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authorJonas Aaberg <jonas.aberg@stericsson.com>2011-09-14 10:32:51 +0200
committerLinus Walleij <linus.walleij@linaro.org>2011-09-22 15:44:10 +0200
commit2f73a06843e357190a7a3924c7afb0534cf6adef (patch)
tree098cc733897c0d182eadcbb445d04d3f129e733e /arch/arm/plat-nomadik
parent5f5663a436a4c54ede441b4f8ab3f947e78db345 (diff)
ARM: plat-nomadik: timer: Add support for periodic timers
This adds support for a periodic mode in the MTU (Nomadik) timer clockevent driver. It also include changes needed for deeper powerstates where MTU block gets powered off. Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Jonas Aaberg <jonas.aberg@stericsson.com> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Diffstat (limited to 'arch/arm/plat-nomadik')
-rw-r--r--arch/arm/plat-nomadik/timer.c88
1 files changed, 60 insertions, 28 deletions
diff --git a/arch/arm/plat-nomadik/timer.c b/arch/arm/plat-nomadik/timer.c
index bd638c552f04..a04b5215b6d8 100644
--- a/arch/arm/plat-nomadik/timer.c
+++ b/arch/arm/plat-nomadik/timer.c
@@ -23,7 +23,12 @@
#include <plat/mtu.h>
+static bool clkevt_periodic;
+static u32 clk_prescale;
+static u32 nmdk_cycle; /* write-once */
+
void __iomem *mtu_base; /* Assigned by machine code */
+
#ifdef CONFIG_NOMADIK_MTU_SCHED_CLOCK
/*
* Override the global weak sched_clock symbol with this
@@ -49,31 +54,55 @@ static void notrace nomadik_update_sched_clock(void)
update_sched_clock(&cd, cyc, (u32)~0);
}
#endif
+
/* Clockevent device: use one-shot mode */
+static int nmdk_clkevt_next(unsigned long evt, struct clock_event_device *ev)
+{
+ writel(1 << 1, mtu_base + MTU_IMSC);
+ writel(evt, mtu_base + MTU_LR(1));
+ /* Load highest value, enable device, enable interrupts */
+ writel(MTU_CRn_ONESHOT | clk_prescale |
+ MTU_CRn_32BITS | MTU_CRn_ENA,
+ mtu_base + MTU_CR(1));
+
+ return 0;
+}
+
+static void nmdk_clkevt_reset(void)
+{
+ if (clkevt_periodic) {
+
+ /* Timer: configure load and background-load, and fire it up */
+ writel(nmdk_cycle, mtu_base + MTU_LR(1));
+ writel(nmdk_cycle, mtu_base + MTU_BGLR(1));
+
+ writel(MTU_CRn_PERIODIC | clk_prescale |
+ MTU_CRn_32BITS | MTU_CRn_ENA,
+ mtu_base + MTU_CR(1));
+ writel(1 << 1, mtu_base + MTU_IMSC);
+ } else {
+ /* Generate an interrupt to start the clockevent again */
+ (void) nmdk_clkevt_next(nmdk_cycle, NULL);
+ }
+}
+
static void nmdk_clkevt_mode(enum clock_event_mode mode,
struct clock_event_device *dev)
{
- u32 cr;
switch (mode) {
case CLOCK_EVT_MODE_PERIODIC:
- pr_err("%s: periodic mode not supported\n", __func__);
+ clkevt_periodic = true;
+ nmdk_clkevt_reset();
break;
case CLOCK_EVT_MODE_ONESHOT:
- /* Load highest value, enable device, enable interrupts */
- cr = readl(mtu_base + MTU_CR(1));
- writel(0, mtu_base + MTU_LR(1));
- writel(cr | MTU_CRn_ENA, mtu_base + MTU_CR(1));
- writel(1 << 1, mtu_base + MTU_IMSC);
+ clkevt_periodic = false;
break;
case CLOCK_EVT_MODE_SHUTDOWN:
case CLOCK_EVT_MODE_UNUSED:
- /* disable irq */
writel(0, mtu_base + MTU_IMSC);
/* disable timer */
- cr = readl(mtu_base + MTU_CR(1));
- cr &= ~MTU_CRn_ENA;
- writel(cr, mtu_base + MTU_CR(1));
+ writel(0, mtu_base + MTU_CR(1));
/* load some high default value */
writel(0xffffffff, mtu_base + MTU_LR(1));
break;
@@ -82,16 +111,9 @@ static void nmdk_clkevt_mode(enum clock_event_mode mode,
}
}
-static int nmdk_clkevt_next(unsigned long evt, struct clock_event_device *ev)
-{
- /* writing the value has immediate effect */
- writel(evt, mtu_base + MTU_LR(1));
- return 0;
-}
-
static struct clock_event_device nmdk_clkevt = {
.name = "mtu_1",
- .features = CLOCK_EVT_FEAT_ONESHOT,
+ .features = CLOCK_EVT_FEAT_ONESHOT | CLOCK_EVT_FEAT_PERIODIC,
.rating = 200,
.set_mode = nmdk_clkevt_mode,
.set_next_event = nmdk_clkevt_next,
@@ -116,11 +138,23 @@ static struct irqaction nmdk_timer_irq = {
.dev_id = &nmdk_clkevt,
};
+static void nmdk_clksrc_reset(void)
+{
+ /* Disable */
+ writel(0, mtu_base + MTU_CR(0));
+
+ /* ClockSource: configure load and background-load, and fire it up */
+ writel(nmdk_cycle, mtu_base + MTU_LR(0));
+ writel(nmdk_cycle, mtu_base + MTU_BGLR(0));
+
+ writel(clk_prescale | MTU_CRn_32BITS | MTU_CRn_ENA,
+ mtu_base + MTU_CR(0));
+}
+
void __init nmdk_timer_init(void)
{
unsigned long rate;
struct clk *clk0;
- u32 cr = MTU_CRn_32BITS;
clk0 = clk_get_sys("mtu0", NULL);
BUG_ON(IS_ERR(clk0));
@@ -138,16 +172,16 @@ void __init nmdk_timer_init(void)
rate = clk_get_rate(clk0);
if (rate > 32000000) {
rate /= 16;
- cr |= MTU_CRn_PRESCALE_16;
+ clk_prescale = MTU_CRn_PRESCALE_16;
} else {
- cr |= MTU_CRn_PRESCALE_1;
+ clk_prescale = MTU_CRn_PRESCALE_1;
}
+ nmdk_cycle = (rate + HZ/2) / HZ;
+
+
/* Timer 0 is the free running clocksource */
- writel(cr, mtu_base + MTU_CR(0));
- writel(0, mtu_base + MTU_LR(0));
- writel(0, mtu_base + MTU_BGLR(0));
- writel(cr | MTU_CRn_ENA, mtu_base + MTU_CR(0));
+ nmdk_clksrc_reset();
if (clocksource_mmio_init(mtu_base + MTU_VAL(0), "mtu_0",
rate, 200, 32, clocksource_mmio_readl_down))
@@ -160,8 +194,6 @@ void __init nmdk_timer_init(void)
clockevents_calc_mult_shift(&nmdk_clkevt, rate, MTU_MIN_RANGE);
- writel(cr | MTU_CRn_ONESHOT, mtu_base + MTU_CR(1)); /* off, currently */
-
nmdk_clkevt.max_delta_ns =
clockevent_delta2ns(0xffffffff, &nmdk_clkevt);
nmdk_clkevt.min_delta_ns =