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Subject[PATCH 3/7] clocksource/cadence_ttc: Store timer frequency in driver data
Date
It is not allowed to call clk_get_rate() from interrupt context. To
avoid such calls the timer input frequency is stored in the driver's
data struct which makes it accessible to the driver in any context.

Signed-off-by: Soren Brinkmann <soren.brinkmann@xilinx.com>
---
drivers/clocksource/cadence_ttc_timer.c | 21 +++++++++++++--------
1 file changed, 13 insertions(+), 8 deletions(-)

diff --git a/drivers/clocksource/cadence_ttc_timer.c b/drivers/clocksource/cadence_ttc_timer.c
index b2bb3a4bc205..a92350b55d32 100644
--- a/drivers/clocksource/cadence_ttc_timer.c
+++ b/drivers/clocksource/cadence_ttc_timer.c
@@ -67,11 +67,13 @@
* struct ttc_timer - This definition defines local timer structure
*
* @base_addr: Base address of timer
+ * @freq: Timer input clock frequency
* @clk: Associated clock source
* @clk_rate_change_nb Notifier block for clock rate changes
*/
struct ttc_timer {
void __iomem *base_addr;
+ unsigned long freq;
struct clk *clk;
struct notifier_block clk_rate_change_nb;
};
@@ -196,9 +198,8 @@ static void ttc_set_mode(enum clock_event_mode mode,

switch (mode) {
case CLOCK_EVT_MODE_PERIODIC:
- ttc_set_interval(timer,
- DIV_ROUND_CLOSEST(clk_get_rate(ttce->ttc.clk),
- PRESCALE * HZ));
+ ttc_set_interval(timer, DIV_ROUND_CLOSEST(ttce->ttc.freq,
+ PRESCALE * HZ));
break;
case CLOCK_EVT_MODE_ONESHOT:
case CLOCK_EVT_MODE_UNUSED:
@@ -273,6 +274,8 @@ static void __init ttc_setup_clocksource(struct clk *clk, void __iomem *base)
return;
}

+ ttccs->ttc.freq = clk_get_rate(ttccs->ttc.clk);
+
ttccs->ttc.clk_rate_change_nb.notifier_call =
ttc_rate_change_clocksource_cb;
ttccs->ttc.clk_rate_change_nb.next = NULL;
@@ -298,16 +301,14 @@ static void __init ttc_setup_clocksource(struct clk *clk, void __iomem *base)
__raw_writel(CNT_CNTRL_RESET,
ttccs->ttc.base_addr + TTC_CNT_CNTRL_OFFSET);

- err = clocksource_register_hz(&ttccs->cs,
- clk_get_rate(ttccs->ttc.clk) / PRESCALE);
+ err = clocksource_register_hz(&ttccs->cs, ttccs->ttc.freq / PRESCALE);
if (WARN_ON(err)) {
kfree(ttccs);
return;
}

ttc_sched_clock_val_reg = base + TTC_COUNT_VAL_OFFSET;
- setup_sched_clock(ttc_sched_clock_read, 16,
- clk_get_rate(ttccs->ttc.clk) / PRESCALE);
+ setup_sched_clock(ttc_sched_clock_read, 16, ttccs->ttc.freq / PRESCALE);
}

static int ttc_rate_change_clockevent_cb(struct notifier_block *nb,
@@ -334,6 +335,9 @@ static int ttc_rate_change_clockevent_cb(struct notifier_block *nb,
ndata->new_rate / PRESCALE);
local_irq_restore(flags);

+ /* update cached frequency */
+ ttc->freq = ndata->new_rate;
+
/* fall through */
}
case PRE_RATE_CHANGE:
@@ -367,6 +371,7 @@ static void __init ttc_setup_clockevent(struct clk *clk,
if (clk_notifier_register(ttcce->ttc.clk,
&ttcce->ttc.clk_rate_change_nb))
pr_warn("Unable to register clock notifier.\n");
+ ttcce->ttc.freq = clk_get_rate(ttcce->ttc.clk);

ttcce->ttc.base_addr = base;
ttcce->ce.name = "ttc_clockevent";
@@ -396,7 +401,7 @@ static void __init ttc_setup_clockevent(struct clk *clk,
}

clockevents_config_and_register(&ttcce->ce,
- clk_get_rate(ttcce->ttc.clk) / PRESCALE, 1, 0xfffe);
+ ttcce->ttc.freq / PRESCALE, 1, 0xfffe);
}

/**
--
1.8.4.2


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