1 files changed, 256 insertions, 0 deletions

diff --git a/arch/sh/kernel/timers/timer-cmt.c b/arch/sh/kernel/timers/timer-cmt.c
new file mode 100644
index 000000000000..9eab395cd341
--- /dev/null
+++ b/arch/sh/kernel/timers/timer-cmt.c
@@ -0,0 +1,256 @@
+/*
+ * arch/sh/kernel/timers/timer-cmt.c - CMT Timer Support
+ *
+ *  Copyright (C) 2005  Yoshinori Sato
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ */
+
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/interrupt.h>
+#include <linux/spinlock.h>
+#include <linux/seqlock.h>
+#include <asm/timer.h>
+#include <asm/rtc.h>
+#include <asm/io.h>
+#include <asm/irq.h>
+#include <asm/clock.h>
+
+#if defined(CONFIG_CPU_SUBTYPE_SH7619)
+#define CMT_CMSTR       0xf84a0070
+#define CMT_CMCSR_0     0xf84a0072
+#define CMT_CMCNT_0     0xf84a0074
+#define CMT_CMCOR_0     0xf84a0076
+#define CMT_CMCSR_1     0xf84a0078
+#define CMT_CMCNT_1     0xf84a007a
+#define CMT_CMCOR_1     0xf84a007c
+
+#define STBCR3          0xf80a0000
+#define cmt_clock_enable() do { ctrl_outb(ctrl_inb(STBCR3) & ~0x10, STBCR3); } while(0)
+#define CMT_CMCSR_INIT  0x0040
+#define CMT_CMCSR_CALIB 0x0000
+#elif defined(CONFIG_CPU_SUBTYPE_SH7206)
+#define CMT_CMSTR       0xfffec000
+#define CMT_CMCSR_0     0xfffec002
+#define CMT_CMCNT_0     0xfffec004
+#define CMT_CMCOR_0     0xfffec006
+
+#define STBCR4          0xfffe040c
+#define cmt_clock_enable() do { ctrl_outb(ctrl_inb(STBCR4) & ~0x04, STBCR4); } while(0)
+#define CMT_CMCSR_INIT  0x0040
+#define CMT_CMCSR_CALIB 0x0000
+#else
+#error "Unknown CPU SUBTYPE"
+#endif
+
+static DEFINE_SPINLOCK(cmt0_lock);
+
+static unsigned long cmt_timer_get_offset(void)
+{
+        int count;
+        unsigned long flags;
+
+        static unsigned short count_p = 0xffff;    /* for the first call after boot */
+        static unsigned long jiffies_p = 0;
+
+        /*
+         * cache volatile jiffies temporarily; we have IRQs turned off.
+         */
+        unsigned long jiffies_t;
+
+        spin_lock_irqsave(&cmt0_lock, flags);
+        /* timer count may underflow right here */
+        count =  ctrl_inw(CMT_CMCOR_0);
+        count -= ctrl_inw(CMT_CMCNT_0);
+
+        jiffies_t = jiffies;
+
+        /*
+         * avoiding timer inconsistencies (they are rare, but they happen)...
+         * there is one kind of problem that must be avoided here:
+         *  1. the timer counter underflows
+         */
+
+        if (jiffies_t == jiffies_p) {
+                if (count > count_p) {
+                        /* the nutcase */
+                        if (ctrl_inw(CMT_CMCSR_0) & 0x80) { /* Check CMF bit */
+                                count -= LATCH;
+                        } else {
+                                printk("%s (): hardware timer problem?\n",
+                                       __FUNCTION__);
+                        }
+                }
+        } else
+                jiffies_p = jiffies_t;
+
+        count_p = count;
+        spin_unlock_irqrestore(&cmt0_lock, flags);
+
+        count = ((LATCH-1) - count) * TICK_SIZE;
+        count = (count + LATCH/2) / LATCH;
+
+        return count;
+}
+
+static irqreturn_t cmt_timer_interrupt(int irq, void *dev_id,
+                                       struct pt_regs *regs)
+{
+        unsigned long timer_status;
+
+        /* Clear CMF bit */
+        timer_status = ctrl_inw(CMT_CMCSR_0);
+        timer_status &= ~0x80;
+        ctrl_outw(timer_status, CMT_CMCSR_0);
+
+        /*
+         * Here we are in the timer irq handler. We just have irqs locally
+         * disabled but we don't know if the timer_bh is running on the other
+         * CPU. We need to avoid to SMP race with it. NOTE: we don' t need
+         * the irq version of write_lock because as just said we have irq
+         * locally disabled. -arca
+         */
+        write_seqlock(&xtime_lock);
+        handle_timer_tick(regs);
+        write_sequnlock(&xtime_lock);
+
+        return IRQ_HANDLED;
+}
+
+static struct irqaction cmt_irq = {
+        .name           = "timer",
+        .handler        = cmt_timer_interrupt,
+        .flags          = SA_INTERRUPT,
+        .mask           = CPU_MASK_NONE,
+};
+
+/*
+ * Hah!  We'll see if this works (switching from usecs to nsecs).
