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Subject: Re: [PATCH v9 2/3] spi: Add Renesas R-Car Gen3 RPC-IF SPI controller
 driver
To:     masonccyang@mxic.com.tw
Cc:     bbrezillon@kernel.org, broonie@kernel.org,
        devicetree@vger.kernel.org,
        Geert Uytterhoeven <geert+renesas@glider.be>,
        Simon Horman <horms@verge.net.au>, juliensu@mxic.com.tw,
        lee.jones@linaro.org, linux-kernel@vger.kernel.org,
        linux-renesas-soc@vger.kernel.org, linux-spi@vger.kernel.org,
        mark.rutland@arm.com, robh+dt@kernel.org,
        Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>,
        zhengxunli@mxic.com.tw
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From:   Marek Vasut <marek.vasut@gmail.com>
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Date:   Wed, 10 Apr 2019 10:03:50 +0200
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On 4/10/19 10:01 AM, masonccyang@mxic.com.tw wrote:
> Hi,
> ?
>> Re: [PATCH v9 2/3] spi: Add Renesas R-Car Gen3 RPC-IF SPI controller
> driver
>>
>> On 4/10/19 3:33 AM, masonccyang@mxic.com.tw wrote:
>> > Hi Sergei,
>> >
>> >> > +static ssize_t rpc_spi_mem_dirmap_write(struct spi_mem_dirmap_desc
>> > *desc,
>> >> > + ? ? ? ? ? ? ? u64 offs, size_t len, const void *buf)
>> >> > +{
>> >> > + ? struct rpc_spi *rpc =
>> >> > + ? ? ? ? spi_controller_get_devdata(desc->mem->spi->controller);
>> >> > + ? int ret;
>> >> > +
>> >> > + ? if (offs + desc->info.offset + len > U32_MAX)
>> >> > + ? ? ?return -EINVAL;
>> >> > +
>> >> > + ? if (len > RPC_WBUF_SIZE)
>> >> > + ? ? ?len = RPC_WBUF_SIZE;
>> >> > +
>> >> > + ? ret = rpc_spi_set_freq(rpc, desc->mem->spi->max_speed_hz);
>> >> > + ? if (ret)
>> >> > + ? ? ?return ret;
>> >> > +
>> >> > + ? rpc_spi_mem_set_prep_op_cfg(desc->mem->spi,
>> >> > + ? ? ? ? ? ? ? ?&desc->info.op_tmpl, &offs, &len);
>> >> > +
>> >> > + ? regmap_update_bits(rpc->regmap, RPC_CMNCR, RPC_CMNCR_MD,
>> > RPC_CMNCR_MD);
>> >> > +
>> >> > + ? regmap_write(rpc->regmap, RPC_SMDRENR, 0);
>> >> > +
>> >> > + ? regmap_update_bits(rpc->regmap, RPC_PHYCNT,
> RPC_PHYCNT_STRTIM(7) |
>> >> > + ? ? ? ? ? ?RPC_PHYCNT_WBUF2 | RPC_PHYCNT_WBUF,
>> >> > + ? ? ? ? ? ?RPC_PHYCNT_WBUF2 | RPC_PHYCNT_WBUF);
>> >> > +
>> >> > + ? memcpy_toio(rpc->wbuf, buf, len);
>> >>
>> >> ? ?Wait, doesn't the manual say that the whole 256-byte buffer
> should be
>> >> filled?
> 
> it could be less than 256 bytes, i.e., 128 bytes to rpc->wbuf !
> 
> ?I think that short chunks have to be written w/o WBUF (done,
>> > in fact,
>> >> by the HF driver).
>> >>
>> >
>> > From spi-nor.c layer always transfer 256 bytes data with page program
>> > command.
>>
>> Does that apply even for flashes with not-256-byte pages ?
>>
> 
> I think it needs to patch in case of nor->page_size = 512 bytes.

There are also flashes with page size < 256 bytes :)

-- 
Best regards,
Marek Vasut