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In 5388a6b266 ("ARM: SMP: Always enable clock event broadcast support")
Russell noted that "the TWD local timers are unable to wake up the CPU
when it is placed into a low power mode".
However, some platforms do not stop the TWD block in low-power mode,
and can thus use the TWD timer in one-shot mode, without setting up
a broadcast device.
Make the driver check for the "always-on" boolean property, and set
the CLOCK_EVT_FEAT_C3STOP flag accordingly.
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Marc Gonzalez <marc_gonzalez@sigmadesigns.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
54 lines
1.2 KiB
Plaintext
54 lines
1.2 KiB
Plaintext
* ARM Timer Watchdog
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ARM 11MP, Cortex-A5 and Cortex-A9 are often associated with a per-core
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Timer-Watchdog (aka TWD), which provides both a per-cpu local timer
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and watchdog.
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The TWD is usually attached to a GIC to deliver its two per-processor
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interrupts.
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** Timer node required properties:
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- compatible : Should be one of:
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"arm,cortex-a9-twd-timer"
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"arm,cortex-a5-twd-timer"
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"arm,arm11mp-twd-timer"
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- interrupts : One interrupt to each core
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- reg : Specify the base address and the size of the TWD timer
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register window.
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Optional
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- always-on : a boolean property. If present, the timer is powered through
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an always-on power domain, therefore it never loses context.
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Example:
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twd-timer@2c000600 {
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compatible = "arm,arm11mp-twd-timer"";
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reg = <0x2c000600 0x20>;
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interrupts = <1 13 0xf01>;
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};
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** Watchdog node properties:
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- compatible : Should be one of:
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"arm,cortex-a9-twd-wdt"
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"arm,cortex-a5-twd-wdt"
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"arm,arm11mp-twd-wdt"
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- interrupts : One interrupt to each core
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- reg : Specify the base address and the size of the TWD watchdog
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register window.
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Example:
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twd-watchdog@2c000620 {
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compatible = "arm,arm11mp-twd-wdt";
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reg = <0x2c000620 0x20>;
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interrupts = <1 14 0xf01>;
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};
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