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Subject: Re: [RESEND PATCH v7] mtd: spi-nor: add hisilicon spi-nor flash
 controller driver
To: Boris Brezillon <boris.brezillon@free-electrons.com>
References: <1456474316-24473-1-git-send-email-xuejiancheng@huawei.com>
 <20160307225229.GC55664@google.com> <56DE9A79.30704@huawei.com>
 <20160308104628.6224bde2@bbrezillon>
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From: Jiancheng Xue <xuejiancheng@huawei.com>
Message-ID: <56DF9A1D.8090100@huawei.com>
Date: Wed, 9 Mar 2016 11:35:57 +0800
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Hi Boris,

On 2016/3/8 17:46, Boris Brezillon wrote:
>> [...]
>>>> +static int hisi_spi_nor_read_reg(struct spi_nor *nor, u8 opcode, u8 *buf,
>>>> +		int len)
>>>> +{
>>>> +	struct hifmc_priv *priv = nor->priv;
>>>> +	struct hifmc_host *host = priv->host;
>>>> +	int ret;
>>>> +
>>>> +	ret = hisi_spi_nor_send_cmd(nor, opcode, len);
>>>> +	if (ret)
>>>> +		return ret;
>>>> +
>>>> +	memcpy(buf, host->iobase, len);
>>>
>>> sparse doesn't like any of these memcpy()'s, since that's __iomem. Are
>>> you sure you want a regular memcpy here, and elsewhere?
>>>
>> It's not a must to use memcpy though host->iobase represents a segment of inner memory
>> which stores data from flash device byte by byte.  I will give up using memcpy here and
>> hisi_spi_nor_write_reg() in next version. Thank you!
> 
> Or you can use memcpy_fromio(), which should give you better perfs than
> using readX() accessors in a loop.
> 

Thank you very much for your suggestion. I'll look into sparse and this function.

Regards,
Jiancheng