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

From: Baolu Lu <baolu.lu@linux.intel.com>
To: Tomasz Jeznach <tjeznach@rivosinc.com>,
	Joerg Roedel <joro@8bytes.org>, Will Deacon <will@kernel.org>,
	Robin Murphy <robin.murphy@arm.com>,
	Paul Walmsley <paul.walmsley@sifive.com>
Cc: baolu.lu@linux.intel.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: Thu, 2 May 2024 09:38:54 +0800	[thread overview]
Message-ID: <104358de-ea86-4e25-8942-ba285d6f317b@linux.intel.com> (raw)
In-Reply-To: <ce3b82a20db0b776685269674ce9b7a926d5680d.1714494653.git.tjeznach@rivosinc.com>

On 5/1/24 4:01 AM, Tomasz Jeznach wrote:
> @@ -128,6 +489,7 @@ void riscv_iommu_remove(struct riscv_iommu_device *iommu)
>   {
>   	iommu_device_unregister(&iommu->iommu);
>   	iommu_device_sysfs_remove(&iommu->iommu);
> +	riscv_iommu_iodir_set_mode(iommu, RISCV_IOMMU_DDTP_MODE_OFF);
>   }
>   
>   int riscv_iommu_init(struct riscv_iommu_device *iommu)
> @@ -138,12 +500,13 @@ int riscv_iommu_init(struct riscv_iommu_device *iommu)
>   	if (rc)
>   		return dev_err_probe(iommu->dev, rc, "unexpected device state\n");
>   
> -	/*
> -	 * Placeholder for a complete IOMMU device initialization.
> -	 * For now, only bare minimum: enable global identity mapping mode and register sysfs.
> -	 */
> -	riscv_iommu_writeq(iommu, RISCV_IOMMU_REG_DDTP,
> -			   FIELD_PREP(RISCV_IOMMU_DDTP_MODE, RISCV_IOMMU_DDTP_MODE_BARE));
> +	rc = riscv_iommu_iodir_alloc(iommu);
> +	if (rc)
> +		goto err_init;
> +
> +	rc = riscv_iommu_iodir_set_mode(iommu, RISCV_IOMMU_DDTP_MODE_MAX);
> +	if (rc)
> +		goto err_init;
>   
>   	rc = iommu_device_sysfs_add(&iommu->iommu, NULL, NULL, "riscv-iommu@%s",
>   				    dev_name(iommu->dev));

The device directory root page might be allocated in
riscv_iommu_iodir_alloc(),

+	if (!iommu->ddt_root) {
+		iommu->ddt_root = riscv_iommu_get_pages(iommu, 0);
+		iommu->ddt_phys = __pa(iommu->ddt_root);
+	}

But I didn't find any place to free it in the error paths. Did I
overlook anything?

Best regards,
baolu