Hi Daniel,

On Wed, Jun 26, 2013 at 11:27:35PM +0200, Daniel Lezcano wrote:

On 06/26/2013 11:16 PM, Maxime Ripard wrote:

quoted

The A10 and the A13 has a 64 bits free running counter that we can use
as a clocksource and a sched clock, that were both not used yet on these
platforms.

Signed-off-by: Maxime Ripard <redacted>
---
 drivers/clocksource/sun4i_timer.c | 27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/drivers/clocksource/sun4i_timer.c b/drivers/clocksource/sun4i_timer.c
index bdf34d9..1d2eaa0 100644
--- a/drivers/clocksource/sun4i_timer.c
+++ b/drivers/clocksource/sun4i_timer.c

@@ -23,6 +23,8 @@
 #include <linux/of_address.h>
 #include <linux/of_irq.h>
 
+#include <asm/sched_clock.h>
+
 #define TIMER_IRQ_EN_REG	0x00
 #define TIMER_IRQ_EN(val)		BIT(val)
 #define TIMER_IRQ_ST_REG	0x04

@@ -34,6 +36,11 @@
 #define TIMER_CNTVAL_REG(val)	(0x10 * val + 0x18)
 
 #define TIMER_SCAL		16
+#define TIMER_CNT64_CTL_REG	0xa0
+#define TIMER_CNT64_CTL_CLR		BIT(0)
+#define TIMER_CNT64_CTL_RL		BIT(1)
+#define TIMER_CNT64_LOW_REG	0xa4
+#define TIMER_CNT64_HIGH_REG	0xa8
 
 static void __iomem *timer_base;
 

@@ -96,6 +103,20 @@ static struct irqaction sun4i_timer_irq = {
 	.dev_id = &sun4i_clockevent,
 };
 
+static u32 sun4i_timer_sched_read(void)
+{
+	u32 reg = readl(timer_base + TIMER_CNT64_CTL_REG);
+	writel(reg | TIMER_CNT64_CTL_RL, timer_base + TIMER_CNT64_CTL_REG);
+	while (readl(timer_base + TIMER_CNT64_CTL_REG) & TIMER_CNT64_CTL_REG);

Isn't a cpu_relax missing here ?

Right.

The AND is wrong as well, it should be TIMER_CNT64_CTL_RL, not the reg
offset.

quoted

 
+	writel(TIMER_CNT64_CTL_CLR, timer_base + TIMER_CNT64_CTL_REG);
+	setup_sched_clock(sun4i_timer_sched_read, 32, clk_get_rate(clk));
+	clocksource_mmio_init(timer_base + TIMER_CNT64_LOW_REG, node->name,
+			      clk_get_rate(clk), 300, 32,
+			      sun4i_timer_clksrc_read);
+
 	writel(rate / (TIMER_SCAL * HZ),

DIV_ROUND_CLOSEST(rate, (TIMER_SCAL * HZ)), ?

It's actually fixed in a later patch, but yes.

Thanks!
Maxime

-- 
Maxime Ripard, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com
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