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Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.11.0 Subject: Re: [PATCH v2 3/3] dmaengine: tegra: Add support for dma-channel-mask Content-Language: en-US To: Akhil R , Laxman Dewangan , "vkoul@kernel.org" , "thierry.reding@gmail.com" , "p.zabel@pengutronix.de" , "dmaengine@vger.kernel.org" , "linux-tegra@vger.kernel.org" , "linux-kernel@vger.kernel.org" References: <20220919112559.58195-1-akhilrajeev@nvidia.com> <20220919112559.58195-4-akhilrajeev@nvidia.com> <8d15c575-a490-e1ed-7e97-5a5cdea0925f@nvidia.com> From: Jon Hunter In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-ClientProxiedBy: LO4P123CA0232.GBRP123.PROD.OUTLOOK.COM (2603:10a6:600:1a6::21) To CO6PR12MB5444.namprd12.prod.outlook.com (2603:10b6:5:35e::8) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: CO6PR12MB5444:EE_|MN0PR12MB5786:EE_ X-MS-Office365-Filtering-Correlation-Id: 59de3676-4b34-4e87-ae92-08da9d591f0c X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0; 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I was wondering how this worked with 'channel_reg_size' but >> looking closer I see channel_reg_size is always SZ_64K. I wonder why we >> even bother having this parameter and don't use SZ_64K directly? > There is an offset from the base address which the per channel registers start. > Although this offset value happens to match with the channel_reg_size, this is > not actually the per channel register size. Yes I see that, but I mean why do we even bother having this channel_reg_size parameter? Does not look like we need this (currently). All we need is ... tdc->chan_base_offset = TEGRA_GPCDMA_CHANNEL_BASE_ADDR_OFFSET + (i * SZ_64K); Jon -- nvpublic