Re: [PATCH v3 5/7] iommu/riscv: Device directory management.

From: Jason Gunthorpe <jgg@ziepe.ca>
To: Tomasz Jeznach <tjeznach@rivosinc.com>
Cc: Joerg Roedel <joro@8bytes.org>, Will Deacon <will@kernel.org>,
	Robin Murphy <robin.murphy@arm.com>,
	Paul Walmsley <paul.walmsley@sifive.com>,
	Palmer Dabbelt <palmer@dabbelt.com>,
	Albert Ou <aou@eecs.berkeley.edu>,
	Anup Patel <apatel@ventanamicro.com>,
	Sunil V L <sunilvl@ventanamicro.com>,
	Nick Kossifidis <mick@ics.forth.gr>,
	Sebastien Boeuf <seb@rivosinc.com>,
	Rob Herring <robh+dt@kernel.org>,
	Krzysztof Kozlowski <krzk+dt@kernel.org>,
	Conor Dooley <conor+dt@kernel.org>,
	devicetree@vger.kernel.org, iommu@lists.linux.dev,
	linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org,
	linux@rivosinc.com
Subject: Re: [PATCH v3 5/7] iommu/riscv: Device directory management.
Date: Wed, 1 May 2024 11:57:31 -0300	[thread overview]
Message-ID: <20240501145731.GE1723318@ziepe.ca> (raw)
In-Reply-To: <ce3b82a20db0b776685269674ce9b7a926d5680d.1714494653.git.tjeznach@rivosinc.com>

On Tue, Apr 30, 2024 at 01:01:55PM -0700, Tomasz Jeznach wrote:
> Introduce device context allocation and device directory tree
> management including capabilities discovery sequence, as described
> in Chapter 2.1 of the RISC-V IOMMU Architecture Specification.
> 
> Device directory mode will be auto detected using DDTP WARL property,
> using highest mode supported by the driver and hardware. If none
> supported can be configured, driver will fall back to global pass-through.
> 
> First level DDTP page can be located in I/O (detected using DDTP WARL)
> and system memory.
> 
> Only simple identity and release (blocking) protection domains are
> supported by this implementation.

Why rename the concept? We call it a BLOCKING domain, just use that
name please.

> +static int riscv_iommu_attach_release_domain(struct iommu_domain *iommu_domain,
> +					     struct device *dev)
> +{
> +	struct riscv_iommu_device *iommu = dev_to_iommu(dev);
> +
> +	if (iommu->ddt_mode > RISCV_IOMMU_DDTP_MODE_BARE)
> +		riscv_iommu_iodir_update(iommu, dev, RISCV_IOMMU_FSC_BARE, 0);
> +
> +	return 0;
> +}
> +
> +static struct iommu_domain riscv_iommu_release_domain = {
> +	.type = IOMMU_DOMAIN_BLOCKED,
> +	.ops = &(const struct iommu_domain_ops) {
> +		.attach_dev = riscv_iommu_attach_release_domain,
> +	}
> +};

'riscv_iommu_release_domain' doesn't make sense..

Jason