mcs814x: add support for 3.18

[openwrt/svn-archive/archive.git] / target / linux / mcs814x / files-3.18 / arch / arm / mach-mcs814x / timer.c

diff --git a/target/linux/mcs814x/files-3.18/arch/arm/mach-mcs814x/timer.c b/target/linux/mcs814x/files-3.18/arch/arm/mach-mcs814x/timer.c
new file mode 100644 (file)
index 0000000..ff9d44a
--- /dev/null
+++ b/target/linux/mcs814x/files-3.18/arch/arm/mach-mcs814x/timer.c
@@ -0,0 +1,132 @@
+/*
+ * Moschip MCS814x timer routines
+ *
+ * Copyright (C) 2012, Florian Fainelli <florian@openwrt.org>
+ *
+ * Licensed under GPLv2
+ */
+#include <linux/kernel.h>
+#include <linux/interrupt.h>
+#include <linux/time.h>
+#include <linux/timex.h>
+#include <linux/irq.h>
+#include <linux/err.h>
+#include <linux/clk.h>
+#include <linux/io.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+
+#include <asm/mach/time.h>
+#include <mach/mcs814x.h>
+
+/* Timer block registers */
+#define TIMER_VAL      0x00
+#define TIMER_CTL      0x04
+#define  TIMER_CTL_EN  0x01
+#define  TIMER_CTL_DBG 0x02
+
+static u32 last_reload;
+static u32 timer_correct;
+static u32 clock_rate;
+static u32 timer_reload_value;
+static void __iomem *mcs814x_timer_base;
+
+static inline u32 ticks2usecs(u32 x)
+{
+       return x / (clock_rate / 1000000);
+}
+
+/*
+ * Returns number of ms since last clock interrupt.  Note that interrupts
+ * will have been disabled by do_gettimeoffset()
+ */
+static u32 mcs814x_gettimeoffset(void)
+{
+       u32 ticks = readl_relaxed(mcs814x_timer_base + TIMER_VAL);
+
+       if (ticks < last_reload)
+               return ticks2usecs(ticks + (u32)(0xffffffff - last_reload));
+       else
+               return ticks2usecs(ticks - last_reload);
+}
+
+
+static irqreturn_t mcs814x_timer_interrupt(int irq, void *dev_id)
+{
+       u32 count = readl_relaxed(mcs814x_timer_base + TIMER_VAL);
+
+       /* take into account delay up to this moment */
+       last_reload = count + timer_correct + timer_reload_value;
+
+       if (last_reload < timer_reload_value) {
+               last_reload = timer_reload_value;
+       } else {
+               if (timer_correct == 0)
+                       timer_correct = readl_relaxed(mcs814x_timer_base + TIMER_VAL) - count;
+       }
+       writel_relaxed(last_reload, mcs814x_timer_base + TIMER_VAL);
+
+       timer_tick();
+
+       return IRQ_HANDLED;
+}
+
+static struct irqaction mcs814x_timer_irq = {
+       .name           = "mcs814x-timer",
+       .flags          = IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL,
+       .handler        = mcs814x_timer_interrupt,
+};
+
+static struct of_device_id mcs814x_timer_ids[] = {
+       { .compatible = "moschip,mcs814x-timer" },
+       { /* sentinel */ },
+};
+
+static void __init mcs814x_of_timer_init(void)
+{
+       struct device_node *np;
+       const unsigned int *intspec;
+
+       np = of_find_matching_node(NULL, mcs814x_timer_ids);
+       if (!np)
+               panic("unable to find compatible timer node in dtb");
+
+       mcs814x_timer_base = of_iomap(np, 0);
+       if (!mcs814x_timer_base)
+               panic("unable to remap timer cpu registers");
+
+       intspec = of_get_property(np, "interrupts", NULL);
+       if (!intspec)
+               panic("no interrupts property for timer");
+
+       mcs814x_timer_irq.irq = be32_to_cpup(intspec);
+}
+
+void __init mcs814x_timer_init(void)
+{
+       struct clk *clk;
+
+       arch_gettimeoffset = mcs814x_gettimeoffset;
+
+       clk = clk_get_sys("timer0", NULL);
+       if (IS_ERR_OR_NULL(clk))
+               panic("unable to get timer0 clock");
+
+       clock_rate = clk_get_rate(clk);
+
+       mcs814x_of_timer_init();
+
+       pr_info("Timer frequency: %d (kHz)\n", clock_rate / 1000);
+
+       timer_reload_value = 0xffffffff - (clock_rate / HZ);
+
+       /* disable timer */
+       writel_relaxed(~TIMER_CTL_EN, mcs814x_timer_base + TIMER_CTL);
+       writel_relaxed(timer_reload_value, mcs814x_timer_base + TIMER_VAL);
+       last_reload = timer_reload_value;
+
+       setup_irq(mcs814x_timer_irq.irq, &mcs814x_timer_irq);
+       /* enable timer, stop timer in debug mode */
+       writel_relaxed(TIMER_CTL_EN | TIMER_CTL_DBG,
+               mcs814x_timer_base + TIMER_CTL);
+}