aboutsummaryrefslogtreecommitdiff
path: root/arch/mips/sibyte/sb1250/time.c
diff options
context:
space:
mode:
Diffstat (limited to 'arch/mips/sibyte/sb1250/time.c')
-rw-r--r--arch/mips/sibyte/sb1250/time.c77
1 files changed, 58 insertions, 19 deletions
diff --git a/arch/mips/sibyte/sb1250/time.c b/arch/mips/sibyte/sb1250/time.c
index 511c89d65f3..1588f6debd9 100644
--- a/arch/mips/sibyte/sb1250/time.c
+++ b/arch/mips/sibyte/sb1250/time.c
@@ -47,23 +47,51 @@
#define IMR_IP3_VAL K_INT_MAP_I1
#define IMR_IP4_VAL K_INT_MAP_I2
+#define SB1250_HPT_NUM 3
+#define SB1250_HPT_VALUE M_SCD_TIMER_CNT /* max value */
+#define SB1250_HPT_SHIFT ((sizeof(unsigned int)*8)-V_SCD_TIMER_WIDTH)
+
+
extern int sb1250_steal_irq(int irq);
+static unsigned int sb1250_hpt_read(void);
+static void sb1250_hpt_init(unsigned int);
+
+static unsigned int hpt_offset;
+
+void __init sb1250_hpt_setup(void)
+{
+ int cpu = smp_processor_id();
+
+ if (!cpu) {
+ /* Setup hpt using timer #3 but do not enable irq for it */
+ __raw_writeq(0, IOADDR(A_SCD_TIMER_REGISTER(SB1250_HPT_NUM, R_SCD_TIMER_CFG)));
+ __raw_writeq(SB1250_HPT_VALUE,
+ IOADDR(A_SCD_TIMER_REGISTER(SB1250_HPT_NUM, R_SCD_TIMER_INIT)));
+ __raw_writeq(M_SCD_TIMER_ENABLE | M_SCD_TIMER_MODE_CONTINUOUS,
+ IOADDR(A_SCD_TIMER_REGISTER(SB1250_HPT_NUM, R_SCD_TIMER_CFG)));
+
+ /*
+ * we need to fill 32 bits, so just use the upper 23 bits and pretend
+ * the timer is going 512Mhz instead of 1Mhz
+ */
+ mips_hpt_frequency = V_SCD_TIMER_FREQ << SB1250_HPT_SHIFT;
+ mips_hpt_init = sb1250_hpt_init;
+ mips_hpt_read = sb1250_hpt_read;
+ }
+}
+
+
void sb1250_time_init(void)
{
int cpu = smp_processor_id();
int irq = K_INT_TIMER_0+cpu;
- /* Only have 4 general purpose timers */
- if (cpu > 3) {
+ /* Only have 4 general purpose timers, and we use last one as hpt */
+ if (cpu > 2) {
BUG();
}
- if (!cpu) {
- /* Use our own gettimeoffset() routine */
- do_gettimeoffset = sb1250_gettimeoffset;
- }
-
sb1250_mask_irq(cpu, irq);
/* Map the timer interrupt to ip[4] of this cpu */
@@ -75,10 +103,10 @@ void sb1250_time_init(void)
/* Disable the timer and set up the count */
__raw_writeq(0, IOADDR(A_SCD_TIMER_REGISTER(cpu, R_SCD_TIMER_CFG)));
#ifdef CONFIG_SIMULATION
- __raw_writeq(50000 / HZ,
+ __raw_writeq((50000 / HZ) - 1,
IOADDR(A_SCD_TIMER_REGISTER(cpu, R_SCD_TIMER_INIT)));
#else
- __raw_writeq(1000000 / HZ,
+ __raw_writeq((V_SCD_TIMER_FREQ / HZ) - 1,
IOADDR(A_SCD_TIMER_REGISTER(cpu, R_SCD_TIMER_INIT)));
#endif
@@ -103,7 +131,7 @@ void sb1250_timer_interrupt(struct pt_regs *regs)
int cpu = smp_processor_id();
int irq = K_INT_TIMER_0 + cpu;
- /* Reset the timer */
+ /* ACK interrupt */
____raw_writeq(M_SCD_TIMER_ENABLE | M_SCD_TIMER_MODE_CONTINUOUS,
IOADDR(A_SCD_TIMER_REGISTER(cpu, R_SCD_TIMER_CFG)));
@@ -122,15 +150,26 @@ void sb1250_timer_interrupt(struct pt_regs *regs)
}
/*
- * We use our own do_gettimeoffset() instead of the generic one,
- * because the generic one does not work for SMP case.
- * In addition, since we use general timer 0 for system time,
- * we can get accurate intra-jiffy offset without calibration.
+ * The HPT is free running from SB1250_HPT_VALUE down to 0 then starts over
+ * again. There's no easy way to set to a specific value so store init value
+ * in hpt_offset and subtract each time.
+ *
+ * Note: Timer isn't full 32bits so shift it into the upper part making
+ * it appear to run at a higher frequency.
*/
-unsigned long sb1250_gettimeoffset(void)
+static unsigned int sb1250_hpt_read(void)
{
- unsigned long count =
- __raw_readq(IOADDR(A_SCD_TIMER_REGISTER(0, R_SCD_TIMER_CNT)));
+ unsigned int count;
- return 1000000/HZ - count;
- }
+ count = G_SCD_TIMER_CNT(__raw_readq(IOADDR(A_SCD_TIMER_REGISTER(SB1250_HPT_NUM, R_SCD_TIMER_CNT))));
+
+ count = (SB1250_HPT_VALUE - count) << SB1250_HPT_SHIFT;
+
+ return count - hpt_offset;
+}
+
+static void sb1250_hpt_init(unsigned int count)
+{
+ hpt_offset = count;
+ return;
+}