Subject: Re: [PATCH V3 7/8] ARM: dts: Add minimal Raspberry Pi 4 support

From: Marc Zyngier <[email-masked]>
Date: Sun, 29 Sep 2019 12:25:19 +0100

On 2019-09-28 13:07, Stefan Wahren wrote:
> This adds minimal support for the new Raspberry Pi 4 without the
> fancy stuff like GENET, PCIe, xHCI, 40 bit DMA and V3D. The RPi 4 is
> available in 3 different variants (1, 2 and 4 GB RAM), so leave the 
> memory
> size to zero and let the bootloader take care of it. The DWC2 is 
> still
> usable as peripheral via the USB-C port.
>
> Other differences to the Raspberry Pi 3:
> - additional GIC 400 Interrupt controller
> - new thermal IP and HWRNG
> - additional MMC interface (emmc2)
> - additional UART, I2C, SPI and PWM interfaces
> - clock stretching bug in I2C IP has been fixed
>
> Signed-off-by: Stefan Wahren <[email-masked]>
> Acked-by: Eric Anholt <[email-masked]>

[...]

> +	timer {
> +		compatible = "arm,armv8-timer";
> +		interrupts = <GIC_PPI 13 (GIC_CPU_MASK_SIMPLE(4) |
> +					  IRQ_TYPE_LEVEL_LOW)>,
> +			     <GIC_PPI 14 (GIC_CPU_MASK_SIMPLE(4) |
> +					  IRQ_TYPE_LEVEL_LOW)>,
> +			     <GIC_PPI 11 (GIC_CPU_MASK_SIMPLE(4) |
> +					  IRQ_TYPE_LEVEL_LOW)>,
> +			     <GIC_PPI 10 (GIC_CPU_MASK_SIMPLE(4) |
> +					  IRQ_TYPE_LEVEL_LOW)>;
> +		/* This only applies to the ARMv7 stub */
> +		arm,cpu-registers-not-fw-configured;
> +
> +		/* The ARM cores doesn't enter deep enough states */
> +		always-on;

I already commented on this. The A72 not entering a deep enough sleep 
state to
lose its comparator seems dubious at best. The right way to do this is 
to have
a global timer, which you said the platform has.

Please drop this.

         M.
-- 
Jazz is not dead. It just smells funny...

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