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Message-ID: <04d68be4-e053-4fea-d50a-217d423bd0e0@quicinc.com>
Date: Wed, 21 Feb 2024 16:06:28 +0530
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Subject: Re: [PATCH 3/5] spi: spi-qpic: Add qpic spi nand driver support
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To: Mark Brown <broonie@kernel.org>
CC: <andersson@kernel.org>, <konrad.dybcio@linaro.org>, <robh@kernel.org>,
        <krzysztof.kozlowski+dt@linaro.org>, <conor+dt@kernel.org>,
        <miquel.raynal@bootlin.com>, <richard@nod.at>, <vigneshr@ti.com>,
        <manivannan.sadhasivam@linaro.org>, <linux-arm-msm@vger.kernel.org>,
        <linux-spi@vger.kernel.org>, <devicetree@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>, <linux-mtd@lists.infradead.org>,
        <quic_srichara@quicinc.com>, <quic_varada@quicinc.com>
References: <20240215134856.1313239-1-quic_mdalam@quicinc.com>
 <20240215134856.1313239-4-quic_mdalam@quicinc.com>
 <21dde665-54b4-48e4-b963-1008ac890df3@sirena.org.uk>
 <4a0e51cf-d29a-5843-9c61-1d31a9721a3d@quicinc.com>
 <8422fb6a-edd4-4911-89b7-2974c197981b@sirena.org.uk>
From: Md Sadre Alam <quic_mdalam@quicinc.com>
In-Reply-To: <8422fb6a-edd4-4911-89b7-2974c197981b@sirena.org.uk>
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On 2/20/2024 9:34 PM, Mark Brown wrote:
> On Tue, Feb 20, 2024 at 05:24:43PM +0530, Md Sadre Alam wrote:
>> On 2/15/2024 7:44 PM, Mark Brown wrote:
>>> On Thu, Feb 15, 2024 at 07:18:54PM +0530, Md Sadre Alam wrote:
> 
>>>> +	if (op->cmd.opcode == SPINAND_READID) {
>>>> +		snandc->buf_count = 4;
>>>> +		read_reg_dma(snandc, NAND_READ_ID, 1, NAND_BAM_NEXT_SGL);
>>>> +
>>>> +		ret = submit_descs(snandc);
>>>> +		if (ret)
>>>> +			dev_err(snandc->dev, "failure in submitting descriptor for readid\n");
>>>> +
>>>> +		nandc_read_buffer_sync(snandc, true);
>>>> +		memcpy(op->data.buf.in, snandc->reg_read_buf, snandc->buf_count);
> 
>>> These memcpy()s don't seem great, why aren't we just reading directly
>>> into the output buffer?
> 
>>    This reg_read_buf is being used in common API so that it will be used by both
>>    serial nand as well raw nand, so I can't directly use the output buffer since
>>    internally CW mechanism I have to maintain in common API.
> 
> We have control over all the source code in the kernel so if there's
> problems with the internal interfaces we can improve them.

Ok , will try to maintain CW mechanism uniform and remove from common API
and move to corresponding driver. Will try to fix in next patch.