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clocksource: pxa: Add device-tree support for PXA timer
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Add device-tree support to PXA platforms.
The driver still needs to maintain backward non device-tree
compatibility as well, which implies :
 - a non device-tree init function
 - a static registers base address in the driver

Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
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Robert Jarzmik authored and Daniel Lezcano committed Jul 23, 2014
1 parent c5421d7 commit ab5354c
Showing 1 changed file with 101 additions and 36 deletions.
137 changes: 101 additions & 36 deletions drivers/clocksource/pxa_timer.c
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Original file line number Diff line number Diff line change
Expand Up @@ -15,14 +15,30 @@
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/clk.h>
#include <linux/clockchips.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
#include <linux/sched_clock.h>

#include <asm/div64.h>
#include <asm/mach/irq.h>
#include <asm/mach/time.h>
#include <mach/regs-ost.h>
#include <mach/irqs.h>

#define OSMR0 0x00 /* OS Timer 0 Match Register */
#define OSMR1 0x04 /* OS Timer 1 Match Register */
#define OSMR2 0x08 /* OS Timer 2 Match Register */
#define OSMR3 0x0C /* OS Timer 3 Match Register */

#define OSCR 0x10 /* OS Timer Counter Register */
#define OSSR 0x14 /* OS Timer Status Register */
#define OWER 0x18 /* OS Timer Watchdog Enable Register */
#define OIER 0x1C /* OS Timer Interrupt Enable Register */

#define OSSR_M3 (1 << 3) /* Match status channel 3 */
#define OSSR_M2 (1 << 2) /* Match status channel 2 */
#define OSSR_M1 (1 << 1) /* Match status channel 1 */
#define OSSR_M0 (1 << 0) /* Match status channel 0 */

#define OIER_E0 (1 << 0) /* Interrupt enable channel 0 */

/*
* This is PXA's sched_clock implementation. This has a resolution
Expand All @@ -33,9 +49,14 @@
* calls to sched_clock() which should always be the case in practice.
*/

#define timer_readl(reg) readl_relaxed(timer_base + (reg))
#define timer_writel(val, reg) writel_relaxed((val), timer_base + (reg))

static void __iomem *timer_base;

static u64 notrace pxa_read_sched_clock(void)
{
return readl_relaxed(OSCR);
return timer_readl(OSCR);
}


Expand All @@ -47,8 +68,8 @@ pxa_ost0_interrupt(int irq, void *dev_id)
struct clock_event_device *c = dev_id;

/* Disarm the compare/match, signal the event. */
writel_relaxed(readl_relaxed(OIER) & ~OIER_E0, OIER);
writel_relaxed(OSSR_M0, OSSR);
timer_writel(timer_readl(OIER) & ~OIER_E0, OIER);
timer_writel(OSSR_M0, OSSR);
c->event_handler(c);

return IRQ_HANDLED;
Expand All @@ -59,10 +80,10 @@ pxa_osmr0_set_next_event(unsigned long delta, struct clock_event_device *dev)
{
unsigned long next, oscr;

writel_relaxed(readl_relaxed(OIER) | OIER_E0, OIER);
next = readl_relaxed(OSCR) + delta;
writel_relaxed(next, OSMR0);
oscr = readl_relaxed(OSCR);
timer_writel(timer_readl(OIER) | OIER_E0, OIER);
next = timer_readl(OSCR) + delta;
timer_writel(next, OSMR0);
oscr = timer_readl(OSCR);

return (signed)(next - oscr) <= MIN_OSCR_DELTA ? -ETIME : 0;
}
Expand All @@ -72,15 +93,15 @@ pxa_osmr0_set_mode(enum clock_event_mode mode, struct clock_event_device *dev)
{
switch (mode) {
case CLOCK_EVT_MODE_ONESHOT:
writel_relaxed(readl_relaxed(OIER) & ~OIER_E0, OIER);
writel_relaxed(OSSR_M0, OSSR);
timer_writel(timer_readl(OIER) & ~OIER_E0, OIER);
timer_writel(OSSR_M0, OSSR);
break;

case CLOCK_EVT_MODE_UNUSED:
case CLOCK_EVT_MODE_SHUTDOWN:
/* initializing, released, or preparing for suspend */
writel_relaxed(readl_relaxed(OIER) & ~OIER_E0, OIER);
writel_relaxed(OSSR_M0, OSSR);
timer_writel(timer_readl(OIER) & ~OIER_E0, OIER);
timer_writel(OSSR_M0, OSSR);
break;

