m68k: mvme147,mvme16x: Don't wipe PCC timer config bits

Don't clear the timer 1 configuration bits when clearing the interrupt flag
and counter overflow. As Michael reported, "This results in no timer
interrupts being delivered after the first. Initialization then hangs
in calibrate_delay as the jiffies counter is not updated."

On mvme16x, enable the timer after requesting the irq, consistent with
mvme147.

Cc: Michael Pavone <pavone@retrodev.com>
Fixes: 7529b90d051e ("m68k: mvme147: Handle timer counter overflow")
Fixes: 19999a8b8782 ("m68k: mvme16x: Handle timer counter overflow")
Reported-and-tested-by: Michael Pavone <pavone@retrodev.com>
Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Link: https://lore.kernel.org/r/4fdaa113db089b8fb607f7dd818479f8cdcc4547.1617089871.git.fthain@telegraphics.com.au
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>

3 files changed, 19 insertions, 12 deletions

diff --git a/arch/m68k/include/asm/mvme147hw.h b/arch/m68k/include/asm/mvme147hw.h
index 257b29184af9..e28eb1c0e0bf 100644
--- a/arch/m68k/include/asm/mvme147hw.h
+++ b/arch/m68k/include/asm/mvme147hw.h
@@ -66,6 +66,9 @@ struct pcc_regs {
 #define PCC_INT_ENAB		0x08
 
 #define PCC_TIMER_INT_CLR	0x80
+
+#define PCC_TIMER_TIC_EN	0x01
+#define PCC_TIMER_COC_EN	0x02
 #define PCC_TIMER_CLR_OVF	0x04
 
 #define PCC_LEVEL_ABORT		0x07
diff --git a/arch/m68k/mvme147/config.c b/arch/m68k/mvme147/config.c
index cfdc7f912e14..e1e90c49a496 100644
--- a/arch/m68k/mvme147/config.c
+++ b/arch/m68k/mvme147/config.c
@@ -114,8 +114,10 @@ static irqreturn_t mvme147_timer_int (int irq, void *dev_id)
 	unsigned long flags;
 
 	local_irq_save(flags);
-	m147_pcc->t1_int_cntrl = PCC_TIMER_INT_CLR;
-	m147_pcc->t1_cntrl = PCC_TIMER_CLR_OVF;
+	m147_pcc->t1_cntrl = PCC_TIMER_CLR_OVF | PCC_TIMER_COC_EN |
+			     PCC_TIMER_TIC_EN;
+	m147_pcc->t1_int_cntrl = PCC_INT_ENAB | PCC_TIMER_INT_CLR |
+				 PCC_LEVEL_TIMER1;
 	clk_total += PCC_TIMER_CYCLES;
 	legacy_timer_tick(1);
 	local_irq_restore(flags);
@@ -133,10 +135,10 @@ void mvme147_sched_init (void)
 	/* Init the clock with a value */
 	/* The clock counter increments until 0xFFFF then reloads */
 	m147_pcc->t1_preload = PCC_TIMER_PRELOAD;
-	m147_pcc->t1_cntrl = 0x0;	/* clear timer */
-	m147_pcc->t1_cntrl = 0x3;	/* start timer */
-	m147_pcc->t1_int_cntrl = PCC_TIMER_INT_CLR;  /* clear pending ints */
-	m147_pcc->t1_int_cntrl = PCC_INT_ENAB|PCC_LEVEL_TIMER1;
+	m147_pcc->t1_cntrl = PCC_TIMER_CLR_OVF | PCC_TIMER_COC_EN |
+			     PCC_TIMER_TIC_EN;
+	m147_pcc->t1_int_cntrl = PCC_INT_ENAB | PCC_TIMER_INT_CLR |
+				 PCC_LEVEL_TIMER1;
 
 	clocksource_register_hz(&mvme147_clk, PCC_TIMER_CLOCK_FREQ);
 }
diff --git a/arch/m68k/mvme16x/config.c b/arch/m68k/mvme16x/config.c
index 30357fe4ba6c..b59593c7cfb9 100644
--- a/arch/m68k/mvme16x/config.c
+++ b/arch/m68k/mvme16x/config.c
@@ -366,6 +366,7 @@ static u32 clk_total;
 #define PCCTOVR1_COC_EN      0x02
 #define PCCTOVR1_OVR_CLR     0x04
 
+#define PCCTIC1_INT_LEVEL    6
 #define PCCTIC1_INT_CLR      0x08
 #define PCCTIC1_INT_EN       0x10
 
@@ -374,8 +375,8 @@ static irqreturn_t mvme16x_timer_int (int irq, void *dev_id)
 	unsigned long flags;
 
 	local_irq_save(flags);
-	out_8(PCCTIC1, in_8(PCCTIC1) | PCCTIC1_INT_CLR);
-	out_8(PCCTOVR1, PCCTOVR1_OVR_CLR);
+	out_8(PCCTOVR1, PCCTOVR1_OVR_CLR | PCCTOVR1_TIC_EN | PCCTOVR1_COC_EN);
+	out_8(PCCTIC1, PCCTIC1_INT_EN | PCCTIC1_INT_CLR | PCCTIC1_INT_LEVEL);
 	clk_total += PCC_TIMER_CYCLES;
 	legacy_timer_tick(1);
 	local_irq_restore(flags);
@@ -389,14 +390,15 @@ void mvme16x_sched_init(void)
     int irq;
 
     /* Using PCCchip2 or MC2 chip tick timer 1 */
-    out_be32(PCCTCNT1, 0);
-    out_be32(PCCTCMP1, PCC_TIMER_CYCLES);
-    out_8(PCCTOVR1, in_8(PCCTOVR1) | PCCTOVR1_TIC_EN | PCCTOVR1_COC_EN);
-    out_8(PCCTIC1, PCCTIC1_INT_EN | 6);
     if (request_irq(MVME16x_IRQ_TIMER, mvme16x_timer_int, IRQF_TIMER, "timer",
                     NULL))
 	panic ("Couldn't register timer int");
 
+    out_be32(PCCTCNT1, 0);
+    out_be32(PCCTCMP1, PCC_TIMER_CYCLES);
+    out_8(PCCTOVR1, PCCTOVR1_OVR_CLR | PCCTOVR1_TIC_EN | PCCTOVR1_COC_EN);
+    out_8(PCCTIC1, PCCTIC1_INT_EN | PCCTIC1_INT_CLR | PCCTIC1_INT_LEVEL);
+
     clocksource_register_hz(&mvme16x_clk, PCC_TIMER_CLOCK_FREQ);
 
     if (brdno == 0x0162 || brdno == 0x172)