev/null
+++ b/arch/m68k/coldfire/sltimers.c
@@ -0,0 +1,149 @@
+// SPDX-License-Identifier: GPL-2.0
+/***************************************************************************/
+
+/*
+ *	sltimers.c -- generic ColdFire slice timer support.
+ *
+ *	Copyright (C) 2009-2010, Philippe De Muyter <phdm@macqel.be>
+ *	based on
+ *	timers.c -- generic ColdFire hardware timer support.
+ *	Copyright (C) 1999-2008, Greg Ungerer <gerg@snapgear.com>
+ */
+
+/***************************************************************************/
+
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/sched.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/profile.h>
+#include <linux/clocksource.h>
+#include <asm/io.h>
+#include <asm/traps.h>
+#include <asm/machdep.h>
+#include <asm/coldfire.h>
+#include <asm/mcfslt.h>
+#include <asm/mcfsim.h>
+
+/***************************************************************************/
+
+#ifdef CONFIG_HIGHPROFILE
+
+/*
+ *	By default use Slice Timer 1 as the profiler clock timer.
+ */
+#define	PA(a)	(MCFSLT_TIMER1 + (a))
+
+/*
+ *	Choose a reasonably fast profile timer. Make it an odd value to
+ *	try and get good coverage of kernel operations.
+ */
+#define	PROFILEHZ	1013
+
+irqreturn_t mcfslt_profile_tick(int irq, void *dummy)
+{
+	/* Reset Slice Timer 1 */
+	__raw_writel(MCFSLT_SSR_BE | MCFSLT_SSR_TE, PA(MCFSLT_SSR));
+	if (current->pid)
+		profile_tick(CPU_PROFILING);
+	return IRQ_HANDLED;
+}
+
+void mcfslt_profile_init(void)
+{
+	int ret;
+
+	printk(KERN_INFO "PROFILE: lodging TIMER 1 @ %dHz as profile timer\n",
+	       PROFILEHZ);
+
+	ret = request_irq(MCF_IRQ_PROFILER, mcfslt_profile_tick, IRQF_TIMER,
+			  "profile timer", NULL);
+	if (ret) {
+		pr_err("Failed to request irq %d (profile timer): %pe\n",
+		       MCF_IRQ_PROFILER, ERR_PTR(ret));
+	}
+
+	/* Set up TIMER 2 as high speed profile clock */
+	__raw_writel(MCF_BUSCLK / PROFILEHZ - 1, PA(MCFSLT_STCNT));
+	__raw_writel(MCFSLT_SCR_RUN | MCFSLT_SCR_IEN | MCFSLT_SCR_TEN,
+								PA(MCFSLT_SCR));
+
+}
+
+#endif	/* CONFIG_HIGHPROFILE */
+
+/***************************************************************************/
+
+/*
+ *	By default use Slice Timer 0 as the system clock timer.
+ */
+#define	TA(a)	(MCFSLT_TIMER0 + (a))
+
+static u32 mcfslt_cycles_per_jiffy;
+static u32 mcfslt_cnt;
+
+static irqreturn_t mcfslt_tick(int irq, void *dummy)
+{
+	/* Reset Slice Timer 0 */
+	__raw_writel(MCFSLT_SSR_BE | MCFSLT_SSR_TE, TA(MCFSLT_SSR));
+	mcfslt_cnt += mcfslt_cycles_per_jiffy;
+	legacy_timer_tick(1);
+	return IRQ_HANDLED;
+}
+
+static u64 mcfslt_read_clk(struct clocksource *cs)
+{
+	unsigned long flags;
+	u32 cycles, scnt;
+
+	local_irq_save(flags);
+	scnt = __raw_readl(TA(MCFSLT_SCNT));
+	cycles = mcfslt_cnt;
+	if (__raw_readl(TA(MCFSLT_SSR)) & MCFSLT_SSR_TE) {
+		cycles += mcfslt_cycles_per_jiffy;
+		scnt = __raw_readl(TA(MCFSLT_SCNT));
+	}
+	local_irq_restore(flags);
+
+	/* subtract because slice timers count down */
+	return cycles + ((mcfslt_cycles_per_jiffy - 1) - scnt);
+}
+
+static struct clocksource mcfslt_clk = {
+	.name	= "slt",
+	.rating	= 250,
+	.read	= mcfslt_read_clk,
+	.mask	= CLOCKSOURCE_MASK(32),
+	.flags	= CLOCK_SOURCE_IS_CONTINUOUS,
+};
+
+void hw_timer_init(void)
+{
+	int r;
+
+	mcfslt_cycles_per_jiffy = MCF_BUSCLK / HZ;
+	/*
+	 *	The coldfire slice timer (SLT) runs from STCNT to 0 included,
+	 *	then STCNT again and so on.  It counts thus actually
+	 *	STCNT + 1 steps for 1 tick, not STCNT.  So if you want
+	 *	n cycles, initialize STCNT with n - 1.
+	 */
+	__raw_writel(mcfslt_cycles_per_jiffy - 1, TA(MCFSLT_STCNT));
+	__raw_writel(MCFSLT_SCR_RUN | MCFSLT_SCR_IEN | MCFSLT_SCR_TEN,
+								TA(MCFSLT_SCR));
+	/* initialize mcfslt_cnt knowing that slice timers count down */
+	mcfslt_cnt = mcfslt_cycles_per_jiffy;
+
+	r = request_irq(MCF_IRQ_TIMER, mcfslt_tick, IRQF_TIMER, "timer", NULL);
+	if (r) {
+		pr_err("Failed to request irq %d (timer): %pe\n", MCF_IRQ_TIMER,
+		       ERR_PTR(r));
+	}
+
+	clocksource_register_hz(&mcfslt_clk, MCF_BUSCLK);
+
+#ifdef CONFIG_HIGHPROFILE
+	mcfslt_profile_init();
+#endif
+}