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[92.233.226.227]) by smtp.googlemail.com with ESMTPSA id x6sm3975204wmj.32.2021.03.05.02.33.35 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Fri, 05 Mar 2021 02:33:36 -0800 (PST) Subject: Re: [PATCH 2/2] nvmem: iomap: new driver exposing NVMEM accessible using I/O mapping To: =?UTF-8?B?UmFmYcWCIE1pxYJlY2tp?= , =?UTF-8?B?UmFmYcWCIE1pxYJlY2tp?= , Rob Herring Cc: devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mips@vger.kernel.org, Florian Fainelli , Vivek Unune , bcm-kernel-feedback-list@broadcom.com, linux-kernel@vger.kernel.org References: <20210304144132.24098-1-zajec5@gmail.com> <20210304144132.24098-2-zajec5@gmail.com> <047bced8-6c20-4a0a-c7ea-e0ad83318461@linaro.org> <93708a21-3444-f68e-c834-a4f769a0acba@milecki.pl> From: Srinivas Kandagatla Message-ID: <35e498b6-3b2c-d154-db00-d755af339b60@linaro.org> Date: Fri, 5 Mar 2021 10:33:35 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: <93708a21-3444-f68e-c834-a4f769a0acba@milecki.pl> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 05/03/2021 10:24, Rafał Miłecki wrote: >>> >>> +static int iomap_read(void *context, unsigned int offset, void *val, >>> +              size_t bytes) >>> +{ >>> +    struct iomap *priv = context; >>> +    u8 *src = priv->base + offset; >>> +    u8 *dst = val; >>> +    size_t tmp; >>> + >>> +    tmp = offset % 4; >>> +    memcpy_fromio(dst, src, tmp); >>> +    dst += tmp; >>> +    src += tmp; >>> +    bytes -= tmp; >>> + >>> +    tmp = rounddown(bytes, 4); >>> +    __ioread32_copy(dst, src, tmp / 4); >>> +    dst += tmp; >>> +    src += tmp; >>> +    bytes -= tmp; >>> + >>> +    memcpy_fromio(dst, src, bytes); >>> + >> >> >> You could just do this! >> >>      while (bytes--) >>          *val++ = readb(priv->base + offset + i++); > > Do you mean that as replacement for "memcpy_fromio" or the whole > function code? Yes please! > The reason for using __ioread32_copy() was to improve reading > performance (using aligned 32 bit access where possible). I'm not sure > if that really matters? Just simple while loop is much readable than the previous code TBH! > > P.S. > Please don't yell at me in every sentence :( Makes me a bit sad :( Sorry!! I did not mean anything as such! :-) --srini