[PATCH v2 2/4] clocksource: add device-tree support for PXA timer

Robert Jarzmik
2014-07-05T11:12:59Z

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-GANU6spQydw@public.gmane.org>

---
Since V1: Daniel's review:
- comments for registers
- registers clean-up
- mach includes removed
- panic() removed
---
drivers/clocksource/pxa_timer.c | 129 +++++++++++++++++++++++++++++-----------
1 file changed, 93 insertions(+), 36 deletions(-)

diff --git a/drivers/clocksource/pxa_timer.c b/drivers/clocksource/pxa_timer.c
index fca174e..5caedd3 100644
--- a/drivers/clocksource/pxa_timer.c
+++ b/drivers/clocksource/pxa_timer.c
@@ -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
@@ -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);
}

@@ -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;
@@ -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;
}
@@ -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:
@@ -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)
@@ -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
@@ -142,21 +163,57 @@ 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)
+{
+ timer_base = base;
+ pxa_timer_common_init(irq, clock_tick_rate);
}