From: nikita.yoush@cogentembedded.com (Nikita Yushchenko)
To: linux-arm-kernel@lists.infradead.org
Subject: [V2, 2/6] tty: serial: lpuart: add little endian 32 bit register support
Date: Wed, 17 May 2017 08:50:39 +0300 [thread overview]
Message-ID: <f096009a-9bcd-e575-2c81-49d08f99fc44@cogentembedded.com> (raw)
In-Reply-To: <20170517054356.GE9913@b29396-OptiPlex-7040>
>>>>> static u32 lpuart32_read(void __iomem *addr)
>>>>> {
>>>>> - return ioread32be(addr);
>>>>> + return lpuart_is_be ? ioread32be(addr) : readl(addr);
>>>>> }
>>>>>
>>>>> static void lpuart32_write(u32 val, void __iomem *addr)
>>>>> {
>>>>> - iowrite32be(val, addr);
>>>>> + if (lpuart_is_be)
>>>>> + iowrite32be(val, addr);
>>>>> + else
>>>>> + writel(val, addr);
>>>>> }
>>>>
>>>> What if this is ever executed on big endian system?
>>>>
>>>
>>> Sorry, not catching the point...
>>>
>>> What issues will meet?
>>
>> Isn't writel() in host endian?
>
> On big endian systems, it is supposed to run iowrite32be.
Your code states, "force BE if lpuart_is_be, don't care otherwise".
This semantics looks questionable for code reviewer.
If driver handles endian, should't it be explicit in both cases?
And if indeed driver means handling BE explicitly, but don't caring
otherwise, maybe variable name should suggest that (i.e. "force_be")?
Although driver maintainer could think differently. I won't insist on this.
Nikita
next prev parent reply other threads:[~2017-05-17 5:50 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-05-15 7:48 [PATCH V2 0/6] tty: serial: lpuart: add imx7ulp support Dong Aisheng
2017-05-15 7:48 ` [PATCH V2 1/6] tty: serial: lpuart: introduce lpuart_soc_data to represent SoC property Dong Aisheng
2017-05-15 13:35 ` Andy Shevchenko
2017-05-15 7:48 ` [PATCH V2 2/6] tty: serial: lpuart: add little endian 32 bit register support Dong Aisheng
2017-05-15 13:36 ` Andy Shevchenko
2017-05-17 3:26 ` Dong Aisheng
2017-05-16 11:08 ` [V2, " Nikita Yushchenko
2017-05-17 3:31 ` Dong Aisheng
2017-05-17 5:43 ` Nikita Yushchenko
2017-05-17 6:01 ` A.S. Dong
2017-05-17 6:25 ` Nikita Yushchenko
2017-05-17 7:00 ` Dong Aisheng
2017-05-17 8:04 ` Nikita Yushchenko
2017-05-19 15:07 ` Dong Aisheng
2017-05-23 5:24 ` Nikita Yushchenko
2017-05-31 8:07 ` Dong Aisheng
2017-05-16 11:15 ` Nikita Yushchenko
2017-05-17 3:39 ` Dong Aisheng
2017-05-17 5:37 ` Nikita Yushchenko
2017-05-17 5:43 ` Dong Aisheng
2017-05-17 5:50 ` Nikita Yushchenko [this message]
2017-05-17 6:09 ` Dong Aisheng
2017-05-17 9:55 ` Andy Shevchenko
2017-05-31 7:47 ` Dong Aisheng
2017-05-17 9:53 ` Andy Shevchenko
2017-05-15 7:48 ` [PATCH V2 3/6] dt-bindings: serial: fsl-lpuart: add i.MX7ULP support Dong Aisheng
2017-05-15 7:48 ` [PATCH V2 4/6] tty: serial: lpuart: add imx7ulp support Dong Aisheng
2017-05-15 7:48 ` [PATCH V2 5/6] tty: serial: lpuart: add earlycon support for imx7ulp Dong Aisheng
2017-05-15 7:48 ` [PATCH V2 6/6] tty: serial: lpuart: add a more accurate baud rate calculation method Dong Aisheng
2017-05-15 17:06 ` Stefan Agner
2017-05-17 3:47 ` Dong Aisheng
2017-05-17 17:35 ` Stefan Agner
2017-05-19 11:50 ` Dong Aisheng
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