ARM: orion: implement ARM delay timer (f19768ce) · Commits · 戴 / test

Implement an ARM delay timer to be used for udelay() on orion legacy platforms. This allows us to skip the delay loop calibration at boot. It also means that udelay() will be unaffected by CPU frequency changes when cpufreq is enabled on these platforms. Tested-by:

Russell King <rmk+kernel@arm.linux.org.uk> Acked-by:

Andrew Lunn <andrew@lunn.ch> Signed-off-by:

Russell King <rmk+kernel@arm.linux.org.uk>

arch/arm/plat-orion/time.c

+13 −0

Original line number	Diff line number	Diff line
		@@ -18,6 +18,7 @@
		#include <linux/irq.h>
		#include <linux/sched_clock.h>
		#include <plat/time.h>
		#include <asm/delay.h>

		/*
		* MBus bridge block registers.
		@@ -188,6 +189,15 @@ orion_time_set_base(void __iomem *_timer_base)
		timer_base = _timer_base;
		}

		static unsigned long orion_delay_timer_read(void)
		{
		return ~readl(timer_base + TIMER0_VAL_OFF);
		}

		static struct delay_timer orion_delay_timer = {
		.read_current_timer = orion_delay_timer_read,
		};

		void __init
		orion_time_init(void __iomem *_bridge_base, u32 _bridge_timer1_clr_mask,
		unsigned int irq, unsigned int tclk)
		@@ -202,6 +212,9 @@ orion_time_init(void __iomem *_bridge_base, u32 _bridge_timer1_clr_mask,

		ticks_per_jiffy = (tclk + HZ/2) / HZ;

		orion_delay_timer.freq = tclk;
		register_current_timer_delay(&orion_delay_timer);

		/*
		* Set scale and timer for sched_clock.
		*/

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