Update Linux to v5.4.2
Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/arch/m68k/atari/time.c b/arch/m68k/atari/time.c
index 9cca642..ce923a5 100644
--- a/arch/m68k/atari/time.c
+++ b/arch/m68k/atari/time.c
@@ -16,6 +16,7 @@
#include <linux/init.h>
#include <linux/rtc.h>
#include <linux/bcd.h>
+#include <linux/clocksource.h>
#include <linux/delay.h>
#include <linux/export.h>
@@ -24,6 +25,35 @@
DEFINE_SPINLOCK(rtc_lock);
EXPORT_SYMBOL_GPL(rtc_lock);
+static u64 atari_read_clk(struct clocksource *cs);
+
+static struct clocksource atari_clk = {
+ .name = "mfp",
+ .rating = 100,
+ .read = atari_read_clk,
+ .mask = CLOCKSOURCE_MASK(32),
+ .flags = CLOCK_SOURCE_IS_CONTINUOUS,
+};
+
+static u32 clk_total;
+static u8 last_timer_count;
+
+static irqreturn_t mfp_timer_c_handler(int irq, void *dev_id)
+{
+ irq_handler_t timer_routine = dev_id;
+ unsigned long flags;
+
+ local_irq_save(flags);
+ do {
+ last_timer_count = st_mfp.tim_dt_c;
+ } while (last_timer_count == 1);
+ clk_total += INT_TICKS;
+ timer_routine(0, NULL);
+ local_irq_restore(flags);
+
+ return IRQ_HANDLED;
+}
+
void __init
atari_sched_init(irq_handler_t timer_routine)
{
@@ -32,31 +62,33 @@
/* start timer C, div = 1:100 */
st_mfp.tim_ct_cd = (st_mfp.tim_ct_cd & 15) | 0x60;
/* install interrupt service routine for MFP Timer C */
- if (request_irq(IRQ_MFP_TIMC, timer_routine, 0, "timer", timer_routine))
+ if (request_irq(IRQ_MFP_TIMC, mfp_timer_c_handler, IRQF_TIMER, "timer",
+ timer_routine))
pr_err("Couldn't register timer interrupt\n");
+
+ clocksource_register_hz(&atari_clk, INT_CLK);
}
/* ++andreas: gettimeoffset fixed to check for pending interrupt */
-#define TICK_SIZE 10000
-
-/* This is always executed with interrupts disabled. */
-u32 atari_gettimeoffset(void)
+static u64 atari_read_clk(struct clocksource *cs)
{
- u32 ticks, offset = 0;
+ unsigned long flags;
+ u8 count;
+ u32 ticks;
- /* read MFP timer C current value */
- ticks = st_mfp.tim_dt_c;
- /* The probability of underflow is less than 2% */
- if (ticks > INT_TICKS - INT_TICKS / 50)
- /* Check for pending timer interrupt */
- if (st_mfp.int_pn_b & (1 << 5))
- offset = TICK_SIZE;
+ local_irq_save(flags);
+ /* Ensure that the count is monotonically decreasing, even though
+ * the result may briefly stop changing after counter wrap-around.
+ */
+ count = min(st_mfp.tim_dt_c, last_timer_count);
+ last_timer_count = count;
- ticks = INT_TICKS - ticks;
- ticks = ticks * 10000L / INT_TICKS;
+ ticks = INT_TICKS - count;
+ ticks += clk_total;
+ local_irq_restore(flags);
- return (ticks + offset) * 1000;
+ return ticks;
}