[MIPS] PNX8550: Fix system timer support

the patch inlined below restores proper time accounting for PNX8550-based
boards. It also gets rid of #ifdef in the generic code which becomes
unnecessary then.

It's functionally identical to the previous patch with the same name but
it has minor comments from Atsushi and Sergei taken into account.

Signed-off-by: Vitaly Wool <vwool@ru.mvista.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/kernel/time.c

@@ -94,10 +94,8 @@ static void c0_timer_ack(void)
 {
 	unsigned int count;
 
-#ifndef CONFIG_SOC_PNX8550	/* pnx8550 resets to zero */
 	/* Ack this timer interrupt and set the next one.  */
 	expirelo += cycles_per_jiffy;
-#endif
 	write_c0_compare(expirelo);
 
 	/* Check to see if we have missed any timer interrupts.  */

arch/mips/philips/pnx8550/common/time.c

@@ -33,7 +33,17 @@
 #include <int.h>
 #include <cm.h>
 
-extern unsigned int mips_hpt_frequency;
+static unsigned long cpj;
+
+static cycle_t hpt_read(void)
+{
+	return read_c0_count2();
+}
+
+static void timer_ack(void)
+{
+	write_c0_compare(cpj);
+}
 
 /*
  * pnx8550_time_init() - it does the following things:
@@ -68,27 +78,47 @@ void pnx8550_time_init(void)
 	 * HZ timer interrupts per second.
 	 */
 	mips_hpt_frequency = 27UL * ((1000000UL * n)/(m * pow2p));
+	cpj = (mips_hpt_frequency + HZ / 2) / HZ;
+	timer_ack();
+
+	/* Setup Timer 2 */
+	write_c0_count2(0);
+	write_c0_compare2(0xffffffff);
+
+	clocksource_mips.read = hpt_read;
+	mips_timer_ack = timer_ack;
 }
 
+static irqreturn_t monotonic_interrupt(int irq, void *dev_id)
+{
+	/* Timer 2 clear interrupt */
+	write_c0_compare2(-1);
+	return IRQ_HANDLED;
+}
+
+static struct irqaction monotonic_irqaction = {
+	.handler = monotonic_interrupt,
+	.flags = IRQF_DISABLED,
+	.name = "Monotonic timer",
+};
+
 void __init plat_timer_setup(struct irqaction *irq)
 {
 	int configPR;
 
 	setup_irq(PNX8550_INT_TIMER1, irq);
+	setup_irq(PNX8550_INT_TIMER2, &monotonic_irqaction);
 
-	/* Start timer1 */
+	/* Timer 1 start */
 	configPR = read_c0_config7();
 	configPR &= ~0x00000008;
 	write_c0_config7(configPR);
 
-	/* Timer 2 stop */
+	/* Timer 2 start */
 	configPR = read_c0_config7();
-	configPR |= 0x00000010;
+	configPR &= ~0x00000010;
 	write_c0_config7(configPR);
 
-	write_c0_count2(0);
-	write_c0_compare2(0xffffffff);
-
 	/* Timer 3 stop */
 	configPR = read_c0_config7();
 	configPR |= 0x00000020;