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From: Christoph Hellwig <hch@infradead.org>
To: Nick Hu <nickhu@andestech.com>
Cc: greentime@andestech.com, palmer@sifive.com,
	linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org,
	green.hu@gmail.com
Subject: Re: [PATCH] riscv: Fix udelay in RV32.
Date: Wed, 29 May 2019 22:52:58 -0700	[thread overview]
Message-ID: <20190530055258.GA7170@infradead.org> (raw)
In-Reply-To: <381ee6950c84b868ca6a3c676eb981a1980889a3.1559035050.git.nickhu@andestech.com>

On Tue, May 28, 2019 at 05:26:49PM +0800, Nick Hu wrote:
> In RV32, udelay would delay the wrong cycle.
> When it shifts right "UDELAY_SHITFT" bits, it
> either delays 0 cycle or 1 cycle. It only works
> correctly in RV64. Because the 'ucycles' always
> needs to be 64 bits variable.

Please use up all your ~72 chars per line in the commit log.

> diff --git a/arch/riscv/lib/delay.c b/arch/riscv/lib/delay.c
> index dce8ae24c6d3..da847f49fb74 100644
> --- a/arch/riscv/lib/delay.c
> +++ b/arch/riscv/lib/delay.c
> @@ -88,7 +88,7 @@ EXPORT_SYMBOL(__delay);
>  
>  void udelay(unsigned long usecs)
>  {
> -	unsigned long ucycles = usecs * lpj_fine * UDELAY_MULT;
> +	unsigned long long ucycles = (unsigned long long)usecs * lpj_fine * UDELAY_MULT;

And this creates a way too long line.  Pleaase use u64 instead of
unsigned long long to clarify the intention while also fixing the long
lines.

  parent reply	other threads:[~2019-05-30  5:53 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-05-28  9:26 [PATCH] riscv: Fix udelay in RV32 Nick Hu
2019-05-30  4:09 ` Palmer Dabbelt
2019-05-30  5:52 ` Christoph Hellwig [this message]
2019-05-30  6:32   ` Nick Hu

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