| Message ID | 20210315043250.45095-5-samuel@sholland.org |
|---|---|
| State | New |
| Headers | show |
| Series | arm64: sunxi: Enable the sun4i timer | expand |
On 3/15/21 1:32 PM, Jernej Škrabec wrote: > Hi! > > Dne ponedeljek, 15. marec 2021 ob 05:32:49 CET je Samuel Holland napisal(a): >> For a CPU to enter an idle state, there must be some timer which can >> trigger an IRQ to wake it back up. The local ARM architectural timer is >> not sufficient, because that timer stops when the CPU is powered down. >> Some other CPU's ARM architectural timer can be used, but this prevents >> that other CPU from entering an idle state. So to allow all CPUs to >> enter an idle state at the same time, some MMIO timer must be available >> that is not tied to any CPU. >> >> The basic "sun4i" timer seems most appropriate for this purpose due to >> its moderate rate, balancing precision and power consumption. >> >> Signed-off-by: Samuel Holland <samuel@sholland.org> >> --- >> arch/arm64/boot/dts/allwinner/sun50i-a64.dtsi | 9 +++++++++ >> arch/arm64/boot/dts/allwinner/sun50i-h6.dtsi | 9 +++++++++ >> arch/arm64/boot/dts/allwinner/sun50i-h616.dtsi | 9 +++++++++ >> 3 files changed, 27 insertions(+) >> >> diff --git a/arch/arm64/boot/dts/allwinner/sun50i-a64.dtsi >> b/arch/arm64/boot/dts/allwinner/sun50i-a64.dtsi index >> 33df866f6ea9..64e8b4a372cc 100644 >> --- a/arch/arm64/boot/dts/allwinner/sun50i-a64.dtsi >> +++ b/arch/arm64/boot/dts/allwinner/sun50i-a64.dtsi >> @@ -905,6 +905,15 @@ uart4_rts_cts_pins: uart4-rts-cts-pins { >> }; >> }; >> >> + timer@1c20c00 { >> + compatible = "allwinner,sun50i-a64-timer", >> + "allwinner,sun8i-a23-timer"; >> + reg = <0x01c20c00 0xa0>; >> + interrupts = <GIC_SPI 18 > IRQ_TYPE_LEVEL_HIGH>, >> + <GIC_SPI 19 > IRQ_TYPE_LEVEL_HIGH>; >> + clocks = <&osc24M>; >> + }; >> + >> wdt0: watchdog@1c20ca0 { >> compatible = "allwinner,sun50i-a64-wdt", >> "allwinner,sun6i-a31-wdt"; >> diff --git a/arch/arm64/boot/dts/allwinner/sun50i-h6.dtsi >> b/arch/arm64/boot/dts/allwinner/sun50i-h6.dtsi index >> 62334054c710..9ba3b30e11fa 100644 >> --- a/arch/arm64/boot/dts/allwinner/sun50i-h6.dtsi >> +++ b/arch/arm64/boot/dts/allwinner/sun50i-h6.dtsi >> @@ -332,6 +332,15 @@ cpu_speed_grade: cpu-speed-grade@1c { >> }; >> }; >> >> + timer@3009000 { >> + compatible = "allwinner,sun50i-h6-timer", >> + "allwinner,sun8i-a23-timer"; >> + reg = <0x03009000 0xa0>; >> + interrupts = <GIC_SPI 48 > IRQ_TYPE_LEVEL_HIGH>, >> + <GIC_SPI 49 > IRQ_TYPE_LEVEL_HIGH>; >> + clocks = <&osc24M>; >> + }; >> + >> watchdog: watchdog@30090a0 { >> compatible = "allwinner,sun50i-h6-wdt", >> "allwinner,sun6i-a31-wdt"; >> diff --git a/arch/arm64/boot/dts/allwinner/sun50i-h616.dtsi >> b/arch/arm64/boot/dts/allwinner/sun50i-h616.dtsi index >> c277b53f94ea..ff55712ce96e 100644 >> --- a/arch/arm64/boot/dts/allwinner/sun50i-h616.dtsi >> +++ b/arch/arm64/boot/dts/allwinner/sun50i-h616.dtsi > > This file does not exist yet upstream. Right. I will remove this section for v2. Cheers, Samuel > Best regards, > Jernej > >> @@ -128,6 +128,15 @@ ccu: clock@3001000 { >> #reset-cells = <1>; >> }; >> >> + timer@3009000 { >> + compatible = "allwinner,sun50i-h616-timer", >> + "allwinner,sun8i-a23-timer"; >> + reg = <0x03009000 0xa0>; >> + interrupts = <GIC_SPI 48 > IRQ_TYPE_LEVEL_HIGH>, >> + <GIC_SPI 49 > IRQ_TYPE_LEVEL_HIGH>; >> + clocks = <&osc24M>; >> + }; >> + >> watchdog: watchdog@30090a0 { >> compatible = "allwinner,sun50i-h616-wdt", >> "allwinner,sun6i-a31-wdt"; > > > >