case CLOCK_EVT_MODE_RESUME:
Expand All @@ -94,12 +115,12 @@ static unsigned long osmr[4], oier, oscr;

static void pxa_timer_suspend(struct clock_event_device *cedev)
{
osmr[0] = readl_relaxed(OSMR0);
osmr[1] = readl_relaxed(OSMR1);
osmr[2] = readl_relaxed(OSMR2);
osmr[3] = readl_relaxed(OSMR3);
oier = readl_relaxed(OIER);
oscr = readl_relaxed(OSCR);
osmr[0] = timer_readl(OSMR0);
osmr[1] = timer_readl(OSMR1);
osmr[2] = timer_readl(OSMR2);
osmr[3] = timer_readl(OSMR3);
oier = timer_readl(OIER);
oscr = timer_readl(OSCR);
}

static void pxa_timer_resume(struct clock_event_device *cedev)
Expand All @@ -113,12 +134,12 @@ static void pxa_timer_resume(struct clock_event_device *cedev)
if (osmr[0] - oscr < MIN_OSCR_DELTA)
osmr[0] += MIN_OSCR_DELTA;

writel_relaxed(osmr[0], OSMR0);
writel_relaxed(osmr[1], OSMR1);
writel_relaxed(osmr[2], OSMR2);
writel_relaxed(osmr[3], OSMR3);
writel_relaxed(oier, OIER);
writel_relaxed(oscr, OSCR);
timer_writel(osmr[0], OSMR0);
timer_writel(osmr[1], OSMR1);
timer_writel(osmr[2], OSMR2);
timer_writel(osmr[3], OSMR3);
timer_writel(oier, OIER);
timer_writel(oscr, OSCR);
}
#else
#define pxa_timer_suspend NULL
Expand All @@ -142,21 +163,65 @@ static struct irqaction pxa_ost0_irq = {
.dev_id = &ckevt_pxa_osmr0,
};

void __init pxa_timer_init(void)
static void pxa_timer_common_init(int irq, unsigned long clock_tick_rate)
{
unsigned long clock_tick_rate = get_clock_tick_rate();

writel_relaxed(0, OIER);
writel_relaxed(OSSR_M0 | OSSR_M1 | OSSR_M2 | OSSR_M3, OSSR);
timer_writel(0, OIER);
timer_writel(OSSR_M0 | OSSR_M1 | OSSR_M2 | OSSR_M3, OSSR);

sched_clock_register(pxa_read_sched_clock, 32, clock_tick_rate);

ckevt_pxa_osmr0.cpumask = cpumask_of(0);

setup_irq(IRQ_OST0, &pxa_ost0_irq);
setup_irq(irq, &pxa_ost0_irq);

clocksource_mmio_init(OSCR, "oscr0", clock_tick_rate, 200, 32,
clocksource_mmio_readl_up);
clocksource_mmio_init(timer_base + OSCR, "oscr0", clock_tick_rate, 200,
32, clocksource_mmio_readl_up);
clockevents_config_and_register(&ckevt_pxa_osmr0, clock_tick_rate,
MIN_OSCR_DELTA * 2, 0x7fffffff);
MIN_OSCR_DELTA * 2, 0x7fffffff);
}

static void __init pxa_timer_dt_init(struct device_node *np)
{
struct clk *clk;
int irq;

/* timer registers are shared with watchdog timer */
timer_base = of_iomap(np, 0);
if (!timer_base)
panic("%s: unable to map resource\n", np->name);

clk = of_clk_get(np, 0);
if (IS_ERR(clk)) {
pr_crit("%s: unable to get clk\n", np->name);
return;
}
clk_prepare_enable(clk);

/* we are only interested in OS-timer0 irq */
irq = irq_of_parse_and_map(np, 0);
if (irq <= 0) {
pr_crit("%s: unable to parse OS-timer0 irq\n", np->name);
return;
}

pxa_timer_common_init(irq, clk_get_rate(clk));
}
CLOCKSOURCE_OF_DECLARE(pxa_timer, "marvell,pxa-timer", pxa_timer_dt_init);

/*
* Legacy timer init for non device-tree boards.
*/
void __init pxa_timer_nodt_init(int irq, void __iomem *base,
unsigned long clock_tick_rate)
{
struct clk *clk;

timer_base = base;
clk = clk_get(NULL, "OSTIMER0");
if (clk && !IS_ERR(clk))
clk_prepare_enable(clk);
else
pr_crit("%s: unable to get clk\n", __func__);

pxa_timer_common_init(irq, clock_tick_rate);
}

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