MIPS: cevt-txx9: Implement read_sched_clock

Use txx9 up-counter for sched_clock source. This implementation will give
high resolution cputime accounting.

Signed-off-by: Deng-Cheng Zhu <dengcheng.zhu@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: macro@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/9484/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

1 files changed, 9 insertions, 0 deletions

diff --git a/arch/mips/kernel/cevt-txx9.c b/arch/mips/kernel/cevt-txx9.c
index 2ae08462e46e..723932441ecc 100644
--- a/arch/mips/kernel/cevt-txx9.c
+++ b/arch/mips/kernel/cevt-txx9.c
@@ -14,6 +14,7 @@
 #include <linux/init.h>
 #include <linux/interrupt.h>
 #include <linux/irq.h>
+#include <linux/sched_clock.h>
 #include <asm/time.h>
 #include <asm/txx9tmr.h>
 
@@ -46,6 +47,11 @@ static struct txx9_clocksource txx9_clocksource = {
         },
 };
 
+static u64 notrace txx9_read_sched_clock(void)
+{
+        return __raw_readl(&txx9_clocksource.tmrptr->trr);
+}
+
 void __init txx9_clocksource_init(unsigned long baseaddr,
                                   unsigned int imbusclk)
 {
@@ -61,6 +67,9 @@ void __init txx9_clocksource_init(unsigned long baseaddr,
         __raw_writel(1 << TXX9_CLOCKSOURCE_BITS, &tmrptr->cpra);
         __raw_writel(TCR_BASE | TXx9_TMTCR_TCE, &tmrptr->tcr);
         txx9_clocksource.tmrptr = tmrptr;
+
+        sched_clock_register(txx9_read_sched_clock, TXX9_CLOCKSOURCE_BITS,
+                             TIMER_CLK(imbusclk));
 }
 
 struct txx9_clock_event_device {