diff --git a/arch/arm64/boot/dts/allwinner/sun50i-a64.dtsi b/arch/arm64/boot/dts/allwinner/sun50i-a64.dtsi index 33df866f6ea9..64e8b4a372cc 100644 --- a/arch/arm64/boot/dts/allwinner/sun50i-a64.dtsi +++ b/arch/arm64/boot/dts/allwinner/sun50i-a64.dtsi @@ -905,6 +905,15 @@ uart4_rts_cts_pins: uart4-rts-cts-pins { }; }; + timer@1c20c00 { + compatible = "allwinner,sun50i-a64-timer", + "allwinner,sun8i-a23-timer"; + reg = <0x01c20c00 0xa0>; + interrupts = <GIC_SPI 18 IRQ_TYPE_LEVEL_HIGH>, + <GIC_SPI 19 IRQ_TYPE_LEVEL_HIGH>; + clocks = <&osc24M>; + }; + wdt0: watchdog@1c20ca0 { compatible = "allwinner,sun50i-a64-wdt", "allwinner,sun6i-a31-wdt"; diff --git a/arch/arm64/boot/dts/allwinner/sun50i-h6.dtsi b/arch/arm64/boot/dts/allwinner/sun50i-h6.dtsi index 62334054c710..9ba3b30e11fa 100644 --- a/arch/arm64/boot/dts/allwinner/sun50i-h6.dtsi +++ b/arch/arm64/boot/dts/allwinner/sun50i-h6.dtsi @@ -332,6 +332,15 @@ cpu_speed_grade: cpu-speed-grade@1c { }; }; + timer@3009000 { + compatible = "allwinner,sun50i-h6-timer", + "allwinner,sun8i-a23-timer"; + reg = <0x03009000 0xa0>; + interrupts = <GIC_SPI 48 IRQ_TYPE_LEVEL_HIGH>, + <GIC_SPI 49 IRQ_TYPE_LEVEL_HIGH>; + clocks = <&osc24M>; + }; + watchdog: watchdog@30090a0 { compatible = "allwinner,sun50i-h6-wdt", "allwinner,sun6i-a31-wdt"; diff --git a/arch/arm64/boot/dts/allwinner/sun50i-h616.dtsi b/arch/arm64/boot/dts/allwinner/sun50i-h616.dtsi index c277b53f94ea..ff55712ce96e 100644 --- a/arch/arm64/boot/dts/allwinner/sun50i-h616.dtsi +++ b/arch/arm64/boot/dts/allwinner/sun50i-h616.dtsi @@ -128,6 +128,15 @@ ccu: clock@3001000 { #reset-cells = <1>; }; + timer@3009000 { + compatible = "allwinner,sun50i-h616-timer", + "allwinner,sun8i-a23-timer"; + reg = <0x03009000 0xa0>; + interrupts = <GIC_SPI 48 IRQ_TYPE_LEVEL_HIGH>, + <GIC_SPI 49 IRQ_TYPE_LEVEL_HIGH>; + clocks = <&osc24M>; + }; + watchdog: watchdog@30090a0 { compatible = "allwinner,sun50i-h616-wdt", "allwinner,sun6i-a31-wdt";
For a CPU to enter an idle state, there must be some timer which can trigger an IRQ to wake it back up. The local ARM architectural timer is not sufficient, because that timer stops when the CPU is powered down. Some other CPU's ARM architectural timer can be used, but this prevents that other CPU from entering an idle state. So to allow all CPUs to enter an idle state at the same time, some MMIO timer must be available that is not tied to any CPU. The basic "sun4i" timer seems most appropriate for this purpose due to its moderate rate, balancing precision and power consumption. Signed-off-by: Samuel Holland <samuel@sholland.org> --- arch/arm64/boot/dts/allwinner/sun50i-a64.dtsi | 9 +++++++++ arch/arm64/boot/dts/allwinner/sun50i-h6.dtsi | 9 +++++++++ arch/arm64/boot/dts/allwinner/sun50i-h616.dtsi | 9 +++++++++ 3 files changed, 27 insertions(+)