Re: [PATCH 3/3] ARM: dts: bcm2711: Enable HWRNG support

From: "Stephen Brennan" <stephen@brennan.io>
To: "Stefan Wahren" <wahrenst@gmx.net>,
	"Nicolas Saenz Julienne" <nsaenzjulienne@suse.de>
Cc: "Mark Rutland" <mark.rutland@arm.com>,
	<devicetree@vger.kernel.org>,
	"Florian Fainelli" <f.fainelli@gmail.com>,
	"Herbert Xu" <herbert@gondor.apana.org.au>,
	"Scott Branden" <sbranden@broadcom.com>,
	"Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
	"Matt Mackall" <mpm@selenic.com>, <linux-kernel@vger.kernel.org>,
	"Arnd Bergmann" <arnd@arndb.de>, <linux-crypto@vger.kernel.org>,
	"Eric Anholt" <eric@anholt.net>,
	"Rob Herring" <robh+dt@kernel.org>,
	<bcm-kernel-feedback-list@broadcom.com>,
	<linux-rpi-kernel@lists.infradead.org>,
	"Ray Jui" <rjui@broadcom.com>,
	<linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH 3/3] ARM: dts: bcm2711: Enable HWRNG support
Date: Mon, 18 Nov 2019 21:49:04 -0800	[thread overview]
Message-ID: <BYJMYLOFLH80.EDWI9BX3JBY3@pride> (raw)
In-Reply-To: <5cc711fd-4d47-5369-c424-363677334b9f@gmx.net>

Hello Stefan & Nicolas,

On Mon Nov 18, 2019 at 8:44 PM, Stefan Wahren wrote:
> Hi,
>
> 
> Am 18.11.19 um 12:44 schrieb Nicolas Saenz Julienne:
> > Hi Stephen,
> >
> > On Sun, 2019-11-17 at 23:58 -0800, Stephen Brennan wrote:
> >> From: Stefan Wahren <wahrenst@gmx.net>
> >>
> >> This enables hardware random number generator support for the BCM2711
> >> on the Raspberry Pi 4 board.
> >>
> >> Signed-off-by: Stefan Wahren <wahrenst@gmx.net>
> >> Signed-off-by: Stephen Brennan <stephen@brennan.io>
> >> ---
> >>  arch/arm/boot/dts/bcm2711.dtsi | 5 ++---
> >>  1 file changed, 2 insertions(+), 3 deletions(-)
> >>
> >> diff --git a/arch/arm/boot/dts/bcm2711.dtsi b/arch/arm/boot/dts/bcm2711.dtsi
> >> index ac83dac2e6ba..2c19e5de284a 100644
> >> --- a/arch/arm/boot/dts/bcm2711.dtsi
> >> +++ b/arch/arm/boot/dts/bcm2711.dtsi
> >> @@ -92,10 +92,9 @@ pm: watchdog@7e100000 {
> >>  		};
> >>
> >>  		rng@7e104000 {
> >> +			compatible = "brcm,bcm2711-rng200";
> >>  			interrupts = <GIC_SPI 125 IRQ_TYPE_LEVEL_HIGH>;
> >> -
> >> -			/* RNG is incompatible with brcm,bcm2835-rng */
> >> -			status = "disabled";
> >> +			status = "okay";
> >>  		};
> >>
> >>  		uart2: serial@7e201400 {
> > We inherit the reg property from bcm283x.dtsi, on which we only define a size
> > of 0x10 bytes. I gather from the driver that iproc-rng200's register space is
> > at least 0x28 bytes big. We should also update the 'reg' property to:
> >
> > 	reg = <0x7e104000 0x28>;
>
> 
> Thanks for sending and noticing. A proper solution would be to move the
> whole rng node from bcm283x.dtsi to bcm283x-common.dtsi and define a
> completely new rng node in bcm2711.dtsi.

Thanks both for your time and consideration. I'm not terribly familiar with 
device tree source but I think I understand what you'd like here. I'll send 
a v2 that does this!

Regards,
Stephen

>
> 
> Regards
> Stefan
>
> 
> >
> > Regards,
> > Nicolas
> >
> >
> > _______________________________________________
> > linux-arm-kernel mailing list
> > linux-arm-kernel@lists.infradead.org
> > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
>
> 
>
> 