Re: [PATCH 1/3] crypto: brcm: DT documentation for Broadcom SPU driver

From: Mark Rutland <mark.rutland@arm.com>
To: Rob Rice <rob.rice@broadcom.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>,
	"David S. Miller" <davem@davemloft.net>,
	Rob Herring <robh+dt@kernel.org>,
	linux-crypto@vger.kernel.org, devicetree@vger.kernel.org,
	linux-kernel@vger.kernel.org, Ray Jui <rjui@broadcom.com>,
	Scott Branden <sbranden@broadcom.com>,
	Jon Mason <jonmason@broadcom.com>,
	bcm-kernel-feedback-list@broadcom.com,
	Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will.deacon@arm.com>,
	linux-arm-kernel@lists.infradead.org,
	Steve Lin <steven.lin1@broadcom.com>
Subject: Re: [PATCH 1/3] crypto: brcm: DT documentation for Broadcom SPU driver
Date: Tue, 6 Dec 2016 14:06:07 +0000	[thread overview]
Message-ID: <20161206140607.GB24177@leverpostej> (raw)
In-Reply-To: <1480536453-24781-2-git-send-email-rob.rice@broadcom.com>

On Wed, Nov 30, 2016 at 03:07:31PM -0500, Rob Rice wrote:
> Device tree documentation for Broadcom Secure Processing Unit
> (SPU) crypto driver.
> 
> Signed-off-by: Steve Lin <steven.lin1@broadcom.com>
> Signed-off-by: Rob Rice <rob.rice@broadcom.com>
> ---
>  .../devicetree/bindings/crypto/brcm,spu-crypto.txt | 25 ++++++++++++++++++++++
>  1 file changed, 25 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/crypto/brcm,spu-crypto.txt
> 
> diff --git a/Documentation/devicetree/bindings/crypto/brcm,spu-crypto.txt b/Documentation/devicetree/bindings/crypto/brcm,spu-crypto.txt
> new file mode 100644
> index 0000000..e5fe942
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/crypto/brcm,spu-crypto.txt
> @@ -0,0 +1,25 @@
> +The Broadcom Secure Processing Unit (SPU) driver supports symmetric
> +cryptographic offload for Broadcom SoCs with SPU hardware. A SoC may have
> +multiple SPU hardware blocks.

Bindings shound describe *hardware*, not *drivers*. Please drop mention
of the driver, and just decribe the hardware.

> +Required properties:
> +- compatible : Should be "brcm,spum-crypto" for devices with SPU-M hardware
> +  (e.g., Northstar2) or "brcm,spum-nsp-crypto" for the Northstar Plus variant
> +  of the SPU-M hardware.
> +
> +- reg: Should contain SPU registers location and length.
> +- mboxes: A list of mailbox channels to be used by the kernel driver. Mailbox
> +channels correspond to DMA rings on the device.
> +
> +Example:
> +	spu-crypto@612d0000 {
> +		compatible = "brcm,spum-crypto";
> +		reg = <0 0x612d0000 0 0x900>,    /* SPU 0 control regs */
> +			<0 0x612f0000 0 0x900>,  /* SPU 1 control regs */
> +			<0 0x61310000 0 0x900>,  /* SPU 2 control regs */
> +			<0 0x61330000 0 0x900>;  /* SPU 3 control regs */

The above didn't mention there were several register sets, and the
comment beside each makes them sound like they're separate SPU
instances, so I don't think it makes sense to group them as one node.

What's going on here?

> +		mboxes = <&pdc0 0>,
> +			<&pdc1 0>,
> +			<&pdc2 0>,
> +			<&pdc3 0>;

Does each mbox correspond to one of the SPUs above? Or is there a shared
pool?

Thanks,
Mark.