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authorYunhong Jiang <yunhong.jiang@intel.com>2015-08-04 12:17:53 -0700
committerYunhong Jiang <yunhong.jiang@intel.com>2015-08-04 15:44:42 -0700
commit9ca8dbcc65cfc63d6f5ef3312a33184e1d726e00 (patch)
tree1c9cafbcd35f783a87880a10f85d1a060db1a563 /kernel/arch/mips/sni/time.c
parent98260f3884f4a202f9ca5eabed40b1354c489b29 (diff)
Add the rt linux 4.1.3-rt3 as base
Import the rt linux 4.1.3-rt3 as OPNFV kvm base. It's from git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git linux-4.1.y-rt and the base is: commit 0917f823c59692d751951bf5ea699a2d1e2f26a2 Author: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Date: Sat Jul 25 12:13:34 2015 +0200 Prepare v4.1.3-rt3 Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> We lose all the git history this way and it's not good. We should apply another opnfv project repo in future. Change-Id: I87543d81c9df70d99c5001fbdf646b202c19f423 Signed-off-by: Yunhong Jiang <yunhong.jiang@intel.com>
Diffstat (limited to 'kernel/arch/mips/sni/time.c')
-rw-r--r--kernel/arch/mips/sni/time.c190
1 files changed, 190 insertions, 0 deletions
diff --git a/kernel/arch/mips/sni/time.c b/kernel/arch/mips/sni/time.c
new file mode 100644
index 000000000..cf8ec568b
--- /dev/null
+++ b/kernel/arch/mips/sni/time.c
@@ -0,0 +1,190 @@
+#include <linux/types.h>
+#include <linux/i8253.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/smp.h>
+#include <linux/time.h>
+#include <linux/clockchips.h>
+
+#include <asm/sni.h>
+#include <asm/time.h>
+#include <asm-generic/rtc.h>
+
+#define SNI_CLOCK_TICK_RATE 3686400
+#define SNI_COUNTER2_DIV 64
+#define SNI_COUNTER0_DIV ((SNI_CLOCK_TICK_RATE / SNI_COUNTER2_DIV) / HZ)
+
+static void a20r_set_mode(enum clock_event_mode mode,
+ struct clock_event_device *evt)
+{
+ switch (mode) {
+ case CLOCK_EVT_MODE_PERIODIC:
+ *(volatile u8 *)(A20R_PT_CLOCK_BASE + 12) = 0x34;
+ wmb();
+ *(volatile u8 *)(A20R_PT_CLOCK_BASE + 0) = SNI_COUNTER0_DIV;
+ wmb();
+ *(volatile u8 *)(A20R_PT_CLOCK_BASE + 0) = SNI_COUNTER0_DIV >> 8;
+ wmb();
+
+ *(volatile u8 *)(A20R_PT_CLOCK_BASE + 12) = 0xb4;
+ wmb();
+ *(volatile u8 *)(A20R_PT_CLOCK_BASE + 8) = SNI_COUNTER2_DIV;
+ wmb();
+ *(volatile u8 *)(A20R_PT_CLOCK_BASE + 8) = SNI_COUNTER2_DIV >> 8;
+ wmb();
+
+ break;
+ case CLOCK_EVT_MODE_ONESHOT:
+ case CLOCK_EVT_MODE_UNUSED:
+ case CLOCK_EVT_MODE_SHUTDOWN:
+ break;
+ case CLOCK_EVT_MODE_RESUME:
+ break;
+ }
+}
+
+static struct clock_event_device a20r_clockevent_device = {
+ .name = "a20r-timer",
+ .features = CLOCK_EVT_FEAT_PERIODIC,
+
+ /* .mult, .shift, .max_delta_ns and .min_delta_ns left uninitialized */
+
+ .rating = 300,
+ .irq = SNI_A20R_IRQ_TIMER,
+ .set_mode = a20r_set_mode,
+};
+
+static irqreturn_t a20r_interrupt(int irq, void *dev_id)
+{
+ struct clock_event_device *cd = dev_id;
+
+ *(volatile u8 *)A20R_PT_TIM0_ACK = 0;
+ wmb();
+
+ cd->event_handler(cd);
+
+ return IRQ_HANDLED;
+}
+
+static struct irqaction a20r_irqaction = {
+ .handler = a20r_interrupt,
+ .flags = IRQF_PERCPU | IRQF_TIMER,
+ .name = "a20r-timer",
+};
+
+/*
+ * a20r platform uses 2 counters to divide the input frequency.
