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authorLinus Walleij <linus.walleij@linaro.org>2013-10-01 12:57:20 +0200
committerOlof Johansson <olof@lixom.net>2013-10-28 15:06:15 -0700
commitf3372c01816ec9e974e449cf7233408a31647dd3 (patch)
treee231213b1acbcace7aa9438b8e46b864bb52727c /arch/arm/mach-gemini
parent43d93947a54cf9323198a3a37eaf3ec14adb23e1 (diff)
downloadlinux-f3372c01816ec9e974e449cf7233408a31647dd3.tar.bz2
ARM: gemini: convert to GENERIC_CLOCKEVENTS
This converts the gemini machine to use generic clockevents by rewriting the timer driver. Cc: arm@kernel.org Cc: Hans Ulli Kroll <ulli.kroll@googlemail.com> Signed-off-by: Linus Walleij <linus.walleij@linaro.org> Signed-off-by: Olof Johansson <olof@lixom.net>
Diffstat (limited to 'arch/arm/mach-gemini')
-rw-r--r--arch/arm/mach-gemini/time.c97
1 files changed, 89 insertions, 8 deletions
diff --git a/arch/arm/mach-gemini/time.c b/arch/arm/mach-gemini/time.c
index 21dc5a89d1c4..0a63c4d25b64 100644
--- a/arch/arm/mach-gemini/time.c
+++ b/arch/arm/mach-gemini/time.c
@@ -13,6 +13,8 @@
#include <mach/hardware.h>
#include <mach/global_reg.h>
#include <asm/mach/time.h>
+#include <linux/clockchips.h>
+#include <linux/clocksource.h>
/*
* Register definitions for the timers
@@ -33,19 +35,89 @@
#define TIMER_3_CR_CLOCK (1 << 7)
#define TIMER_3_CR_INT (1 << 8)
+static unsigned int tick_rate;
+
+static int gemini_timer_set_next_event(unsigned long cycles,
+ struct clock_event_device *evt)
+{
+ u32 cr;
+
+ cr = readl(TIMER_CR(IO_ADDRESS(GEMINI_TIMER_BASE)));
+
+ /* This may be overdoing it, feel free to test without this */
+ cr &= ~TIMER_2_CR_ENABLE;
+ cr &= ~TIMER_2_CR_INT;
+ writel(cr, TIMER_CR(IO_ADDRESS(GEMINI_TIMER_BASE)));
+
+ /* Set next event */
+ writel(cycles, TIMER_COUNT(IO_ADDRESS(GEMINI_TIMER2_BASE)));
+ writel(cycles, TIMER_LOAD(IO_ADDRESS(GEMINI_TIMER2_BASE)));
+ cr |= TIMER_2_CR_ENABLE;
+ cr |= TIMER_2_CR_INT;
+ writel(cr, TIMER_CR(IO_ADDRESS(GEMINI_TIMER_BASE)));
+
+ return 0;
+}
+
+static void gemini_timer_set_mode(enum clock_event_mode mode,
+ struct clock_event_device *evt)
+{
+ u32 period = DIV_ROUND_CLOSEST(tick_rate, HZ);
+ u32 cr;
+
+ switch (mode) {
+ case CLOCK_EVT_MODE_PERIODIC:
+ /* Start the timer */
+ writel(period,
+ TIMER_COUNT(IO_ADDRESS(GEMINI_TIMER2_BASE)));
+ writel(period,
+ TIMER_LOAD(IO_ADDRESS(GEMINI_TIMER2_BASE)));
+ cr = readl(TIMER_CR(IO_ADDRESS(GEMINI_TIMER_BASE)));
+ cr |= TIMER_2_CR_ENABLE;
+ cr |= TIMER_2_CR_INT;
+ writel(cr, TIMER_CR(IO_ADDRESS(GEMINI_TIMER_BASE)));
+ break;
+ case CLOCK_EVT_MODE_ONESHOT:
+ case CLOCK_EVT_MODE_UNUSED:
+ case CLOCK_EVT_MODE_SHUTDOWN:
+ case CLOCK_EVT_MODE_RESUME:
+ /*
+ * Disable also for oneshot: the set_next() call will
+ * arm the timer instead.
+ */
+ cr = readl(TIMER_CR(IO_ADDRESS(GEMINI_TIMER_BASE)));
+ cr &= ~TIMER_2_CR_ENABLE;
+ cr &= ~TIMER_2_CR_INT;
+ writel(cr, TIMER_CR(IO_ADDRESS(GEMINI_TIMER_BASE)));
+ break;
+ default:
+ break;
+ }
+}
+
+/* Use TIMER2 as clock event */
+static struct clock_event_device gemini_clockevent = {
+ .name = "TIMER2",
+ .rating = 300, /* Reasonably fast and accurate clock event */
+ .features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
+ .set_next_event = gemini_timer_set_next_event,
+ .set_mode = gemini_timer_set_mode,
+};
+
/*
* IRQ handler for the timer
*/
static irqreturn_t gemini_timer_interrupt(int irq, void *dev_id)
{
- timer_tick();
+ struct clock_event_device *evt = &gemini_clockevent;
+ evt->event_handler(evt);
return IRQ_HANDLED;
}
static struct irqaction gemini_timer_irq = {
.name = "Gemini Timer Tick",
- .flags = IRQF_DISABLED | IRQF_TIMER,
+ .flags = IRQF_TIMER,
.handler = gemini_timer_interrupt,
};
@@ -54,9 +126,9 @@ static struct irqaction gemini_timer_irq = {
*/
void __init gemini_timer_init(void)
{
- unsigned int tick_rate, reg_v;
+ u32 reg_v;
- reg_v = __raw_readl(IO_ADDRESS(GEMINI_GLOBAL_BASE + GLOBAL_STATUS));
+ reg_v = readl(IO_ADDRESS(GEMINI_GLOBAL_BASE + GLOBAL_STATUS));
tick_rate = REG_TO_AHB_SPEED(reg_v) * 1000000;
printk(KERN_INFO "Bus: %dMHz", tick_rate / 1000000);
@@ -82,8 +154,17 @@ void __init gemini_timer_init(void)
* Make irqs happen for the system timer
*/
setup_irq(IRQ_TIMER2, &gemini_timer_irq);
- /* Start the timer */
- __raw_writel(tick_rate / HZ, TIMER_COUNT(IO_ADDRESS(GEMINI_TIMER2_BASE)));
- __raw_writel(tick_rate / HZ, TIMER_LOAD(IO_ADDRESS(GEMINI_TIMER2_BASE)));
- __raw_writel(TIMER_2_CR_ENABLE | TIMER_2_CR_INT, TIMER_CR(IO_ADDRESS(GEMINI_TIMER_BASE)));
+
+ /* Enable and use TIMER1 as clock source */
+ writel(0xffffffff, TIMER_COUNT(IO_ADDRESS(GEMINI_TIMER1_BASE)));
+ writel(0xffffffff, TIMER_LOAD(IO_ADDRESS(GEMINI_TIMER1_BASE)));
+ writel(TIMER_1_CR_ENABLE, TIMER_CR(IO_ADDRESS(GEMINI_TIMER_BASE)));
+ if (clocksource_mmio_init(TIMER_COUNT(IO_ADDRESS(GEMINI_TIMER1_BASE)),
+ "TIMER1", tick_rate, 300, 32,
+ clocksource_mmio_readl_up))
+ pr_err("timer: failed to initialize gemini clock source\n");
+
+ /* Configure and register the clockevent */
+ clockevents_config_and_register(&gemini_clockevent, tick_rate,
+ 1, 0xffffffff);
}