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enable 4.19.x-rt with preempt-rt Linux 4.19.15
Signed-off-by: Tiejun Chen <tiejun.china@gmail.com>
This commit is contained in:
@@ -0,0 +1,157 @@
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From: Benedikt Spranger <b.spranger@linutronix.de>
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Date: Mon, 8 Mar 2010 18:57:04 +0100
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Subject: clocksource: TCLIB: Allow higher clock rates for clock events
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As default the TCLIB uses the 32KiHz base clock rate for clock events.
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Add a compile time selection to allow higher clock resulution.
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(fixed up by Sami Pietikäinen <Sami.Pietikainen@wapice.com>)
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Signed-off-by: Benedikt Spranger <b.spranger@linutronix.de>
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Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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---
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drivers/clocksource/tcb_clksrc.c | 36 +++++++++++++++++++++---------------
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drivers/misc/Kconfig | 12 ++++++++++--
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2 files changed, 31 insertions(+), 17 deletions(-)
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--- a/drivers/clocksource/tcb_clksrc.c
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+++ b/drivers/clocksource/tcb_clksrc.c
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@@ -25,8 +25,7 @@
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* this 32 bit free-running counter. the second channel is not used.
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*
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* - The third channel may be used to provide a 16-bit clockevent
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- * source, used in either periodic or oneshot mode. This runs
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- * at 32 KiHZ, and can handle delays of up to two seconds.
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+ * source, used in either periodic or oneshot mode.
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*
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* A boot clocksource and clockevent source are also currently needed,
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* unless the relevant platforms (ARM/AT91, AVR32/AT32) are changed so
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@@ -127,6 +126,7 @@ struct tc_clkevt_device {
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struct clock_event_device clkevt;
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struct clk *clk;
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bool clk_enabled;
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+ u32 freq;
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void __iomem *regs;
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};
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@@ -135,13 +135,6 @@ static struct tc_clkevt_device *to_tc_cl
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return container_of(clkevt, struct tc_clkevt_device, clkevt);
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}
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-/* For now, we always use the 32K clock ... this optimizes for NO_HZ,
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- * because using one of the divided clocks would usually mean the
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- * tick rate can never be less than several dozen Hz (vs 0.5 Hz).
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- *
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- * A divided clock could be good for high resolution timers, since
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- * 30.5 usec resolution can seem "low".
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- */
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static u32 timer_clock;
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static void tc_clk_disable(struct clock_event_device *d)
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@@ -191,7 +184,7 @@ static int tc_set_oneshot(struct clock_e
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tc_clk_enable(d);
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- /* slow clock, count up to RC, then irq and stop */
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+ /* count up to RC, then irq and stop */
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writel(timer_clock | ATMEL_TC_CPCSTOP | ATMEL_TC_WAVE |
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ATMEL_TC_WAVESEL_UP_AUTO, regs + ATMEL_TC_REG(2, CMR));
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writel(ATMEL_TC_CPCS, regs + ATMEL_TC_REG(2, IER));
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@@ -213,10 +206,10 @@ static int tc_set_periodic(struct clock_
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*/
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tc_clk_enable(d);
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- /* slow clock, count up to RC, then irq and restart */
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+ /* count up to RC, then irq and restart */
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writel(timer_clock | ATMEL_TC_WAVE | ATMEL_TC_WAVESEL_UP_AUTO,
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regs + ATMEL_TC_REG(2, CMR));
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- writel((32768 + HZ / 2) / HZ, tcaddr + ATMEL_TC_REG(2, RC));
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+ writel((tcd->freq + HZ / 2) / HZ, tcaddr + ATMEL_TC_REG(2, RC));
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/* Enable clock and interrupts on RC compare */
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writel(ATMEL_TC_CPCS, regs + ATMEL_TC_REG(2, IER));
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@@ -243,7 +236,11 @@ static struct tc_clkevt_device clkevt =
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.features = CLOCK_EVT_FEAT_PERIODIC |
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CLOCK_EVT_FEAT_ONESHOT,
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/* Should be lower than at91rm9200's system timer */
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+#ifdef CONFIG_ATMEL_TCB_CLKSRC_USE_SLOW_CLOCK
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.rating = 125,
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+#else
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+ .rating = 200,
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+#endif
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.set_next_event = tc_next_event,
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.set_state_shutdown = tc_shutdown_clk_off,
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.set_state_periodic = tc_set_periodic,
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@@ -265,8 +262,9 @@ static irqreturn_t ch2_irq(int irq, void
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return IRQ_NONE;
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}
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-static int __init setup_clkevents(struct atmel_tc *tc, int clk32k_divisor_idx)
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+static int __init setup_clkevents(struct atmel_tc *tc, int divisor_idx)
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{
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+ unsigned divisor = atmel_tc_divisors[divisor_idx];
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int ret;
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struct clk *t2_clk = tc->clk[2];
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int irq = tc->irq[2];
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@@ -287,7 +285,11 @@ static int __init setup_clkevents(struct
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clkevt.regs = tc->regs;
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clkevt.clk = t2_clk;
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- timer_clock = clk32k_divisor_idx;
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+ timer_clock = divisor_idx;
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+ if (!divisor)
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+ clkevt.freq = 32768;
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+ else
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+ clkevt.freq = clk_get_rate(t2_clk) / divisor;
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clkevt.clkevt.cpumask = cpumask_of(0);
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@@ -298,7 +300,7 @@ static int __init setup_clkevents(struct
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return ret;
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}
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- clockevents_config_and_register(&clkevt.clkevt, 32768, 1, 0xffff);
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+ clockevents_config_and_register(&clkevt.clkevt, clkevt.freq, 1, 0xffff);
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return ret;
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}
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@@ -435,7 +437,11 @@ static int __init tcb_clksrc_init(void)
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goto err_disable_t1;
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/* channel 2: periodic and oneshot timer support */
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+#ifdef CONFIG_ATMEL_TCB_CLKSRC_USE_SLOW_CLOCK
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ret = setup_clkevents(tc, clk32k_divisor_idx);
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+#else
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+ ret = setup_clkevents(tc, best_divisor_idx);
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+#endif
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if (ret)
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goto err_unregister_clksrc;
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--- a/drivers/misc/Kconfig
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+++ b/drivers/misc/Kconfig
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@@ -69,8 +69,7 @@ config ATMEL_TCB_CLKSRC
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are combined to make a single 32-bit timer.
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When GENERIC_CLOCKEVENTS is defined, the third timer channel
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- may be used as a clock event device supporting oneshot mode
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- (delays of up to two seconds) based on the 32 KiHz clock.
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+ may be used as a clock event device supporting oneshot mode.
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config ATMEL_TCB_CLKSRC_BLOCK
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int
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@@ -83,6 +82,15 @@ config ATMEL_TCB_CLKSRC_BLOCK
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TC can be used for other purposes, such as PWM generation and
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interval timing.
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+config ATMEL_TCB_CLKSRC_USE_SLOW_CLOCK
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+ bool "TC Block use 32 KiHz clock"
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+ depends on ATMEL_TCB_CLKSRC
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+ default y
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+ help
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+ Select this to use 32 KiHz base clock rate as TC block clock
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+ source for clock events.
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+
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+
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config DUMMY_IRQ
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tristate "Dummy IRQ handler"
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default n
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