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authorJames <>2015-11-04 11:49:21 +0000
committerJames <>2015-11-04 11:49:21 +0000
commit716ca530e1c4515d8683c9d5be3d56b301758b66 (patch)
tree700eb5bcc1a462a5f21dcec15ce7c97ecfefa772 /target/linux/mcs814x/files-3.18/arch/arm/mach-mcs814x/timer.c
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Diffstat (limited to 'target/linux/mcs814x/files-3.18/arch/arm/mach-mcs814x/timer.c')
-rw-r--r--target/linux/mcs814x/files-3.18/arch/arm/mach-mcs814x/timer.c132
1 files changed, 132 insertions, 0 deletions
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
index 0000000..31d0ba6
--- /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 <linux/of_irq.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 of_device_id mcs814x_timer_ids[] = {
+ { .compatible = "moschip,mcs814x-timer" },
+ { /* sentinel */ },
+};
+
+static int __init mcs814x_of_timer_init(void)
+{
+ struct device_node *np;
+ int irq;
+
+ 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");
+
+ irq = irq_of_parse_and_map(np, 0);
+ if (!irq)
+ panic("no interrupts property/mapping failed for timer");
+
+ return irq;
+}
+
+void __init mcs814x_timer_init(void)
+{
+ struct clk *clk;
+ int irq;
+
+ 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);
+
+ irq = 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;
+
+ if (request_irq(irq, mcs814x_timer_interrupt,
+ IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL,
+ "mcs814x-timer", NULL))
+ panic("unable to request timer0 irq %d", irq);
+
+ /* enable timer, stop timer in debug mode */
+ writel_relaxed(TIMER_CTL_EN | TIMER_CTL_DBG,
+ mcs814x_timer_base + TIMER_CTL);
+}