Re: [PATCH v6 2/4] dmaengine: tegra: Add tegra gpcdma driver

From: Jon Hunter <jonathanh@nvidia.com>
To: Akhil R <akhilrajeev@nvidia.com>
Cc: "dan.j.williams@intel.com" <dan.j.williams@intel.com>,
	"dmaengine@vger.kernel.org" <dmaengine@vger.kernel.org>,
	Krishna Yarlagadda <kyarlagadda@nvidia.com>,
	Laxman Dewangan <ldewangan@nvidia.com>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"linux-tegra@vger.kernel.org" <linux-tegra@vger.kernel.org>,
	"p.zabel@pengutronix.de" <p.zabel@pengutronix.de>,
	Rajesh Gumasta <rgumasta@nvidia.com>,
	"thierry.reding@gmail.com" <thierry.reding@gmail.com>,
	"vkoul@kernel.org" <vkoul@kernel.org>,
	Pavan Kunapuli <pkunapuli@nvidia.com>
Subject: Re: [PATCH v6 2/4] dmaengine: tegra: Add tegra gpcdma driver
Date: Thu, 23 Sep 2021 13:22:16 +0100	[thread overview]
Message-ID: <5a3de015-a0d1-4440-12d0-06297ac7f9d0@nvidia.com> (raw)
In-Reply-To: <BN9PR12MB5273F667288F7DEE99BA275DC0A29@BN9PR12MB5273.namprd12.prod.outlook.com>

On 22/09/2021 15:46, Akhil R wrote:
> 
>> On 17/09/2021 15:11, Akhil R wrote:
>>> +static int tegra_dma_slave_config(struct dma_chan *dc,
>>> +				  struct dma_slave_config *sconfig) {
>>> +	struct tegra_dma_channel *tdc = to_tegra_dma_chan(dc);
>>> +
>>> +	if (tdc->dma_desc) {
>>> +		dev_err(tdc2dev(tdc), "Configuration not allowed\n");
>>> +		return -EBUSY;
>>> +	}
>>> +
>>> +	memcpy(&tdc->dma_sconfig, sconfig, sizeof(*sconfig));
>>> +	if (tdc->slave_id == -1)
>>> +		tdc->slave_id = sconfig->slave_id;
>>> +
>>> +	tdc->config_init = true;
>>> +	return 0;
>>> +}
>>
>> So you have a function to reserve a slave ID, but you don't check here if it is
>> already reserved.
> slave-id is reserved considering the direction as well.
> 'direction' is available only during prep_slave_sg function, I guess.

Sorry I don't understand what you mean by that.

Jon

-- 
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