+ */
+static unsigned long cmt_timer_get_frequency(void)
+{
+        u32 freq;
+        struct timespec ts1, ts2;
+        unsigned long diff_nsec;
+        unsigned long factor;
+
+        /* Setup the timer:  We don't want to generate interrupts, just
+         * have it count down at its natural rate.
+         */
+        
+        ctrl_outw(ctrl_inw(CMT_CMSTR) & ~0x01, CMT_CMSTR);
+        ctrl_outw(CMT_CMCSR_CALIB, CMT_CMCSR_0);
+        ctrl_outw(0xffff, CMT_CMCOR_0);
+        ctrl_outw(0xffff, CMT_CMCNT_0);
+
+        rtc_sh_get_time(&ts2);
+
+        do {
+                rtc_sh_get_time(&ts1);
+        } while (ts1.tv_nsec == ts2.tv_nsec && ts1.tv_sec == ts2.tv_sec);
+
+        /* actually start the timer */
+        ctrl_outw(ctrl_inw(CMT_CMSTR) | 0x01, CMT_CMSTR);
+
+        do {
+                rtc_sh_get_time(&ts2);
+        } while (ts1.tv_nsec == ts2.tv_nsec && ts1.tv_sec == ts2.tv_sec);
+
+        freq = 0xffff - ctrl_inw(CMT_CMCNT_0);
+        if (ts2.tv_nsec < ts1.tv_nsec) {
+                ts2.tv_nsec += 1000000000;
+                ts2.tv_sec--;
+        }
+
+        diff_nsec = (ts2.tv_sec - ts1.tv_sec) * 1000000000 + (ts2.tv_nsec - ts1.tv_nsec);
+
+        /* this should work well if the RTC has a precision of n Hz, where
+         * n is an integer.  I don't think we have to worry about the other
+         * cases. */
+        factor = (1000000000 + diff_nsec/2) / diff_nsec;
+
+        if (factor * diff_nsec > 1100000000 ||
+            factor * diff_nsec <  900000000)
+                panic("weird RTC (diff_nsec %ld)", diff_nsec);
+
+        return freq * factor;
+}
+
+static void cmt_clk_init(struct clk *clk)
+{
+        u8 divisor = CMT_CMCSR_INIT & 0x3;
+        ctrl_inw(CMT_CMCSR_0);
+        ctrl_outw(CMT_CMCSR_INIT, CMT_CMCSR_0);
+        clk->parent = clk_get("module_clk");
+        clk->rate = clk->parent->rate / (8 << (divisor << 1));
+}
+
+static void cmt_clk_recalc(struct clk *clk)
+{
+        u8 divisor = ctrl_inw(CMT_CMCSR_0) & 0x3;
+        clk->rate = clk->parent->rate / (8 << (divisor << 1));
+}
+
+static struct clk_ops cmt_clk_ops = {
+        .init           = cmt_clk_init,
+        .recalc         = cmt_clk_recalc,
+};
+
+static struct clk cmt0_clk = {
+        .name           = "cmt0_clk",
+        .ops            = &cmt_clk_ops,
+};
+
+static int cmt_timer_start(void)
+{
+        ctrl_outw(ctrl_inw(CMT_CMSTR) | 0x01, CMT_CMSTR);
+        return 0;
+}
+
+static int cmt_timer_stop(void)
+{
+        ctrl_outw(ctrl_inw(CMT_CMSTR) & ~0x01, CMT_CMSTR);
+        return 0;
+}
+
+static int cmt_timer_init(void)
+{
+        unsigned long interval;
+
+        cmt_clock_enable();
+
+        setup_irq(TIMER_IRQ, &cmt_irq);
+
+        cmt0_clk.parent = clk_get("module_clk");
+
+        cmt_timer_stop();
+
+        interval = cmt0_clk.parent->rate / 8 / HZ;
+        printk(KERN_INFO "Interval = %ld\n", interval);
+
+        ctrl_outw(interval, CMT_CMCOR_0);
+
+        clk_register(&cmt0_clk);
+        clk_enable(&cmt0_clk);
+
+        cmt_timer_start();
+
+        return 0;
+}
+
+struct sys_timer_ops cmt_timer_ops = {
+        .init           = cmt_timer_init,
+        .start          = cmt_timer_start,
+        .stop           = cmt_timer_stop,
+        .get_frequency  = cmt_timer_get_frequency,
+        .get_offset     = cmt_timer_get_offset,
+};
+
+struct sys_timer cmt_timer = {
+        .name   = "cmt",
+        .ops    = &cmt_timer_ops,
+};
+