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author | James <> | 2015-11-04 11:49:21 +0000 |
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committer | James <> | 2015-11-04 11:49:21 +0000 |
commit | 716ca530e1c4515d8683c9d5be3d56b301758b66 (patch) | |
tree | 700eb5bcc1a462a5f21dcec15ce7c97ecfefa772 /target/linux/mcs814x/files-3.18/arch/arm/mach-mcs814x/timer.c | |
download | trunk-47381-master.tar.gz trunk-47381-master.tar.bz2 trunk-47381-master.zip |
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.c | 132 |
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); +} |