[ARM] 3822/1: iop3xx: rewrite time handling

Merge and rewrite the iop32x/iop33x time code to do lost jiffy
tracking properly, and put the result in plat-iop/time.c.

Signed-off-by: Lennert Buytenhek <buytenh@wantstofly.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 94 insertions, 0 deletions

diff --git a/arch/arm/plat-iop/time.c b/arch/arm/plat-iop/time.c
new file mode 100644
index 000000000000..5730a0d7ed67
--- /dev/null
+++ b/arch/arm/plat-iop/time.c
@@ -0,0 +1,94 @@
+/*
+ * arch/arm/plat-iop/time.c
+ *
+ * Timer code for IOP32x and IOP33x based systems
+ *
+ * Author: Deepak Saxena <dsaxena@mvista.com>
+ *
+ * Copyright 2002-2003 MontaVista Software Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.
+ */
+
+#include <linux/kernel.h>
+#include <linux/interrupt.h>
+#include <linux/time.h>
+#include <linux/init.h>
+#include <linux/timex.h>
+#include <asm/hardware.h>
+#include <asm/io.h>
+#include <asm/irq.h>
+#include <asm/uaccess.h>
+#include <asm/mach/irq.h>
+#include <asm/mach/time.h>
+
+#ifdef CONFIG_ARCH_IOP32X
+#define IRQ_IOP3XX_TIMER0       IRQ_IOP321_TIMER0
+#else
+#ifdef CONFIG_ARCH_IOP33X
+#define IRQ_IOP3XX_TIMER0       IRQ_IOP331_TIMER0
+#endif
+#endif
+
+static unsigned long ticks_per_jiffy;
+static unsigned long ticks_per_usec;
+static unsigned long next_jiffy_time;
+
+unsigned long iop3xx_gettimeoffset(void)
+{
+        unsigned long offset;
+
+        offset = next_jiffy_time - *IOP3XX_TU_TCR1;
+
+        return offset / ticks_per_usec;
+}
+
+static irqreturn_t
+iop3xx_timer_interrupt(int irq, void *dev_id, struct pt_regs *regs)
+{
+        write_seqlock(&xtime_lock);
+
+        asm volatile("mcr p6, 0, %0, c6, c1, 0" : : "r" (1));
+
+        while ((signed long)(next_jiffy_time - *IOP3XX_TU_TCR1)
+                                                        >= ticks_per_jiffy) {
+                timer_tick(regs);
+                next_jiffy_time -= ticks_per_jiffy;
+        }
+
+        write_sequnlock(&xtime_lock);
+
+        return IRQ_HANDLED;
+}
+
+static struct irqaction iop3xx_timer_irq = {
+        .name           = "IOP3XX Timer Tick",
+        .handler        = iop3xx_timer_interrupt,
+        .flags          = IRQF_DISABLED | IRQF_TIMER,
+};
+
+void __init iop3xx_init_time(unsigned long tick_rate)
+{
+        u32 timer_ctl;
+
+        ticks_per_jiffy = (tick_rate + HZ/2) / HZ;
+        ticks_per_usec = tick_rate / 1000000;
+        next_jiffy_time = 0xffffffff;
+
+        timer_ctl = IOP3XX_TMR_EN | IOP3XX_TMR_PRIVILEGED |
+                        IOP3XX_TMR_RELOAD | IOP3XX_TMR_RATIO_1_1;
+
+        /*
+         * We use timer 0 for our timer interrupt, and timer 1 as
+         * monotonic counter for tracking missed jiffies.
+         */
+        asm volatile("mcr p6, 0, %0, c4, c1, 0" : : "r" (ticks_per_jiffy - 1));
+        asm volatile("mcr p6, 0, %0, c0, c1, 0" : : "r" (timer_ctl));
+        asm volatile("mcr p6, 0, %0, c5, c1, 0" : : "r" (0xffffffff));
+        asm volatile("mcr p6, 0, %0, c1, c1, 0" : : "r" (timer_ctl));
+
+        setup_irq(IRQ_IOP3XX_TIMER0, &iop3xx_timer_irq);
+}