+ * Counter 2 output is connected to Counter 0 & 1 input.
+ */
+static void __init sni_a20r_timer_setup(void)
+{
+ struct clock_event_device *cd = &a20r_clockevent_device;
+ struct irqaction *action = &a20r_irqaction;
+ unsigned int cpu = smp_processor_id();
+
+ cd->cpumask = cpumask_of(cpu);
+ clockevents_register_device(cd);
+ action->dev_id = cd;
+ setup_irq(SNI_A20R_IRQ_TIMER, &a20r_irqaction);
+}
+
+#define SNI_8254_TICK_RATE 1193182UL
+
+#define SNI_8254_TCSAMP_COUNTER ((SNI_8254_TICK_RATE / HZ) + 255)
+
+static __init unsigned long dosample(void)
+{
+ u32 ct0, ct1;
+ volatile u8 msb;
+
+ /* Start the counter. */
+ outb_p(0x34, 0x43);
+ outb_p(SNI_8254_TCSAMP_COUNTER & 0xff, 0x40);
+ outb(SNI_8254_TCSAMP_COUNTER >> 8, 0x40);
+
+ /* Get initial counter invariant */
+ ct0 = read_c0_count();
+
+ /* Latch and spin until top byte of counter0 is zero */
+ do {
+ outb(0x00, 0x43);
+ (void) inb(0x40);
+ msb = inb(0x40);
+ ct1 = read_c0_count();
+ } while (msb);
+
+ /* Stop the counter. */
+ outb(0x38, 0x43);
+ /*
+ * Return the difference, this is how far the r4k counter increments
+ * for every 1/HZ seconds. We round off the nearest 1 MHz of master
+ * clock (= 1000000 / HZ / 2).
+ */
+ /*return (ct1 - ct0 + (500000/HZ/2)) / (500000/HZ) * (500000/HZ);*/
+ return (ct1 - ct0) / (500000/HZ) * (500000/HZ);
+}
+
+/*
+ * Here we need to calibrate the cycle counter to at least be close.
+ */
+void __init plat_time_init(void)
+{
+ unsigned long r4k_ticks[3];
+ unsigned long r4k_tick;
+
+ /*
+ * Figure out the r4k offset, the algorithm is very simple and works in
+ * _all_ cases as long as the 8254 counter register itself works ok (as
+ * an interrupt driving timer it does not because of bug, this is why
+ * we are using the onchip r4k counter/compare register to serve this
+ * purpose, but for r4k_offset calculation it will work ok for us).
+ * There are other very complicated ways of performing this calculation
+ * but this one works just fine so I am not going to futz around. ;-)
+ */
+ printk(KERN_INFO "Calibrating system timer... ");
+ dosample(); /* Prime cache. */
+ dosample(); /* Prime cache. */
+ /* Zero is NOT an option. */
+ do {
+ r4k_ticks[0] = dosample();
+ } while (!r4k_ticks[0]);
+ do {
+ r4k_ticks[1] = dosample();
+ } while (!r4k_ticks[1]);
+
+ if (r4k_ticks[0] != r4k_ticks[1]) {
+ printk("warning: timer counts differ, retrying... ");
+ r4k_ticks[2] = dosample();
+ if (r4k_ticks[2] == r4k_ticks[0]
+ || r4k_ticks[2] == r4k_ticks[1])
+ r4k_tick = r4k_ticks[2];
+ else {
+ printk("disagreement, using average... ");
+ r4k_tick = (r4k_ticks[0] + r4k_ticks[1]
+ + r4k_ticks[2]) / 3;
+ }
+ } else
+ r4k_tick = r4k_ticks[0];
+
+ printk("%d [%d.%04d MHz CPU]\n", (int) r4k_tick,
+ (int) (r4k_tick / (500000 / HZ)),
+ (int) (r4k_tick % (500000 / HZ)));
+
+ mips_hpt_frequency = r4k_tick * HZ;
+
+ switch (sni_brd_type) {
+ case SNI_BRD_10:
+ case SNI_BRD_10NEW:
+ case SNI_BRD_TOWER_OASIC:
+ case SNI_BRD_MINITOWER:
+ sni_a20r_timer_setup();
+ break;
+ }
+ setup_pit_timer();
+}
+
+void read_persistent_clock(struct timespec *ts)
+{
+ ts->tv_sec = -1;
+ ts->tv_nsec = 0;
+}